PB97-964610
EPA/541/R-97/072
January 1998
EPA Superfund
Record of Decision:
East Multnomah County Groundwater
Contamination, OU 1
Multnomah County, OR
12/31/1996
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DEQ Remedial Action Record of Decision
for the
East Multnomah County Groundwater Contamination
Site
Troutdale Sandstone Aquifer
Oregon Department of Environmental Quality
Waste Management & Cleanup Division
December 1996
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CONTENTS
LIST OF TABLES AND ILLUSTRATIONS iv
1. INTRODUCTION l-l
i.l INTRODUCTION l-l
1.2 SCOPE AND ROLE OF THE REMEDIAL ACTION l-l
2. SUMMARY OF THE SELECTED REMEDY 2-1
3. SITE DESCRIPTION , 3-1
3.1 SITE SETTING 3-1
3 2 PHYSICAL SETTING 3-3
4. SITE HISTORY '. 4-1
4.1 SITE DISCOVERY AND PRELIMINARY ASSESSMENTS 4-1
4.2 DEQ RESPONSE ACTIONS 4-1
4.3 EPA RESPONSE ACTIONS 4-3
4.4 ENFORCEMENT ACTIVITIES 4-4
4.5 INTERIM REMOVAL ACTION MEASURES 4-5
5. INVESTIGATION SUMMARY _ 5-1
5.1 CONTAMINANTS AND SOURCES 1 5-1
5.2 EXTENT OF CONTAMINATION 5-2
5.3 CONTAMINANT FATE AND TRANSPORT 5-3
5.4 ENDANGERMENT ASSESSMENT 5-4
6. REMEDIAL ACTION OBJECTIVES AND CLEANUP LEVELS 6-1
6.1 REMEDIAL ACTION OBJECTIVES 6-1
6.2 CLEANUP GOALS 6-2
6.3 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS : 6-2
7. DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES ™ 7-1
7.1 AREAS & VOLUMES .": 7-1
7.2 COMMON ELEMENTS OF ALTERNATTVES '. 7-1
7.3 DESCRIPTION OF ALTERNATIVES 7-3
7.4 SCREENING OF ALTERNATTVES .= 7-7
8. EVALUATION OF REMEDIAL ACTION ALTERNATIVES 8-1
8.1 PROTECTION AND FEASIBILITY REQUIREMENTS 8-1
8.2 EVALUATION SUMMARY : 8-6
9. THE SELECTED REMEDIAL ACTION 9-1
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9.1 DESCRIPTION OF SELECTED ALTERNATIVE 9-1
9.2 SATISFACTION OF PROTECTION AND FEASIBILITY REQUIREMENTS 9-7
10. PUBLIC NOTICE AND COMMENTS 10-1
11. CONSIDERATION OF PUBLIC COMMENTS 1 l-l
11.1 AMBIGUITY OF RECOMMENDED REMEDY 11-1
11.2 PROPOSED CLEANUP LEVELS AND RESIDUAL RISK 11-2
11.3 PROPOSED REMEDY PERFORMANCE CRITERIA „ 11-3
11.4 REQUEST FOR MORE EXPLICIT DEFINITION OF REMEDY COMPONENTS 11-4
11.5 AIR EMISSIONS FROM AIR STRIPPER TREATMENT SYSTEMS 11-6
11.6 GROUNDWATER DISPOSAL, REINJECTION OR BENEFICIAL REUSE 11-7
11.7 ADDITIONAL PROTECTIVE MEASURES 11-11
11.8 CONTINGENCY PLAN 11-14
11.9 OTHER ISSUES H-14
12. DOCUMENTATION OF SIGNIFICANT CHANGE 12-1
13. FINAL DECISION OF THE DIRECTOR 13-1
13.1 DIRECTOR'S SIGNATURE 13-1
in
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TABLES AND ILLUSTRATIONS
Tables Following Document
3-1 Groundwater Users Summary
5-1 Summary of Groundwater Contaminant Concentrations
5-2 Summary of Volatile Organic Compounds in Columbia Slough West of Fair-view
Lake
5-3 Summary of Risk Estimates for Current Exposure Scenarios
6-1 Groundwater Cleanup Levels for TSA
8-1 Cost-Effectiveness Evaluation
9-1 Performance Monitoring Sampling Plan
Figures
3-1 Project Area
3-2 Location of Existing Wells in the TSA, SGA and BLA
3-3 Location of Wells in South Shore Well Field
3-4 Typical Geologic and Hydrogeologic Column
3-5 Geologic & Hydrogeologic Cross Section
3-6 TSA Sandstone Groundwater Elevations and Flow Directions
3-7 TSA Conglomerate Groundwater Elevations and Flow Directions
3-8 CU2 Thickness and Extent
5-1 Total VOC Concentrations in the TGA: Summer 1994
5-2 Approximate Extent of TCE in TSA Sandstone: August 1994
5-3 Approximate Extent of TCE in TSA Conglomerate: August 1994
5-4 SGA Water Quality
7-1 Alternative 3: Hydraulic Control
7-2 Alternative 4: Plume Reduction
7-3 Alternative 5: Aquifer Restoration
7-4 Alternative 5A: TSA Conglomerate Well Locations and Rates
7-5 Alternative 5C: TSA Conglomerate Well Locations and Rates
7-6 Alternative 6: TSA Conglomerate Well Locations and Rates
9-1 Restoration Areas for the TSA
9-2 TSA Sandstone Performance Monitoring Well Locations
9-3 TSA Conglomerate Performance Monitoring Well Locations
9-4 SGA Performance Monitoring Well Locations
APPENDIX A - ADMINISTRATIVE RECORD INDEX
1-4
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1. INTRODUCTION
1.1 Introduction
This document presents the selected remedial action for groundwater contamination within the
Troutdale Sandstone Aquifer (TSA) originating from the Cascade Corporation (Cascade) and
Boeing of Portland (Boeing) facilities, in Gresham, Oregon. The contaminants of concern are
volatile organic chemicals (VOCs) including trichloroethylene (TCE), tetrachloroethylene (PCE),
cis-1,2-dichloroethylene (cis-1,2-DCE), and I.Vdichloroethylene (1,1-DCE). The selected
action was selected in accordance with Oregon Revised Statutes 465.200 through 465.380 and
Oregon Administrative Rules (OAR) Chapter 340, Division 122. Section 080-110 (340-122-010
to 340-122-110). Also, to the extent practicable, the selected remedial action is consistent with
the federal Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) and implementing regulations contained in the National Contingency Plan (NCP), 40
CFR Part 300. The East Multnomah County Groundwater Contamination site was proposed for
inclusion on the National Priorities List (NPL or "SuperfuncT ) in May 1993. A final decision on
listing the site on the NPL is pending.
The selected remedial action is based on the administrative record for the site. A copy of the
administrative record index is attached as Appendix A. This staff report summarizes the more-
detailed information contained in the administrative record, particularly the Remedial
Investigation and Feasibility Study reports.
•
Cascade and Boeing conducted the remedial investigation and feasibility study (RI/FS) under a
Consent Order with DEQ. Prior to initiating the joint RI/FS, Cascade and Boeing implemented
an interim removal action measure (IRAM) in an effort to control the further spread of
groundwater contamination to the north of their facilities. The groundwater I RAM is a
component of the selected remedial action.
1.2 Scope and Role of the .Remedial Action
The selected remedial action addresses groundwater contamination in the TSA. Contaminant
sources in the Troutdale Gravel Aquifer (TGA) are excluded from the TSA remedy decision
process and are being addressed by Cascade and Boeing pursuant to separate consent orders
with the DEQ and U.S. Environmental Protection Agency (EPA), respectively.
EMC Record of Oedsion 12/19/96 1 _-j
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2. SUMMARY OF THE SELECTED REMEDY
The selected remedial action for the Troutdale Sandstone Aquifer (TSA) contaminant plume
includes the following components:
• Restoration of the TSA to federal drinking water standards (maximum contaminant
levels [MCLs]) through groundwater extraction from wells placed throughout the area of
contamination;
• Treatment of extracted groundwater using air-stripping treatment technology;
• Discharge of treated groundwater to Fairview Lake and the Columbia Slough directly or
via Multnomah County storm water drainage ways;
• If feasible, reinjection/reinfiltration of treated groundwater into the TSA to improve the
effectiveness of the remedy;
• Provisions allowing beneficial reuse of treated groundwater for industrial, agricultural or
domestic use;
• Abandonment of six private Sand and Gravel Aquifer (SGA) water supply wells located
within the area of the TSA contaminant plume and a provision to replace the
abandoned wells with an alternative source of water;
• Institutional controls to restrict groundwater use of the TSA and SGA to prevent
exposure to contaminated groundwater and the spread of groundwater contamination
during remediation;
• Groundwater monitoring to assess compliance with performance criteria established for
the remedy;
• A contingency plan to address emergency operation of the Portland Water Bureau's
South Shore Wellfield; and
• Hydraulic containment of those areas of the TSA for which it may be technically
impractical to restore to MCL cleanup levels within 20 years.
Section 9 provides a detailed description of the final remedy components.
EMC Record of Decision 12/19/96 2-1
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3. SITE DESCRIPTION
3.1 Site Setting
The East Multnomah County (EMC) project area includes an area bounded by the Columbia
River to the North, Fairview Avenue and Campbell Road to the east. NE Halsey Street to the
south, and NE 181st Avenue to the west (Rgure 3-1). The project area, which is approximately
3.6 square miles, includes most of Sections 19, 20, 28 and 29 in Township 1 North. Range 3
East. Willamette Meridian. Approximately 45 percent of the project area is in Gresham, 35
percent is in Fairview, 15 percent is unincorporated Multnomah County, and 5 percent is in
Portland. The "site", for purposes of discussion in this document, refers to all areas in the EMC
project area where the Troutdale Sandstone Aquifer (TSA) contains concentrations of
halogenated volatile organic compounds at concentrations requiring remediation. The site,
which is approximately 300 acres, lies in the central part of the project area.
3.1.1 Land Uses
The EMC project area includes industrial, residential, agricultural and recreational land uses.
Prior to 1960, land use was primarily rural and agricultural, and the conversion of agricultural
lands to other uses has occurred gradually since then and is still ongoing. As of 1990,
approximately 14,476 people reside within these tracts. Specific land uses in the area are as
follows:
• A transportation corridor bisecting the project area from the east to west, consisting of
Interstate 84 and the Union Pacific RaHroad tracks;
• Commercial businesses and heavy and light industry predominate in the southwest and
west (south of NE Sandy Boulevard and west of NE 201st Avenue). Major industrial
facilities in this area include Boeing south of Sandy Boulevard in the western part of the
project area. Cascade located just south of Interstate 84 and west of NE 201st Avenue,
Boyd Coffee located north of Cascade and east of Boeing, and Viking Industries,
Associated Foods and Swift Adhesive Company all located south of the Boeing Facility
and south of Interstate 84;
• Recreational'areas in the northeast part of the project area include Blue Lake and
Fairview Lake, Blue Lake Park, and marinas on the Columbia Riven
• Residential areas are located along the ridge between Blue Lake and Fairview Lakes,
south and east of Blue Lake, and east of NE 201st Avenue;
EMC Recort of Decision 12/19/96 3-1
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• Agricultural areas are located west of Blue Lake and Fairview Lake, just west of the
Boeing Facility, and north of the intersection of NE Sandy Boulevard and NE 205th. The
uncultivated fields west of Blue and Fairview Lakes along NE 181st Avenue are currently
being converted to commercial uses.
3.1.2 Groundwater and Surface Water Uses
There are three principal groundwater aquifers in the project area that are used for private and
municipal drinking water supply and for irrigation. These include the Blue Lake Aquifer (BLA),
Troutdale Sandstone Aquifer (TSA) and Sand and Gravel Aquifer (SGA). Fifty-three water
supply wells are located within the project area (Figures 3-2a, 3-2b, and 3-2c. and Table 3-1).
Fourteen wells are completed in the TSA, one inactive well is completed in both the TSA and
the SGA, seventeen wells are completed in the SGA, 10 wells are completed in the BLA, and
the construction of the eleven other wells is unknown. The active wells in each aquifer are as
follows:
• Nine TSA wells are currently used: six for domestic supply, two for irrigation, and one for
municipal supply by the City of Fairview.
• Thirteen SGA wells are currently used: six for domestic supply, three for irrigation, one for
municipal supply by the City of Fairview, and three are part of the City of Portland's South
Shore Well Field;
• Eight BLA wells are currently used: two for domestic supply, one for irrigation, and five are
part of the City of Portland's South Shore Well Reid;
• Four of the wells with unknown completion intervals are used for domestic supply, and one
is used for irrigation.
Eight wells in the project area are part of the City of Portland's South Shore Well Field,
operated by the Portland Water Bureau (PWB). The South Shore Well Reid includes the
northern part of the project area, and an area extending westward along the Columbia River for
about 4.5 miles from the western boundary of the project area (Figure 3-3). The well field
currently consists of 22 active production wells with a total designed pumping capacity of 100
million gallons per day (mgd). An additional four wells in the far western part of the well field
are currently used for monitoring and are designed for future pumping of an additional 14 mgd.
The completion intervals of the production wells are as follows:
• one is completed in the TGA with a current pumping capacity of 2 mgd;
• 5 are completed in the TSA with a current pumping capacity of 10 mgd;
• 10 are completed in the SGA with a current pumping capacity of 34 mgd;
• 5 are completed in the BLA with a current pumping capacity of 45 mgd; and
• one is completed in the Columbia River Sand Aquifer (CRSA) with a current pumping
capacity of 4 mgd.
The City has water permits for expansion of the well field up to a total of 337 mgd. The PWB's
capital improvement project for the year 2001 includes the completion of 15 additional
production wells in the TGA, TSA and CRSA. The total future design pumping capacity of the
well field is estimated to be about 150 mgd. The pumping capacity of the well field has been
EMC Record of Decision 12/19/96 3_2
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taken into account in the development of remedial options for the ISA because of the potential
influence of pumping on movement of the existing groundwater contamination when the wefl
field is operated currently, and in the future.
The Columbia South Shore Well Field was designed to supplement surface water supplies
during times of drought or system emergencies. In the event of a water shortage, the PWB
reports that its first priority is to pump groundwater from the well field and blend it with surface
water from the Bull Run Reservoir, the city's primary source of water. The City ran the well field
for seasonal summer supply purposes in 1985, 1987, 1992 and 1994 and 1996. During the
winters of 1986 and 1996, the City ran the well field for short periods because Bull Run water
exceeded the federal drinking water standard for turbidity. The highest usage was in 1987 when
the well field was operated for approximately 90 days at an average rate of 60 mgd. Future use
of the well field is expected to increase as the region grows.
Surface water in the project area is used for irrigation. The agricultural fields east and west of
Blue and Fairview lakes are irrigated in part with water withdrawn from the Columbia Slough
and Fairview Lake. There are no other known uses of surface water in the project area.
3.2 Physical Setting
The topography of the project area is dominated by a series of historical river terraces which
generally slope toward the Columbia River. Elevations range from approximately 200 feet
mean sea level (MSL) in the southern part of the project area to approximately 10 to 20 feet
MSL on the lower terrace, which is the current floodplain of the Columbia River.
The climate in the project area is west coast marine. The average annual rainfall is about 37
inches, based on records at the Portland airport from 1961 to 1990. Eighty percent of the
annual precipitation occurs from October through May. December is the wettest month, with
rainfall averaging 6.1 inches. July is the driest month, averaging 0.6 inches of rainfall. The
winds are usually northwesterly in the spring and summer, and southeasterly in the fall and
winter. The average annual wind speed is about 8 miles per hour (mph) based on data from
the Portland airport. Average wind speed ranges from approximately 6.5 mph in early autumn
to 10 mph in the winter. Temperatures in the winter generally range from 32° F to 52° F and in
the summer range from 54° F to 78° F.
3.2.1 Geologic Setting
The project area is iocated in the Portland Basin, which is a northwest-southeast-trending.
seclimert filled structural depression bounded oy the Tualatin Mountains to the west and the
Cascade Range to the east, north and south. A typical geologic and hydrogeclogic column of
the project area is shown on Figure 3-4. A large portion of the basin has been filled with
Tertiary-age sediments that include the Troutdale Formation and the underlying Sandy River
Mudstone (not shown on -igure 3-4). These geologic units are overlain by Quaternary-age
terrace, glacio-fluvial. and floodplain alluvial sediments referred to in the project area as
Troutdale Gravel. Blue Lake Gravel and Floodplain sand and silt.
EMC Record of Dedsion 12/19/96 3.3
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The Troutdale Formation consists of a sequence of fine-grained units, separated by thicker
sandstone and gravel units. The uppermost fine-grained unit, Siltstone Unit 1 (SU1). contains
four distinct subunits of sa"hdstone. siltstone and clayey siltstone. Underlying the SU1 are the
Troutdale Sandstone and, below that, the Troutdale Conglomerate. Both of these units have
been identified over most of the project area and comprise the portion of the geologic column
that is the subject of the East Multnomah County groundwater contamination project. Siltstone
Unit 2 (SU2) underlies the Troutdale Conglomerate, and consists of distinct subunits of
interbedded siltstone and sandstone. SU2 is present across most of the project area, but is not
present in a few localized areas. The lower portion of the Troutdale Formation, beneath the
SU2, consists of sandstone and conglomerate. The Sandy River Mudstone is present at some
depth below the basal Troutdale Sandstone and Conglomerate, but has not been identified in
any of the wells installed for the East Multnomah County project.
The geologic units in the project area have been influenced by structural deformation in the
form of folding and potential faulting, with concurrent erosion of the Troutdale Formation.
Structural deformation of the Troutdale Formation in the project area has resulted in an upward
folding of the Troutdale strata into a dome-like feature, or "structural high". The structural high
is centered south of Fairview Lake, in the vicinity of the intersection of Sandy Boulevard and
201st Avenue. Deformed Troutdale Formation strata slope down and away from the center of
the structural high, and generally increase in thickness to the west and south. In and near the
structural high, the Troutdale Gravel and the SU1 (the upper portion of the Troutdale
Formation) have been removed by erosion and possible nondeposition, leaving the Troutdale
Sandstone at ground surface covered by only a thin veneer of modem Floodplain silt. The
edges..of-.where Jhe. JTrautdale.-GcavjeLand.-SUl .are _noLpresent.are .referred Jo..as..the -
"truncation" of the Troutdale Gravel and SU1. This truncation, or limit of extent, is represented
on site maps by a line (for example, see Figure 5-1).
Near the northeast portion of the project area, between Blue Lake and the south shore of the
Columbia River, additional erosion and suspected faulting of the Troutdale Formation has
occurred. A deep channel of the Columbia River has incised the Troutdale Formation. The
channel has been subsequently filled with gravel referred to as the Blue Lake Gravel. Incision
of this channel, and the subsequent filling with gravel, is presumed to have occurred with the
erosion of the Troutdale Formation near the structural high.
These geologic features, a structural high, truncation of the Troutdale Gravel and SU1, near-
surface presence of the Troutdale Sandstone in the central portion of the project area, and the
Blue Lake Gravel-filled channel, play a. critical role in groundwater hydraulics and contamination
fate and transport and will be discussed further in this section and in Section 5.
3.2.2 Hydrogeologic Setting
The following sections include a description of hydrogeologic units identified in the project area.
significant hydrogeologic features, and the presence and movement of groundwater in and
between the hydrogeologic units. Hydrogeologic units are defined based upon hydraulic
characteristics of the geologic materials, and may be different than geologic units. For the
purpose of this discussion, hydrogeologic units include aquifers, water-bearing and permeable
material able to transmit water, and confining units, materials of low permeability that retard or
restrict groundwater flow through them. In general, the most permeable of the geologic units
are grouped into aquifers and the least permeable are grouped into confining units. The
EMC Record of Decision 12;i9/96 3_4
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relationship between the hydrogeologic units and geologic units previously described can be
seen on Figure 3-4 and in a north-south cross-section through the project area (Figure 3-5).
Four aquifers in the project area have a role in the presence and movement of groundwater
contamination and are discussed in this report Three of these aquifers cover most of the
project area and are. from shallowest to deepest, the Troutdale Gravel Aquifer (TGA), the
Troutdale Sandstone Aquifer (TSA). and the Sand and Gravel Aquifer (SGA). The fourth. Blue
Lake Aquifer (BLA), is located in the northeastern portion of the project area. The TGA and the
underlying TSA are separated by a confining unit, the CU1. The TSA and the lowermost SGA
are separated by a second confining unit, the CU2. As can be seen from Figure 3-4, these
hydrogeologic units are in most cases defined differently than the previously described geologic
units. For example, the hydrogeologic unit CU1 consists of clayey siltstone, the least
permeable of the four subunits of the geologic unit SU1.
Troutdale Gravel Aquifer. The TGA is present throughout most of the Portland basin, except
in the central and northeastern portion of the project area where it. along with the underlying
CU1. has been truncated (see Figure 5-1). In the project area the TGA is unconfined,
Groundwater flows northward in the TGA from the Cascade site toward the truncation, or edge,
of the TGA/CU1. Groundwater exits the TGA in the area of the truncation, north of the Cascade
site, by three mechanisms: discharge to springs like Shepard Spring, subsurface flow of
groundwater over the CU1 truncation (beneath a surficial veneer of Floodplain sand and silt),
and vertical leakage downward through CU1. Each of these three mechanisms of flow of
groundwater from the TGA serve as recharge to the TSA. These three mechanisms also
represent a major pathway for migration of contamination from source areas in the TGA. to the
TSA. At the Boeing facility groundwater in the TGA flows northwest, away from the north-south
trending line of TGA/CU1 truncation, and discharges into the Columbia Slough.
ConfinJrig.-JJnil.-K .- 3U1.is present-throughout. the project ,aeea,; wherever. the- TGA-exist3_£see .-
Figure 5-1). CU1 consists of interbedded siltstone and daystone and is approximately 40 to 50
feet thick at the Cascade and Boeing sites, gradually thinning at the line of truncation. Where
the CU1 is thickest, the estimated vertical hydraulic conductivity is very low; in the range of 10"6
to 10"* ft/day. In these areas, estimated vertical groundwater velocities are small. Nc^r the
TGA/CU1 truncation, vertical groundwater velocities increase as a result of weathering and
thinning of CU1, allowing vertical leakage of TGA groundwater downward to the TSA through
theCLM. ... .
Troutdale Sandstone Aqu'fer. The TSA is a regional aquifer that is continuous beneath the
project area except where incised by the channel-fill gravel deposit of the BLA. The TSA
consists of two subunits: an upper sandstone and a Icwer conglomera'a (see Figure 2-4). The
average thickness of the TSA subunits in the project area is apprc ornately 50 feet for the
sandstone, and 70 feet for the conglcmerate. In the central and northeastern part of ~e project
area, where the TSA is exposed at the ground surface, in the area of the structural nigh, the
TSA is a water-table aquifer. Here, at the structural high, the saturated thickness cr the upper
sandstone subunit is thin or absent. The saturated thickness in the TSA sandstone increases
away from ;he structural high, to the west, south, and east, to where the TSA is overlain by the
TGA/CU1. until eventually the TSA becomes ful'y saturated and confined.
Regional TSA groundwater flow in the project area is northeast toward groundwater discharge
areas along the Columbia Slough and rairview Lake. Groundwater flow directions in the TSA
EMC Record of Decision 12/19/96 3,5
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sandstone and conglomerate are generally similar, wnen me ^rcys wen neia is operated,
groundwater flow directions in the TSA may change to a northerly to westerly direction,
depending on which wells in the well field are pumped. Water levels for the TSA sandstone and
conglomerate subunits shown on Figures 3-6 and 3-7, for late November 1994, are
representative of water levels during well field non-pumping conditions.
Locally, groundwater flow in the TSA is influenced by a groundwater mound that has developed
in the vicinity of the geologic structural high, east of the Boeing facility and north of the Cascade
site. The highest TSA water levels in the project area are measured in the groundwater mound
(Figure 3-7). Groundwater flows radially away from the mound to the west, south, and east,
and eventually coincides with the regional groundwater flow. The groundwater mound has
formed because of decreased aquifer transmissivity where saturated portions of the TSA
sandstone thin or are absent, and increased recharge to the TSA east and north of the
TGA/CU1 truncation where the TSA is exposed at ground surface.
Primary sources of recharge to the TSA in the project area include upgradient regional
groundwater flow, direct infiltration of precipitation where the TGA and CU1 are absent,
groundwater flow from the SGA in areas where CU2 is more permeable and an upward
gradient exists, spring flow and discharge from the TGA at the CU1 erosional truncation, and
possibly irrigation.
The hydraulic conductivity of the entire saturated thickness of the TSA is estimated to range
from about 30 to 90 feet per day (ft/day) with an average of about 50 ft/day. Aquifer test data
and numerical analyses suggest that the TSA sandstone is generally more permeable than the
TSA conglomerate. The hydraulic conductivity of the sandstone unit is estimated to range from
38 to 78 ft/day, and the hydraulic conductivity of the conglomerate is estimated to range from 5
to 19 ft/day. In the numerical groundwater model developed for the project area, the TSA
sandstone unit is assigned a hydraulic conductivity of 80 ft/day and the conglomerate is
assigned a hydraulic conductivity of 10 ft/day. The specific yield of both the sandstone and
conglomerate units is estimated to be 0.15. Based on estimated aquifer parameters and
measured water level gradients, groundwater velocities in the project area are estimated to
range from 93 to 810 feet per year in the TSA sandstone, and from 28 to 930 feet per year in
the TSA conglomerate.
Confining Unit 2. The CU2 separates the TSA from the SGA. Where the CU2 is present, it
generally consists of a siltstone-sandstone-siltstone sequence and is greater than 30 feet thick.
The CU2 is absent in the northeastern part of the study area beneath the BLA channel-fill
deposit where a portion of the TSA and the CU2 are eroded away, north of the groundwater
mound in the vicinity of Sandy Boulevard and NE 201st Avenue, and in ah area east of NE
205th Avenue (Figure 3-8). In some areas where the CU2 is missing, a zone of increased fines
is interpreted as a "stratigraphic equivalent".
The vertical hydraulic conductivity of the CU2, and its stratigraphic equivalent, has been
investigated in great detail because of the potential for contaminant migration downward
through the CU2, from the TSA to the SGA. Where the CU2 has significant thickness, the
estimated vertical hydraulic conductivity is very low; in the range of 10"6 to 10"4. ft/day. In these
areas, estimated vertical groundwater velocities are very small, and the potential for
contaminant migration from the TSA to the SGA in reasonable time periods is highly improbable
except where leaking well casings penetrate both aquifers.
EMC Record of Decision 12/19/96
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North of the groundwater mound, where the CU2 is missing, about 10 feet of fine-grained CU2-
equivalent materials separate the TSA from the SGA. The CU2-equivalent materials have an
estimated vertical hydraulic conductivity in the range of 3x10"3 to 2x10"2 ft/day. Groundwater
travel times from the TSA to the SGA in this area, after 25 days of operation of the SGA wells in
the South Shore Well Field, were estimated to be in the range of 30 to 190 days.
Sand and Gravel Aquifer. The SGA is present beneath the entire project area and is 200 to
500 feet thick. In the central and western portions of the project area, the SGA consists of
sandstone underlain by conglomerate. In the eastern part of the project area, sandstone is not
present in the upper SGA. To the northeast near Blue Lake, the sandstone and conglomerate
that are typical of the SGA in most of the project area are not present; instead, the SGA
lithology is predominately siltstone and sandstone, with minor conglomerate. The hydraulic
conductivity of the SGA is similar to that of the TSA.
Regional groundwater flow in the SGA is east-northeast toward groundwater discharge areas in
the northeast part of the project area, near Blue Lake and along the Columbia River. SGA
vertical groundwater gradients in most of the project area are upward from the SGA to the TSA,
as would be expected in an area of regional groundwater discharge. The exception is in the
vicinity of the TSA groundwater mound where the vertical groundwater gradient is downward
from the TSA to the SGA. During periods when SGA wells in the South Shore Well Field are
operating. SGA horizontal groundwater flow is toward the west-northwest, and normally upward
vertical groundwater gradient between the TSA and SGA reverses and becomes downward.
Blue Lake Aquifer The BLA is a highly transmissive aquifer present in the northeastern
portion of the project area. The BLA is in direct contact with the underlying TSA and SGA near
the southwest shore of Blue Lake, but the hydraulic connection between the aquifers appears to
be limited. Hydraulic connection with the Columbia River appears to be good. The
transmissivity of the BLA has been estimated to range from 60.000 to 140,000 ftz/day. Based
on an aquifer thickness of 100 to 200 feet, the hydraulic conductivity of the BLA is estimated to
range from 100 to 200 ft/day.
3.2.3 Surface Water Features
The major surface water features in the project area are Blue and Fairview Lakes; the Columbia
River; the Columbia Slough; Taggart.,Shepard and Osboum springs; and Fairview, Osbourn
and Storm Drain creeks ^gure 3-1). "The two lakes are located adjacent to each other in the
northeastern part of the project area, and are separated by a narrow TSA sandstone ridge.
Fairview Lake is approximately 65.acres in size and is very srallow; average depth in the
summer is reported to 5e cnly 4 feet, and in winter only about 1 foot. The lake is a discharge
area for the TSA. Blue Lake is similar in size to Fairview Lake, but :t is much deeper. The lake
overlies the BLA. and is in contact with the TSA on its southern shore.
The Columbia River, along the northern boundary of the project area, is a regional groundwater
discharge area. The Columbia Slough, in the west-central part of the project area, is an
engineered waterway controlled by pumps and diversions to provide drainage, flood control and
irrigation on the Columbia River floodplain. The Slough originates at Fairview Lake and flows
west toward Portland for approximately 30 miles. The TSA discharges to the slough along an
EMC Reccrd of Decision 12/19/96 3.7
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estimated 1,500 foot stretch west of Fairview Lake. West of this area, the TGA and floodplain
deposits discharge to the slough.
Storm Drain Creek is a tributary of the Columbia Slough. Most of its recharge is from a local
storm drain system. The creek also receives discharge from 1) the TSA groundwater extraction
and treatment system at well RPW-2, 2) from the TGA groundwater extraction and treatment
system at the Boeing Facility. 3) from a 400-foot long trench and treatment system designed to
capture TGA groundwater prior to discharge at Shepard Spring north of the Cascade
Corporation facility, and 4) from Taggart Spring. Storm Drain Creek is not in direct contact with
the TGA. Osboum Creek and Fairview Creek, in the eastern part of the project area, flow north
and northwest, respectively, into Fairview lake. Osboum Creek is fed by Osbourn Spring.
which discharges from the TGA east of NE 205th Avenue and south of Interstate 84.
Other springs in the study area include Taggart and Shepard springs which discharge from the
TGA north of the Cascade site and east of the Boeing facility. Discharge at Taggart and
Shepard springs is typically less than 30 gpm and 5 gpm. respectively; the highest flows occur
in winter and spring, coincident with higher precipitation. Discharge from Taggart spring is
diverted to a tight-line storm sewer system that discharges to Storm Drain Creek. Shepard
Spring has been dry since December 1995 when an upgradient TGA groundwater extraction
trench began operation (see Section 4.5).
Stormwater runoff from NE 201st Avenue south of Interstate 84 and from the Cascade site
discharges to the east ditch which is part of the Multnomah County storm sewer system. Other
discharges to the east ditch include seepage from the TGA south of the Cascade site, runoff
from the Cascade site and effluent from the TGA groundwater extraction and treatment system
on the Cascade site. Water in the ditch flows east and northeast to Osbourn Creek.
EMC Record of Decision 12/19/96 30
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4. SITE HISTORY
The administrative record index identifies the documents providing the details on the site history
summarized below.
4.1 Site Discovery and Preliminary Assessments
Site discovery activities in the project area began in 1986. DEQ and EPA evaluated facilities
within the area to identify those that were likely to use the chlorinated VOCs found in
groundwater. DEQ completed federal preliminary assessments on the following facilities:
• Boyd Coffee
• Cascade Corporation
• Dirt 1 Aggregate Interchange
• Dry Cleaning Chemical Storage
• Ubby McNeil & Libby
• NW Retreaders
• Norwest Publishing
• Swift Adhesives
• Viking Industries
In addition to the federal preliminary assessments, DEQ conducted state preliminary
assessments on the following facilities:
• Multnomah County Parks - Blue Lake
• Opti-Craft
Following the preliminary assessments, additional investigations were performed on the
Cascade Corporation. Norwest Publishing. Swift Adhesives and Viking Industries facilities. A
summary of these investigations is provided in Section 4.4.
4.2 DEQ Response Actions
Concurrent with site discovery and assessment activities, DEQ undertook other actions in the
EMC project area. DEQ -esponse actions related to the groundwater contamination in the
project area included mor toeing of private supply wells to evaluate the extent of contamination,
providing alternate water supplies to residences with contaminated water supplies,
management of groundwater use in the area to control the spread of contamination. Installation
and testing of monitoring wells to further evaluate the extent of contamination, and development
EMC Record of Decision 12/19/96 4_-|
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of a database and groundwater flow model to evaluate interim groundwater use in the area and
develop cleanup alternatives for the contamination.
4.2.1 Groundwater Monitoring
DEQ sampled a number of private water supply wells in 1986 following the discovery of
groundwater contamination at the Boeing facility. Resulting data was used to determine the
scope of the Boeing monitoring and alternative water supply responsibilities to be conducted
under their 1986 Consent Order with EPA and DEQ. In 1988, DEQ performed additional
sampling of private supply wells to further investigate the extent of groundwater contamination
in the area. In 1989, DEQ began quarterly monitoring of private supply weHs located east of the
Boeing facility when it was determined that Boeing was not the source of the contamination in
this area. The responsibility for monitoring these wells was transferred to Boeing and Cascade
in 1993, as part of the joint RI/FS for the ISA.
4.2.2 Alternate Water Supplies and Interim Groundwater Use Management
In 1989, DEQ provided bottled water to several single family residences located on 205th
Avenue and north of I-84, which had previously received bottled water from Boeing.
Responsibility for providing bottled water was transferred to Cascade in 1990.
DEQ began efforts to manage use of groundwater in the vicinity of the EMC groundwater
contamination in 1990. Actions taken by DEQ to reduce the spread of contamination from the
pumping of water supply wells included requiring the abandonment of two Rockwood Public
Utility District wells in 1990, discontinued use of the Rolling Homes Mobile Terrace well, and
development of pumping guidelines to protect the Portland Water Bureau's South Shore Well
Field. Since development of the guidelines, the Portland Water Bureau has annually submitted
pumping plans to DEQ.
4.2.3 Well Installations
In 1990, DEQ installed 8 wells at the site to determine the extent of groundwater contamination
and the potential threats to the Portland well field and other supply wells located between Blue
and Fairview Lakes. Another goal was to determine whether contamination in the area east of
201st Avenue was from an unknown upgradient source south of I-84 and east of Cascade. No
groundwater contamination was found in that area.
In 1993, DEQ installed three additional wells south of Boeing and west of Cascade to determine
whether an upgradient source of contamination existed in this area. No contamination was
detected in any of these wells.
4.2.4 Database and Groundwater Flow Model Development
In 1993, DEQ initiated a project to integrate site specific information into a regional conceptual
geologic and hydrogeologic model. The project involved evaluation of geologic information from
a large number of well logs to refine the geologic model published by the U.S. Geological
Survey (USGS), the Portland Water Bureau and others. The geologic interpretations and
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hydrogeological data, including water levels and aquifer pumping data, were used to develop a
groundwater flow model. The model provided a quantitative tool to simulate the affects of
pumping of .the City of Portland's well field, to predict the future spread of groundwater
contamination, and to investigate various cleanup alternatives for the TSA contaminant plume.
DEQ completed its model project in June 1993. and provided the model to the City of Portland
for their use in well field management, and to Boeing and Cascade for use in development of
cleanup alternatives for the TSA.
4.3 EPA Response Actions
EPA has been the lead agency overseeing the investigation and cleanup of the Boeing facility
since 1985. These enforcement actions are being conducted pursuant to federal Resource
Conservation and Recovery Act (RCRA) authorities.
In coordination with DEQ, EPA evaluated the EMC site for inclusion on the federal National
Priorities List (NPL), performed a site investigation of the Libby, McNeil & Ubby site (Associated
Foods facility) and entered into a memorandum of understanding with DEQ.
4.3.1 Site Inspection & Proposed NPL Listing
In 1991. EPA conducted a NPL listing site inspection at the EMC site. The investigation
included performance of a soil gas survey at or in the vicinity of a number of facilities, and
sampling of approximately 60 wells for futt priority pollutant constituent analyses. Reports on
these investigation activities were issued in the fall of 1991.
In May 1993. EPA issued public notice of the proposed listing of the E'< C site on the NPL In
1995. EPA requested the State of Oregon's concurrence to finalize the listing of the site on the
NPL. Sased on the progress being made on the completion of investigations and
implementation of interim cleanup activities by Boeing snd Cascade under State oversight, the
State requested that EPA defer listing. EPA has taken no further action since then.
4.3.2 Associated Foods Site Investigation
In 1992. EPA performed a preliminary assessment and site investigation of the former Libby,
McNeil & Libby site- owned by Associated Foods. This investigation was prompted by
allegations from a former employee that solvent wastes had been disposed at the site. No
VOCs were detected in soil samples and no further action was taken.
4.3.3 Memorandum of Agreement with DEQ
In August 1994, DEQ and EPA entered 'nto a memorandum of agreement (MOA) ror the EMC
site. The MOA formalized the respective roles and responsibilities of DEQ and EPA on the
coordination of future ir.estigation and cleanup at the EMC site. The MOA designated DEQ as
the lead agency for the investigation and cleanup of Swift Adhesives. Cascade Corporation and
the TSA area-wide groundwater contamination under State authorities. EPA retained lead for
the Boeing facility under RCRA authorities.
EMC Record of Decision 12/19/S6 4.3
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4.4 Enforcement Activities
This section summarizes the enforcement activities taken in response to the discovery of
groundwater contamination in the EMC project area in 1986.
4.4.1 Boeing
In 1986, Boeing entered into an Administrative Order on Consent with EPA and DEQ to
address groundwater contamination detected at the facility. This order required Boeing to
characterize the nature and extent of contamination at the facility, to provide alternate water
supplies for contaminated groundwater supply wells, and to conduct monitoring of off-site
supply wells. In 1989, Boeing's responsibility for providing alternate water supplies and
monitoring was revised to eliminate areas east and south of the Boeing facility that apparently
were not contaminated by the Boeing facility.
In 1993, Boeing entered into a second Order with EPA for completion of the facility
investigation and the development and implementation of final corrective measures for soil and
TGA groundwater contamination at the facility. EPA, with DEQ's concurrence, will be selecting
a final cleanup for the Boeing facility later this year.
4.4.2 Cascade
In 1988, Cascade entered into a Consent Order with DEQ for a preliminary remedial
investigation. A second Order was issued in 1989 for completion of a remedial investigation
and feasibility study. Cascade has completed these activities. Public comment on DEQ's
selected final remedy for the Cascade facility is proceeding concurrently with the TSA remedy
selection process.
4.4.3 Swift Adhesives
In 1989, Reichhold Chemicals, Inc., owner of Swift Adhesives, entered into a Consent Order
with DEQ for completion of a site investigation. In 1990, an amendment to the Consent Order
was issued requiring completion of a RI/FS for VOC contamination discovered in a shallow TGA
"perched" aquifer. In May 1994, DEQ selected a cleanup remedy and issued a record of
decision for the site based on the results of the RI/FS. Reichhold Chemicals, Inc. is currently
implementing the final remedy which includes groundwater extraction and treatment from a
shallow perched aquifer.
4.4.4 Viking Industries
In 1989, Viking Industries entered into a Consent Order with DEQ requiring completion of a site
investigation related to historical solvent disposal practices and a RI/FS for a release of diesel
from an underground storage tank at the facility. The investigations were completed in 1991.
No evidence of soil or groundwater contamination related to historical solvent disposal was
discovered. The cleanup of the diesel contamination is being overseen by DEQ.
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4.4.5 Boeing/Cascade
In July 1993, OEQ enteredTnto a Consent Order with Boeing and Cascade requiring them to
perform a removal action to control the northerly migration of the TSA contaminant plume. In
1994. an amendment to the Order (1994 Consent Order) was issued for completion of a
comprehensive RI/FS for the TSA contaminant plume. •
4.5 Interim Removal Action Measures
This section summarizes the interim removal actions (IRAMs) performed by Boeing and
Cascade to control sources of contamination in the TGA at their respective facilities and
prevent further migration of the area-wide TSA contaminant plume to the north.
4.5.1 TGA Source Control
Boeing and Cascade have implemented measures at their respective facilities to control the
spread of groundwater contamination within the TGA, and control the migration of
contamination from the TGA to the TSA.
Boeing Facility. IRAMs implemented at and near the Boeing facility to address TGA source
areas include installation and operation of a groundwater extraction and treatment system, soil
vapor extraction, abandonment of several supply wells, and soil excavation and disposal.'
The groundwater extraction and treatment system is designed to centre! groundwater
movement in the TGA under the Boeing facility and to capture and remove VCCs from this
groundwater. The system, which began operation on March 1989, currently consists of 13
groundwater extraction wells and an air stripping tower. Between March 1989 and January
1996, the system extracted and treated approximately 740 million gallons of TGA grour.dwater
containing approximately 3,100 pounds of VOCs.
Boeing implemented a soil vapor extraction (SVE) system to remove VOCs from soil above the
saturated zone of the TGA beneath the Boeing facility. Two SVE wells (VE-3 and VE-4) are
currently operating and two additional wells are planned to be operational by July 1996. The
SVE system removed approximately 300 pounds of VOCs from soil between September 1995
anc January 1996.
Other measures implemented by Boeing include the abandonment of former Boeirg supply
well A-2(d) and Rockwood Water District wells RW-1 and RW-2. abandonment of two domestic
supply wells, and excavation and disposal of VOC-contaminated soil during builc r.g expansion
in 1992.
Groundwater monitoring data suggests that Boeing's IRAMs are currently controlling migration
of contamination within the TGA.
Cascade Facility. Cascade has implemented two IRAMs on its plant site to address TGA
source areas and an offsite IRAM to cut off the discharg-e of contaminated TGA ;:c .ndwater to
the TSA north of the facility. These removal actions include installation and operation of a
groundwater extraction and treatment system at the north property boundary (the cn.iite IRAM).
EMC Record of Decision 12/19/96 4.5
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decommissioning a former industrial supply well, removal of contaminated soil from several
areas, and installation and operation of an offsite groundwater interceptor trench and treatment
system (the offsite IRAM).
The onsite IRAM consists of five extraction wells located along the northern property boundary
and an air stripping tower. Through December 1995, the onsite IRAM has removed and treated
more than 27 million gallons of TGA groundwater containing approximately 380 pounds of
VOCs.
The offsite IRAM. located approximately 600 ft north of the Cascade site, is a 400-ft long trench
with the bottom keyed into CU1 designed to capture the off-site groundwater VOC plume
causing contamination to the underlying TSA. The TGA control trench extraction and treatment
system was brought on line in October 1995, and has operated continuously since December
1995. Preliminary monitoring data indicate the off-site IRAM system is functioning as designed.
Cascade has completed other IRAMs at its facility. A TSA industrial water supply well was
abandoned because of a leaky well casing allowed contaminated TGA groundwater to flow to
the lower TSA. Contaminated soil has been removed from several parts of the site, including
the removal of approximately 160 yd3 of soil from a drainage ditch along the northern property
boundary.
4.5.2 TSA Interim Removal Measures
Boeing and Cascade implemented an IRAM to control the northerly migration of the TSA
contaminant plume pursuant to the joint 1993 Consent Order (see section 4.4.5). Three
extraction wells were installed in the TSA (identified as RPW-1ds, RPW-ldg and RPW-2). The
RPW-1 wells are located west of Fairview Lake, and RPW-2 is located about 1000 feet
southwest of Fairview Lake. RPW-2 has been operated since August 1994. Groundwater is
treated by an air stripping system and discharged to the Columbia Slough. The RPW-1 wells
are currently not pumped because they are beyond the extent of the TSA contaminant plume.
The RPW-1 wells are not a component of the selected remedy, but will be maintained for
monitoring and possible contingency operation in the event of an emergency requiring long-
term operation of the entire PWB well field.
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5. INVESTIGATION SUMMARY
5.1 Contaminants and Sources
The TSA is contaminated with several halogenated volatile organic compounds (VOCs).
Compounds that have been consistently detected in TSA groundwater in the project area
include trichloroethene (TCE). tetrachloroethene (PCE). and 1 ,2-dichloroethene (1,2-DCE).
Two other compounds. 1,1,1-trichloroethane (1,1,1-TCA) and 1 . 1 -dichloroethene (1.1-DCE)
also have been detected in the TSA at low concentrations. The VOCs considered chemicals of
potential concern (COPCs) that have been detected at concentrations above federal drinking
water standard maximum contaminant levels (MCLs) include TCE. PCE. cis-1,2-DCE, and
1,1-DCE. The maximum concentrations of these COPCs detected in the TSA in a sampling
round conducted in August 1994 were: 160 ^g/L for TCE, 8 ng/L for PCE, 29 ng/L for cis-1,2-
DCE, and 2 ng/L for 1,1-DCE. TCE is the most widespread of the VOCs detected in the TSA,
and is also the VOC detected at the highest concentrations.
VOCs have also been detected in the SGA beneath the area where the TSA is contaminated.
The VOCs detected in the SGA include TCE, cis-1,2-DCE and PCE. but concentrations are
significantly lower than those in the TSA. TCE is the only contaminant detected above the
MCL. A summary of TSA and SGA groundwater contaminant concentrations is listed on Table
5-1 . The maximum TCE concentration detected in the SGA in late 1995 was 16
The primary source of contamination to the TSA is the discharge of contaminated groundwater
from the TGA. The areal extent of total VOC contamination in the TGA as of summer 1994 is
shown on Figure 5-1. Potential migration pathways from the TGA to the TSA include infiltration
from springs, seeps, and vertical leakage downward through the CU1 near the TGA/CU1
truncation north of Cascade, and leakage along well casings of former water supply wells at the
Boeing and Cascade facilities. The areas of highest TCE concentrations in the TSA, shown on
Figures 5-2 and 5-3. correlate to locations of potential pathways from the TGA to the TSA and
subsequent migration from these areas. TGA source control measures implemented by Boeing
and Cascade, which have included intercepting the contaminated groundwater flow that
formerly discharged at springs and seeps and abandonment of wells with leaking casings, have
eliminated or are expected to eliminate or control transport of VOCs to the TSA.
The source of VOC contamination in the SGA is most likely leakage along well casings
completed through CU2. Four water supply wells have had confirmed detections of VOCs. and
these wells were all constructed without a seal through CU2 and have been, or are currently.
used.
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5.2 Extent of Contamination
Contamination in the ISA generally extends over an area of about 300 acres in the central part
of the project area frorrTsouth of Interstate 84 near the Cascade site, northward just beyond the
Columbia Slough. The extent of contamination in the TSA Sandstone and Conglomerate
subunits, as defined by the presence of TCE in groundwater. is shown on Figures 5-2 and 5-3,
respectively. The highest TCE concentration in both the TSA Sandstone and Conglomerate.
reported in August 1994. occurred in and west of the groundwater mound area. The maximum
TCE concentrations were 140 ^igA. at MW-18(ds) in the TSA Sandstone and 160 pg/L at well
BOP-13(dg) in the TSA Conglomerate. The historical source of contamination to these
locations is interpreted to be discharge of contaminated groundwater from TGA near the
TGA/CU1 truncation and TSA recharge in the groundwater mound area. Outside of the mound
area the maximum observed TCE concentration was 90 u,g/L in the TSA Sandstone on the
Boeing facility near the location of a former supply well. The areal extent of TSA Sandstone
and Conglomerate groundwater contaminated above the TCE MCL of 5 jig/L is illustrated by
the 5 ng/L contour on Figures 5-2 and 5-3. Approximately 3 billion gallons of water in the TSA
contain concentrations of TCE in excess of the MCL (based on an aquifer porosity of 0.25).
The total mass of TCE in this volume is estimated to be about 1900 pounds.
The distributions of PCE and total 1.2-DCE in the TSA Sandstone and Conglomerate are less
extensive than the TCE distribution, and concentrations are much lower. PCE concentrations
exceed the MCL (5 jig/L) at a few wells within the groundwater mound area. 1,2-DCE
concentrations do not currently exceed the MCL (70 jig/L) within the project area. In August
1994. detections of 1.1-DCE were only reported at three wells; none of these detections exceed
the MCL of 7 jig/L Maximum concentrations of PCE and 1,2-DCE in the TSA Sandstone
generally occur within and downgradient of the groundwater mound area. The maximum
concentration of 1.1-DCE occurs in the TSA Sandstone beneath the Boeing facility.
For the COPCs, contaminant distributions are slightly more widespread and at higher
concentrations in the TSA Sandstone than in the TSA Conglomerate, except in the groundwater
mound area where the TSA sandstone is not saturated or the saturated thickness is minimal.
In the mound area, concentrations in the upper part of the conglomerate are similar to. or
exceed, concentrations in the sandstone. The VOC concentrations in the TSA are very low
compared to their aqueous solubility, indicating that there is no direct source of contamination
within the TSA (e.g. pure solvents within the soil matrix).
The leading edge of the VOC plume has been defined by wells with no TCE detections. The
TCE plume, as shown on Figures 5-2 and 5-3, encompasses the plumes for the other COPCs
and, therefore, is considered to be the primary representative of contaminant distributions within
the TSA. Uncertainty currently exists as to the northeast extent of the TSA VOC plume
between MW-23(ds) and DEQ-4(s) and the VOC concentrations at the base of the TSA at MW-
23(ds) (see Figure 3-2a). Additional investigations are being implemented to address these
uncertainties.
The available water quality data for the SGA indicates that there is most likely not a continuous
plume of groundwater contamination in that aquifer. Confirmed detections (two or more
consecutive detections since 1991) have been reported in four water supply wells beneath the
TSA plume, where natural hydraulic gradients are downward from the TSA to the SGA. In
EMC Record of Decision 12/19/96 5_2
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November 1995, TCE was only detected at three of these wells at concentrations ranging from
1.4 to 16 ng/L (Figure 5-4). VOCs have been detected at four other SGA wells located north
and northwest of the TSAj)lume. but these detection have been at low concentrations and have
not been confirmed in consecutive samples from these wells.
The only surface water body that receives discharge from the TSA or SGA. in the project area
where VOCs have been detected, is the Columbia Slough just downstream of Fairview Lake.
The Columbia Slough was sampled at two stations east of the erosional truncation of CU1, in
the area where groundwater from the TSA discharges to the slough. At the downstream
station, TCE has been detected intermittently at low concentrations, up to 2.3 ng/L, over the
monitoring period. In addition to the Columbia Slough, water samples were also collected from
Fairview Lake and Osboum Creek. No VOCs were detected from these sampling events.
Surface-water sampling data for the Columbia Slough are summarized on Table 5-2.
5.3 Contaminant Fate and Transport
The VOCs in the TSA result from migration of dissolved VOCs from the TGA to the TSA via
discharge of contaminated groundwater from the TGA to the TSA, and leakage along unsealed
water supply well casings. Within the TSA, the primary VOC transport process is advective
transport with the groundwater (refer to Section 3.2.2 and Figures 3-6 and 3-7). VOCs have
migrated radially from the TSA mound to the east and west and eventually farther downgradient
move in the direction of regional TSA groundwater flow, to the north/northeast toward Fairview
Lake. Contaminants have been transported a shorter distance to the northeast of the
groundwater mound because of the decreased sandstone saturated thickness in that direction
(Figure 5-2), the lower transmissh/ity of the conglomerate, and because most of the TGA
recharge to the TSA occurs on the south side of the mound where groundwater flows to the
south. VOCs in the TSA originating from a leaky well casing at the Boeing facility have
migrated toward the northeast. The VOC plume in the TSA currently extends to the western
comer of Fairview Lake and the Columbia Slough which is a groundwater discharge area for
the TSA. The eastern portion of the VOC contaminant plume is migrating toward discharge
areas south of the eastern end of Fairview Lake. Other less significant contaminant transport
and fate processes include sorption and biotic and abiotic transformations. Sorption processes
are estimated to be relatively low due to the low organic and silt/clay content in the TSA, and
biotic and abiotic transformations apparently occur very slowly.
Pumping from the City of Portland's - South Shore well field has the potential to affect the
direction and rate of groundwater flow in the TSA. A numerical groundwater transport model
was used to investigate potential plume migration under four different wellfield use scenarios
and the absence of remediation:
• Reasonable Current Average (RCA) Scenario. Pumping of the existing BLA production
wells at estimated maximum capacity of 50 mgd, for 90 days per year, for 20 years.
• Reasonable Current Maximum (RCM) Scenario. Pumping of existing TSA, BLA, SGA,
CRSA and TGA production wells at estimated maximum capacity of 99 mgd, for 151
days per year, for 20 years.
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• Reasonable. Future Maximum (RFM) Scenario. Pumping of existing and proposed
production wells at estimated total maximum capacity of 150 mgd, for 151 days per
year, for 20 years.
• Emergency-Use Scenario. Continuous pumping of existing production wells at
estimated maximum capacity of 99 mgd. for 3 years.
The results of the modeling analyses indicate that, in the absence of remediation, the TCE
plume would expand significantly beyond its current configuration. Under the RCA scenario.
most of the plume eventually discharges to the surface water bodies, but the plume also
expands to encompass the BLA production wells. Under the RCM and RFM scenarios the
VOC plume expands to the west and is not substantially captured by the surface water bodies.
The TCE plume in the TSA is calculated to extend to the BLA and TSA production wells under
these scenarios. Under the emergency use scenario, the TCE plume is primarily northwesterly
and is less extensive than predicted under the RCM or RFM scenarios. The plume front is not
predicted to extend to either the BLA or TSA production wells within the simulated 3-year
period.
5.4 Endangerment Assessment
An endangerment assessment was performed as part of the Rl, in accordance with OAR 340-
122-080 and USEPA guidance to evaluate the potential risks to human health and the
environment and the need for remedial action, or no action, at the site. The endangerment
assessment included a human health evaluation and an ecological evaluation. Each evaluation
included an evaluation of the chemicals of concern, a toxicity assessment, an exposure
assessment, risk characterization, and an uncertainty assessment.
5.4.1 Human Health Evaluation
TCE, PCE, cis-1,2-DCEt and 1,1-DCE were identified as COPCs based on chemical toxicity,
and detection frequency in groundwater and surface water. TCE and cis-1.2,-DCE were
identified as COPCs in TSA and SGA groundwater and in surface water in the Columbia
Slough. PCE was identified as a COPC in both TSA and SGA grqundwater, and 1,1-DCE was
identified as a COPC in TSA groundwater.
Residential, occupational, and recreational exposure scenarios were evaluated based on land
use and zoning information. For each of these scenarios, the following potential current
exposure pathways were quantitatively evaluated for potential impacts from the TSA VOC
plume:
• Residential ingestion. dermal contact, and inhalation of chemicals volatilizing from TSA
water during household use;
• Residential ingestion, dermal contact, and inhalation of chemicals volatilizing from SGA
water during household use;
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• Residential ingestion of food crops that have been irrigated with water from the ISA, the
SGA, or the Columbia Slough;
• Residential and occupational inhalation of chemicals volatilizing from TSA water through
soil into a residence and workplace environment, respectively;
• Recreational dermal contact with surface water in the Columbia Slough.
For each of these exposure pathways, central tendency exposure (CTE) and reasonable
maximum exposure (RME) conditions were used to evaluate potential impacts to human health.
CTE and RME intake assumptions from EPA guidance, professional judgment, and data
collected from the ISA, the SGA, and the Columbia Slough were used to estimate chronic daily
intakes (COIs) and lifetime daily intakes (LDIs).
Potential non-carcinogenic effects were evaluated by comparing the GDIs with non-
carcinogenic indicators of safe daily intakes (i.e., EPA-established reference doses). The
reference dose is the estimate of a daily exposure for humans that is unlikely to produce an
appreciable risk or deleterious effect. The ratio of the calculated intake of a chemical to its
reference dose is called the hazard quotient. The sum of the hazard quotients for each COPC
at the site is a hazard index. A hazard index greater than one suggests that deleterious effects
may occur to exposed individuals.
The increased probability of developing cancer (excess cancer risk) from exposure to TSA-
related compounds was estimated with EPA-established carcinogenic slope factors and the
calculated LDIs. Total excess cancer risk is determined by dividing the intake of each COPC by
its slope factor and summing all of the ratios. The risk is expressed as a probability, such as 1
in 1,000.000 or 1 x lO'6.
The non-cancer hazard index for all exposure pathways for both the CTE and RME
assumptions were less than one. The excess lifetime cancer risk under the CTE assumptions
exceeded 10"6 for the residential use of TSA groundwater exposure scenario, and under the
RME assumptions exceed 10"6 for both the residential use of TSA groundwater and use of SGA
groundwater from supply wells with leaking well casings. The excess lifetime cancer risk
estimated for the residential use of TSA groundwater is 4.8x10"6 under the-CTE assumptions
and 4.0x10"5 under the RME assumptions. Most of the excess lifetime cancer risk is from
inhalation of TCE during showering. The estimated excess lifetime cancer risk for the
residential use of SGA groundwater under the RME assumptions is 3.4x10"6, with most of the
risk associated with the inhalation of TCE vapors from the water. A summary of the estimated
risks is provided in Table 5-3.
A numerical groundwater model was used to evaluate transport of the TSA VOC plume and to
estimate exposures for hypothetical future exposure pathways under the four aquifer-use
scenarios described in Section 5.3. Under the RCA scenario, TCE concentrations at the BLA
wells are predicted to be less than the MCL, due to dilution from Columbia River recharge of the
BLA. Private supply wells PMX-345 and PMX-189 (see Figure 3-2a) were predicted to be
impacted. Under the RCM and RFM scenarios, PWB wells 5 and 15 may become impacted.
Limited contamination of the SGA was also predicted under the RCA and RCM scenarios. The
spread of contamination was predicted to be greater under the RCM and RFM pumping
EMC Record of Decision 12/19/96 5-5
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scenarios than under the 3 year continuous emergency use scenario.
5.4.2 Ecological Evaluation
Potential impacts to ecological receptors from discharge of TSA groundwater into surface water
bodies were also evaluated. Cis-1,2-DCE and TCE in Columbia Slough water were identified
as the COPCs for ecological receptors. No COPCs were identified for the other surface water
bodies evaluated. No TSA-related chemicals were detected in sediments of the Columbia
Slough. The COPCs were used to estimate potential adverse ecological effects associated with
ingesting water from the slough.
The marsh wren and the common muskrat were selected as the indicator species for assessing
ecological impacts, on the basis of size and higher food and water intake rates relative to body
weight The muskrat was also selected because it can ingest bottom-dwelling plants in the
slough while foraging. Two sensitive-critical species (i.e., the painted turtle and western pond
turtle) were identified in the project area, but were observed only at Fairview Lake, a surface
water body that had no detectable levels of VOCs.
Two methods were used to evaluate potential impacts to ecological receptors using parameters
and assumptions for the indicator species. First, COPC concentrations in surface water were
compared with published water quality criteria intended to protect freshwater life. Second, the
potential risks to the health of individual members of a wildlife species expected to have high
exposure were estimated, by comparing GDIs with toxicity reference values. The results of the
ecological assessment indicate the ecological receptors are not expected to be impacted by the
COPCs in the Columbia Slough.
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6. REMEDIAL ACTION OBJECTIVES AND CLEANUP LEVELS
This section summarizes the remedial action objectives and cleanup goals developed for the
site to protect human health and welfare, and the environment.
6.1 Remedial Action Objectives
Remedial action objectives (RAOs) are site-specific goals for protection of human health and
the environment. The RAOs for the EMC site were established in the consent order for the TSA
RI/FS. In the consent order. RAO-a specified restoration of the TSA to background conditions.
The technical feasibility of restoring the TSA to MCLs and to background was evaluated in
detail in the FS. Restoration to background conditions in a reasonable time frame was
determined to be infeasible. Restoration to background, defined as 0.05 ng/L TCE
concentration, was estimated to take from 2.5 to 4 times longer than restoration to MCLs. For
the most effective alternative presented in the FS. a time frame of 45 to 80 years was predicted
to achieve background. A time frame of this magnitude was not considered reasonable.
The analyses conducted during the Rl and FS process indicate that restoration of the TSA to
protective levels (MCLs) is feasible. The relatively low dissolved VOC concentrations in TSA
groundwater and the aquifer characteristics (e.g., low organic content and moderate
permeability) indicate there is a reasonable potential for restoration of the TSA using
groundwater extraction and treatment technologies. RAO-a, as revised by DEQ. and the
remaining RAOs for protection of human health, welfare, and the environment specified in the
consent order are summarized below.
a) Restore the TSA to protective concentrations in a reasonable time, if feasible. If not
feasible, minimize the extent of the TSA containing VOCs above MCLs, or 1 x 10"6
excess cancer risk levels, whichever is more stringent, and provide long-term
containment of areas where concentrations are above MCLs;
b) Prevent ingestion of TSA groundwater that contains TCE, PCE, cis-1.2-DCE and 1.1-
DCE at concentrations above their respective MCLs;
c) Protect..environmental, .receptors..by preventing, surface water -discharge, o/. TSA
groundwater with VOC concentrations that exceed surface water ambient water-quality
criteria;
d) Prevent the further spread of contamination in the TSA to the extent practicable;
e) Protect groundwater quality in the SGA and the BLA; and
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f) Allow existing uses of groundwater resources in eastern Multnomah County, or if not
feasible, minimize the type and length of groundwater use restrictions.
6.2 Cleanup Goals
The cleanup goals for the four COPCs in groundwater (TCE, PCE, cis-1,2-DCE and 1.1-DCE)
are the federal drinking water MCLs promulgated under the Safe Drinking Water Act (SDWA).
MCLs are the maximum concentrations of contaminants allowed in water used for drinking.
Oregon has adopted the federal regulations as state water regulations (OAR Chapter 333
Division 61). The current MCLs for the COPCs and corresponding risk levels are listed on
Table 6-1. The risk levels were estimated using EPA residential exposure assumptions for
ingestion of, dermal contact with, and inhalation of vapors from chemicals in groundwater.
during normal household use.
The excess cancer risks corresponding to the MCLs for 1,1-DCE and PCE exceed 1 x 1CT6.
The groundwater contaminant plumes for these chemicals are encompassed by the TCE
plume. The maximum concentrations of PCE is slightly above the MCL, and 1,1-DCE is below
the MCL.. Cleanup of the TSA to the TCE MCL, therefore, will reduce the concentration of the
other chemicals well below their respective MCLs. To illustrate, remediation of the highest
TCE concentration (160 ppb) to the MCL (5 ppb) represents a 32-fold reduction in
concentration. If this 32-fold factor is similarly applied to the maximum TSA plume
concentrations for PCE (7.9 ppb) and 1.1-DCE (2.2 ppb). it is anticipated that the
concentrations will be proportionally reduced to 0.25 ppb and 0.07 ppb, respectively. These
concentrations correspond to estimated cancer risk levels of 3 x 10 for PCE and 1 x 10"* for
1,1-DCE (based on residential exposure).
The cleanup goals for the COPCs in surface water are the ambient water-quality criteria
developed under the federal Clean Water Act, as administered by the state of Oregon. These
criteria are:
• TCE — 45,000 p.g/L for acute exposure. 21,000 ngJL for chronic exposure;
• PCE — 5,280 ng/L acute, 840 ^g/L chronic; and
• cis-1,2-DCE and 1,1-DCE — 11,600 jig/L total DCE for acute and criterion for
chronic exposure.
The maximum concentrations of these COPCs in TSA groundwater are well below their
respective water quality criteria. Therefore, future groundwater discharges to surface water will
not cause exceedances of these criteria.
6.3 Applicable or Relevant and Appropriate Requirements
While not a remedy selection criterion or State law requirement, remedy implementation will
comply with "applicable or relevant and appropriate requirements" (ARARs) to help meet RAOs
and provide consistency with the federal NCP. The ARARs identified for the TSA'cleanup are
described below.
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6.3.1 Resource Conservation and Recovery Act (RCRA)
DEQ's Hazardous Waste Management rules, Oregon Administrative Rules (OAR). 340-100-
OOlef.seg., generally adopt the federal RCRA regulations. These regulations are applicable to
cleanups involving "hazardous wastes" as defined in RCRA. Hazardous wastes must meet the
applicable regulations under OAR 340-122-100, 101, 102, 104, 105. and 106, as well as
Sections 260, 261, 262, 265 and 268 of RCRA. unless specific requirements are exempted by
the Director of DEQ under Oregon Revised Statutes (ORS) 465.315, or are determined to be
procedural requirements only. Oregon regulations in OAR Chapter 340 establish state
requirements that are in addition to federal requirements, including annual reporting and fees
for hazardous waste generation.
The VOCs in the TSA contaminant plume may be hazardous constituents from historical
releases of spent solvents and sludge, from former vapor degreaser operations, or cutting oils
used in parts machining at the Cascade and Boeing facilities. However, dissolved VOCs in the
TSA groundwater are from multiple sources from the Boeing and Cascade facilities and a
definitive determination cannot be made as to the source of the VOCs. Therefore, soil drill
cuttings, excavated soil, or groundwater extracted during the TSA remedy would not be a
hazardous waste, unless contaminant concentrations exceed toxicity characteristic regulatory
levels specified in 40 CFR Part 261.24. Maximum reported TCE. PCE and DCE concentrations
in the TSA are below these regulatory levels.
Drill cuttings from installation of TSA extraction wells in source areas on the Boeing facility.
where highly contaminated soils may exist, will also need to be characterized to determine if
they are a hazardous waste. Wastes determined to be hazardous under RCRA would need to
be disposed in accordance with Sections 265 and 268 of RCRA.
Drill cuttings from wells installed in other portions of the TSA contaminant plume would not
contain sufficient concentrations of hazardous constituents to exceed risk based concentrations
in soil, based on knowledge of groundwater contaminant concentrations and chemical partition
coefficients, and the results of previous drill cutting characterizations. Wastes determined to be
non-hazardous pursuant to Section 261, must be managed in accordance Oregon rules for
solid waste in OAR 340-93 through 97.
6.3.2 Clean Air Act
Oregon Air Pollution Control Laws (OAR 340-20 and 28) regulate operation of stationary air
pollution sources. These regulations are applicable to groundwater air-stripping treatment
systems. DEQ has determined that VOC emissions from a packed tower air-stripping systems
located at least 100 meters upwind from residential populations would not exceed significant
emission rates under OAR 340-20-225. Treatment of VOC emissions from the air stripping
units will, therefore, not be required provided the system is located at least 100 meters from
residential populations.
6.3.3 Drinking Water Quality Act
The Oregon Drinking Water Act (ORS 448.115 through 990) authorizes adoption of federal
regulations for drinking water promulgated under the Safe Drinking Water Act (SDWA)
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(40 CFR 141.11-141.16). The Oregon rules for public water systems (OAR 333-61) implement
this statute, and are applicable to any cleanup which involves beneficial reuse of treated
groundwater as a source of public water supply. The maximum contaminant levels (MCLs)
presented in Table 6-1 are applicable standards for beneficial reuse of treated groundwater.
6.3.4 Clean Water Act
Oregon Water Pollution Laws regulate the discharge of pollutants to surface waters of the State
and are applicable to the discharge of treated groundwater. Rules applicable to the TSA
cleanup include OAR 340-41 which specify surface water quality standards, and regulations
pertaining to National Pollutant Discharge Elimination System (NPDES) and Water Pollution
Control Facility (WPCF) permit requirements under OAR 340-45.
6.3.5 Water Resource Department Regulations
Oregon Water Resource Department regulations under OAR Chapter 690 may be applicable to
one or more of the remedial alternatives. Regulations that may be applicable include:
• Division 10 - Appropriation and Use of Groundwater;
• Division 11 - Applications and Permits;
• Division 15 - Water Right Transfers; and
• Division 210 well construction standards; and Division 220 abandonment of wells.
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7. DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES
This section summarizes the areas and volumes of TSA groundwater contamination exceeding
the cleanup levels and the remedial alternatives developed by Boeing and Cascade in the FS.
Also included is a summary of additional remedial alternatives developed by DEQ and its
contractor. S.S. Papadopulos & Associates, to identify the best feasible remedial alternative for
the TSA groundwater contaminant plume.
7.1 Areas & Volumes
The areal extent of the zone within the TSA that contains TCE at concentrations above the 5
ng/L MCL cleanup goal is approximately 300 acres. The areal extent of the zones in the TSA
sandstone and conglomerate subunits that contain TCE concentrations above 5 jig/L are both
approximately 287 acres, but the footprint of these zones is not the same (Figures 5-2 and 5-3).
There are approximately 3 billion gallons of groundwater (based on an aquifer porosity of 0.25)
within the zone of contamination. The volume of contaminated groundwater in the conglomerate
subunit is about 40% larger than that in the sandstone subunit, because the average saturated
thickness of the conglomerate is greater than that of the sandstone subunit. Approximately
1900 pounds of TCE are contained in the TSA; 1085 pounds dissolved in the groundwater and
815 pounds sorbed to the aquifer matrix (based on a retardation coefficient of 1.75). Over 75%
of the contaminated zone in the TSA contains TCE concentrations of less than 50 ng/L, and
greater than 90% of the contaminated zone contains TCE concentrations of less than 100
jig/L
7.2 Common Elements of Alternatives
Five remedial alternatives were developed by Boeing and Cascade in the FS for the TSA, and
DEQ analyzed four variations of theif Alternative 5. These alternatives were all developed
under the FS supported assumptions that restoration of the TSA to MCLs in a reasonable
timeframe is feasible, and that the time for restoration can be estimated, based on travel times
derived from the numerical groundwater flow model developed for the site and the batch flush
model explained below.
Groundwater restoration in the alternatives theoretically occurs as a result of a very simple
concept: contaminated groundwater is replaced with clean water. In all alternatives except for
alternatives 1 and 2. the contaminated water is actively extracted through extraction wells and
clean water is drawn in from beyond the perimeter of the plume toward the extraction wells. In
alternatives 1 and 2 the contaminated groundwater passively discharges via natural processes
to the Columbia Slough and other surface water bodies. The rate at which aquifer restoration is
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achieved, in those cases where restoration is possible, is related to the rate at which clean
water replaces the extracted water.
The prediction of restoration times for the various remedial alternatives has associated with it a
large uncertainty. The cause of this uncertainty has been well discussed in a number of articles
and texts (for example. National Research Council, 1994). The FS used the batch flush method
as a means of estimating restoration times. This method is the one most commonly used for
estimating aquifer cleanup times, but as noted, these estimates have a large uncertainty
associated with them. The batch flush method essentially relates the restoration time to how
quickly clean water is flushed through the aquifer. The rate of flushing of clean water is defined
as the time required to remove one volume of contaminated water from the aquifer.
Each of the remedial alternatives, except for the no action alternative, have several common
components. All of the alternatives: 1) assume that remedial actions in the TGA will effectively
eliminate contaminant migration to the TSA; 2) include an interim removal action for the SGA;
3) provide an alternate water supply to existing well users within the TSA VOC plume; 4)
implement groundwater use controls until TSA restoration is complete; and 5) provide for
performance groundwater monitoring. Interim actions for the TGA are discussed in Section 4.5.
Final remedial actions for the Boeing and Cascade facilities will incorporate these interim
measures, as well as additional remedial components. The remaining common remedial
components are discussed below.
7.2.1 SGA Interim Removal Measures
As discussed in Section 5. four water supply wells have low levels of VOCs. To correct this
problem, which is believed to be due to leakage along the well casings, six SGA wells will be
abandoned, or partially abandoned for conversion to TSA monitoring wells to evaluate remedy
performance. They are:
• The Handy well (PMX-195) owned by Silent Creek Joint Venture;
• The Shepard well (PMX-207) owned by Sandy Boulevard Development Corp. (a
subsidiary of Cascade);
• Two supply wells owned by Sandy .Mobile Villa (PMX 208 and .409);
• A supply well owned by Terrand Mobile Terrace (PMX 410); and
• A supply well owned by Cherry Blossom Manor (PMX 225).
The locations of these wells are shown" in Figure 3-2b.
7.2.2 Alternate Water Supply
An existing public water supply system would be extended to serve residences with
groundwater wells in the area affected by the TSA VOC plume, to prevent ingestion of TSA
groundwater that contains VOCs above MCLs. Six TSA domestic water supply wells (PMX-
196. PMX-345. PMX-417. PMX-434, PMX-189 and PMX-198) would be connected to the City of
Fairview municipal water supply system (refer to Figure 3-2a for well locations). These wells
would either be abandoned to prevent future use or maintained for remedy performance
monitoring. The Terrand Mobile Terrace mobile home park would also require an alternate
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water supply. This will be provided in 1996 and will come either from the Rockwood Water
District municipal supply or from a new supply well completed in deeper zones in the SGA.
7.2.3 Ground water Use Restrictions
All of the remedial alternatives, except for the no action alternative, place restrictions on
groundwater use within the area of contamination. The goal of these restrictions is to prevent
the spread of contamination in the TSA or the SGA during remediation. The FS indicated that
those restrictions could be accomplished through rules of the Oregon Water Resource
Commission designating the area a "critical groundwater area" pursuant to ORS 537.730.
7.2.4 Performance Monitoring
Each of the alternatives would include monitoring of water levels and water quality of the TSA
and SGA during remedy implementation, to assess progress on restoration of the TSA, and to
assess control of the spread of contamination during pumping of the Portland Water Bureau
South Shore Well Field. Wells would be monitored semi-annually for up to the first 5 years. The
groundwater would be analyzed for VOCs. Section 9 describes the performance monitoring
components for the selected remedy.
7.3 Description of Alternatives
7.3.1 Alternative 1
Alternative 1 is a no action alternative. This alternative has no active remedial components, and
does not include monitoring for the TSA. The no action alternative is retained for consideration,
as required by the 1994 Consent Order, Oregon administrative rules, and consistent with the
NCR. This alternative does not meet the RAOs described in Section 6.1.
7.3.2 Alternative 2
Alternative 2 would implement institutional controls along with the following components:
• Monitoring to identify and prevent potential exposure to the affected groundwater, to
evaluate impacts on the VOC plume from PWB pumping, and to assess progress toward
achieving the RAOs for the TSA;
• Providing alternate water supplies to serve residences with groundwater wells in the area
affected by the TSA VOC plume; and
• Applying groundwater use restrictions in and adjacent to the TSA plume area.
This alternative would rely on the TGA source controls described above and on natural aquifer
processes to achieve aquifer restoration.
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Restoration Time Frame. The time for achieving restoration has been estimated as
significantly greater than 100 years.
7.3.3 Alternative 3
Alternative 3 includes the components described for Alternative 2 and adds groundwater
extraction for hydraulic control of the TSA contaminant plume, and treatment and discharge of
treated groundwater to surface water. The goal of these additional actions is to prevent further
spread of the VOC plume in the TSA. The main additional components in this alternative are
described below.
Groundwater Extraction. The groundwater hydraulic control system would include installation
of 3 new extraction wells and 1 existing TSA extraction well (RPW-2). The system would
prevent the spread of the VOC plume in the TSA and protect groundwater quality in the SGA
and BLA to the extent practicable during baseline conditions (non-pumping of PWB south shore
well field). The extraction system would provide limited aquifer restoration during nonpumping
conditions. The wells would have a total extraction rate of approximately 300 gallons per minute
(gpm). A conceptual layout of the extraction wells is presented on Figure 7-1.
Groundwater Treatment and Disposal. Groundwater would be treated with an air stripper to
remove VOCs. The locations and treatment system configurations would be evaluated during
final design. Discharge from the treatment system would be conveyed to the Columbia Slough
or other surface waters in the vicinity. Contaminant discharge limits and monitoring
requirements for the treated water would be in accordance with DEQ rules.
Restoration Time Frame. Although the primary objective of this alternative is hydraulic
control, water quality within the aquifer would gradually improve. The time for achieving full
restoration has been estimated as significantly greater than 100 years.
7.3.4 Alternative 4
Alternative 4 includes all the components of Alternatives 2 and 3 as well as additional extraction
wells to increase the total groundwater extraction rate. The goals of Alternative 4 are to
prevent spreading of contamination, to minimize the areal extent of the TSA that contains
VOCs above MCLs (i.e., restore portions of the aquifer), and to provide long-term containment
for those areas where concentrations remain above MCLs.
Groundwater Extraction. The groundwater extraction system would provide additional
extraction wells and an increased rate of the groundwater extraction, relative to Alternative 3.
The groundwater extraction system would include six new extraction wells, one existing TSA
extraction well (RPW-2). and one monitoring well (MW-24) converted to an extraction well. A
conceptual layout of the extraction wells is presented on Figure 7-2. Existing wells RPW-2 and
MW-24, completed in the TSA conglomerate, would be incorporated into the system along with
three new wells installed in the TSA sandstone and three new wells in the TSA conglomerate.
The conceptual operating scenario includes groundwater extraction at a total rate of
approximately 500 gpm during PWB non-pumping, and increased extraction during PWB well
field operation.
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Restoration Time Frame. Although the primary objectives of this alternative are plume
reduction and long-term ^containment, this alternative would eventually restore the aquifer to
MCLs. The time for achieving restoration was estimated as 50 to 60 years in the FS. However.
DEQ estimates that about 85 years would be required to restore 80% of the contaminated
aquifer volume to MCLs.
7.3.5 Alternative 5
Alternative 5 would incorporate all the components of Alternatives 2 through 4 and provide
additional extraction wells and an increased total groundwater extraction rate for restoration of
the TSA to MCLs in a reasonable timeframe.
Groundwater Extraction. The details of the groundwater extraction system would be
developed during remedial design activities. Based on existing data, the groundwater
extraction system would include 12 new and one existing TSA extraction well and one
converted existing monitoring well (MW-24) with a total extraction rate of about 1,100 gpm. A
conceptual layout of the extraction wells is presented on Figure 7-3. The existing wells RPW-2
and MW-24, completed in the TSA conglomerate, would be incorporated into the system, along
with four new wells installed in the TSA sandstone and eight new wells in the TSA
conglomerate.
Groundwater Treatment and Disposal. The FS identified air stripping as the primary
treatment technology. Advanced oxidation treatment (e.g., ultraviolet radiation, ozone and/or
hydrogen peroxide) and beneficial reuse of treated groundwater for public water supply were
retained for further evaluation during remedial design. Reinjection/reinfiltration of treated
groundwater was also retained for evaluation during remedial design, but was not developed
specifically with reinjection/reinfiltration as a component.
Restoration Time Frame. The FS provided estimates indicating Alternative 5 would restore
75% of the TSA to MCLs within 20 years. DEQ has estimated, however, that with the well
locations shown on Figure 7-3 and the preliminary estimates of the extraction rates for these
wells, 80% of the.TSA would be restored to MCLs in 24 years, and 90% would be restored to
MCLs in 35 years.
7.3.6 Other Remedial Alternatives
DEQ evaluated four additional remedial action alternatives, beyond those evaluated in the FS.
The evaluation of these alternatives is documented in a memorandum from Charles Andrews of
S.S. Papadopulos & Associates, to Bruce Gilles of DEQ, dated June 12, 1996. These
additional alternatives are all variations of Alternative 5 with the only differences being the
number of extraction wells and extraction rates, and in one of the additional alternatives, the
addition of reinjection wells. These additional alternatives were developed to evaluate the
preliminary design for Alternative 5 provided in the FS, and determine whether restoration times
faster than those predicted for Alternative 5 are feasible. The additional alternatives that were
evaluated are described below.
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Alternative 5A. The primary objective of this alternative, is to evaluate the preliminary design
for Alternative 5. This alternative consists of extraction wells placed along the centerline of the
contaminant plume in the TSA conglomerate. This alternative has 4 TSA sandstone wells and
13 TSA conglomerate wells. Total pumping from the sandstone is 350 gpm, and total pumping
from the conglomerate is 813 gpm. The location of the TSA conglomerate extraction wells are
shown on Figure 7-4. The TSA sandstone extraction wells are as described for Alternative 5.
This alternative was initially designed to have identical pumping rates as those in Alternative 5.
The additional pumping from the conglomerate above that in Alternative 5 occurs near the
Columbia Slough north of the existing TSA recovery well RPW-2. Cleanup times north of RPW-
2 are relatively slow in Alternative 5. and the placement of an additional conglomerate
extraction well in this area greatly increases the rate of cleanup.
Alternative SB. This alternative has well locations identical to those in Alternative 5A. The
total pumping rate from the sandstone wells is the same, but the pumping rate from the
conglomerate is 20% greater or 970 gpm. The objective of this alternative is to evaluate
restoration effectiveness and reduction in restoration time frames which might be realized
through increased groundwater extraction.
Alternative 5C. This alternative has the same total pumping rate as Alternative 5B. Nineteen
conglomerate extraction wells are specified, rather than 13 (Figure 7-5). The additional wells
reduce the amount of TSA groundwater drawdown near the wells and shorten the travel time for
contaminated-groundwater capture^ This-altemative^wasrdevelopedc ia-party la-ascertain, the^
sensitivity of total remediation costs to the number of wells.
Alternative 6. This alternative uses reinjection of treated water to shorten the estimated
restoration times. The total pumping rate for this alternative is 1.185 gpm from 18
conglomerate extraction wells and 350 gpm from 4 sandstone extraction wells. The injection
rate into the conglomerate is approximately 250 gpm using 4 injection wells. The locations of
the extraction and injection wells are shown on Figure 7-6.
The amount of extraction from the TSA conglomerate is limited by the available drawdown in
the aquifer. Based on model calculations, all of the alternatives are technically feasible.
However, it is possible that actual field conditions will be different than those assumed in the
model.
Restoration Time Frames. The estimated time to restore 80% of the TSA to MCLs is 20 years
for Alternative 5A, 17 years for Alternative 58, 15 years for Alternative 5C and 12 years for
Alternative 6. These cleanup times are faster than the estimated 24 years required to restore
80% of the TSA to MCLs for the extraction well locations and rates described for Alternative 5.
The estimated time to restore 90% of the TSA to MCLs for Alternatives 5. 5A, 5B. 5C and 6 are
35 years, 26 years, 22 years, 20 years, and 16 years, respectively.
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7.4 Screening of Alternatives
In the FS, Alternatives 2 and 3 were eliminated from further consideration, because they did not
satisfy the RAOs summarized in Section 6.1. Alternative 1, the no-action alternative, was
retained to provide a baseline for evaluating the remedial alternatives against the protection and
feasibility requirements in OAR 340-122-090. Section 8 summarizes the evaluation of
alternatives, including the 4 supplemental alternatives developed by DEQ.
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8. EVALUATION OF REMEDIAL ACTION ALTERNATIVES
This section presents a comparative evaluation of Alternatives 1, 4. 5, 5a, 5b. 5c and 6 with
respect to the remedy selection criteria in OAR 340-122-090 and the NCR requirements
(40 CFR § 300.430 (a)(2)(e)(iii)). As discussed in Section 7, Alternatives 2 and 3 were
eliminated from further consideration because they did not adequately satisfy the RAOs which
identify how requirements in Oregon rules (OARs) and the NCR would be met. The comparative
analysis includes a description of the strengths and weaknesses of the alternatives relative to
one another for these criteria. The following sections, which detail the comparative evaluation
of alternatives, provide the basis for the selected remedial alternative described in Section 9.
8.1 Protection and Feasibility Requirements
8.1.1 Overall Protection of Human Health and the Environment
The evaluation of this criterion is based on how the remedial alternatives satisfy RAO-a through
RAO-e which are presented in Section 6.1. RAO-a and RAO-b address protection of human
health. RAO-c through RAO-e address protection of the environment which includes both
ecological receptors and uncontaminated groundwater resources in east Multnomah County.
The evaluation considers protection of human health and the environment under current
conditions (e.g.. the existing domestic wells within the TSA VOC plume) and future conditions
(e.g.. existing or new domestic and municipal wells inside and outside of the VOC plume and
wells that could be impacted under PWB pumping conditions including the RFM or emergency
use scenarios).
Alternatives 5 through 6 provide the greatest level of protection of human health and the
environment. They include a combination of restoration of the TSA, abandonment of wells and
alternate water supply to prevent current exposures to contaminated groundwater, use of
institutional controls including groundwater use restrictions, and monitoring, to reduce the
potential for future human exposure to'contaminated groundwater.
Alternative 4 generally satisfies the RAOs for protection of human health. Alternative 4 is
considered less protective than Alternative 5 because the increased length of the restoration
time frame results in a considerable increase in the potential for groundwater quality in the SGA
to be affected by migration of contaminants from the TSA where CU2 is thin or absent.
Alternative 1 is not protective of human health and the environment because it does not
eliminate existing exposures and does not prevent or control further impacts to groundwater
resources in east Multnomah County.
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8.1.2 Use of Permanent Solutions and Alternative Technologies
Alternatives 5, 5a, 5b, 5c and 6 are expected to result in permanent aquifer restoration.
Alternative 6 would result in the greatest removal of VOCs from the TSA groundwater in the
shortest time frame. Alternative 4 would result in a slower rate of VOC mass removal from the
TSA, which could result in permanent aquifer restoration, although it would require a
significantly longer time frame. No alternative cleanup technologies (e.g. physical barriers) are
included in Alternatives 4 through 6. .
Alternative 1 would not provide a permanent solution.
8.1.3 Cost-Effectiveness
The estimated costs for each remedial alternative are summarized in Table 8-1. The cost
estimates have an order of magnitude accuracy (approximately -30 percent to +50 percent of
estimated costs) and are primarily intended to compare the estimated cost of an alternative
relative to other alternatives. The estimated cost of the alternative includes the capital
construction costs and the operation and maintenance (O&M) costs for the duration of the
action.
The evaluation of cost-effectiveness includes the following criteria :
• The cost of a remedial action relative to the costs of another remedial action option
that achieves the same concentration level;
• The extent to which the remedial action's short term and long term incremental costs
are proportionate to its incremental results; and
• The extent to which the remedial action's short term and long term total costs are
proportionate to its total result.
Alternative 4 has the lowest cost and rates highest under the first criterion, followed by
Alternatives 5. 5b, 5a, 5c and 6. The increases in capital costs are related to the increased
number of extraction or injection wells, treatment system(s). conveyance piping, easements and
contingencies (35 percent of total cost). Generally, those alternatives with lower capital costs
have higher O&M costs due to the longer time frame to restore the TSA.
For evaluation of the second criterion, DEQ compared the relative rate of VOC mass removal in
pounds per year (incremental result) against the relative increase in short term costs (capital
costs) and long term cost (O&M costs) between Alternatives 4 and Alternative 5, and between
Alternative 5 and Alternatives 5a, 5b, 5c and 6. The objective of this analysis is to determine
whether the incremental capital investment provides proportionate benefits in the short term
(increased mass removal resulting in reduced volume of TSA plume) and reduction in long term
cost for O&M. As shown in Table 8-1, the incremental increase in capital costs between
Alternatives 4 and Alternatives 5 is proportionate to the incremental increase in mass/volume
removal. This holds true for the same comparison between Alternative 5 and Alternatives 5a.
5b and 5c. The increase in capital cost between Alternative 5 and Alternative 6 becomes
somewhat disproportionate with the percent increase in mass/volume reduction, but not
significantly. The long term benefits in terms of decreased O&M are not realized for Alternative
6, largely due to significant maintenance costs for injection wells assumed in the cost estimate.
EMC Record of Decision 12/19/96 Q_2
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For evaluation of the third criterion, DEQ evaluated the short term and total costs against the
incremental difference in time to achieve restoration of the TSA plume (total result). This
evaluation shows that the decrease in cleanup time between Alternative 4 and Alternative 5,
and between Alternative 5 and Alternatives 5a through 6. is proportionate to the short term.
and total costs.
In summary, Alternatives 5 through 6 are cost-effective in comparison to Alternative 4, as is
Alternative 5a and 5b and 5c in comparison to Alternative 5. Alternative 6 is less cost-effective
than Alternative 5 under the first two criterion, but is cost-effective under the third criterion.
However, Alternative 5 will likely require more wells than those identified which would make the
differential between Alternative 5 and Alternative 6 less than shown.
Alternative 1 is not cost-effective, because it does not achieve any contaminant mass or volume
reduction.
8.1.4 Effectiveness
In evaluating whether a remedial action alternative is effective, DEQ considers:
• the expected reduction in toxicity, mobility and volume of contaminants;
• the short-term risk posed to the community, workers and the environment during
implementation of the alternative;
• the length of time until full protection is achieved;
• the magnitude of residual risk in terms of amounts and concentrations of hazardous
substances remaining following implementation of the alternative;
• the type and degree of long-term management required including monitoring and
O&M;
• the long term potential for exposure to remaining contaminants;
• the long term reliability of engineering or institutional controls; and
• the potential for failure of the remedial action.
In addition to these criteria, DEQ evaluated RAO-f under the effectiveness criteria to determine
to what extent existing uses of groundwater resources are restored by the remedial
alternatives.
Reduction in Toxicity, Mobility and Volume. To evaluate reduction in toxicity, mobility, and
volume of contaminants, DEQ estimated the initial VOC mass removal rates from the TSA (see
Table 8-1), and the reduction in size or area of the TSA contaminant plume over time.
Alternative 6 would provide the greatest reduction in toxicity, mobility and volume in the shortest
timeframe with and estimated 315 pounds of TCE being removed in the first year (Table 8-1).
Alternatives 5b and 5c provide nearly equivalent initial mass removal rates estimated at 310
pounds. Alternative 5a is predicted to removed less VOCs than Alternative 5b or 5c but more
than Alternative 5. Alternative 4 is predicted to remove approximately half the amount of VOCs
as Alternative 5 in the first year.
Alternative 6 is predicted to reduce the areal extent of the plume in the shortest timeframe, with
the area north of Sandy Boulevard and the western half of the Boeing facility being restored in
10 years and the remaining portion of the plume restored in approximately 20 years.
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Alternatives 5b and 5c are predicted to reduce the size of the plume similar to that of Alternative
6 with the exception of the ISA mound area. Alternative 5 and 5a reduce the areal extent of
the plume in a longer timSframe than Alternatives 5b through 6. No significant reduction in the
areal extent of the ISA plume is expected from Alternative 4 in 20 to 30 years. Alternatives 5
through 6 would likely provide a .greater degree of hydraulic control of the VOC plume during
PWB wellfield operation than Alternative 4. Alternative 1 would not achieve reduction in VOC
mass except through natural attenuation.
Short-term Risk. The short-term risks associated with remedy implementation are slightly
greater for Alternatives 5 through 6, which have a greater degree of construction activities (e.g.,
installation of extraction wells) as compared to Alternative 4. However, short-term risks could be
controlled by the use of appropriate construction techniques and health and safety procedures.
Time to Full Protection. Alternative 6 would achieve full protection through aquifer restoration
in the shortest timeframe (16 years for 90% restoration), followed by Alternative 5c, 5b. 5a and
5 respectively. Near-term protection would be achieved by providing alternate water supplies
and institutional controls to prevent exposure to TSA groundwater.
Residual Risk. Alternatives 4 through 6 are all designed to restore the TSA to MCLs and
therefore result in the same residual n'sk (10"6). As noted above, the primary difference
between these alternatives is the time necessary to achieve MCLs: Alternative 1 would
maintain relatively high residual risks of human exposure to VOCs in TSA groundwater.
Type and Degree of Long-Term Management All the alternatives have similar requirements
in terms of monitoring, and operation and maintenance of the groundwater pump and treat
systems. Alternative 4 involves fewer wells and associated treatment facilities but would need
to be managed for 60 to 80 years. Alternatives 5 through 5c have comparable long term
management requirements. Alternative 6 would have the highest level of management
requirements related to maintenance of injection wells and monitoring to ensure hydraulic
control of reinjection areas.
Reliability. Alternatives 5 through 5c are considered highly reliable and are unlikely to require
replacement. Alternative 6 is considered slightly less reliable because the technical feasibility of
reinjection of treated groundwater would need to be pilot tested. The likelihood of failure,
however, is considered low because the TSA groundwater does not contain high levels of
dissolved minerals or nitrates that might lead to clogging, of injection wells. Alternative 4 is
considered the least reliable because it may be ineffective in controlling the spread of TSA
contaminant plume during PWB pumping of the South Shore Well Field.
The reliability of institutional controls has a high degree of uncertainty. The reliability of
designation of the critical groundwater area (see Section 7.2.3) in controlling use of the TSA
during restoration would need to be evaluated over time.
Allowing Existing Uses of Groundwater Resources. Alternatives 5 through 6 would allow
the greatest amount of existing use of groundwater resources. DEQ evaluations indicate that
these alternatives would allow unrestricted use of the PWB supply wells in the TSA and BLA
aquifers without adversely spreading the TSA contaminant plume during remediation. The PWB
TSA and BLA wells reportedly can produce up to 60 million gallons per day. However, pumping
from the PWB's SGA supply wells, especially wells 7. 8, and 14, results in significant
depression of water levels in the SGA beneath the TSA contaminant plume including areas
EMC Record of Decision 12/19/96 Q_4
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where the TSA conglomerate is contaminated and CU2 is either thin or absent (see Figures 3-3
and 3-8). To minimize potential contaminant transport from the TSA to the SGA in these areas,
.average hydraulic gradients between the TSA and SGA would need to be maintained upward.
DEQ has determinedjthat Alternatives 5 through 6 could achieve this criteria, if the PWB uses a
risk management approach to operation of its SGA wells. Vertical gradients between the SGA
and the TSA can be maintained upward on an annual average basis during remedy
implementation if all SGA supply wells (equivalent to 33 million gallons per day) are pumped
up to 60 days, and if all SGA supply wells except wells 7, 8 and 14 (equivalent to 30 million
gallons per day) are pumped up to 90 days on an annual basis. Alternative 4 would be less
effective in restoring existing use of SGA pumping from the South Shore Well Field than
Alternatives 5 through 6. Alternative 1 would be ineffective in allowing existing uses of
groundwater without detrimental effects to groundwater resources in EMC.
8.1.5 Implementability
Alternative 1 has no actions to implement. Alternatives 4 through 6 would be implemented with
established construction techniques, would also have high operational reliability (extraction
wells and treatment systems) with regularly scheduled maintenance, and would require
authorization from state and local agencies for construction and for discharge from treatment
systems.
Alternatives 5 through 6 may have significant implementability issues involved with
abandonment of private supply wells, and/or placement of extraction wells and necessary
conveyance piping on private properties. Although alternate water supplies are readily
available in the area through Rockwood Water District or the city of Fairview, private parties
may refuse to have their wells abandoned and to accept an alternate water supply, or may
refuse access for remediation. Generally, the alternatives with more wells on private properties
(e.g. Alternative 5c and 6) are likely to be the most difficult to implement.
Alternative 6 would potentially require the shortest duration of groundwater use controls.
Alternatives 4 and 5 included designation of a Critical Groundwater Area by the Oregon Water
Resources Commission. This process requires rule making which would likely take a
considerable time period, could face public opposition, and have an uncertain outcome. It is
unclear that this is a workable mechanism for achieving groundwater use controls. An
appropriate mechanism will be determined during the remedial design stage.
8.1.6 Compliance with Other Regulatory Requirements
Each of the alternatives has been developed to comply with all other regulatory requirements
including NPDES. RCRA and air quality. In addition, federal requirements in CERCLA and the
NCP were also considered.
EMC Record of Decision 12/19/96 3.5
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8.2 Evaluation Summary
Alternatives 5 through 6 satisfy the protection and feasibility requirements in OAR 340-122-090.
The evaluation of these alternatives indicates that Alternative 5 can be designed to satisfy the
RAOs for the site and to restore the TSA in a reasonable time frame of 20 years, by refining the
number and location of extraction wells and implementing of reinjection of treated groundwater:,
in a cost-effective manner.
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9. THE SELECTED REMEDIAL ACTION
DEQ has selected Alternative 5. modified as discussed below, as the remedial action
alternative for cleanup of the TSA. The selection is based on the evaluation and comparison of
remedial alternatives presented in Section 8 and consideration of public comment on the
recommended remedy. Alternative 5 is modified by increasing the number, location and
extraction rates for extraction wells, similar to DEQ Alternatives 5b, 5c and 6. Institutional
controls will be implemented during remediation to prevent exposure to contaminated TSA
groundwater or adverse spread of contamination due to pumping. The estimated cost for the
selected remedy is $9 to $11 million. The capital costs are estimated to range from $4 million
to $5 million, and long-term operation and maintenance costs from $5 million to $6 million.
The goal of the remedial action is to restore groundwater to its beneficial use, which at this site
is a drinking water source. The cleanup levels to be achieved by the remedy are the drinking
water MCLs presented in Table 6-1. Based on a careful analysis of all remedial alternatives,
DEQ believes the selected remedy, with appropriate modifications, can restore the TSA to
these levels in 20 years and significantly reduce the areal extent of contamination exceeding
MCLs in 10 years.
Section 9.1 provides a detailed description of the selected remedial alternative. Section 9.2
describes how the selected alternative satisfies the remedy selection criteria in DEQ's current
rules and is consistent with the NCR and Oregon's revised environmental cleanup law.
9.1 Description of Selected Alternative
Components of the selected alternative include groundwater extraction from the TSA,
treatment of extracted groundwater using air stripping technology, discharge of treated
groundwater to surface water and, if feasible, reinjection of treated groundwater into the TSA,
and performance monitoring. The remedy includes additional protective measures, including
abandonment of supply wells in the SGA, institutional controls, and contingency measures.
Each of these components is described below.
9.1.1 Aquifer Restoration Pumping
The selected remedy includes groundwater extraction for an estimated period of 20 years. The
aquifer restoration pumping will extract sufficient groundwater to meet the following
performance criteria:
• Maintain horizontal hydraulic control of the TSA contaminant plume exceeding the
MCL cleanup levels;
EMC Record of Decision 12/19/96 g.-|
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• Maintain an upward hydraulic gradient between the TSA and SGA where the ISA
conglomerate-is contaminated at levels equal to or exceeding MCLs and the
confining layer separating the ISA and SGA is thin or absent; and
• Remove at least 350 gpm from the ISA sandstone and at least 970 gpm from the
TSA conglomerate, on a monthly average basis.
The remedy will include sufficient groundwater monitoring points at the perimeter of the plume
to demonstrate that the horizontal gradients are inward toward the extraction wells on an annual
average basis, and will include sufficient monitoring wells to demonstrate that the vertical
gradient is upward on an annual average basis. The horizontal gradient criteria shall apply at
all times. The vertical gradient criteria shall apply at all times with the following exceptions:
when all of the PWB's SGA supply wells are operated for a continuous period of more than 60
days; when the PWB's SGA wells with the exception of wells 7, 8, and 14 are operated for a
continuous period of more than 90 days; and when an equivalent level of pumping from a
subset of the PWB's SGA supply wells occurs. The contingency plan described in Section 9.1.5
shall be implemented when an emergency affecting the City's primary water supply
necessitates continuous operation of all PWB wells for more than 60 days.
The spatial distribution of extraction will be similar to that described for Alternative 5B and 5C.
Subject to DEQ approval, specified minimum groundwater extraction rates may be adjusted
annually based on the current volume of water exceeding the MCL cleanup levels (e.g..
extraction rates may decrease proportionate to the decrease in plume size and volume). The
specified minimum extraction rates ensure that the remedy is designed to:
• Restore groundwater in the TSA sandstone and conglomerate to MCLs within 10
years of implementation of Phase 2 of the remedy in the area north of Sandy
Boulevard, and in the area south of Sandy Boulevard, east of 205th Avenue, and
west of a north-south trending line from well BOP-44 to DEQ-5, as shown in Figure
9-1; and
• Restore the remaining portion of the TSA sandstone and conglomerate to the MCL
cleanup levels within 20 years of implementation of Phase 2 of the remedy.
The number of wells and well locations for the extraction wells that will be used for aquifer
restoration will be determined during the remedial design phase and remedy implementation,
but 17 to 22 extraction wells will likely tie required, as shown on Figure 9-1.
The remedial design activities will include an evaluation of the following three components for
achieving the performance criteria for the selected remedial alternative:
• Evaluate the number of extraction wells needed to extract the specified minimum
total pumping rates, their locations and individual pumping rates;
• Evaluate the technical feasibility and implementability of reinfiltration or reinjection
and assess whether this technology should be integrated into the remedy to
accelerate aquifer restoration; and
EMC Record of Decision 12/19/96 g_2
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• Evaluate beneficial reuse options and appropriate treatment or conveyance
requirements for the extracted groundwater.
Remedial design will be performed concurrently with remedy implementation. The remedy will
be implemented in three phases.
Phase 1 Early Implementation. Phase 1 implementation began in 1996. and includes the
following actions:
• Providing an alternate water supply to Terrand Mobile Terrace mobile home park,
which currently obtains its water from SGA supply well PMX-410;
• Abandonment, or conversion to monitoring wells, six SGA supply wells (PMX-195, -
207,-208.-225, 409, and-410);
• Installation of one TSA monitoring well and two SGA monitoring wells to further
characterize the extent of groundwater contamination in those aquifers;
• Collection of water samples from the TSA and/or SGA during the abandonment of
SGA supply wells, to obtain additional water-quality data for those aquifers in the
area of the TSA VOC plume, and resolve uncertainties;
• Installation of at least three TSA extraction wells and conversion of two existing
monitoring wells to TSA extraction wells, performance of aquifer tests, design and
installation of groundwater treatment and discharge systems, and initiation of
groundwater extraction and treatment from these wells.
Phase 2 Implementation. The second phase of remedy implementation shall involve
installation of all the additional extraction wells required to achieve the performance criteria
described above. An additional 10 to 12 extraction wells are likely to be required at the locations
shown in Figure 9-1. Detailed remedial design activities will evaluate a range of extraction well
locations and numbers, and reinjection, for effectiveness and implementability (e.g., site
access constraints).
Phase 3 Implementation. Phase 3 shall be implemented if; after the remedy has operated for
three to four years, the aquifer monitoring data indicate that the restoration time frames
described above are unlikely to be obtained. The likelihood of obtaining the restoration time
frames will be assessed by projecting the best fit line to the logarithms of average annual
aquifer concentration as a function of time; or an equivalent method. This phase would
optimize and enhance the performance of the remedy by improving the rate of aquifer flushing.
Modifications may include any or all of the following:
• Installation of additional extraction wells to expedite restoration of the TSA;
• Alternating extraction at wells to eliminate stagnation areas within the aquifer;
• Pulse pumping;
• Reinjection or reinfiltration of treated groundwater, if technically feasible.
EMC Record of Decision 12/19/96 9.3
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The modifications would be such that the total groundwater extraction and injection rates do not
exceed those described for Alternative 6, as this alternative approaches the limits of feasibility
as defined in DEQ rules.
Performance Monitoring. A detailed monitoring plan will be developed during remedial design
to monitor system performance against the criteria described above. The plan shall include
performance monitoring at the perimeter of the TSA plume and in the underlying SGA to
address the remedy performance criteria including plume containment. Subject to DEQ
approval, the monitoring program may be modified to decrease monitoring locations based on
the progress of remediation, and shall be expanded if areas of TSA contamination beyond the
limits of contamination currently understood, or contamination in the SGA is discovered. The
performance monitoring program shall include, but not be limited to. the following:
Groundwater Elevation Measurements — Groundwater level measurements shall be taken at
the TSA monitoring wells shown on Figures 9-2 and 9-3, and at the SGA monitoring wells
shown on Figure 9-4. Measurements shall be taken continuously at selected wells with
electronic data collection systems, and periodically at other wells with hand-held equipment.
Continuous water-level monitoring will be conducted at 24 TSA well locations and 7 SGA well
locations. The TSA wells to be continuously monitored are near the boundaries of the VOC
plume, and the SGA wells are in areas where VOC concentrations in the TSA conglomerate are
above MCLs and CU2 is thin or absent, and groundwater flow is downward during pumping of
the PWB SGA wells. Manual groundwater level measurements shall be taken monthly at the
locations shown on Figures 9-2 through 9-4. and every two weeks when PWB pumps its SGA
wells.
Water-Quality Sampling — Semi-annual and annual water quality samples for VOCs will be
taken at the locations shown on Figures 9-2 through 9-4. The sampling schedule is listed on
Table 9-1. Monitoring for additional parameters in a subset of wells may also be required
during remedial design and remedy implementation to evaluate reinjection or beneficial reuse of
treated groundwater. The sampling program will be reevaluated annually and modified, if
appropriate, on the basis of the past year's performance.
Performance evaluation reports will be submitted to DEQ annually until Phase 3, if necessary,
is complete and operated for a period of two years, and at five year intervals thereafter.
Monitoring reports documenting compliance with hydraulic gradient criteria and groundwater
quality shall be submitted to DEQ annually during the entire period of remedy implementation.
At a minimum, the performance evaluations shall assess compliance with the remedy gradient
control criteria, document groundwater and VOC mass removal rates, assess TCE
concentration reductions, provide an assessment of the groundwater extraction and
performance monitoring network, and propose modifications to the pumping program (e.g.
variable or pulse pumping and eventually termination of groundwater extraction).
9.1.2 Groundwater Treatment
Extracted groundwater will be treated using one or more packed air-stripping treatment units
with a VOC removal efficiency of at least 95%. Advanced oxidation (ozone, peroxide, and/or
ultraviolet radiation) treatment may be used instead of air stripping treatment, if beneficial reuse
EMC Record of Decision 12/19/S6 Q_4
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of treated groundwater is implemented, to potentially eliminate the requirement for chlorination
of the water. The advanced oxidation treatment process must meet all applicable state and
federal performance standards for disinfection. The final number, location and capacity of the
treatment units will be determined during remedial design.
The remedial design shall evaluate VOC air emissions for each treatment system proposed to
be sited within 100 meters of residential properties. No treatment systems'shall be allowed
closer than 100 meters from a residential property, unless the VOC emissions assessment
demonstrates that VOC inhalation exposure would be less than 1 x 10"6 excess cancer risk.
9.1.3 Groundwater Disposal, Reinjection or Beneficial Reuse Requirements
Treated groundwater shall be discharged to surface water bodies and/or reinjected into the
TSA to enhance aquifer flushing. Discharge requirements will be specified in the consent order
for implementation of the selected remedy, pursuant to OAR 340-45-062 or in a permit.
Contaminant discharge limits will be established at the MCLs shown in Table 6-1. Groundwater
treatment is expected to reduce contaminant concentrations to below detectable levels of 0.5
ug/L. Treatment system effluent samples will be collected and analyzed monthly for VOCs, and
quarterly for nitrate and nitrite, orthophosphate, total phosphate, lead, and hardness.
Provisions will also be included in the order or permit for flow management or other measures
necessary to avoid violation of water quality standards related to a water quality-limited
parameter.
Boeing and/or Cascade may beneficially use treated groundwater for their respective industrial
processes or enter into agreements with local water districts or private parties to beneficially
use treated groundwater. Applicable requirements of the Oregon Water Resource Department
(WRD) and the Oregon Health Division must be satisfied prior to DEQ approval of these
actions.
9.1.4 Additional Protective Measures
Abandonment of Private SGA Water Supply Wells. As discussed in Section 7.2.1, six
existing private water wells completed in the SGA and located within the TSA contaminant
plume have been identified as potential pathways of contaminant migration between the TSA
and the SGA. These wells shall be abandoned in accordance with Water Resource Department
regulations. New replacement SGA supply wells designed with a telescoped seal between the
TSA and CU2 to prevent leakage of contaminated groundwater from the TSA to the SGA, may
be installed, subject to DEQ approval and satisfaction of the following criteria:
• Groundwater extraction rates are less than 15,000 gallons/day (gpd); or
• There is an existing water right for the well or user can obtain a water right if
groundwater use would exceed the 15,000 gallon/day exemption established under
WRD regulations; and
• The groundwater usage would not result in the reversal of vertical gradients between the
TSA and SGA on an annual average.basis where CU2 is thin or absent and the lower
TSA conglomerate is contaminated;
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Private TSA Water Supply Wells. ISA supply wells that have been contaminated at levels
exceeding MCLs (PMX^17 and PMX-198) will be taken out of service and supplied with
municipal water from the city of Fairview. These wells will be evaluated during remedial design
for possible conversion to extraction wells.
Institutional Controls. Institutional control components for the selected remedy include
monitoring of any existing supply wells within or in the vicinity of the TSA plume, provisions for
alternate water supply for existing groundwater users whose wells are or become contaminated
above MCLs, and restricting groundwater use in the area of the TSA contaminant plume. Each
of these institutional controls are described below.
Assessment — TSA supply wells PMX-196, PMX-345. PMX^134. PMX-189. and SGA supply
well PMX-192 will be evaluated to determine whether their continued use could spread the TSA
contaminant plume once Phase 2 of the remedy is operational. Well pumping that compromise
the remedy's horizontal or vertical hydraulic control shall be taken out of service, and provided
municipal water supply.
Monitoring — Monitoring of existing private water supply wells (including any replacement
supply wells discussed above) will be performed semi-annually for VOCs. In the event that
VOCs are detected at or above the MCLs. the well will be resampled within 6 weeks of the
initial sampling event. Municipal water supply shall be provided within 6 months for
groundwater users whose well has been confirmed to be contaminated at or above the MCL
Alternate Water Supply — All groundwater users whose wells are to be abandoned or taken out
of service shall be provided with municipal water supply. Extensions to existing water supply
mains and connections to individual users will be designed in coordination with the local public
water suppliers (e.g., the City of Fairview or Rockwood Water District).
Groundwater Use Controls — The selected remedy vertical gradient criteria is protective of
water quality in the SGA. To ensure overall protectiveness of the remedy, DEQ assumes that
the PWB will develop and implement wellfield operational strategies to minimize the threat to
the SGA aquifer, by. consistent with the ROD assumptions, limiting annual pumping of all of the
PWB's SGA supply wells to 60 days, or SGA wells except 7, 8 and 14 for 90 days, except in the
event of an emergency affecting the City's primary water supply from Bull Run. DEQ will
request that the PWB submit a pumping plan describing their well field operational strategies, to
facilitate implementation of this ROD and protection of the SGA.
During remedial design, DEQ, Boeing, Cascade, and other parties identified by DEQ. will
evaluate mechanisms to control use of groundwater within and in the vicinity of the TSA
contaminant plume. The objectives of these measures are to prevent exposure to
contaminated groundwater and/or spreading contamination to currently unaffected portions of
the TSA or to the SGA. Options which may be considered include designation of a Critical
Groundwater Management Area, modifications to comprehensive land use plans for the area,
coordination between DEQ and Oregon Water Resources Department (WRD) on water right
applications, and periodic review of start cards filed with WRD for well installations. If
necessary, other vehicles for groundwater use controls also will be developed.
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9.1.5 Contingencies
Contingency Plan forPWB Emergency Pumping. A contingency plan shall be developed
during Phase 2 of remedy implementation. The contingency plan shall be activated in the event
of an emergency affecting the City's primary water supply which necessitates continuous
operation of all PWB supply wells for more than 60 days.
The additional response actions to be incorporated into the contingency plan include:
• Increased extraction rates from TSA extraction wells to minimize the magnitude of
gradient reversal between the TSA and SGA where CU2 is thin or absent, and the TSA
conglomerate is, or becomes, contaminated, and to ensure horizontal hydraulic control
of the plume;
• Increased frequency of monitoring for TSA and SGA detection monitoring wells;
• Identifying the location for additional monitoring wells in the TSA and/or SGA and the
criteria and schedule for installation;
• Identifying locations, criteria and schedule for installation and operation of SGA
extraction wells to hydraulically control the spread of contamination if detected in the
SGA above MCLs.
The contingency plan will be reevaluated during remedy performance monitoring reviews and,
subject to DEQ approval, modified or terminated based on progress in the restoration of the
TSA.
Long- Term Containment Restoration of limited areas of the TSA may be technically
impractical to achieve within 20 years, due to on-going uncontrollable migration of VOCs from
the TGA to the TSA or due to asymptotic leveling of contaminant concentrations. In this event,
Boeing and Cascade shall provide long-term hydraulic control of these areas, to minimize the
area! extent of TSA contamination above MCLs.
9.2 Satisfaction of Protection and Feasibility Requirements
The selected remedy is protective of human health and the environment. Restoration of the
TSA to drinking water MCLs would" result in a residual excess lifetime cancer risk of
approximately 1 x 10"6 and a non-carcinogenic hazard index less than one, which is protective
of human health and would allow beneficial use. Restoration of the TSA to the MCL for TCE will
result in residual concentrations for the other VOCs that are well below their respective MCLs.
Alternate water supplies will be provided to existing groundwater users whose wells have been
contaminated at levels equal to or exceeding the MCLs. Institutional controls and contingency
measures will be utilized during the TSA restoration process, to control exposures to
groundwater contamination exceeding MCLs or the spread of contamination within the TSA or
to the SGA.
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9.2.1 Permanent Solutions and Alternative Technologies
The selected remedy wilt-permanently remove contaminants from soil and groundwater within
the TSA. Groundwater contaminant concentrations are predicted to be reduced to MCLs or
lower. Institutional controls and hydraulic control of portions of the TSA exceeding MCLs will be
maintained until cleanup levels are achieved.
9.2.2 Cost-Effectiveness
As discussed in Section 8.1.3, the selected alternative is cost-effective, because the
incremental and total costs are proportionate to the incremental and total results.
9.2.3 Effectiveness
Reduction in Toxicity, Mobility, and Volume. The selected remedy is expected to remove a
significant mass of VOCs from the TSA and significantly reduce the areal extent of groundwater
contamination exceeding MCLs.
Short-term Risks
Protection of Community During Remedial Action — The primary potential risk to the
community during implementation of the selected remedy is from air emissions from the
groundwater treatment systems. However, VOC emissions from groundwater treatment
systems will not be significant and will not pose an unacceptable risk to neighboring residents.
Protection of Workers During Remedial Action — Compliance with state occupational safety
and health codes, and enforcement of site health and safety plan provisions, will ensure the
protection of on-site workers during installation of the remedial systems. Operation,
maintenance, and monitoring of these systems pose only minimal risks to remediation workers.
Environmental Impact — The selected remedy is expected to effectively control potential
threats to water quality in the SGA. Contingency measures will minimize adverse impacts to
the SGA should they occur. No adverse ecological impacts are predicted from the discharge of
treated groundwater to surface water.
Time Until Full Protection Is Achieved-'— Full protection of human health through groundwater
restoration may take up to 20 years. Alternate water supplies to affected groundwater users,
and institutional actions to control future exposures, should be in place within 1 year of DEQ's
selection of a final remedy.
Magnitude of Residual Risk After Implementatinq Remedial Action — Based on the information
obtained during the RI/FS and the analysis of all remedial alternatives. DEQ believes that the
selected remedy will be able to achieve MCLs presented in Table 6-1.
Type and Degree of Long-term Management. Including Monitoring and Operation and
Maintenance. — Groundwater contamination may be persistent in the vicinity of the TSA
mound, and near the TGA outcrop north of Cascade, where concentrations are relatively high.
The ability to achieve cleanup levels throughout the plume area cannot be determined, until the
EMC Record of Decision 12/19/96 Q_8
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remedy has been implemented, modified as necessary, and plume response monitored over
time. The selected remedy will require intermediate to long-term groundwater monitoring.
Long-term operation and maintenance, and performance monitoring will be required. The
degree of long-term management will be reduced through time, as the areal extent of the
contaminant plume decreases.
Long-term Potential for Exposure of Human and Environmental Receptors to Remaining
Contaminants — The potential for exposure to contaminants remaining after completion of the
remedy is low. The selected remedy includes contingencies for long-term containment and
continued institutional controls, for those areas which cannot be restored to protective levels.
Potential for Failure of Remedial Action or for Need to Replace Remedy — The selected
remedy is not expected to fail or has a low potential for failure. As noted in Section 9.1.1,
modifications to the remedy may be necessary through time to improve performance.
9.2.4 Implementability
Degree of Difficulty. The technologies to be used are proven and readily implementable. A
pilot test on reinjection of treated groundwater into the TSA would be necessary, to evaluate
the effectiveness of this option and complete design specifications.
The selected remedy may have significant implementability issues involved with the
abandonment of private supply wells, and/or placement of extraction wells and necessary
conveyance piping on private properties. Although alternate water supplies are readily
available in the area through the Rockwood Water District or the City of Fairview, private parties
could refuse to have their wells abandoned or accept an alternate water supply, and/or may
refuse access for remediation activities. Private party agreements will need to be obtained, or
DEQ's statutory authorities may need to employed, if these private agreements cannot be
negotiated in a timely manner or are unsuccessful.
Expected Operational Reliability. The groundwater extraction and treatment technologies
that will be used for TSA restoration are commonly used, proven, and generally reliable. The
reliability of reinjection of treated groundwater would be determined through a pilot test.
Need to Coordinate with and Obtain Approval from Other Agencies. Implementation of the
selected alternative would involve DEQ's establishment of discharge requirements in a consent
order or permit, for groundwater disposal to surface water and reinjectjon, and should not pose
any significant delays or problems. Continued coordination with PWB on wellfield pumping will
be necessary to effectively implement horizontal and vertical control gradient criteria
components of the remedy. The Oregon Water Resources Department will need to issue water
rights or water rights transfers for beneficial reuse of treated groundwater.
Availability of Equipment and Specialists. Equipment for the groundwater extraction and
treatment system is readily available.
Available Capacity and Location of Treatment, Storage, and Disposal Services.
Hazardous wastes are not expected to be generated for off-site treatment, storage and/or
disposal.
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Ability to Monitor Effectiveness of Remedy. The selected remedy can be effectively
monitored and modifications implemented, to satisfy the remedy performance criteria.
Implementation of the monitoring program may require long-term access to private properties,
which can be obtained through private party agreements or DEQ's statutory authorities.
9.2.5 Compliance with Other Regulatory Requirements
Alternative 5 would comply with the regulatory requirements under the Clean Air Act, Clean
Water Act. Safe Drinking Water Act, and Resource Conservation and Recovery Act as follows:
Clean Air Act An Air Contaminant Discharge Permit would not be required for the air-stripping
treatment unit(s). VOC emissions from the treatment unit(s) would be approximately 2 orders
of magnitude below DEQ's significant emission rates for TCE. An air quality Notice of
Construction would be filed with DEQ, in accordance with OAR 340-20.
Clean Water Act DEQ will specify monitoring requirements for discharge of treated
groundwater to Fairview Lake or the Columbia Slough, through direct discharge or via
conveyance through the Multnomah County drainage system, in the consent order for remedy
implementation pursuant to OAR 340-45-062 or by NPDES permit The contaminant discharge
limits will be the MCLs specified in Table 6-1. Monitoring for nutrients (e.g., nitrate, nitrite, total
phosphate and orthophosphate), lead, and hardness will also be performed.
Authorization of reinfiltration or reinjection of treated groundwater into the TSA, to facilitate
flushing of contaminants, will be as described for surface water discharges.
Safe Drinking Water Act Beneficial reuse of treated groundwater for drinking water supplies
shall comply with all applicable requirements specified under OAR 333, Division 61.
Resource Conservation and Recovery Act The hazardous waste generator requirements
under 40 CFR Part 262 and OAR 340-100 do not apply to groundwater extracted from the TSA
under this selected remedy. Drill cuttings generated during extraction well installations in
source areas at the Boeing facility shall be characterized to determine whether they are a
hazardous waste. Soils determined to be hazardous waste will be managed in accordance with
applicable regulations under 40 CFR Parts 262, 263, 264 and 268. Soil drill cuttings from other
well installation locations may be used as clean fill at the Boeing or Cascade facilities.
CERCLA. The selected remedy satisfies remedy threshold and balancing criteria in CERCLA
and the NCP. The selected remedy is protective of human health and the environment, and
complies with all ARARs.
9.2.6 Consistency with Revised Oregon Environmental Cleanup Statutes
The State of Oregon's Environmental Cleanup Statutes (ORS 465.315 through 465.325) were
amended in 1995 by the 68th Oregon Legislative Assembly. Certain provisions became
effective July 18, 1995. Other provisions will not become operative until rulemaking by DEQ is
completed. DEQ, nonetheless, is required to select remedial actions consistent with the
purpose and intent of the revised statutes, to the maximum extent practicable within the bounds
EMC Record of Decision 12/19/96 9-10
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of existing cleanup rules. This section evaluates consistency of the selected remedial action
with the amendments in the statute.
Protectiveness. Under the revised statutes, the protectiveness of a remedial action is
determined by application of both acceptable risk levels prescribed by the statute and a risk
assessment undertaken for the site in question. This provision will not be fully operative until
rulemakino, is completed. The selected remedial action is nonetheless consistent with this
provision of the revised statutes and the current rules.
The acceptable risk levels prescribed by the revised statutes for human health are 1 x 1C"6
excess lifetime cancer risk for individual carcinogens and a hazard index of one for non-
carcinogens. The selected remedy restores the TSA aquifer to MCLs for drinking water which
are essentially equivalent to 1 x 10"6 excess cancer risk and below a hazard index of one for
non-carcinogens.
Treatment of Hot Spots. Once the revised statutes become fully operative, treatment of hot
spots of contamination will be required to the extent feasible. The TSA groundwater
contaminant plume is considered a hot spot because the TSA is currently used as a source of
residential drinking water supply, and the presence of contamination at concentrations
exceeding MCLs has an adverse effect on existing and reasonably likely future beneficial use of
both the TSA and SGA groundwater resources in eastern Multnomah County. The selected
remedy requires treatment of groundwater contamination at concentrations equal to or
exceeding MCLs.
Remedial Methods. The selected remedy is consistent with the remedial methods described
in the revised statutes, by including a combination of groundwater removal and treatment using
"presumptive or generic" remedies such as groundwater "pump and treat", institutional controls,
and other measures such as monitoring and maintenance.
Balancing Factors. Under the revised statutes, remedial actions selected by OEQ will balance
effectiveness, implementability, long-term reliability, short-term risk, and reasonableness of
cost. The evaluation included in Section 8.1 of this document includes consideration of each of
these criteria. Alternative 5 selected by DEQ provides the best balance against these criteria.
The increase in cost for modifications of Alternative 5 to accelerate restoration of the TSA is
reasonable, because the benefits (e.g., mass removal/risk reduction and time until full
protection is achieved) are proportionate to the increase in cost.
Land Use. The revised statutes requires DEQ to consider current and reasonably-anticipated
future land uses at the facility and surrounding properties when selecting a remedial action.
The selected cleanup levels for groundwater are based on current and future use of the TSA
aquifer as a source of residential drinking water supply.
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10. PUBLIC NOTICE AND COMMENTS
DEQ's notice of the proposed remedial action was published in the Secretary of State's
Bulletin on September 1, 1996, and in the Gresham Outlook and Oregonian newspapers
on September 14, 1996, and September 15. 1996. respectively. On September 1, 1996.
DEQ also mailed copies of a fact sheet and proposed plan (8-10 page summary of the
DEQ Staff Report) to people on the DEQ mailing list for the site. Copies of the DEQ
Staff Report describing the proposed remedial action, the Rl and FS Reports, and other
documents in the Administrative Record for the site were made available for public
review at DEQ headquarters in Portland and at the Rockwood Public Library. The 60
day public comment period began on September 1. 1996 and ended on October 30.
1996.
DEQ participated in several public meetings held during the public comment period to
describe aspects of the DEQ recommended remedial action for the Cascade
Corporation site and the Troutdale Sandstone Aquifer site:
• September 4, 1996 - Friends of Blue and Fairview Lake Community Group
• September 10, 1996 - Portland Water Quality Advisory Committee
• September 24, 1996 - Regional Water Supply Managers Meeting
• October 2. 1996 - Fairview City Council Meeting
• October 17, 1996 - Friends of Blue and Fairview Lake
DEQ held two public hearings to accept verbal comments from the general public on the
recommended remedial action for the TSA. DEQ issued press releases to the media
several days prior to the public hearings, to remind the public of the scheduled public
hearings. The first hearing was held on October 10, 1996. from 7:00 PM to 9:00 PM at
the Gresham City Council Chambers located . at 1333 N.W. Eastman Parkway,
Gresham, Oregon. The second public hearing was held on October 30. 1996, from 1:30
to 3:00 P.M. at DEQ Headquarters located at 811 S.W. 6th Avenue, Portland. Oregon.
Section 11 provides a summary of the public comments received on the proposed
cleanup plan for the TSA.
EMC Record of Decision 12/19/96 10-1
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11. CONSIDERATION OF PUBLIC COMMENTS
This section summarizes the verbal and written public comments received by DEQ on
the recommended remedial action for the TSA. The comments are summarized by
major topics followed by a detailed discussion of issues raised by the public or the
responsible- parties--and-DEQ's -response-, to-the issues- raised;--The-Administrative-
Record Index (Appendix A) identifies the comment letters received and any DEQ
response to individual comment letters.
11.1 Ambiguity of Recommended Remedy
Commenters: Columbia Corridor Association, Boeing, Cascade Corporation, City of
Portland, Oregon Environmental Council.
Comment Two parties commented that DEQ had not identified and evaluated the
feasibility of remedial alternatives that would achieve superior cleanup more rapidly.
Response: DEQ did evaluate more aggressive remedial alternatives than the
alternatives developed in the FS. DEQ believes that Alternative 5C and 6, which are
very aggressive remediation options, approach the limits of feasibility in terms of
groundwater extraction, contaminant mass removal rates and implementability. DEQ
concurs that the FS prepared by Boeing and Cascade, although it met the minimum
requirements specified in the consent order, did not make the case that Alternative 5
represented the best feasible remedial alternative. The variations of Alternative 5
developed by DEQ's contractor and under DEQ's direction, focused on improving the
design and predicted performance of Alternative 5.
Comment DEQ did not consider non-restoration costs and benefits, such as increased
or reduced impacts on beneficial uses of water, in its cost-effectiveness evaluation.
Response: These types of costs and benefits are not considered when evaluating the
cost-effectiveness of a remedy under state rules.
Comment Did the components of the alternatives evaluated comprise the universe of
activities that could be used to clean up such contamination?
Response: The FS evaluated a full range of treatment technologies and process
options potentially applicable to remediation of the TSA. Groundwater pump and treat is
the principal method employed to clean up groundwater contamination nationwide.
Reinjection of treated groundwater was retained for further evaluation as an option that
might increase aquifer flushing rates and groundwater extraction rates.
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Comment DEQ has set an extraction drawdown limit in the ISA, but has not
conducted any analysis or provided any explanation of why that limit was chosen.
Response: DEQ has not set an extraction drawdown limit in the ISA. However, DEQ
does believe that excessive drawdown of the saturated thickness of the TSA, to allow
some incremental increased pumping of the Portland South Shore Wellfield's SGA
wells, is counterproductive to effective remediation of the TSA because it would lead to
long term dewatering of the TSA leaving contamination trapped in void spaces in the
aquifer.
Comment The recommended alternative selected by DEQ is ambiguous, because it
does not identify a specific alternative, but instead relies on specific performance
criteria. This approach is misleading, because the impression is given that there is no
limit on the number, location or extraction rates for wells to be installed as part of the
remedy. Therefore, the final remedy should clearly indicate that the components
identified in Alternative 5 (and its variations, Alternative 5A through 6) serve as bounds
for the alternative.
Response: DEQ concurs. The recommended remedy was not intended to be open
ended. The groundwater restoration components of the final remedy include a minimum
groundwater extraction rate equal to the groundwater extraction rates in Alternatives
5B and 5C. The final remedy also indicates that modifications to Alternative 5 will not
result in total groundwater extraction and injection rates which exceed those described
for Alternative 6.
11.2 Proposed Cleanup Levels and Residual Risk
Commenter. City of Portland
Comment DEQ should consider pumping the remedy's extraction wells long enough to
achieve background. The commenter also noted that the excess cancer risk at the MCL
for TCE. reported as 1 x 10"6 in the Staff Report, does not appear consistent with EPA
Region III 1995 Risk Based Calculations and Guidance. The Commenter further noted
that DEQ failed to consider inhalation risk to children, which when considered, results in
a residual excess lifetime cancer risk of 2 x 10"6 at the TCE MCL.
Response: The FS demonstrated that cleanup to background levels was impractical,
because it would take two to four times longer than cleanup to the MCL for TCE. With
respect to the EPA Region III- Guidance, the document states that: "the guidance
document should generally not be used to set cleanup levels at CERCLA sites or RCRA
Corrective Action site". Also, the Region III Guidance used the oral slope factor for TCE
withdrawn from IRIS.
DEQ acknowledges that the estimated residual excess lifetime cancer risk increases
when children exposure is considered. However, the increased risk is still well within
EPA's acceptable risk range of 10"* to 10"6. The MCL is the standard established by
EPA for safe public water supply systems. In addition, Oregon Rules for Public Water
Systems (OAR 333-61-097(1)(A)) states that the MCL is considered safe.
EMC Record of Decision 12/19/96 11-2
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Lastly, it should be noted that excess cancer risk level at the MCL is based on a 30 year
exposure timeframe. In reality. TCE concentrations will continue to decline through
natural attenuationrfollowing the completion of the remedial action. It is therefore highly
unlikely that future groundwater users within the present area of TSA contamination
would be exposed to TCE at the MCL level for 30 years, and actual risks should be
much lower than presented here.
11.3 Proposed Remedy Performance Criteria
Commenters: City of Portland, Columbia Corridor Association, Friends of Blue and
Fairview Lake, Boeing, Cascade Corporation, and Water Managers Advisory Board of
Bull Run Water Users.
11.3.1 Restoration Time Frames
Comment The 10 year and 20 year restoration time frame performance criteria should
be identified as goals and not absolute standards for noncompliance. As noted in
several locations in Section 7 of the Staff Report, the methods used to derive cleanup
time frames have a high degree of uncertainty in them. The final remedy should specify
the time frames as design goals which the remedy may or not be able to achieve,
despite best efforts and implementation of the most aggressive alternative - Alternative
6.
Response: DEQ concurs. The remedy may not restore water quality within the entire
contaminated portion of the TSA to MCLs, within the time frame specified in the
recommended remedy. The final remedy retains the restoration time frames as design
criteria and specifies that, if restoration is not achieved within these time frames through
implementation of a remedy designed to do so, then groundwater pump and treat would
continue in those areas where MCLs have not been achieved, until restoration is
achieved.
Comment The specification of time-based performance criteria in a ROD is
unprecedented. A review of RODs throughout the country showed no examples of time-
based performance standards being set for contaminated aquifers, either at EPA or at
the State level.
Response: Although RODs issued by EPA and States may not have explicitly specified
restoration time frames. DEQ .believes the restoration time frames are an implicit
element of these selected remedies. As noted above, DEQ has revised the final remedy
to address the inherent uncertainties related to restoration time frame estimates.
11.3.2 Horizontal and Vertical Gradient Control
Comment The final ROD should provide a more explicit description of the performance
criteria, to include time requirements for implementing response actions, should the
performance criteria be exceeded. One commenter provided specific language and
EMC Record of Decision 12/19/96 11-3
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times for response actions, should contamination be detected beyond the limits of the
TSA contaminant plume or within the SGA.
Response: DEQ understands the commenter's concerns, but does not believe it is
appropriate for the performance criteria to explicitly address potential non-attainment of
the remedial action objectives, such as spreading of the plume in the TSA or expansion
of the plume to the SGA. Rather, response actions to address non-attainment of the
performance criteria are more appropriately addressed as contingency measures and
are described in Section 9.1.5. Response times are more appropriately addressed by
the Consent Order for implementation of the selected remedy, and/or work plans
developed pursuant to the Consent Order requirements.
11.4 Request for More Explicit Definition of Remedy
Components
Commenters: Oregon Environmental Council, Friends of Blue and Fairview Lakes, City
of Portland, and Water Managers Advisory Board of Bull Run Water Users.
11.4.1 Timing of the Initiation of Hydraulic Control and Restoration
Comment The final ROD should specify deadlines for when the remedy must be in
place, specifically, July 1998.
Response: DEQ will specify an enforceable schedule for implementation of the final
remedy, in a consent order to be issued following DEQ selection of the final remedy.
DEQ will take this comment into consideration during consent order negotiations.
Comment The ROD should also state that DEQ will take steps within its legal
authority, to ensure that access to private property for remedy implementation is
accomplished in a timely manner.
Response: DEQ intends to use its legal authority to obtain property access, if the
responsible parties cannot obtain access after reasonable efforts and as necessary to
ensure timely implementation of the final remedy. As requested, a statement of this fact
has been added to Section 9.2.4 of the ROD for clarity.
11.4.2 Performance Evaluations
Comment The ROD should describe how DEQ will assess whether the remediation
plan is working by establishing interim benchmarks, and identifying the steps that would
be taken if remediation seems to have lagged behind schedule.
Response: DEQ will assess performance of the remedy by evaluating predicted VOC
concentration reductions at various locations throughout the contaminant plume. The
final remedy identifies one such method for assessing remedy performance, and others
may be developed. This method involves projecting contaminant concentration
EMC Record of Decision 12/19/96 11-4
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reductions as a function of time. The final remedy specifies minimum groundwater
extraction rates, which will result in the removal of one pore volume of the contaminant
plume in approximately 3 to 4 years. VOC concentrations should decline by
approximately 40% with the removal of the first contaminant plume pore volume. Phase
3 would be implemented if TCE concentrations have not declined by approximately 40%
after 3-4 years of implementation of Phase 2 of the final remedy. Any steps to be taken
by DEQ in regard to an implementation schedule will be specified in the negotiated
consent order for remedy implementation.
Comment. More frequent performance evaluations should be included in the early
years of implementation.
Response. The performance evaluations will be conducted at a frequency that is
consistent with the relatively slow rates of change in groundwater quality expected
during remedy implementation, as noted above. The final remedy specifies that
performance evaluations will be submitted to DEQ annually until Phase 3 is installed (if
Phase 3 is necessary) and operated for two years, and at five year intervals thereafter.
In addition, monitoring reports documenting compliance with gradient criteria and
groundwater quality would be submitted to DEQ annually, during the entire period of
remedy implementation. At a minimum, the performance evaluations would assess
compliance with the remedy gradient control criteria, document groundwater and VOC
mass removal rates, assess TCE concentration reductions, provide an assessment of
the groundwater extraction and performance monitoring network, and propose
modifications to the pumping, program (e.g. variable or pulse pumping and, eventually.
termination of groundwater extraction).
Comment The computer model has flaws that make its use to formulate management
decisions limited. Specifically, the model overpredicts the efficiency of the remediation
efforts, under-predicts point concentrations of the plume in the SGA as a result of
pumping by the COP wellfield, and overpredicts the time the plume would take to reach
the COP wells. The management decisions made by DEQ must carefully show which
ones are based on field data and which ones are based on model predictions.
Response: DEQ acknowledges that all computer models have an inherent degree of
uncertainty. However, DEQ does not believe that this model has significant flaws that
seriously affect its predictive capabilities. The model has been calibrated and validated
by a number'of aquifer tests. The .model has accurately simulated the hydraulic effects
of the operation of portions of the Portland South Shore Wellfield on a number of
occasions. Accordingly, DEQ concluded that the model is a useful tool for
understanding the groundwater system. DEQ anticipates that the model will be used to
design the final groundwater extraction system and will be used to assess potential
changes in the extraction system during remedy implementation.
It is important to clarify, however, that compliance with the remedy performance criteria
will be assessed on the basis of field measurements, not on computer model
projections. These field measurements will include water level data to assess
compliance with the gradient control criteria, pump rates to assess compliance with the
minimum extraction rate criteria, and water-quality data to assess the rate of aquifer
restoration.
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11.4.3 Groundwater Monitoring
Comment The ROD should specify performance criteria for the groundwater
monitoring program. Specific language was recommended describing how and where
monitoring wells will be placed in both the TSA and SGA.
Response: Typically, details of the monitoring program are not determined until
remedial design and during remedy implementation, when the dynamics of the system
are better understood. The final remedy requires sufficient groundwater monitoring
points to demonstrate that both the horizontal and vertical gradient control criteria are
being attained, and includes considerable details of the monitoring program not typically
specified in a ROD (see Section 9.1.1). In addition, the final remedy specifies that
additional monitoring wells, beyond those existing or currently being installed, may be
necessary to demonstrate compliance with the remedy gradient control performance
criteria. The groundwater monitoring network developed during remedial design will be
evaluated during remedy implementation and, if the monitoring network is found to be
inadequate, then additional well(s) will be installed.
11.5 Air Emissions from Air Stripper Treatment Systems
Commenters: Friends of Blue and Fairview Lakes, Metro, and Oregon Environmental
Council.
Comment The impact of the remediation plan has not been formally evaluated by DEQ
for inhalation risk from air-stripping towers. The high density of the pump and treat
systems for both the TGA and TSA raise concerns about the amount of contaminants
that will be volatilized into the air.
Response: The FS Report evaluated VOC air emission rates against significant
emission rates (SERs) established by DEQ's Air Quality Control Division. SERs were
developed by DEQ to provide a link between point source emissions (e.g., air stripping
towers) and potential harmful effects resulting from offsite ambient air concentrations.
The SERs assume that the closest human receptor is located 100 meters (328 feet)
downwind of the emission source. .The SER for TCE is 15,000 pounds per year (Ib/yr).
The excess cancer risk to an individual living 100 meters downwind of an emission
source discharging 1500 Ib/yr of TCE is 1 x 10 . The estimated annual VOC emissions
. for TCE associated with the selected remedy is less than 300 Ib/yr, or two percent of the
SER. The excess cancer risk to an individual living within 100 meters of a centralized
air stripper would therefore be in the range of 1 x 10"8 (one in one hundred million).
In response to public concerns of VOC emissions from multiple cleanups, DEQ
evaluated the combined VOC emissions from the TGA cleanups at Boeing and Cascade
Corporation sites and the VOC emissions from the TSA cleanup. The TGA
remediation at the Boeing and at the Cascade facilities are predicted to produce
approximately 1 Ib/day and 0.5 Ib/day, respectively. With the projected 1 Ib/day VOC
emissions from the TSA remedy, the total VOC emissions are expected to be less than
EMC Record of Decision 12/19/96 11-6
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3 Ib/day. or less than 1000 Ib/year which is again well below the SER for TCE. The final
remedies for Cascade and Boeing in the TGA and the TSA could involve 6 to 8 air
stripping systems, with the highest emission source being the air stripper on the Boeing
facility, located approximately 1000 feet from the nearest residential property.
Residents within the area would not be subjected to significant risk from inhalation of
VOCs, due to the dispersion of VOCs in the atmosphere from the multiple emission
sources.
Lastly, the final remedy requires a further assessment of VOC emissions, as part of the
remedy design for any air stripping system proposed to be located closer than 100
meters to residential properties, to ensure protection of these populations.
Comment: The staff report does not address the risks associated with, or treatment for,
the degradation products of PCE and TCE. Vinyl chloride is the most hazardous of this
group. The monitoring and treatment should effectively address the degradation
compounds as well.
Response: Vinyl chloride has not been detected in the TSA. The SER for vinyl chloride
is 310 Ib/yr. As noted above, the estimated annual VOC emissions for TCE is less than
300 Ib/yr. Even if all the TCE were degraded to vinyl chloride, which is improbable, the
emissions would still be below the vinyl chloride SER.
11.6 Groundwater Disposal, Reinjection or Beneficial Reuse
Commenters: Friends of Blue and Fairview Lake, City of Portland, Oregon.
Environmental Council, and Cascade Corporation.
11.6.1 Establishing Discharge Limits at MCLs
Comment Will the reduction of TCE to the MCL be sufficiently protective of beneficial
uses in the surface waters to which waste water will be discharged?
Response: Yes. As noted in Section 6.2 of the ROD, the chronic ambient water quality
crtterrafvforrT:CE'isv2t;000 *igyt:,.
Comment? Vinyl chloride has been detected in 1 1 percent of the groundwater samples:
The- monitoring and treatment -should effectively address such degradation products, as
well as the parent compounds. .
Response: To clarify, vinyl chloride has not been detected in the TSA, but has been
detected in 11% of the groundwater samples from the TGA at the Cascade Corporation
facility. Vinyl chloride has been added to the list of cleanup criteria in Table 6-1 of the
ROD, because it is a breakdown product of TCE. and although unlikely, might appear in
the TSA.
Comment The proposed treatment system discharge limitations are too stringent.
Although the treatment systems will have the ability to bring concentrations below
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drinking water standards, the actual discharge limits in the NPDES permit should be set
at applicable concentration for the receiving waters as laid out in applicable state and
federal law.
Response: DEQ regulations specify that "best available technologies" will be employed
to minimize pollutant discharges to surface water. The air stripping systems in operation
at the site, since as early as 1989, have demonstrated that treatment removes VOCs to
levels well below their respective MCL, without significant system maintenance
requirements. Accordingly, the proposed discharge limits are not overly stringent and
are consistent with DEQ regulations.
11.6.2 Consideration of Metals and Nutrients Contamination and Discharge
to Fairview Lake or Columbia Slough
Comment: An oversight in the staff report has been to propose remediation strategies
without linking these strategies to surface water discharge limitations that are being
formulated, as a result of the total maximum daily load fTMDL) process for the Columbia
Slough. Until the TMDLs are established, state regulations do not allow new discharges
into water quality-limited water bodies such as the Columbia Slough. DEQ appears not
to have assessed the effects on the Slough of plume co-contaminants, such as metals.
as well as naturally occurring compounds such as phosphorus and other nutrients, iron,
manganese, and low levels of dissolved oxygen. DEQ's plan should include a system to
monitor for these constituents in the treatment plant discharges, and should incorporate
alternate discharge strategies, in case discharges exceed TMDLs or other established
limits.
Response: Toxics which have been found to be imparing beneficial uses in the Slough
include DDT and its metabolites, dieldrin, dioxins, lead and PCBs. None of these toxics,
with the exception of lead, were detected in the TSA during investigations conducted by
DEQ, EPA, Boeing and Cascade prior to issuance of the 1994 Consent Order. Lead
was detected in only 10 of 160 groundwater samples collected from the TSA, Of the six
wells where lead was detected, four have subsequently been tested with no lead being
detected (analytical detection limit of 2 ug/L). Based on existing data, DEQ has
concluded that the TSA is not impacted with lead at levels that exceed chronic criteria
contained in Table 20 of OAR 340-41-445. Therefore, the discharge of treated
groundwater is not prohibited due to toxics pursuant to OAR 340-41-26(3)(a).
The Slough is also water quality limited for dissolved oxygen (DO) and temperature, and
discharge of pollutants that would indirectly cause the receiving stream to violate water
quality standards would be prohibited. The presence of nutrients such as nitrates and
phosphates in treated groundwater could potentially indirectly affect DO concentrations
in the Slough by promoting algae growth or increased biological oxygen demand for in-
stream sediments. Nitrates and phosphates are present in the TSA. in the area of
remediation presumably related to historical agriculture practices in the area. Nitrate
and phosphate concentrations in treated groundwater are expected to be in the range of
3 mg/L and 0.15 mg/L, respectively. TSA groundwater within the project area currently
discharges either to Fairview Lake or the Slough.
EMC Record of Decision 12/19/96 11-8
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Monitoring of the Slough has shown frequent and long-term depressions in dissolved
oxygen (DO), within the project area near the outlet from Fairview Lake. Flow from
Fairview Lake is limited by summer operations designed to keep the water level high in
the lake. The limited flow to the Slough from the lake creates a stagnant area which
exhibits concentrations of DO below state water quality standards. Because the
groundwater is being treated by air stripping, the effluent would contain high levels of
oxygen, not low levels as the comments suggest. The discharge of treated groundwater
should aid in restoring the beneficial uses of the Slough due to the following:
1. The discharge of highly oxygenated groundwater (approximately 2.5 cubic feet
per second) would offset stagnant areas in the Slough, by increasing summer
time low flows and help off-set current in-stream low DO concentrations;
2. Average nitrate concentrations within the TSA remediation area are comparable
to concentrations measured in surface water discharges to Fairview Lake from
Fairview Creek and from Taggard spring to the Slough;
3. Average phosphate concentrations wrthin the TSA remediation area are
comparable to concentrations measured in surface water discharges to Fairview
Lake from Fairview Creek and from Taggard spring to the Slough, and
approximately 3 times the instream concentrations measured at the dam at
Fairview Lake. Measureable increases in instream phosphate concentrations
attributable to the discharge of treated groundwater are not expected;
4. In the absence of remediation, groundwater containing elevated nutrients would
otherwise discharge to the Slough without the benefits of oxygenation; and
5. The remediation of the TSA will decrease the rate of natural groundwater
recharge to the Slough and Fairview Lake and could lead to increased
stagnation, resulting in lower DO concentrations in the project area, if treated
groundwater were discharged to an alternate water body such as the Columbia
River.
The discharge of highly oxygenated treated groundwater containing nutrients should not
indirectly cause the Slough to violate water quality standards and being designated
water quality limited, and the discharge of treated groundwater should not be prohibited
pursuant to OAR 340-41 -026(a)(C.)(i). In addition, through its TMDL program. DEQ is
likely to use flow management or the Slough to restore beneficial uses; the increased
flow from the remedy may be a tool which will aid in the flow managment strategy.
However, DEQ acknowledges that the nature of the nutrient discharges is different than
what would occur from natural groundwater discharge, and unanticipated adverse
effects might occur. Therefore, the final remedy and the implementing order or permit
for discharge will include flow management or other measures as necessary to avoid
violation of water quality standards related to a water quality-limited parameter.
11.6.3 Reinjection of Treated Groundwater as a Remedy Component
Commenter. Friends of Blue and Fairview Lake.and Cascade Corporation.
EMC Record of Decision 12/19/96 11-9
-------
Comment Before reinjection is attempted, an evaluation of the possible effects on the
sandstone need to be carried out. Injection of oxygenated water into the ISA would
oxidize the vitric sandstone and create clay minerals and palagonite which may greatly
decrease the porosity and permeability of these deposits. Also the introduction of
oxygenated water into the ISA may lead to degradation of TCE to the more-toxic vinyl
chloride.
Response: The upper vitric sandstone portion of the TSA is either unsaturated or has
very limited saturated thickness in the area identified for reinjection. Reinjection of
treated groundwater would likely occur into the lower conglomerate and would therefore
not be expected to cause significant clogging of the gravel.
The reinjection of treated, oxygenated water into the TSA is not expected to promote
significant biological degradation of TCE to vinyl chloride. Aerobic biological
degradation of TCE requires a "co-metabolite" or a food source to the natural bacteria
present in soil (e.g., toluene or phenol, as described in the DEQ Staff Report for
Cascade Corporation for the TGA). Even if vinyl chloride were generated, it would
degrade at rates higher than TCE. Therefore, significant accumulation of vinyl chloride
is considered unlikely.
Properties where the TSA mound exists have been used extensively for agriculture for
years. In recent years, spray irrigation at rates as high as 100,000 gallons per day have
occurred in the area of the mound. Vinyl chloride has not been produced as a result of
infiltration of irrigation water, nor has mineralization of the sandstone been documented
in samples collected from the sandstone during well installations. DEQ believes that
recharge to the TSA can be achieved either with wells, as described in Alternative 6, or
by surface infiltration of treated groundwater in the area of the mound, without significant
adverse impacts.
Comment: Reinjection is simple to model, but the actual field implementation has been
shown to be more difficult and is not a well proven or documented technology.
Response: DEQ disagrees. Artificial recharge (reinjection with wells, infiltration basins.
etc.) has been employed at a number of sites throughout the country, as a method to
increase flushing rates in contaminated aquifers. The presence of non-aqueous-phase-
liquids (NAPLs) within the aquifer; matrix is generally one limiting factor on whether
reinjection. used to increase flushing rates and reduce restoration time-frames, is
successful. No conditions have been documented that suggest NAPLs are present in
the TSA. Another limiting factor is high dissolved solids naturally occuring in
groundwater causing precipitation and clogging injection wells. This condition is not
expected to occur due to the relatively low dissolved solids concentrations in TSA
groundwater at the site.
11.6.4 Beneficial Reuse of Treated Groundwater
Comment: The use of treated groundwater by the City of Portland would be an
expensive source of water for the City's customers most of the year, because it would
EMC Record of Decision 12/19/96 11-10
-------
require pumping to Powell Butte. The City requests that it, and other water providers in
the region be participants in a process to evaluate the future use of treated water.
Response: DEQ recognizes that, because of contractual arrangements with other local
water districts and water rights, the City of Portland will need to be involved in beneficial
use evaluations. The timing of these evaluations have not yet been determined. The
evaluations may be scheduled for completion after Phase 2 of the remedy has been
installed and is operational.
11.7 Additional Protective Measures
11.7.1 Abandonment of Private Water Supply Wells and Alternate Water
Supply
Commenters: Friends of Blue and Fairview Lake, Cascade Corporation. John Simpson
owner of Sandy Mobile Villa, and Loraine McCurdy owner of Terrand Mobile Terrace.
Comment: Private SGA water supply wells PMX-195 (Handy well) and PMX-410
(Terrand Mobile Terrace water supply well), that have had several detections of TCE,
should be immediately prohibited from use for public consumption.
Response: The Handy well (PMX-195) was abandoned this summer, pursuant to a
Prospective Purchaser Agreement between DEQ and Silent Creek Joint Venture. A
monitoring well has been installed to assess whether contamination exists in the area
of the abandoned well.
DEQ has been working with the owner of Terrand Mobile Home Terrace and Cascade
Corporation since May 1996, to abandon their well and provide an alternate water
supply. Monitoring of their well has been performed in the interim. One sample showed
very low concentrations (less than 2 ug/L). the second non-detect Accordingly,
continued use of the well as a domestic water supply, while an alternate source is being
provided, should not pose a significant risk.
Comment: We were forced to discontinue use of our well in 1988, due to contamination
in our area, even though our well tested under federal drinking water limits. Our costs
for operating the well were $1200 per year, and now we pay over $20,000 per year for
Rockwood water. We need relief.
Response: DEQ is sympathetic to the plight of this commenter. It is unfortunate when
innocent parties are adversely affected (in this case financially) by contamination caused
by others. DEQ requested the cooperation of several well owners in the area of
contamination to discontinue use of their well to reduce the potential for adverse spread
of groundwater contamination due to pumping, during the RI/FS. DEQ cannot
compensate affected parties for their losses, and does not posses the legal authority to
stipulate financial compensation between affected parties and the parties responsible for
the contamination. DEQ will, however, continue to work with existing well owners whose
wells have been identified for abandonment, to receive the alternate water supply of
EMC Record of Decision 12/19/96 11-11
-------
their choice from the responsible parties. Installation of new, groundwater supply well(s)
is* arr option, 'provided? tllter use of •grbundwater'does- not 'result 'in thefortrrerr spread of -
contamination horizontally within the TSA or vertically to the SGA, as discussed in
Section 11.7.2.
Comment The proposed TSA well abandonments should be reconsidered. Two of the
wells have been identified as potential extraction wells. The remainder are either not
contaminated at levels exceeding drinking water standards or are used for irrigation and
do not adversely impact the spread of contamination.
Response: The recommended remedy did not stipulate abandonment of the TSA wells.
There was a discrepancy in the FS which stated that the wells would be abandoned (see
Section 5.2.2.2) and also would be used for performance monitoring.
Alternate water supplies will be necessary to replace the Claflin well (PMX-417) and the
Hoyt well (PXM-198). Although DEQ will consider conversion to extraction wells, there
will be a need for monitoring points in the area of 205th Avenue, to assess remedy
performance. No formal assessment has been performed for the remaining TSA wells
located north/northeast of 205th Avenue. The final remedy requires an assessment of
the potential adverse impacts of continued use of these wells, during the institutional
controls evaluation. A final decision on the continued use of these wells will be based
on the results of this evaluation.
11.7.2 Groundwater Use Controls
Commenters: City of Portland, Oregon Environmental Council, Friends of Blue and
Fairview Lake, Water Managers Advisory Board of Bull Run Water Users, and
Columbia Corridor Association.
Comment The final remedy should include a moratorium on all new supply well
construction in the EMC site, in order to protect against reversing the gradient between
the TSA and the SGA, If this is not automatic in a state cleanup site, perhaps the
groundwater management area designation can be invoked even though it is not
commonly done. What good are pumping restrictions on the Portland Water Bureau, if
new wells can be drilled?
Response: One of the remedial action objectives for the cleanup is to allow existing
groundwater use in eastern Multnomah County. The final remedy includes criteria for
determining whether or not to allow new replacement SGA supply wells. There would
not be a significant threat to the SGA provided these criteria are met.
DEQ and the responsible parties will evaluate whether the critical groundwater
management area designation is the appropriate tool for managing groundwater
resources in eastern Multnomah County during cleanup. Other options which may be
considered include modifications to comprehensive land use plans for the area,
coordination between DEQ and Oregon Water Resources Department (WRD) on water
right applications, and periodic review of start cards filed with WRD for well installations.
EMC Record of Decision 12V19/96 11-12
-------
As previously noted, the final remedy does not impose PWB wellfield use restrictions,
but does assume, consistent with the ROD assumptions, that PWB will implement well
operation strategiesjo reduce the threat of contamination to the SGA.
Comment Are the limitations on the pumping of the Portland supply wells sufficiently
protective against the migration of the contamination in the TSA to the SGA? Could
other existing supply wells in the area have an effect on the plume? Why are no other
entities restricted even in the event of a Bull Run emergency when Portland will be
allowed to pump their wells? Will the parties pay to supply water to the customers
whose use may need to be curtailed under Portland's restrictions as they do for the local
communities that have had to move off their drinking water wells?
Response: Maintaining the vertical gradient criteria is protective of the SGA. The
RI/FS focused on the pumping of the Portland supply wells and did not specifically
address other existing users, except those identified with potential leaky well casings.
Remaining wells will be evaluated during remedial design and implementation, and may
need to be taken out of service. If this is the case, the responsible parties and the well
owner may negotiate the terms for compensation.
Comment: The potential impacts on SGA water levels, and therefore, vertical hydraulic
gradients could be significant (e.g. Terrand Mobile Villa), thus further reducing the ability
of the City to pump its SGA wells. New SGA wells should be avoided during the early
stages of the remedy to achieve the greatest good for the greatest number unless it is
stated that the parties' responsibility to meet the performance criteria remain
unchanged, irrespective of SGA pumping by others.
Response: The level of pumping for a new supply well for Terrand Mobile Terrace
(approx. 12.000 gallons per day, based on 40 households using an assumed 300
gallons per day) is approximately 10% of the historical pumping of the Shepard well
(PMX-207) for irrigation. Shepard well pumping resulted in water level drawdowns at
DEQ-3, a vertical gradient compliance point, of approximately 1 foot With one tenth the
level of pumping, DEQ would expect SGA water level drawdowns at DEQ-3 from a new
supply well at Terrand to be in the range of one to two tenths of a foot, which is
insignificant in comparison to the 40 or more feet of drawdown in the SGA that result
from pumping of the City's SGA supply wells. The vertical gradient criteria would apply
irrespective of other SGA groundwater users.
Comment: The City of Portland would agree to limit pumping of its SGA wells, and will
enter into an agreement with DEQ, with the conditions that: the City have the right to
exceed the limits for environmental and economic reasons; the responsible parties must
agree to pay additional costs incurred or revenues lost, as a result of actions taken in
order to not exceed the guidelines; the ROD must unambiguously state that Boeing and
Cascade are responsible for controlling and remediating their pollution; and Boeing and
Cascade must meet the horizontal and vertical gradient control criteria.
Response: Since DEQ does not have the authority to mandate compensation to the
City by Boeing and Cascade, it cannot enter into an agreement with the City under the
conditions specified by the City. DEQ will, however, continue to work with the City, as it
EMC Record of Decision 12/19/96 11-13
-------
has in the past, including discussions of agreements to facilitate implementation of the
remedy and use of the wellfield.
Comment: The City of Portland needs to operate its wellfield with the understanding
that their actions can substantially affect the plume's movement. Any unilateral pumping
by the City, without regard for the plume movement, could endanger the existing
groundwater supply of the community of Blue and Fairview Lake.
Response: DEQ agrees. DEQ recognizes that the City's cooperation in operating its
wellfield during cleanup will help ensure that the remedial action objectives are met and
that water quality in the TSA is restored in a timely and efficient manner. The City has
also acknowledged this.
11.8 Contingency Plan
Commenter: City of Portland..
Comment: The description of the circumstances under which the contingency plan will
be invoked are not sufficiently inclusive, and should include performance standards.
Response:- - The contingeney plan- -in the final remedy- requires -additional response
actions to be implemented to minimize the spread of contamination within the TSA or to
the SGA. including the identification of location for additional monitoring and/or
extraction wells and criteria for implementation of additional hydraulic control in the TSA
and SGA. The final remedy does not, however, include establishing a 10-year time-
frame for restoration of an SGA plume of contamination. DEQ believes that if a plume
were created, it would be minor compared to the TSA. and could be addressed in a
much shorter time-frame than 10 years.
11.9 Other Issues
Comment The vertical hydraulic conductivity of CU2 cited in the staff report does not
necessarily reflect the actual range in vertical conductivity values measured, or even all
the estimated values. The staff report should recognize the possibility that contaminant
time of travel from the TSA to the SGA could be very short (e.g., weeks to months).
Response: DEQ agrees the contaminant time of travel from the TSA to the SGA could
be short in areas where CU2 is thin or absent. This was acknowledged in the first
paragraph on Page 3-7 of the Staff Report which stated: "Groundwater travel times
between the TSA and the SGA..., were estimated to be in the range of 30 to 190 days."
Detailed discussion of hydraulic conductivities and contaminant transport are presented
in the Rl, which are the basis for the ROD.
Comment I am not convinced that there is not a connection between Blue Lake, the
Blue Lake Aquifer and the TSA.
EMC Record of Decision 12/19/96 11-14
-------
Response: The RI/FS and the DEQ Staff Report do not claim that there is no
connection. Studies performed by the U.S. Geological Survey and the Portland Water
Bureau have demonstrated a connection between the BLA. Blue Lake and the ISA.
Pumping of the City's BLA wells, however, does not cause significant hydraulic
influences (e.g. water level depressions and gradient variations) in the area of the TSA
contaminant plume that would result in the significant spread of contamination to Blue
Lake or the BLA.
Comment. The description of well field capacity and well field use patterns found in the
Staff Report is not exact. The City suggests that it be amended to reflect the
information contained in their comments.
Response: Section 3.1.2 of the ROD have been revised consistent with the comment.
EMC Record of Decision 12/19/96 11-15
-------
12. DOCUMENTATION OF SIGNIFICANT CHANGE
As noted in Section 11, several changes were made in the selected'remedial action, in
response to public comments received on the recommended remedial action. The
changes to the recommended remedy are summarized below.
Remedy Performance Criteria. The aquifer restoration time frame criteria for the
recommended remedy were changed to design criteria for the selected remedy. As
noted in Section 7, the restoration time frames have an inherent decree of uncertainty
and the selected remedy may not be able to achieve these restoration times.
Accordingly, the remedy does not specify a time frame, but DEQ has added minimum
groundwater extraction rates to the selected remedy to insure that the remedy is
designed to achieve the restoration time frame goals.
Remedy implementation Phases. Phase 2 and Phase 3 of the selected remedy were
changed. Phase 2 will require installation of sufficient extraction wells to achieve the
minimum groundwater extraction rates specified in the final remedy. Phase 2 had
previously contemplated groundwater extraction rates equivalent to Alternative 5, which
are approximately 25 percent less than the rates for Alternative 5B. Phase 3, which was
to be implemented after Phase 2 had operated for one year, will now be implemented
after 3-4 years. This time frame is necessary to determine whether the selected
remedy is reducing the area and concentration of groundwater contamination above the
cleanup levels at a rate necessary to achieve restoration time frames. Time is also
needed to develop the design for reinjection of treated groundwater, if minimum
extraction rates cannot be sustained without excessive dewatering of the TSA. It is
unlikely that any definitive determinations of remedy performance could be made after
only one year of extraction.
Upper Bounds of Selected Remedy. The final remedy includes upper limits on the
rate of groundwater extraction and injection, as defined by Alternative 6. Alternative 6
represents the upper bounds of remedial components evaluated and demonstrated to
be feasible in the remedy selection process.
Assessment for Air Emissions. The final remedy requires an air emissions
assessment in the remedial design, for air stripping systems proposed to be located
closer than 100 meters from any residential property. The 100 meter distance was used
by DEQ in significant emission rate calculations for the contaminants of concern.
Groundwater Disposal. The final remedy includes provisions to monitor additional
constituents which may be present in treated groundwater, and which are of interest for
the TMDL development process for the Columbia Slough.
EMC Record of Decision 12/19/96 12-1
-------
Criteria for New SGA Supply Wells. The final remedy incorporates criteria for
determining whether new SGA supply wells will be installed to replace those SGA wells
identified for abandonment.
Abandonment of ISA Supply Wells. The recommended remedy indicated that 6 TSA
supply wells would either be abandoned or taken out of service and used for remedy
performance monitoring. The final remedy does not require abandonment of existing
TSA supply wells and defers a final decision on whether the wells will be taken out of
service, based on an assessment of pumping influences and hydraulic control of the
contaminant plume. This assessment will be completed during Phase 2 remedy
implementation.
EMC Record of Decision 12/19/96 12-2
-------
13. FINAL DECISION OF THE DIRECTOR
The selected remedial action for the East Multnomah County Troutdale Sandstone
Aquifer site is protective, and to the maximum extent practicable, uses permanent
solutions and alternative technologies, is cost-effective, effective and implementable. It
therefore satisfies the requirements of ORS 465.315, and OAR 340-122-040 and 340-
122-090. The detailed evaluation of how the selected remedial action meets the
regulatory requirements is provided in Section 9.2.
13.1 Director's Signature
12-31
Laftgdbn Marsh, Director Date
DefJartment of Environmental Quality
EMC Record of Decision 12/19/96 -| 3_-j
-------
TABLES
EMC Record of Decision'
-------
POTENTIAL GROUNDWATER USERS SUMMARY
PMX Well ID
PMX 199
PMX 129/1 30
PMX1%
PMX 345
PMX 417
PMX 434
PMX 169
PMX 183
PMX 189
PMX 198
PMX 226
PMX 124
PMX 128 1
PMX 120
PMX 232
Common Well Name
Cily of Fairvicw No. 4
Dig Eddy Marina*
Andrews
Edwards
Claflin
Schmaulz
Schloredt
City of Fairview
Wallers
Hoy!
llockwood Water District
PW-3
PW-5
PW-15
Union Plaza
Aquifer
TGA and TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA
TSA WELLS
Is well within current TSA VOC
plume, beneath surface expression
of TSA VOC plume, or have VOC
been delecled?W
No
No
Yes
No
Yes
Yes
No
No
Yes
Yes
No
No
No
No
No
Potentially
Impacted
Well?W
No
Possible
-
Possible
_
No
No
-
No
No
No
No
No
Proposed AclionM
No action at present
No action at present
Supply municipal water;
Supply municipal water;
Supply municipal water;
well; use for monitoring
Supply municipal water;
No action at present
No action at present
Supply municipal water;
use for monitoring
use for monitoring j
evaluate for possible extraction
use for monitoring
use for monitoring
Supply municipal water; evaluate for possible extraction
well; use for monitoring
No action at present
No action at present
No action at present
No action at present
No action at present
EMC Record of Decision
I'agc I of -I
-------
TABLE 3-1
POTENTIAL GROUNDWATER
SGA WELLS
PMX Well ID
PMX 166
PMX 174
PMX 192
PMX 195
PMX 207
PMX 410
PMX 193
PMX 202
PMX 225
PMX 409
PMX 176
PMX 208
PMX 185
PMX 184 (
PMX 122
PMX 126
PMX 136
PMX 132
PMX 142
I'MX419
Common Well Name
W. Inlerlachcn Waler Corp.
Inicrlachcn Corp.
Wade (Peffry)
Handy
Shepard
Terrand Mobile Terrace
Willard
Rolling Hills
Cherry Blossom
Sandy Mobile Villa
Columbia Acres
Sandy Mobile Villa
City of Fairview No. 3
City of Fairview No. 5
PW-4
PW-9
PW-7
PW-14
I'W-8
Ilij- lliUy M-mnaf'1)
USERS SUMMARY
Aquifer la well within current ISA VOC Potentially
plume, beneath surface expression Impacted
of ISA VOC plume, or have VOC Well?
been detected?
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
SGA
No
No
No
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
No
No
No
No
No
No
No
No
No
No
Possible
-
-
--
Possible
Possible
-
'
No
-
No
No
No
No
No
No
No
No
Proposed Action
Monitor
Monitor
Supply municipal water and monilor(c) 1
Abandon well(e)
Abandon weU(e)
Abandon wcll(e)
Monltor(e)
Monltor(e)
Abandon weU(e)
Abandon well(e)
No action at present
Abandon well(e)
No action at present
No action at present
No action at present
No action at present
No action at present
No action at present
No action at present
No action at JUCSIMII
EMC Record of Decision
Page 2 i>f-»
-------
TABLE 3-1
POTENTIAL GROUNDWATER USERS SUMMARY
DLA & UNKNOWN CONSTRUCTION WELLS
PMX Well ID
PMX 163
-
PMX 16-1
PMX 159
PMX 158
PMX 162
PMX 148
PMX 150
PMX 155
PMX 149
PMX 173
PMX 175
1
PMX 168
PMX 285
PMX 197
PMX 437
PMX 433
-•
Common Well Name
Multnomuh County
Toornbs No. 1
Toombs No. 2
Mulliioiii.il> County
Mullnomah County
PW-19
PW-13
PW-17
l'W-12
PW-18
Multnomali County
InterlachenCorp.
Tullle
Blue Lake Water District
Nielsen
Kirchcrn
SosakJ
SclmtiUl
NyquiM
Aquifer
BLA
DLA
BLA
BLA
BLA
BLA
BLA
BLA
DLA
BLA
7
'
?
7
7
7
1
?
Is well within current ISA VOC
plume, beneath surface expression
of ISA VOC plume, or have VOC
been delected?'
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Potentially
Impacted
Well?b
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Action
No action al present
No action ul present
No action al present |
No action al present
No action at present
No action at present
No action al present
No action at present
No action at present
No action at present
No action at present
No action al present
No action at present
No action at present
No action at present
No action at present
No action al present
No action al present
No action at present
1IMC Record of Decision
P;ige3oM
-------
TABLE 3-1
PMX Well ID
Common Well Name
POTENTIAL GROUNDWATER USERS SUMMARY
BLA & UNKNOWN CONSTRUCTION WELLS
Aquifer Is well within current ISA VOC Potentially
plume, beneath surface expression Impacted
of ISA VOC plume, or have VOC Well?
been detected?
Proposed Action
Paulson
Shepard
No
No
No No action at present
No No action at present
(a) TSA VOC plume as defined in Endangcrment Assessment Report
(b) Potentially impacted (i.e. above MCLs) wells are based on results of modeling 20 year simulation periods with various PWB pumping conditions and no
remedial action.
(c) See Table 9-1 for monitoring frequency for wells to be monitored as part of the recommended remedy.
(d) There are two TSA (PMX 129 and PMX 130) and one SOA well (PMX 419) for Big Eddy Marina
(e) Based on recommendations in EMCON TSA/SGA Data Gap Investigation Report.
-------
TABLE 5-1
EAST MULTNOMAH COUNTY GROUNDWATER CONTAMINATION SITE
SUMMARY OF GROUND-WATER CONTAMINANT CONCENTRATIONS '
Compound
trichloroeihene
leirachlorocthene
cis- 1 ,2-dichloroellicne
1,1,1-trichloroclhane
methylene chloride
l,!-dichloroeihene
iraris- 1 ,2-dichloroeihcnt:
chloroform
Troutdale Sandstone Aquifer (TSA)
No. of
Samples
549
546
• 538
541 '
541
547
541
541
No. of
Detects
457
314
271
25
19
16
13
9
Range (ug/L)
Min.
0.42
0.1
0.2
0.2
0.4
0.22
0.2
0.4
Max.
410
16
210
8.5
2.4
15
2.6
2.6
Sand and Gravel Aquifer (SGA)
No. of
Samples
130
130
98
130
119
130
-
130
No. of
Delects
34
10
4
0
0
0
--
17
Range (>ig/L)
Min.
0.6
0.4
0.7
--
--
--
-
0.85
Max. I
16.8
1.3
1.2
--
-
--
--
7.6
V Include all volatile organic compounds detected in more than two percent of the total samples.
I-MC Hccoitl uf Dccmuii
-------
TABLE 5.2
SUMMARY~OF VOLATILE ORGANIC COMPOUNDS IN
COLUMBIA SLOUGH WEST OF FAJRVIEW LAKE '
Compound
trichloroethene
toulene
cis- 1 ,2-dichloroethene
Number of
Samples
16
16
16
Number of
Detects
6
1
2
Range (ug/L)
Minimum
0.8
~
0.29
Maximum
2.3
7
0.5
V Summary of data from surface water sampling stations CS-A and CS-8, which were located
900 feet and 1800 feet, respectively, downstream of Fairview Lake.
EMC Record of Decision
-------
TA3LE5-3
EAST MULTNGMAH COUNTY GROUNDWATER CONTAMINATION SITE
SUMMARY OF RISK ESTIMATES FOR CURRENT EXPOSURE SCENARIOS
Scenario {'<»stcr Source) cxcsa Lifesimc Cancer Risk^"*
Occupational (TSA)(I>
Residential (TSA)1*1
Residential
-------
TABLE 6-1
GROUNDWATER CLEANUP LEVELS FOR THE
COPC
TCE
PCE
cis-l,2-DCE
1,1-DCE
vinyl chloride
Total Estimated Risk
Ground water
Cleanup Level
(W?/L)«
5
5
70
7
2
at MCLsW
Corresponding
Excess Cancer Risk
Levels)
1x10-6
5x10-6
NC
1x10-4
7x10-4
1x10-4
TSA
Corresponding
Noncancer Hazard
Quotient^)
0.03
0.02
0.2
0.03
NC
0.3
Notes: NC Not considered carcinogenic or calcuable due to lack of reference dose.
a) Based on Federal MCL.
b) Based on RME exposure for residential ingenstion of, inhalation of, and
dermal contact with drinking water.
c) Cleanup of TCE to MCL will reduce other chemicals of potential concern
to levels well below the MCL. Risk at MCL not reflective of risk to future
groundwater users at the completion of cleanup.
EMC Record of Decision
-------
TABLE 8-1
EAST MULTNOMAH COUNTY GROUNDWATER SITE
REMEDIAL ALTERNATIVE COST-EFFECTIVENESS EVALUATION
Remedial Alternative
Alternative 4
Alternative 5
Alternative 5a
Alternative 5b
Alternative 5c
Alternative 6
Present Worth Cost*
Capital
$2.0
$3.5
$4.0
$4.1
$4.8
$5.3
O&M
$6.6
$5.6 '
$5.8
$5.2
$6.2
$6.5
Tola!
$8.6
$9.1
i
$9.8
$9.3
$11.0
$11.8
Incremental Increase In
Cost"
Capital
0%
75%
14%
17%
37%
51%
O&M
0%
-15%
4%
-7%
-11%
16%
Total
0%
6%
8%
-2%
21%
31%
Estimated Mass
Removed In 1 Year
(Ib* of TCE)C
Incremental
Increase In Mas*
Removal*
Estimated
Cleanup
Tlmeframe
(year* (or 80%
restoration)
Incremental
Decrease In
Cleanup
Tlmeframe*
110
230
270
310
310
315
0%
113%
17%
34%
34%
37%
104
35
26
22
20
16
0%
66%
26%
37%
43%
54%
'Costs in Smillions in 1995 dollars w/ nel present value (NPV) using 5% discount rale ( from Andrews Memorandum, dated June 1996 - Table I).
^Incremental Difference calculated between Alternative 4 and 5, and Alternative 5 and 5a. 5b, 5c, and 6.
'Mass removal estimates based on extraction well pumping rales and average TCE concentration within 300 feet of extraction wells for each alternative.
-------
TABLE 9-1
PERFORMANCE MONITORING
WATER QUALITY SAMPLING PLAN
TSA Sandstone
Morutonng Point
Well rtequency
Perimeter Wells*
BOP-22(ds) i— :^y
BCF-41ios) Annually
BOP-42(ds) .Annually
CMW-19(di) Annually
CMW-20(ds) Annually
CMW-29(ds) Annually
D-tS(ds) Annually
D-16{ds) Annually
D-18(ds) Annually
EMC-l(ds) Annually
PNCX-138.180 Annually
PMX-141 Annuauy
PMX-189 Annually
RPW-l(ds) Annually
Interior Well*
BOP-13(ds) SemiannuaDy
BOP-2Q
-------
FIGURES
EMC Record of Decision
-------
Ai d.l«»d n ili. Cwu.i.l 0(d« lAllocl.mnl A)
-------
dij ol PonluHd of Old*/
flwftlClpul I SA Pv*PlAQ WlV
iutoito*
ISA Woll Locations
-------
UQA Wull Locailoos
-------
HI0610 Bo....) Poiilo«J/l5AHOO IGl »/Q6
OLA Wall Locations
and Well Locutions with Uncertain Aquifor
-------
Bo*nt PcrlUndTSAROtVFIe. 3 8 (U)
< «*
* • %. v
> ;*V- >*• .
i?fif I • ,;
i i-. - • '£»> «A .• * __.
amsra* •;•'.,-
• or O Troutdale Sandstone Aquller
• «» Q Columbia River Sandstone Aquller
4 °' 0 Sand aftd Gravel Aquller
A Trouldale Gravel Aquller
V Blue Lake Aquller
Approximate
Extent ol ISA
Plume
-------
-
c
o
S. £ Geologic Description
QUATERNARY
TERTIARY
TROUTDALE FORMATION
Ftoodpfein Sand and Silt
Sandy and sflty , Sandy
GRAVEL with \ GRAVEL
boulders x^ with cobbles
\
Sandy and silly GRAVEL with cobbles
Subunit A; SANDSTONE and SILTSTONE
Subunit 3: Clayey SILTSTONE
Subunit C: SANDSTONE (t| with satstone
Subunit 0: SILTSTONE with sandstone
SANDSTONE0' with conglomerate lenses
CONGLOMERATE with sandstone '"
SILTSTONE with sandstone
SANDSTONE'" with satstone
SILTSTONE with sandstone
SANDSTONE '"
CONGLOMERATE with sandstone"1
SANDSTONE and SILTSTONE wibn
conglomerate
o
g = Geologic™
o 3 Column Hydrogeologlc Unit
I
Trouldale Gra
_
3S
M*
CO
Trouldale S and t lone
<0
« •
^1
11
If
l§
•A
CO
o S
§1
0 =
*• '• T-
ffl
'. ! : ' •
' i I : : .' i
1
•• i • * .
> •
>; -i
il •:
JTr
liVriiniiili
**• .= *> ^ ^
PI
SS
M^
OO^OQOQ^
D°OooooOf
S"
Hill
B
Unconsolidated .
: Gravel Aquifer X^ 3iue '_3*a
, \
:
t Troutdate Gravel Aquifer
< (TGA)
/ Confining Unit 1 (GUI) C3)
. ~1
LJ
/
/
3
a
§
7
= Troutdale
« Sandstone
l Aquifer
CTSA)
rr
o 5
/
/
• Confining Unit 2
1 (CU2)
/
<
) Sand and Grave! Aquifer
-f (SGA)
[j
II
'.
Noiei: i Sinds:on« may conuin large imounu of vine Itrtc sand.
2. Geoiocic column d intended D repreteni a ompojite
-------
•100
C/
Noun
7
i
I At i*i»il*(t* «lih >n«ri ihin •«• •••. (hi |**>i|r
t A dlll*i*ni CUI htundui liliiil* «•• «>.•< !•( OfQ-)(4|. Ill*
• '
CUI
*!*•).
lUlllMUl l»ll to tut
vtiiuti lulu i iMk . 111 i
• IIA lit III (IIIIIIM
MtMMf* •• IUII •«• IUII/II
IflttMl)
. Qiologlc and Hydiooioloolc Cio» Stcilon c C'
Flgult 33
-------
?SI06)0 IB.-J f«. ilto.d/l JAROO ICt 1/96 10 \
S»ndi ont Not Situitttd
In this App/OMlm»t» Ar»i
III GrovtdiOltr ElfvQhOA
il
Sviloct Wol«r
Location
and EI..OI.DI. III. ClSLI
VOOO 4000
Scole in P «I I
1
TSA
Sandstone
November
Groundwaler
20-29, 1994
lilavallons and Flow Dlrocilons
- Nonpumplng Condlllons
Figure 3-6
-------
t/t«
in r.«i
TJiA Conolomoruiu Groiinilwuiur l-luvailui.r, and I low |)i,uoil«n
Novombof 20-20. 1004 . Nonpumplno Conilliloni (E.cupi (or
N
-------
LLflDfi
KM HIM On • MtlMI. >X
0* OOMOOI-«UMB.
or ru OMKMXin MU
«*OM UO-.
R/lSK^i.
«s#P.?5fe?
i
emcon
DATE ?/96
OWN. MK
APPR
REV1S
PROJECT NO.
40683008.006
Figure 3-8
CU2 THICKNESS AMD EXTENT
C \OWC\OfiO.J\000\HCU2-5 fi/l.i/96 mk PLOI 1 = 2000
-------
* 00 iCi I/H m.\lflf\l>««lll/tn>-t|i: I Uio) VOC ».J.J«.: II-DC6. IfUCA
laiJ I?-OC£: I2-OCA. Ill ICA:
ICE ll?-rCA: fCE: y»J fdoa II
Sowed-' tatdiH Attatitlti HOOial
Tola! VOC ConconUallona IM Iho TGA; Sununur 100*1
i-muro 5-1
-------
10 MOF\l1AAOO\riGI->
on* A/o/ Stturttid
Approxlmtlt Af$t
I SA rioniionni) W»
f ot ititn* ConciMf ohoit
ond dolt, if difftr«At ihofl
1994 (NO • Nol Dittoed)
/
I
Appr o ii«oi 0 Trtchlor o« ihtnt
ConctAiroiion Conlgwr
5Appf Oli
Coactnlroiion Conioyr tu^/Lt
Eqwol 10 MCL
No it i I Whtr t dtld dwpticoit or ipli
ftiJu ort otoilobl. iK. •o
i
coActnirohon u tnutn.
? Wit*/ • Mvlhpl* lomplti itrt coHvcitd
• illnn AwQwll 1994 or tiltiM ill* ftOfllh
o'irtotoi no i tit nunnv'4 cunc *
-------
0 II—•* «• IMIll'
X 3 Cw»c«»i(oi,o« Co«io./ I.^/LI
f Eo.ul iu nCL
NOKI: I Oolu ar< ai»a«i4 far til aairi.
BOP-ZUi «)q 0-Vdi J* CM/-l4J,du:
Cnw ??Ji oini
unnbiiii• a, llii *uiiAwa cuncinlfuhu%
Approxlmaio Extunl ol TCE In tho TSA Conoloinorulo: August
-------
RQONC AMD CASCADt
PRCPlHTY SOUNOAHiCS
IOIAL l«Ci ISOCONUNlHAHCn
CONIQUD (PPB) roA int nt
CONIXOuOlAlI (HOv. U»S)
|.J THE BOEING
1000 2000
»••••
SCALC IN rcci
i__ ,, '' _
ll~ii ^Tfcrli-'%-:!r4—.r1- • : "
.
HlviS.
_
PROXCI NO
4M&JOOA.OO7
fltju<«
CA5CAOC CORPORAllOll
SCA OAIA CAM INWS IIC/>. Hun
JQA WA1ER QUAUIY
C. \l)M:\U6B>\00»\6Cul-) B/J/S6 UK PIOI I-10OO
-------
Stndiloni
In Ihti Appr
ot SilunuJ
flmtit Artt '
|> pfili TCE
C«(iglom«ul«
be o I • in f: •« I
-------
)*»OtlO lo.-i f „.,!*•D TCE
AppKilmilf ConglooooK Plumt
IS pot) TCi
Altornailvo 4: Plume Roductlon
Flguro 7-2
-------
Not Stlu(»l»d
Af»t
Appioil*n«i«
(» ff» 'Ct Conctnu.ilonl
TIA Cengiomiitli Eiuicilon W«U
Hoi.:
W>U numb ii i hivi no InliUtilo
miming. Tnty hivt bun
piniixd liom triilout raodillng
ic«n«iloi «nd ait lAdudtd htit
only foi companion lo llguiti
pumping
vooo
•1000
. ul
Feel
m
Alternatlvo 5: Aquifer Restoration
Figure 7-3
-------
m Plum*
Duumliry (5 ppb TCE Concontitlioii)
A|)|«O«|IIIIIIO Coiujioinuniii Piunio
UuunOxy (S p|>ti ICE CoiKunliiilui)
TSA SinOtiatio E«u«cilan WiiB
O TSA Coiujloidciilu Eilxcllon W«H
Altunuitivcs 5A nnd GO
-------
Appioilmaie SamJsiono Piuma
Boundary (S ppb 7CE ConcaoUallon)
Appionlrnilo ConolomiUI* Plum*
Bourxliry (S ppb ICE Conctnunlon)
TSA Sandsiona Enucilon Wen
ISA Conglomeraia Exuacilon Well
1000 2000
Alternative 5C
Figure 7-ii
-------
Key
Appio»lmale Sandstorm Plume
OounJaty (S p|)b TCE Concanliillan)
Appioilmelo Connlommalo Plume
Boundary (S ppb TCE Cancenuillon)
Q TSA Sandsiona Eiincitori Weil
Q TSA Conytomeiale Eiuscilon Well
Q ISA Conglomeois Injecilon Wall
0 1000 2000
-1000
—-]
Itel
-------
Alternative 5: Potential Extraction Well Locations
Figure 9-1
Approximate
Eastern Lrai Of
Trouidale Grovel
Aqufer
Ifeor
Restoration Zone
xtraction Veil*
COP Uelis
:_!•:• :fTQir!view Lake:
noOv-
?c m^
Q " ^-i'"v'
I«—-•'-' ^
-------
ISA So»dilo*f Oo«»n«c or
Irngouo*
ISA SoftdllOflt Apf>r0H>Ol>
rttNoiotlhim CoAC*«lroliOA
E^ol 10 nCl
ISA Sandstone Performance Monllorlng Woll Locations
-------
J5«oajO
lo1 PhX Ml .1 ic'«*
lltk ISA |U*tJtlW
ISA Cun^lu«tfui
tbt Pnx 11; .or b.
IA boil* it.l ISA
OAIJ tK» ISA
-------
nchlor otlhcn* Co»c«nlt olio
OMOW l-q/Lt Eqvol lo
Sea I • in F«t 1
SGA Porlormance Monitoring Woll Locations
Flguro 9--J
-------
Appendix A
"East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
1.0 SITE IDENTIFICATION
1.1 DEQ. Preliminary Assessment. Cascade Corporation Facility. DEQ Environmental Cleanup
Division. February 3, 1989. (DEQ Site I.D. No. 635; CERCLIS No. ORD 009031378)
1.2 DEQ. Preliminary Assessment. Swift Adhesives. DEQ Environmental Cleanup Division.
March 10,1989. (DEQ Site I.D. No. 884; CERCLIS No. ORD 990751828)
1.3 DEQ. Preliminary Assessment. Boyd Coffee Facility. DEQ Environmental Cleanup
Division. March 1989. (DEQ Site I.D. No 967; CERCLIS No ORD 009052218)
1.4 DEQ. Preliminary Assessment. Viking Industries Inc. DEQ Environmental Cleanup
Division. March 6,1989. (DEQ Site I.D. No. 885; CERCLIS No. ORD 009620113)
1.5 DEQ. Preliminary Assessment. Norwest Publishing Co.. DEQ Environmental Cleanup
Division. August 1989. (DEQ Site ID. No. 962; CERCLIS No. ORD 044108603)
1.6 DEQ. Preliminary Assessment. Dirt & Aggregate Interchange. DEQ Environmental Cleanup
Division. March 6T1989. (DEQ Site LD. No. 874; CERCLIS No. ORD 060582236) 1989.
1.7 E&E 1991 a. Final Report for East Multnomah County Vadose Zone Gas Survey, Portland,
Oregon. Prepared for the U.S. Environmental Protection Agency, Region 10, Seattle,
Washington, by Ecology and Environment, Inc., Seattle, Washington. October.
1.8 E&E 1991b. East Multnomah%Cqunty Groundwater Study, Gresham, Oregon. Prepared for
the U.S. Environmental Protection Agency, Region 10, Seattle, Washington, by Ecology &
Environment, Inc., Seattle, Washington. October.
1.9 EPA 1992. Preliminary Assessment & Site Investigation. Libby, McNeil & Libby. (DEQ
Site I.D. No. 1259; CERCLIS No. ORD 042484188)
1.10 DEQ. Preliminary Assessment. NW Retreaders. DEQ Environmental Cleanup Division.
August 1993. (DEQ Site I.D. No. 1268; CERCLIS No. ORD 987197415).
East Multnomah County Record of Decision A-1
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
1.11 EMS 1992. Level I Environmental Site Assessment of the Multnomah County Park
Services Building located in Blue Lake Park, Gresham, Oregon. Prepared by Environmental
Management Solutions for Multnomah County Parks Services Division. May 22.
1.12 TAG 1991. Phase I/Phase n Environmental Property Evaluation, Opti-Craft Facility;
Prepared for Optical Radiation Corp. by Technical Action Group, Inc.; September 3.
2.0 REMOVAL RESPONSE
Boeing Portland
2.1 Landau Associates, Inc. Final Report - Initial Corrective Action Study, Boeing Portland
(as Revised). December 15, 1988.
2.2 Landau Associates, Inc. 1990 Work Plan Rockwood Well Abandonment, Boeing
Portland, Gresham, Oregon. July 17, 1990
2.3 Landau Associates, Inc. 1990 Final Report, Rockwood Well Abandonment, Rockwood
Water District, Boeing Portland, Gresham, Oregon. November 16, 1990:
2.4 Landau Associates, Inc. 1994. Work Plan, Interim Corrective Action System, Boeing
Portland, Gresham, Oregon. March 4
2.5 Landau Associates, Inc. 1994. Report, Status of Interim Measures, Boeing, Portland.
March 4.
2.6 Landau Associates. 1995. SbilVapor Extraction Interim Measure Work Plan. Prepared
for The Boeing Company by Landau Associates, Inc., Edmonds, Washington.
September 11.
2.7 Landau Associates. 1995. Interim Measures Evaluation Report. Prepared for The
Boeing Company by Landau Associates, Inc., Edmonds, Washington. September 15.
East Mulmomah Councy Record of Decision A-2
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
Cascade Corporation
2.8 C WE 1991 Interim Removal Action Measures Report, Cascade Corporation, Troutdale,
Oregon. Prepared for Cascade Corporation by Century West Engineering Corp., Portland,
Oregon. September.
2.9 CWE 1991 Industrial Well Abandonment Plan, Cascade Corporation. Prepared for
Cascade Corporation by Century West Engineering Corp., Portland, Oregon. June 4.
2.10 NeoMedia/SE/E. 1991. Interim Removal Action Measures Implementation Work Plan.
December 11.
2.11 CWE 1991. Industrial Well Abandonment Report, Cascade Corporation, Troutdale,
Oregon. Prepared for Cascade Corporation by Century West Engineering Corp., Portland,
Oregon. November 8.
2.12 EMCON 1992. Interim Removal Action Measures Implementation Workplan, Cascade
Corporation, Workplan Amendment Prepared for Cascade Corporation by EMCON
Northwest, Inc., Portland, Oregon March 23.
2.13 EMCON 1994. Revised Workplan, Evaluate Off-Site TGA Control Options: Cascade
Corporation. Prepared for Cascade Corporation by EMCON Northwest, Inc., Portland,
Oregon. April 26.
2.14 EMCON 1995. Pilot Test for Troutdale Gravel Aquifer Control. Prepared for Cascade
Corporation by EMCON Northwest, Inc., Portland, Oregon. May 23.
2.15 EMCON 1995. Revised Workplan, Expansion of Off-Site TGA Trench Recovery System.
Prepared for Cascade Corporation by EMCON Northwest, Inc., Portland, Oregon. August
14
2.16 EMCON. 1996. Evaluation of TGA/IRAM Control Trench Performance Technical
Memorandum. Prepared for Cascade Corporation. January 16.
East Multnomah County Record of Decision A-3
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
Boeing & Cascade Corporation
2.17 EMCON and Landau Associates. 1993. Troutdale Sandstone Aquifer Removal Action
and Blue Lake Aquifer Resource Protection Work Plan. Prepared for Cascade
Corporation and The Boeing Company.
2.18 EMCON and Landau Associates. 1993. Draft Troutdale Sandstone Aquifer Removal
Action and Blue Lake Aquifer Resource Protection Evaluation Report. Prepared for
Cascade Corporation and The Boeing Company. December 1.
2.19 EMCON and Landau Associates. 1994. RPW-2 Work Plan Amendment - Troutdale
Sandstone Aquifer Removal Action and Blue Lake Aquifer Resource Protection Work
Plan. Prepared for Cascade Corporation and The Boeing Company.
2.20 Landau Associates and EMCON. 1994. RPW-2 Capture Zone Report, Troutdale
Sandstone Aquifer Removal Action. Prepared for Cascade Corporation and The Boeing
Company. June 27.
3.0 REMEDIAL INVESTIGATION (Rl)
•
Department of Environmental Quality
3.1 Parametrix 1991. East Multnomah County Database and Model: Final Geologic
Interpretation, Detailed Modeling Area. Prepared for Oregon Department of
Environmental Quality by Parametrix, Inc., Kirkland, Washington. July.
3.2 SSP&A. East Multnomah County Data Base and Model: Preliminary Groundwater Flow
Model Report. Prepared for the Oregon Department of Environmental Quality by S.S.
Papadopulos & Associates, Inc., Bethesda. October 1991.
3.3 SSP&A East Multnomah County Database and Model: Ground-Water Flow Model
Report. Prepared for the Oregon Department of Environmental Quality by S.S.
Papadopulos & Assoc., Inc., Bethesda, Maryland, in association with Parametrix, Kirkland,
Washington. June, 1993.
East MuJtnomih County Record of Decision A-4
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
Boeing of Portland
3.4 Landau Associates, Inc. 1986 Revised Phase I Investigation Work Plan, Boeing Portland,
Gresham, Oregon. December 10, 1986
3.5 Landau Associates, Inc. 1987 Final Report, Phase I Investigation Draft, Boeing Portland,
Gresham, Oregon. September 28,1987.
3.6 Landau Associates, Inc. I988a. Final Report of Boeing of Portland, Phase I Investigation.
Prepared for The Boeing Company by Landau Associates, Inc., Edmonds, Washington.
March 17, 1988.
3.7 Landau Associates, Inc. 1988 Phase n Investigation Work Plan, Boeing Portland
Gresham, Oregon. August 8, 1988
3.8 Landau Associates, Inc. Workplan, Investigation of Troutdale Sandstone Aquifer, Boeing
Portland, Gresham, Oregon. November 30,1988
3.9 Landau Associates, Inc. 1991 Work Plan Hydrogeologic Investigation Troutdale
Sandstone Aquifer, Boeing Portland, Gresham, Oregon. November 12,1991.
3.10 Landau Associates, Inc. 1993 Final Report Phase n Investigation, Boeing of Portland.
Prepared for The Boeing Company by Landau Associates, Inc.JEdmonds, Washington.
June 21,1993.
3.11 Landau Associates 1994. Work Plan, Phase III RCRA Facilities Investigation, Boeing
Portland, Portland, Oregon. March 11.
3.12 Landau Associates. 1995. Phase III RCRA Facility Investigation Report, Boeing
Portland, Gresham, Oregon. Prepared for The Boeing Company by Landau Associates,
Inc., Edmonds, Washington. July 31.
East Multnonuh County Record of Decision A-5
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
Cascade Corporation
3.13 D&M 1988. Preliminary Remedial Investigation Plan for Cascade Corporation,
Troutdale, Oregon. Prepared for Cascade Corporation by Dames & Moore, Inc., Portland,
Oregon. August 25.
3.14 D&M 1989 Preliminary Remedial Investigation for Cascade Corporation, Troutdale,
Oregon. Prepared for Cascade Corporation by Dames & Moore, Inc., Portland, Oregon.
March 31.
3.15 CWE. 1989a. Excavation plan, north drainage ditch. Prepared for Cascade Corporation
by Century West Engineering Corporation, Portland, Oregon. June 15.
3.16 CWE. 1989b. Letter (re: results of north receiving ditch excavation and soil analysis,
Cascade Corporation facility) to P. Bumet, DEQ Site Response Section, from J. Snell,
Century West Engineering Corporation, Portland, Oregon. October 19.
3.17 CWE. 1989. Final Work Plan, Remedial Investigation/Feasibility Study for Cascade
Corporation Troutdale Facility. Prepared for Cascade Corporation by Century West
Engineering Corporation, Portland, Oregon. December.
3.18 CWE. 199la. Phase I interim data report, remedial investigation/feasibility study,
Cascade Corporation Troutdale facility. February I.
3.19 CWE. 1991b. Phase 2 Troutdale Gravel Aquifer plume characterization report, remedial
investigation/feasibility study. Cascade Corporation Troutdale facility. Prepared for
Cascade Corporation by Century West Engineering Corporation, Portland, Oregon. June
21.
3.20 Century West 1991. Phase 2 work plan amendments. Rl/FS Cascade Corporation.
February 1.
3.21 Century West. 1991. Phase 2 Troutdale Gravel Aquifer Plume Characterization Report,
Remedial Investigation and Feasibility Study, Cascade Corporation Facility. August 7.
East Multnomah County Record of Decision A-6
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
3.22 Sweet-Edwards/EMCON Phase III Remedial Investigation and Feasibility Study
Workplan for the Cascade Corporation, Troutdale, Oregon Facility. Sweet-
Edwards/EMCON, Inc., Portland, Oregon, in association with NeoMedia, Beaverton,
Oregon. March 23, 1992
3.23 EMCON. 1992. Off-site source and receptor Survey, Cascade Corporation, Troutdale,
Oregon. Prepared for Cascade Corporation by EMCON Northwest, Inc. October 2.
3.24 EMCON. 1995a. Installation and sampling of additional on-site TGA monitoring wells
near former vapor degreaser at Cascade Corporation. Prepared for Cascade Corporation by
EMCON, Portland, Oregon. February 23.
3.25 EMCON. 1995. Phase 3 Remedial Investigation/Feasibility Study, Troutdale Gravel
Aquifer. Part 1: Remedial Investigation, Part 2: Endangerment Assessment. Final
Report. Prepared for Cascade Corporation by EMCON, Portland, Oregon. March 10.
Boeing and Cascade Corporation
3.26 EMCON and Landau Associates. 1994. Remedial Investigation/Feasibility Study,
Workplan for the Troutdale Sandstone Aquifer. Prepared for Cascade Corporation and The
Boeing Company. November 17
3.27 EMCON and Landau Associates. 1995. Sand and Gravel Aquifer Pumping Test Data
Report. Two Volumes. Prepared for Cascade Corporation and The Boeing Company.
3.28 EMCON and Landau Associates. 1995. Sand and Gravel Aquifer Pumping Test
Evaluation. Prepared for Cascade Corporation and The Boeing Company. May 4.
3.29 EMCON and Landau Associates. 1995. Remedial Investigation/Feasibility Study,
Troutdale Sandstone Aquifer. Part 1: Remedial Investigation, Part 2: Endangerment
Assessment. Prepared for Cascade Corporation and The Boeing Company. October 6.
3.30 EMCON. 1996. Draft TSA-SGA Data Gap Investigation and SGA Interim Removal
Measure Report. Prepared for Cascade Corporation by EMCON, Portland, Oregon.
January 31.
East Midmomah County Record of Decision A-7
-------
East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
4.0 FEASIBILITY STUDY (FS)
Boeing Portland
4.1 Landau Associates, Inc. 1995 Phase I Corrective Measures Study, Boeing Portland
Gresham, Oregon. July 17.
4.2 Landau Associates, Inc. 1995 Phase El Corrective Measures Study Work Plan, Boeing
Portland Gresham, Oregon. August 14.
Cascade Corporation
4.3 EMCON. 1996b. Phase 3 Remedial Investigation/Feasibility Study, Troutdale Gravel
Aquifer. Pan 3: Feasibility Study. Final Report. Prepared for Cascade Corporation by
EMCON, Portland, Oregon. January 15.
Boeing and Cascade Corporation
4.4 EMCON and Landau Associates. 1995. Remedial Investigation/Feasibility Study,
Troutdale Sandstone Aquifer, Feasibility Study Scoping Technical Memorandum.
Prepared for Cascade Corporation and The Boeing Company. August 1.
4.5 EMCON and Landau Associates. 1996. Troutdale Sandstone Aquifer, Feasibility Study
Report. Prepared for Cascade Corporation and The Boeing Company. March 4.
4.6 EMCON and Landau Associates. Technical Memorandum -. Response Memorandum to
DEQ Comments on TSA FS Report.. Prepared for Cascade Corporation and The Boeing
Company. June 17.
East Multnomah County Record of Decision A-8
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East Multnomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
Department of Environmental Quality
4.7 SSPA. Memorandum from DEQ contractor Charles Andrews, S.S. Papadopulos &
Associates, to Bruce Gilles, DEQ Project Manager. Additional Remedial Options for
TSA. June 12, 1996
4.8 SSPA. Memorandum from DEQ contractor Charles Andrews, S.S. Papadopulos &
Associates, to Bruce Gilles, DEQ Project Manager. TCE Contamination in TSA - A real
Extent and Mass. June 18, 1996
4.9 SSPA. Memorandum from DEQ contractor Charles Andrews, S.S. Papadopulos &
Associates, to Bruce Gilles, DEQ Project Manager. TSA ROD. July 26, 1996
5.0 RECORD OF DECISION (ROD)
5.1 Record of Decision for Swift Adhesives; May 10, 1994. Prepared by Oregon
Department of Environmental Quality.
5.2 DEQ Staff Report DEQ Recommended Remedial Action for the Cascade Corporation Site.
Department of Environmental Quality, Waste Management and Cleanup Division. August
1996.
5.3 DEQ Staff Report DEQ Recommended Remedial Action for the East Multnomah County
Groundwater Contamination Site, Troutdale Sandstone Aquifer. Department of
Environmental Quality, Waste Management and Cleanup Division. August 1996.
\
5.4 Memorandum to Project File from Bruce Gilles, DEQ Project Manager, dated November
1996; Summarizes two public hearings held on die DEQ Recommended Remedial Action
for die Troutdale Sandstone Aquifer and Cascade Corporation (TGA).
East Mulmomah County Record of Decision A-9
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East Multaomah County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
5.5 Public Comment Letters on DEQ Recommended Remedial Action:
• Letter from Lorraine McCurdy, owner of Terrand Mobile Terrace, to Bruce
Gilles, dated October 11, 1996. Written transcript of verbal testamony given at
DEQ Public Hearing on October 10, 1996.
• Letter from Doug Morgan, Portland Utilities Review Board, to Bruce Gilles,
DEQ, dated October 14, 1996.
• Lener from Paulette Rossi, member of Portland Utilities Review Board, to Bruce
Gilles, DEQ, dated October 24, 1996.
• Letter from Dale Anderson, Chair of Water Managers Advisory Board of Bull Run
Water Users, to Bruce Gilles, DEQ, dated October 21, 1996.
• Letter and attached report from Ann Nickel, Executive Director of Columbia
Corridor Association, to Bruce Gilles, DEQ, dated October 25, 1996
• Letter and report from Scott A. Wells, Portland State University, to Bruce Gilles,
DEQ Project Manager, dated October 28, 1996. Prepared in behalf of Freinds of
Blue and Fairview Lake under support of the U.S. EPA Technical Assistance
Grant.
• Letter from Taryn McCain, The Boeing Company, to Bruce Gilles, DEQ, dated
October 29, 1996.
Letter from Gayle Killam, Water Program Director for Oregon Environmental
Council, to Bruce Gilles, DEQ, dated October 29, 1996.
Letter and enclosed Resolution No. 35559 from Mike Lindberg, Commissioner
City of Portland Office of Public Utilities, to Langdon Marsh, Director Department
of Environmental Quality, dated October 29, 1996.
East Mulmomah County Record of Decision A-10
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East MuJtnomah County Area
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ADMINISTRATIVE RECORD INDEX
• Letter from Gregory E. DiLoreto, Director City of Gresham Environmental
Services, to Bruce Gilles, DEQ, dated October 30, 1996.
• Letter and enclosure from David Blount, Copeland, Landye, Bennett and Wolf, to
Bruce Gilles, DEQ, dated October 30, 1996.
6.0 INTERAGENCY COORDINATION
6.1 Memorandum of Agreement between the U.S. Environmental Protection Agency Region
10 and the Oregon Department of Environmental Quality for the East Multnomah Counry
Groundwater Contamination Site. August 1994.
7.0 ENFORCEMENT
7.1 DEQ. Order on Consent between the Oregon Department of Environmental Quality and
Cascade Corporation. DEQ No. ECSR-NWR-88-01. July 1988.
7.2 DEQ. Order on Consent between the Oregon Department of Environmental Quality and
Cascade Corporation. DEQ No. ECSR-NWR-89-11. August 1989.
7.3 DEQ Order on Consent and Addendums between the Oregon Department of Environmental
Quality and Reichhold Chemicals. DEQ No. ECSR-NWR-89-07.
7.4 DEQ. Order on Consent between the Oregon Department of Environmental Quality, the
Boeing Company and Cascade Corporation. DEQ No. ECSR-NWR-93-07. July 1993.
7.5 DEQ. Addendum to Order on Consent between the Oregon Department of Environmental
Quality, the Boeing Company and Cascade Corporation. DEQ No. ECSR-NWR-93-07.
July 1994.
7.6 DEQ. Second Addendum to Order on Consent between the Oregon Department of
Environmental Quality, the Boeing Company and Cascade Corporation. DEQ No. ECSR-
NWR-93-07. January 1996.
East Mulmomah County Record of Decision A-l 1
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East Multnomab County Area
Groundwater Contamination Site
ADMINISTRATIVE RECORD INDEX
7.7 DEQ. Prospective Purchaser Agreement between the Oregon Department of
Environmental Quality and Silent Creek Joint Venture. DEQ No. 95-01. October 31, 1995
8.0 HEALTH ASSESSMENTS
8.1 ATSDR. Public Health Assessment for East Multnomah County Groundwater
Contamination, Gresham, Multnomah County, Oregon. CERCLJS No. ORD987185030.
U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic
Substances and Disease Registry. July 14, 1995.
8.2 ATSDR. Toxicological Profile for 1,1-dichloroethene. Atlanta: U.S. Department of
Health and Human Services, Public Health Service, May 1994
8.3 ATSDR. Toxicological Profile for cis-l,2-dichloroethene. Atlanta: U.S. Department of
Health and Human Services, Public Health Service, August 1994.
8.4 Toxicological Profile for trichlororoethylene. Atlanta: U.S. Department of Health and
Human Services, Public Health Service, August 1995.
8.5 Toxicological Profile for tetrachlororoethylene. Atlanta: U.S. Department of Health and
Human Services, Public Health Service, 1992.
9.0 NATURAL RESOURCE TRUSTEE NOTIFICATIONS
9.1 Letter from Bruce Gilles, Oregon DEQ to Mr. Charles Polityka, U.S. Department of
Interior Federal Natural Resource Trustee Notification East Multnomah County
Groundwater Contamination Site, September 6, 1994.
9.2 Letter from Bruce Gilles, Oregon DEQ to Mr. Chris Mebane, NOAA Coastal Resource
Coordinator, Federal Natural Resource Trustee Notification for the East Multnomah
County Groundwater Contamination Site, September 6, 1994.
East Multnomah Councy Record of Decision A-12
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