PB97-964611
EPA/541/R-97/199
January 1998
EPA Superfund
Record of Decision:
East Multnomah County Ground Water
Contamination, OU 2
Multnomah County, OR
12/31/1996
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DEQ Remedial Action Record of Decision
for the
Cascade Corporation Site
Troutdale Gravel Aquifer
Oregon Department of Environmental Quality
Waste Management & Cleanup Division
December 1996
Cascade Corporation - Remedial Action Record of Decision
12/18/96
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CONTENTS
LIST OF TABLES AND ILLUSTRATIONS iii
1. INTRODUCTION 1-1
1.1 INTRODUCTION 1-1
1.2 SCOPE AND ROLE OF SELECTED REMEDIAL ACTION i-l
2. SUMMARY OF SELECTED REMEDY 2-1
3. SITE DESCRIPTION. _.. -—,-,-.. --,.„...,...,,.....-.......,- - —..- ~. ._„__. 3-1
3.1 SITE SETTING ; 3-1
3.2 PHYSICAL SETTING 3-1
4. SITE HISTORY 4-1
4.1 OPERATIONAL HISTORY 4-1
4.2 HISTORY OF ENVIRONMENTAL INVESTIGATIONS 4-2
4.3 INTERIM REMOVAL ACTION MEASURES 4-4
5. REMEDIAL INVESTIGATION SUMMARY 5-1
5.1 TYPES OF CONTAMINATION 5-1
5.2 SOURCE AREAS 5-1
5.3 NATURE AND EXTENT OF CONTAMINATION 5-2
5.4 CONTAMINANT FATE AND TRANSPORT 5-6
5.5 ENDANGERMENT ASSESSMENT.... 5-7
6. REMEDIAL ACTION OBJECTIVES AND CLEANUP LEVELS 6-1
6.1 REMEDIAL ACTION OBJECTIVES 6-1
6.2 CLEANUP LEVELS 6-2
6.3 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS .*. 6-3
7. DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES 7-1
7.1 AREAS AND VOLUMES 7-1
7.2 COMMON REMEDIAL COMPONENTS 7-1
7.3 DESCRIPTION OF ALTERNATIVES 7-3
8. EVALUATION OF REMEDIAL ACTION ALTERNATIVES 8-1
8.1 PROTECTION AND FEASIBILITY REQUIREMENTS 8-1
8.2 EVALUATION SUMMARY 8-4
9. THE SELECTED REMEDIAL ACTION 9-1
9.1 DESCRIPTION OF RECOMMENDED ALTERNATIVE 9-1
9.2 SATISFACTION OF PROTECTION AND FEASIBILITY REQUIREMENTS 9-5
10. PUBLIC NOTICE AND COMMENTS 10-1
11. CONSIDERATION OF PUBLIC COMMENTS 11-1
12. DOCUMENTATION OF SIGNIFICANT CHANGE 12-1
13. FINAL DECISION OF THE DIRECTOR ; 13-1
13.1 DIRECTOR'S SIGNATURE 13-1
Cascade Corporation - Remedial Action Record of Decision 12/18/96
ii
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TABLES AND ILLUSTRATIONS
Tables Following Document
3-1 Correlation of Geologic and Hydrogeologic Units
5-1 Summary of Soil Contaminant Concentrations
5-2 Summary of VOC Concentrations in Soil Gas
5-3 Summary of Groundwater Contaminant Concentrations
5-4 Summary of Surface Water Contaminant Concentrations
5-5 Summary of Potential Site Risks
6-1 Groundwater Cleanup Levels
6-2 Unsaturated Soil Cleanup Levels
7-1 Summary of Estimated Costs
8-1 Cost-Effectiveness Evaluation
Figures
3-1 S ite Location Map
3-2 Site Features
5-1 Approximate Source Area Locations
5-2 TGA and IRAM Well Locations
5-3 Extent of TCE in TGA Groundwater
5-4 Extent of Total VOCs in TGA Groundwater
5-5 Conceptual Site Model
7-1 Existing IRAM Components'
9-1 Recommended Alternative Components
Administrative Record Index
Cascade Corporation - Remedial Action Record of Decision 12/18/96
iii
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1. INTRODUCTION
1.1 Introduction
This document presents the selected remedial action for soil and shallow groundwater
contamination within the Troutdale Gravel Aquifer (TGA) at the Cascade Corporation (Cascade)
site, in Gresham, Oregon. The selected remedial action was developed in accordance with
Oregon Revised Statutes 465.200 through 465.380, 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 regulations contained in
the National Contingency Plan (NCP), 40 CFR Part 300. The Cascade site is within the East
Multnomah County Groundwater Contamination site proposed for inclusion on the National
Priorities List (NPL or "Superfund" List) in May 1993 by the U.S. Environmental Protection
Agency (EPA). 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 record of decision summarizes the
more-detailed information, contained in the administrative record, particularly the Remedial
Investigation Reports (RT) and Final Feasibility Study (FS).
Cascade conducted the remedial investigation and feasibility study (RI/FS) and several interim
removal action measures (IRAMs) to control contaminant migration in soil and groundwater in
accordance with the requirements specified in DEQ Consent Order Number ECSR-NWR-89-11
issued August 28, 1989. The groundwater IRAMs are components of the selected remedial
action.
1.2 Scope and Role of Selected Remedial Action
The selected remedial action addresses soil and groundwater contamination in the Troutdale
Gravel Aquifer (TGA) at the Cascade site. The remedial action for the groundwater
contamination in the Troutdale Sandstone Aquifer (TSA) underlying the TGA originating from
historical releases at the Cascade facility and the Boeing of Portland facility, will be addressed
under a separate remedial action record of decision. The investigation and development of
remedial action alternatives for the TSA are being jointly performed by Cascade and the Boeing
Company under the requirements of DEQ Consent Order Number ECSR-NWR-93-07.
Cascade Corporation Record of Decision 12/18/96 1-1
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2. SUMMARY OF SELECTED REMEDY
The selected remedial action for soil source areas and the Troutdale Gravel Aquifer (TGA)
contaminant plume includes the following components:
Unsaturated Zone Soil Remediation
• Soil vapor extraction (SVE) to remove volatile organic chemicals (VOCs) from
unsaturated zone soil;
• Destruction of VOCs in soil gas vapors using a catalytic oxidation unit or equivalent
treatment system, prior to venting to the atmosphere;
• Additional characterization of several areas of soil contaminating to determine whether
SVE is necessary in these areas;
• Maintenance of existing asphalt and concrete paved areas where soil contaminant
concentrations exceed protective levels; and.
• Application of institutional controls for soil source areas where residual contaminant
concentrations exceed protective levels.
Groundwater Remediation in the Shallow Troutdale Gravel Aquifer (TGA)
• Continued operation of the on- and off-site interim removal measures (IRAMs),
consisting of a hydraulic control system for TGA contaminant plume;
• Expansion of the off-site IRAM system, if remedy performance monitoring indicates that
hydraulic capture of the off-site component of the contaminant plume is not effective
with existing components;
• Removal of light non-aqueous phase liquids (LNAPL) by co-pumping LNAPL and
groundwater;
• Additional on-site groundwater extraction from 8 existing extraction wells and one new
extraction well;
• Air sparging from approximately 25 air sparging wells in on-site source areas;
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• Discharge of treated groundwater to the Columbia Slough or Fairview Lake via
Mulmomah County storm water drainage ways;
• Long-term groundwater monitoring;
• A contingency to provide long-term hydraulic control of those portions of the TGA
contaminant plume that cannot be restored to cleanup levels; and
t
• Institutional controls for groundwater use restrictions for the TGA, should restoration of
the TGA be determined to be infeasible.
Section 9 provides a detailed description of the selected remedy summarized above.
Cascade Corporation Record of Decision 12/18/96 7.9
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3. SITE DESCRIPTION
3.1 Site Setting
The Cascade facility is located within Section 29, Township 1 North, Range 3 East, Willamette
Meridian at 2201 NE 201st Avenue, Gresham, Oregon (Figure 3-1). The facility is owned and
operated by Cascade Corporation. Cascade's property is approximately 47 acres in size. The
production facility where Cascade manufactures fork lift truck attachments and the product
development center located on the northeast corner of the property occupy approximately 8 acres
(Figure 3-2). The remaining portions of the property are undeveloped and are covered by natural
vegetation (trees, grasses, etc.).
3.1.1 Site Definition
For purposes of the discussion in this document, the terms "site" or "on site" refer to portions of
Cascade's property containing contaminated soil and/or groundwater contamination at levels
requiring remedial action. "Off site" refers to the properties north of the Cascade property with
soil and/or groundwater contamination.
3.1.2 Surrounding Land Use and Populations
The Cascade site is bounded on the north by a Union Pacific Railroad (UPRR) corridor and
Interstate 84 (1-84), on the east by NE 201st Avenue, on the south by undeveloped portions of
Cascade's property. Cascade's property to the south is bordered by residential properties, and
on the west by undeveloped property zoned for industrial use. Between 1-84 and Sandy
Boulevard is a 26 acre tract of land owned by Sandy Boulevard Development Corporation (a
subsidiary of Cascade). This property was used for growing vegetables by a commercial produce
company until the summer of 1996. An adjacent tract to the west is owned by Boyd Coffee
Company.
3.2 Physical Setting
This section summarizes the physical setting of the Cascade site including topography, climate,
surface water, geology, hydrogeology, and surface water and groundwater beneficial uses.
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3.2.1 Topography
The site slopes gently toward the north, from an elevation of approximately 170 feet (ft) above
mean sea level (MSL) along the southern property line to 140 ft MSL along the northern
boundary. The topography of the area north of the site has a more pronounced slope, descending
from south to north in a series of terraces to the modem alluvial plain of the Columbia River
(Figure 3-2).
3.2.2 Climate
Eastern Multnomah County is characterized by mild, wet winters and moderately warm, dry
summers. The mild climate is a result of the surrounding terrain and distance from the Pacific
Ocean. Temperatures typically range between 35° F to 52° F in the winter, and 54° F to 78° F in
the summer. Average annual rainfall in the Portland area is 37 inches with approximately 80
percent occurring between October and May. Prevailing winds are generally from the east
paralleling the Columbia River during the spring and summer, and from the southwest during the
summer.
3.2.3 Surface Water
r
Surface water near the site includes:
• Taggart and Shepard springs, which emerge from the TGA along the erosional
truncation of the TGA; see Section 3.2.4 for description of hydrogeologic units.
• Osboum Spring and Osboum Creek, which emerge southeast of the site and flow
north, approximately one-quarter mile east of the site.
• Fairview Lake, approximately 4,000 feet (ft) to the north-northeast
• The Columbia Slough, which originates at Fairview Lake.
• A drainage ditch (the east ditch) that flows east from NE 201st Avenue to Osboum Creek,
approximately 1,500 ft northeast of the site.
• A drainage ditch at the north site boundary (the north ditch) that parallels the
UPRR corridor and is routed southeast to join the east ditch.
Stormwater runoff from the site discharges into the north and east ditches, which form part of the
Multnomah County storm sewer system.
3.2.4 Geologic and Hydrogeologic Setting
Geologic units under the site include Quaternary deposits and the Tertiary Troutdale Formation.
The Quaternary deposits are less than 15 ft thick and consist of unconsolidated gravel with silt,
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sand and clay. The Troutdale Formation consists of interbedded clastic deposits of volcanic and
fluvial origin consisting of silt, clay, sand, sandstone, siltstone and conglomerate.
Hydrogeologic Units beneath and in the vicinity of the site, listed in order of increasing depth,
are the Troutdale Gravel Aquifer (TGA), confining unit one (GUI), the Troutdale Sandstone
Aquifer (TSA), confining unit two (CU2), and the Sand and Gravel Aquifer (SGA) (Table 3-1).
GUI and CU2 are aquitards that separate the TGA from the TSA and the TSA from the SGA,
respectively.
The TGA consists of gravel with sand, silt, and clay, and is approximately 50 feet thick on-site.
The TGA gradually thins and terminates at an erosional interface located on the sloping terrace at
the Sandy Boulevard Development and Boyd Coffee properties. The upper TGA consists
primarily of unconsolidated silty, sandy gravel with cobbles and boulders. The lower TGA is
typically an indurated sandstone.
GUI is estimated to be more than 60 ft thick beneath the southern portion of the site. It gradually
thins to less than 15 ft in thickness north of the site, being thinner near the erosional boundary.
GUI is 40 to 45 ft thick near the north property boundary. It consists of interbedded siltstone and
claystone; sandstone interbeds are common within GUI.
The TGA is an unconfined aquifer that is recharged both locally and farther upgradient, primarily
by infiltration of precipitation from the ground surface. Groundwater in the TGA flows north
(Figure 3-3). Prior to implementing interim hydraulic control of the contaminant plume off-site,
groundwater in the TGA exited the aquifer in the immediate vicinity of the site by one of three
mechanisms: discharge from Shepard Spring, subsurface flow over the GUI truncation north of
the site where it recharged the TSA, or vertical leakage downward through GUI. Spring flow
from Shepard Spring reinfiltrates into the ground and also recharges the TSA.
The upper portion of the TSA consists of sandstone, and the lower portion consists of
unconsolidated conglomerate. Regional groundwater flow in the TSA is toward the northeast.
Local groundwater flow in the TSA is influenced by TGA recharge north of the TGA truncation
which creates a groundwater mound and complex radial groundwater flow patterns.
3.2.5 Groundwater and Surface Water Use
No domestic, industrial, or irrigation wells completed in the TGA were identified within one
mile of the Cascade site. No surface water rights were identified for Taggard or Shepard Springs,
or Osboum Creek. Fairview Lake uses include agricultural irrigation water supply, recreation
and fishing.
Cascade Corporation Record of Decision. 12/18/96
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4. SITE HISTORY
This section summarizes the manufacturing activities conducted at the Cascade facility, the types
of chemicals used during manufacturing operations, and historical releases related to
manufacturing activities.
4.1 Operational History
The Cascade forklift manufacturing facility has operated continuously at the site since 1956.
Between 1956 and 1963, the production facility included a paint booth, a parts and hydraulic
cylinders assembly area and a maintenance shop. From 1963-1966, the facility was expanded to
incorporate nickel and chrome electroplating operations and vapor degreasing of parts. The
vapor degreaser was removed in 1975 and replaced by hot water and biodegradable soaps for
cleaning of parts.
The production facility was expanded to nearly its present size between 1976 and 1985. Cascade
discontinued chrome and nickel plating operations in 1978. Nickel plating was resumed
between 1982 and 1986. Since 1985, Cascade manufacturing operations have involved parts
machining, welding, maintenance, aqueous degreaser washing, painting, and assembly.
4.1.1 Process Wastes, Management and Disposal Practices
Wastes associated with the historical manufacturing processes at the facility have included
cutting oil, hydraulic fluid and coolants from the machine shop, spent nickel and chrome plating
processing solutions, cyanide salts and contaminated heat treatment pots from the carburizing
process, and paint sludge and paint booth wash water containing minor amounts of paint
ingredients such as toluene, methyl isobutyl ketone (MIBK) and alcohols. Since 1980, Cascade
has maintained manifests for wastes sent off-site for disposal.
Electroplating Operations. Wastes associated with electroplating operations included plating
solutions and wastewater. Wastewaters were discharged to the City of Gresham sanitary sewer
system. Electroplating solutions were drummed and manifested for off-site disposal. Incidental
releases from electroplating operations have not been reported but are suspected, based on
detections of chromium in soil and groundwater in the vicinity of the plating areas.
Parts Painting. Paint dry filters and paint dust were disposed of off-site at St. Johns Landfill.
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Parts Machining and Cleaning. Wastes associated with parts machining included cutting oils
and cooling liquids. Cutting oils typically contained chlorinated solvents. Parts cleaning included
spent solvents (trichlorjthene [TCE]), and sludges which accumulated in the vapor degreaser
tank.
Cascade installed two underground storage tanks (USTs) in 1971 to store used coolants and oils
associated with parts machining. Waste coolants and oils were transferred to the tanks manually
or by a pump in a cutting bin collection sump installed near the UST locations in 1978. Waste
fluids from the USTs were periodically removed for off-site disposal. The USTs were removed
in 1988 and replaced with above-ground storage tanks.
Historical releases of process wastes were not well documented by Cascade during the RI. Prior
to completion of the FS, the only known releases reported by Cascade to DEQ involved an
overflow and release of approximately 40 gallons of cutting oil from the UST in 1985, a 25
gallon spill of methylene chloride inside the plant in 1986, and hydraulic oil within a hydraulic
trench within the production facility in 1990. The first two releases were reportedly cleaned up.
The contamination in the trench line is being addressed as part of the final remedial action for the
site.
In 1995, Cascade reported information obtained from former and current Cascade employees
indicating that wastes from the parts machining and cleaning had been land disposed on-site in
several areas. Spent TCE was reportedly discharged to the ground in two locations (defined as
Area 2 in Section 5.2). These areas are beneath the production facility, which expanded after
these disposal practices occurred. In addition, sludges from the degreaser tank and cutting oils
were disposed near the former UST location and the edge of the parking lot located west of the
production facility (defined as Area 6 in Section 5.2). Both of these areas are now beneath the
current limits of the paved parking lot.
4.2 History of Environmental Investigations
Investigations of the Cascade site began in 1988 following the discovery of soil contamination
during decommissioning of the two underground storage tanks used for storage of fluid used for
machining of fork lift parts. During 1986 and 1987, and prior to tank decommissioning, Cascade
sampled its industrial water supply wefl for halogenated volatile organic compounds (VOCs) at
the request of DEQ. The monitoring was performed in response to the discovery of groundwater
contamination at and in the vicinity, of the Boeing of Portland facility in 1986. The following
sections summarize the historical investigations of the Cascade site. The results of these
investigations are summarized in Section 5.
4.2.1 Industrial Well Monitoring
Cascade performed monthly sampling of its industrial well (completed in the TSA) from 1986 to
1988 after dissolved solvents were detected in groundwater at The Boeing Company (Boeing) of
Cascade Corporation Record of Decision 12/18/96 4_2
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Portland facility. Analytical results from the industrial well samples showed TCE concentrations
ranging from 20 to 130 parts per billion (ppb). The source of VOCs in the industrial well was
determined to be leakage of contaminated TGA groundwater along the well casing to the ISA.
The well was decommissioned in 1991 to eliminate this localized pathway.
4.2.2 Preliminary Remedial Investigation
A preliminary RI and hydrogeological investigation of the Cascade site was performed in 1988
in accordance with DEQ Consent Order No. ECSR-NWR-88-01. The preliminary RI included
review of Cascade's waste management records related to manufacturing operations and
sampling of soil and groundwater, to determine whether historical manufacturing waste
management practices had resulted in contamination to these media requiring additional
investigation. The preliminary RI included installation of 8 monitoring wells on-site, sampling
of soils during drilling of those wells, and collection of surface soil samples in the north ditch.
The investigation documented contamination of soil and groundwater at the site leading to the
DEQ issuance of a Consent Order for completion of an RI/FS.
4.2.3 Remedial Investigation Phases 1 and 2
Cascade conducted phases 1 and 2 of the RI between December 1989 and September 1991.
Phases 1 and 2 of the RI included:
• Installation and sampling of 17 groundwater monitoring wells on- and off-site and one on-
site recovery well;
• Sampling of soils in the north and east ditches, and in the vicinity of the waste coolant USTs;
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• Surface water sampling of Shepard and Taggart Springs and the east ditch;
• Completion of a geophysical survey to characterize the TGA and CU1 off-site;
• Completion of a soil gas survey beneath and in the vicinity of the production facility;
• Additional investigations of the industrial supply well;
• Completion of an aquifer test at the recovery well; and
• Preparation of an interim remedial action measures (IRAM) report
The results of these investigations and the preliminary RI were used to identify potential
contaminant sources at the site, design interim removal actions, which are discussed in Section
4.3, and scope additional investigations for completion of the RI/FS.
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4.2.4 Phase 3 Remedial Investigation and Feasibility Study
Phase 3 of the RI/FS began in March 1992. The Phase 3 RI/FS included:
• Evaluation of the effectiveness of the on-site IRAM pump-and-treat system for
hydraulic control and contaminant removal;
• Completion of an off-site source and receptor survey;
• Characterization of the nature and extent of the Cascade-related contamination in the
ISA;
• Development of a site specific groundwater flow model;
• Completion of a treatability study for biological treatment of groundwater;
• Completion of a potassium bromide tracer study in the TGA;
• Pilot tests for soil vapor extraction and for expansion of the IRAM for the off-site
component of the plume not controlled by the on-site actions;
• Completion of a human and environmental risk assessment; and
• Development and evaluation of cleanup options for the site.
The Phase 3 RI/FS was completed in January 1996 with submittal of the final FS report.
Investigation results related to the TSA were incorporated into the TSA RI/FS, which was
conducted jointly by Cascade and Boeing under a separate DEQ consent order.
4.3 Interim Removal Action Measures
This section summarizes the interim removal action measures (IRAMs) performed by Cascade
since initiation of investigations in 1988. The IRAMs were implemented to control contaminant
migration in groundwater, both on- and off-site, and for removal of soil contamination in selected
areas at the facility that acted as sources of groundwater contamination.
4.3.1 TGA Groundwater
The on-site IRAM is a TGA groundwater extraction and treatment system designed to prevent
further off-site migration of a dissolved VOC plume. The system consists of five removal wells
spaced approximately 50-100 ft apart (one which was a monitoring well converted for
extraction), and an air stripping tower located along the northern property boundary. The pump
and treat system began operation with one removal well in June 1991 and was expanded to three
wells in 1992, four wells in 1994, and to its current configuration of five wells in February 1996.
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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 off-site IRAM, located approximately 600 ft north of the Cascade site, is a 400-ft long trench
with the bottom keyed into the GUI. The trench is designed to intercept the off-site dissolved
VOC plume-in-TGA .groundivater-and:xeduce.the contaminant:flux from the TGA .to the TSA via
groundwater and spring flow over the GUI outcrop. Groundwater collected from the trench is
treated in an air stripper and discharged to the Multnomah County storm sewer system under
discharge requirements specified in the Cascade consent order. The TGA control trench has
operated since December 1995, except for two brief periods of shutdown due to power outages.
Groundwater discharge flow to Shepard Spring ceased soon after operation of the trench began.
4.3.2 Soil Source Area Removals and Other Actions
North Ditch Soil Source Area. Approximately 190 cubic yards (yd3) of contaminated soil was
excavated from the north ditch in 1989 and disposed of at St. John's Landfill. This area received
runoff from the parking areas of the facility. Soil was excavated to a depth of 4-7 feet below
ground surface. Soil contamination remained at the side wall and base of the excavation.
However, additional excavation was discontinued, due to the concerns of impacting the structural
integrity of the Union Pacific Railroad spur.
Oil/Water Separator Removal and Replacement. An oil and water separator and surrounding
petroleum contaminated soil were removed in March and April 1990, and a new oil and water
separator installed. Some of the excavated soil was landfarmed in a lined area south of the
research and development building and subsequently used for fill on the site, and the remainder
transported off-site for disposal.
Industrial Well Decommissioning. An industrial supply well located just west of the production
facility was decommissioned in the summer of 1991, because of leakage of contaminated
groundwater from the TGA to the TSA along the well casing.
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5. REMEDIAL INVESTIGATION SUMMARY
This section summarizes the findings of the Remedial Investigation and Endangerment
Assessment for the Cascade site conducted in accordance with OAR 340-122-080 and EPA's
guidance Guidance for Conducting Remedial Investigations and Feasibility Studies, EPA/540/G-
89/004, October 1988.
5.1 Types of Contamination
Contamination at the Cascade site includes solvents, primarily TCE, from historical parts
degreasing and painting activities, petroleum hydrocarbons from oils and lubricants used for
parts machining, and chromium and nickel from plating operations.
5.2 Source Areas
Six contaminated areas have been identified at the site (Figure 5-1). The source areas located
inside Cascade's production facility were identified from evaluations of past manufacturing
processes and associated waste streams, and from the distribution of high concentrations of
VOCs in soil vapor. Sources outside the production facility were identified based on knowledge
of waste management practices and soil, soil vapor, and groundwater data.
5.2.1 Area 1 - Former Waste Coolant USTs.
Area 1 includes the area around the former USTs, the former cutting bin storage area that was
near the USTs and connected to them, and the cutting bin drainage collection system. Area 1 is
the primary source area at the site in terms of magnitude of soil and groundwater contamination
with petroleum hydrocarbons and VOCs.
5.2.2 Area 2 - Former Vapor Degreaser
A vapor degreaser, formerly located in the northwest part of the production facility, is a source of
VOCs in soil and groundwater. This area also includes locations beneath the existing production
building where spent solvents were reportedly disposed.
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5.2.3 Area 3 - Former Chrome Plating Facility.
The area in the vicinity, of the former chrome plating facility inside the western part of the
production facility is a source of chromium and VOCs contamination of soil and groundwater.
The chrome plating facility was removed in 1978. The area is covered by the production facility
building and pavement adjacent to the production building.
5.2.4 Area 4 - North Ditch.
Soil contamination in the drainage ditch at the north site boundary (the north ditch) which
receives stormwater runoff from the site, consists primarily of petroleum hydrocarbons. VOCs
have also been detected in north ditch soil samples. Contaminated soil was removed to a depth
ranging from 4-7 feet below ground surface from part of the ditch in 1989. Additional
contamination remains below the depth of the 1989 soil removal.
5.2.5 Area 5 - Hydraulic Line Trench
Soil with elevated concentrations of TPH, presumably from hydraulic fluid leaks, remains in the
area of the hydraulic line trench inside the southern part of the production facility. A precast
liner was installed in the trench in 1990 during facility upgrades.
5.2.6 Area 6 - Vapor Degreaser Sludge and Coolant Disposal Area
Soil in this disposal area is impacted primarily by petroleum hydrocarbons. Visual evidence of
contamination is present in the upper 2-4 feet below ground surface. No VOCs were detected in
any of the soil samples collected in this area.
5.3 Nature and Extent of Contamination
The nature and extent of contamination is described below. The nature and extent of
contamination was determined from the results of numerous analyses of soil, soil vapor,
groundwater and surface water samples'collected from the Cascade site since 1988.
5.3.1 Soil and Soil Vapor
The characterization of soil contamination included sampling from over 15 soil borings, 20 test
pits, and 40 soil vapor test or extraction points. The analyses performed on various soil samples
have included aromatic and halogenated VOCs, polynuclear aromatic hydrocarbons (PAHs) and
other semi-volatile compounds, metals, cyanide and total petroleum hydrocarbons (TPH). Table
5-1 summarizes the range of contaminants detected in site soil.
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Metals. Chromium, nickel and copper are the metals associated with Cascade's manufacturing
processes. Chromium was the only metal detected at levels significantly above background
levels. None of the soil.metals concentrations exceeded risk-based screening concentrations.
Volatile Organic Compounds. Trichlorethene (TCE), 1,2-dichloroethene (1,2-DCE),
tetrachlorethene (PCE), and fuel-related compounds toluene, ethyl benzene and xylene have been
detected in site soil. TCE was detected in 5 of 82 soil samples analyzed for VOCs. The
maximum TCE concentration of 5.5 parts per million (ppm or mg/kg) was found in a soil sample
from Area 1 - former waste coolant USTs, at a depth of 10 feet below ground surface (bgs). The
maximum level of 1,2-DCE in soil was found in the same location and depth at a concentration
of 10 ppm. The maximum PCE concentration was found at 9 feet bgs in Area 4. The maximum
concentrations of toluene, ethyl benzene and xylene were detected at a depth of 5 feet bgs in Area
1.
VOCs in Soil Vapor. A total of 41 soil vapor samples were collected from known or suspected
source areas at the site. A total of 13 soil vapor samples were collected in the parking lot area and
along the perimeter of the production plant and 28 from within the production facility. The
predominant VOCs detected were PCE, TCE, 1,2-DCE, and vinyl chloride. VOCs detected in
soil vapors are summarized in Table 5-2.
Semi-Volatile Organic Compounds. A total of 35 samples were analyzed for semi-volatile
organic compounds. PAHs were detected in 5 samples. The sum of the PAHs detected in soil
samples was less than 1 ppm and below risk-based screening concentrations. The low level
PAHs are associated with TPH contamination at the site.
Petroleum Hydrocarbons (TPH). TPH was detected in soil samples from Area 1 - USTs, Area
4 - North Ditch, Area 5 - Hydraulic Trench Line and Area 6 - Sludge Disposal Area. The
maximum TPH concentration detected in Area 1 was 35,000 mg/kg at 10 feet bgs. Between
Area 1 and Area 4, TPH contamination has been detected at levels up to 15,000 mg/kg and in
Area 4 at levels up to 7,000 mg/kg. The maximum TPH concentrations in Area 6 was 800
mg/kg. TPH was detected in Area 5 at a level of 73,000 mg/kg. The source of the TPH in Area 5
is presumed to be leaks from hydraulic fluid lines.
Summary. VOCs in unsaturated zone soil at the source areas are the primary contaminants of
concern to groundwater contamination. VOCs are known to be present in Areas 1 through 4,
although Area 1 appears to be the area of highest VOC contamination. Area 1 is also the
location of the highest TPH contamination. The TPH contamination extends through the entire
unsaturated zone. TPH contamination in the north ditch extends laterally beneath the Union
Pacific Railroad Spur and vertically beyond the maximum depth of soil removed from this area
in 1989. TPH contamination in Area 5 is believed to be associated with incidental leaks from
hydraulic lines. In Area 6, TPH contamination is shallow and confined to an approximate 2-4
foot interval immediately beneath the parking lot subgrade. An evaluation of PAH
contamination associated with TPH indicates that the PAH concentrations do not pose a
significant human health risk from direct contact. Chromium contamination is present in the
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chrome plating area at levels below risk-based screening levels and does not pose a threat to
human health from direct contact.
5.3.2 Groundwater
The groundwater investigation included the installation of 36 monitoring wells, piezometers and
extraction wells in the TGA (Figure 5-2). Groundwater has been monitored since the fall of
1988. Routine monitoring on at least a quarterly basis began in February 1992, and on a monthly
schedule from selected TGA wells during initial groundwater IRAM baseline performance
monitoring. Water levels have been measured monthly in each of Cascade's on- and off-site
TGA and TSA monitoring wells, since February 1991. Currently, 25 TGA monitoring wells, 2
piezometers, 5 vapor extraction wells, 5 recovery wells, and 2 surface water points are sampled
quarterly and analyzed for VOCs.
Groundwater in the TGA has been contaminated both on- and off-site by a number of VOCs, and
to a limited extent by chromium, iron, manganese and lead. A summary of on-site groundwater
metals and VOC data by source area and representative data from select off-site monitoring wells
is presented in Table 5-3.
Metals. Groundwater data from upgradient monitoring wells MW-4a and MW-4b indicate no
detectable concentrations of chromium, lead, manganese, and iron. Dissolved chromium has
been detected in 5 on-site wells and one off-site well. The maxjjrnum chromium levels were
detected in the vicinity of Area 3 - Chrome Plating Area, at a concentration of 172 ug/L.
Chromium concentrations in this well have subsequently declined to levels below the federal
maximum contaminant level (MCL) drinking water standard for chromium of 100 ug/L. No off-
site wells have shown chromium at levels exceeding the MCL. Lead and iron have been
detected in several wells at concentrations less than health-based screening levels. Manganese
has been detected in approximately half of the groundwater samples collected for metals
analyses. The maximum manganese detection was recorded in monitoring well MW-5a located
downgradient of Area 1.
VOCs. A total of 13 VOCs have been detected in groundwater (see Table 5-3). The VOCs of
concern include TCE, cis-l,2-DCE, PCE, and vinyl chloride. Other VOCs which were detected
at low concentrations and are of limited extent include 1,1-dichloroethane (1,1-DCA), 1,2-
dichloroethane (1,2-DCA), 1,1-dichloraethene (1,1 -DCE), and benzene.
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The extent of TCE and total VOC contamination in the TGA is shown in Figures 5-3 and 5-4,
respectively. TCE and cis-l,2-DCE make up the bulk of the total VOC plume shown in this
figure. The highest levels of TCE are in and immediately downgradient of Area 1, the former
UST location. High TCE concentrations have also been found in groundwater at or
downgradient of Areas 2 and 3. Vinyl chloride, a breakdown product of DCE, is localized to
Area 1 (the former USTs location), with concentrations approximately 2-3 orders in magnitude
less than TCE concentrations. The highest levels of PCE were found in the vicinity of Area 3,
the chrome plating area (MW-7) at concentrations generally an order of magnitude less than
maximum TCE concentrations. PCE concentrations off-site are generally 1 to 2 orders in
magnitude less than TCE concentrations.
LNAPL. Light non-aqueous phase liquids (LNAPL) or floating product was discovered in Area
1 near the former USTs location in 1995. LNAPL has been detected in two monitoring wells in
Area 1 at thicknesses of up to 1 foot LNAPL has not been observed in any other areas or
downgradient of Area 1. The LNAPL is believed to be used cutting oils and to contain
chlorinated solvents. TCE and 1,1-DCE were detected in a sample of the LNAPL at
concentrations of 26,000 ppm (2.6 percent) and 2,630 ppm, respectively. The LNAPL serves as
a long-term source of dissolved phase VOCs contamination to groundwater.
Summary. The primary contaminants in the TGA are TCE, cis-l,2-DCE, PCE and vinyl
chloride. Maximum TCE, 1,2-DCE, PCE and vinyl chloride concentrations are located on-site in
the immediate vicinity of groundwater contamination source areas. Groundwater contamination
extends off-site to the TGA outcrop north of the site and has impacted Shepard Spring.
Maximum off-site VOC concentrations are generally one to two orders of magnitu.de less than
maximum on-site concentrations. Chromium and manganese contamination are present in on-
site TGA groundwater above risk-based screening concentrations, but do not extend off-site
above these levels. Lead concentrations are below risk-based screening levels. Iron is considered
non-toxic.
5.3.3 Surface Water
The surface water investigation focused on Shepard and Taggart Springs and the east drainage
ditch which historically received stomiwater runoff from the Cascade site and the north ditch.
Table 5-4 summarizes the range of contaminants detected in Shepard and Taggart Springs
surface water.
Shepard Spring. Shepard Spring has been sampled over 20 times for site related contaminants
(chlorinated VOCs and chromium). TCE and cis-l,2-DCE have been consistently detected at
significant levels (see Table 5-5). TCE concentrations ranged from 105 ppb to 950 ppb, and cis-
1,2-DCE from 93 ppb to 1,200 ppb. Chromium has been detected once at a concentration of 6
ppb.
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Taggart Spring. TCE, cis-l,2-DCE and PCE in the concentration range of 1-2 ppb were
consistently detected in Taggart Spring up until 1992. Most samples collected since that time
have been "non-detect" for VOCs. Chromium was detected twice at a concentration of 6 ppb.
East Drainage Ditch. Seven sediment samples and four surface water samples were collected
from the east drainage ditch, to assess whether historical storm water drainage from the site had
impacted the ditch. No contamination was detected in sediments. Chloroform was the only VOC
detected in surface water at a maximum concentration of 18 ppb. Chloroform is not a significant
site-related contaminant and the detections are not directly attributable to the Cascade site.
5.4 Contaminant Fate and Transport
The contamination in one or more of the six source areas includes VOCs, petroleum
hydrocarbons, and chromium. Each of these contaminants has impacted soil and groundwater in
at least one of the source areas. Figure 5-5 illustrates the transport pathways discussed below.
VOCs disposed at the site volatilized to a limited extent and percolated into the subsurface soil
and TGA groundwater. VOCs trapped in soil void spaces will volatilize to a limited extent and
gradually vent to the soil surface and/or dissolve into infiltrating rainfall. Soil vapor data
indicate that transport of volatile gases in the subsurface occurs at the Cascade site. The highest
soil vapor concentrations are found near source Areas 1 and 2; concentrations generally decrease
rapidly with distance from these sources. It is unlikely that soil vapors emitted from source areas
or concentrated portions of the VOC plume will vent to the surface at significant levels (e.g.
detectable), because most of the site is paved or covered by buildings.
Advective flow with groundwater is the primary contaminant transport pathway in the saturated
portion of the TGA. This is demonstrated by the VOC contaminant distributions near and
hydraulically downgradient of the identified source areas. Advection has caused the VOC plume
in the TGA to move beyond the northern site boundary. The TGA plume consists of
commingled contamination originating primarily from source Areas 1 and 2, with lesser
contribution from source Area 3. Advective transport of chromium and TPH contamination,
however, is limited to the vicinity of the source areas and has not resulted in off-site groundwater
contamination at levels of concern.
The range of groundwater flow velocities in the TGA beneath the Cascade site is estimated to be
from 0.2 to 1.0 ft per day (assuming a range of hydraulic conductivity from 1.7 to 7.2 ft per day).
Without retardation, chemical transport rates would range from 0.2 to 1.0ft per day. With
retardation, a result of the aquifer's organic content, transport rates of 0.2 to 0.8 ft per day for cis-
1,2-DCE, 0.1 to 0.5 ft per day for TCE, and 0.06 to 0.3 ft per day for PCE are expected for the
range of groundwater flow velocities estimated for the site.
Vertical gradients in the TGA show a downward component of flow at the site. The vertical
distribution of contaminants, however, suggests that flow from the upper TGA to the more
indurated lower TGA is limited. An exception is found near the removal wells, where pumping
stresses have increased the hydraulic connection between the TGA subunits. North of the site,
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the contamination has migrated into the lower portion of the TGA, due to thinning of most of the
saturated thickness of the aquifer to the lower portion of the TGA.
Water quality data from the TGA, including Shepard Spring, and the TSA indicate that dissolved
VOCs have been transported from the TGA to the TSA. Transport to the TSA occurs (a) by
infiltration of surface water discharge from Shepard Spring and lesser seeps, (b) by subsurface
flow through the surficial alluvium that covers the truncated surface of GUI, and (c) by leakage
downward through GUI via fractures and other pathways north of the site. Transport to the TSA
by infiltration of spring discharge (surface water) and subsurface flow through the alluvium at
the GUI truncation has decreased since construction of the cutoff trench.
Contaminants will not migrate through GUI beneath the site (and source areas) without first
spreading to the lower TGA. As the TGA thins north of the site, the saturated thickness of the
upper TGA decreases; only the lower TGA is saturated immediately south of the TGA-CU1
truncation. Thus, TGA contamination extends to the top of GUI north of 1-84, which is the area
where downward leakage through GUI is considered most likely.
5.5 Endangerment Assessment
An endangennent assessment (EA) was performed as part of the RJ, 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 EA included a
human health evaluation and an ecological evaluation. Each evaluation includes an evaluation of
the chemicals of concern, a toxicity assessment, an exposure assessment, risk characterization,
and uncertainty assessment
"\
5.5.1 Human Health Evaluation
Chemicals of Potential Concern. Chemicals detected in soil and groundwater were screened to
determine those that posed the greatest potential risk to human health and the environment. The
screening process included the following:
• Calculating the relative risk factor for each detected chemical, on the basis of maximum
concentrations detected and chemical toxicity.
• Evaluating the frequency of detection for the chemicals posing the highest relative risk.
Health-based screening levels were derived consistent with EPA Region 10 guidelines. The
screening levels were based on standard default exposure factors and on a hazard quotient of 0.1
for non-carcinogens or 1 x 10"7 excess cancer risk for carcinogens. The chemicals of concern
(COCs) are TCE, PCE, cw-l,2-DCE, vinyl chloride, chromium, and manganese. TPH was
identified as a COG for the FS due to the magnitude of contamination in certain areas, but was
not carried through the quantitative risk characterization because of the lack of toxicity
information for petroleum products. The hazardous constituents which may be associated with
TPH (e.g. TCE), however, were quantitatively evaluated.
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Exposure Assessment. The exposure assessment evaluates current or potential future exposure
scenarios whereby humans might be exposed to contaminants in affected media (e.g., soiJ,
groundwater, or air). The EA evaluation of soil found no compounds at concentrations sufficient
to identify them as COCs in soil. Exposure to soil was, therefore, not quantitatively evaluated.
Significant exposure to contaminants through inhalation of particulates (metals and semi-volatile
compounds) or vapors (VOCs) was also not considered likely because the source areas are either
paved or contaminants are present at depths greater than 4 feet (north ditch).
An assessment of the beneficial uses of groundwater within 1 mile of the site identified no water
supply wells completed in the TGA. Although there are no current uses of TGA water in the
study area, the exposure assessment presumed future residential use of contaminated TGA
groundwater for domestic use in the absence of remedial action. Future use of TGA groundwater
for normal household use could result in exposure through ingestion or inhalation of chemicals
volatilizing from water. The exposure assessment estimated daily intake for each COC on the
basis of an average exposure scenario and a reasonable maximum exposure (RME) scenario.
Data collected from the lower TGA, the upper TGA, Taggart Spring, and Shepard Spring were
used.
Toxicity Assessment. For the EA, human health effects were divided into two groups, non-
carcinogenic and carcinogenic. The division is based on the mechanism of action associated with
the COCs. Toxicity factors for the assessment were obtained from EPA's Integrated Risk
Information System (IRIS) and/or EPA's Health Effects Summary Tables (HEAST).
A reference dose, or RfD, is the toxicity value used in evaluating non-carcinogenic effects
resulting from exposure to contaminants. The RfD is the estimate of a daily exposure for
humans that is unlikely to produce an appreciable risk or deleterious effect during an exposure
period. The calculated intake of a chemical divided by its reference dose is called the hazard
quotient (HQ). The sum of the HQs for each pathway for each COC at the site is a hazard index
(HI). An HI greater than one (1.0) suggests that deleterious effects may occur to exposed
individuals.
For carcinogens, a slope factor (SF) is used to estimate an upper-bound lifetime probability of an
individual developing cancer as a result of exposure to a potential carcinogen. Total excess
cancer risk (TECR) is determined by dividing the intake of a chemical by its SF for each COC
and summing the individual risk contributions. The risk is expressed as a probability (e.g., 1 x
10 means one additional chance in one million).
Risk Characterization. As previously noted, the EA did not quantify the potential cancer and
non-cancer risks related to soil contamination, based on the screening evaluation and
consideration of background concentrations for metals, and the occurrence and depth of
contamination.
Table 5-5 summarizes the calculated hazard index and excess cancer risk for the potential future
household TGA groundwater and Shepard spring use scenarios. The combined ingestion and
inhalation His were found to exceed 1.0 (and thus represent a risk) for cis-l,2-DCE, and
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manganese in the TGA. These results suggest potential concern for adverse non-carcinogenic
effects from future exposure to water from the aquifer via ingestion or inhalation, in the absence
of remediation. There was also found to be potential concern for such effects at Shepard Spring,
but not at Taggart Spring. The potential TECRs associated with future use of contaminated TGA
groundwater ranged from approximately 4x10" for an average exposure to approximately 3 x
10 for an RME. These estimates exceed applicable MCLs and the State of Oregon protective
level of Ix 10^.
Uncertainty Evaluation. The evaluation of site risks involves the use of assumptions on
potential exposure scenarios and toxicity of chemicals based on animal studies. Conservative
parameters were used for exposure duration, frequency and water ingestion rates. Also, the
exposure assessment assumed that no degradation of site contaminants would occur with time,
which might overestimate or underestimate risks, because vinyl chloride, a degradation product
of PCE and TCE, has a higher toxicity than these chemicals.
Toxiciry data used in the EA were derived by the EPA in a conservative fashion and incorporate
uncertainty factors in the reference dose and carcinogenic slope factors to account for
extrapolation of toxicity data from animals to humans or the level of confidence in the toxicity
studies. Thus, potential risks may be overestimated.
The EA did not quantify potential risk from exposure to PCE and TCE through ingestion,
because EPA has withdrawn the toxicity parameters from their database and is re-evaluating the
toxicity of these chemicals. Since TCE and PCE are two of the major contaminants in TGA
groundwater, the potential risks could be greater than the estimates presented in Table 5-7.
5.5.2 Ecological Evaluation
Ecological receptors were qualitatively evaluated, with the focus on fauna. The potential for
adverse population-level effects on wildlife was evaluated by estimating the size of the
population expected to be exposed to impacted water at Shepard Spring and Taggart Spring.
Estimates of the size of the potentially exposed population were then compared with the natural
population size to determine the overall system impact. The following were concluded:
• Site-related chemicals were not expected to adversely impact the environment;
• Stressed vegetation has not been observed around Shepard Spring or Taggart Spring;
• No federal or state threatened, endangered, or sensitive species inhabit the area of Shepard
Spring or Taggart Spring or are expected to depend on either spring; and
• The number of animals expected to be exposed to impacted water at either Shepard Spring or
Taggart Spring is too small to significantly affect local wildlife populations.
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As noted in Section 4 above, contaminated groundwater flow to Shepard spring has been
eliminated as a result of operation of the TGA cutoff trench. This will result in a relocation of
wildlife which may have inhabited this area to nearby areas such as Taggart Spring.
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6. REMEDIAL ACTION OBJECTIVES AND CLEANUP LEVELS
The overall goal of the remedial action for the Cascade site is to protect human health and the
environment from exposure to contaminated soil and groundwater while allowing existing and
future use of the site consistent with land use zoning. This section summarizes the site specific
remedial action objectives (RAOs) and cleanup levels for soil, surface water and groundwater
that will achieve the overall goal and eliminate the potential risks to human health and the
environment which were described in Section 5.5. Additionally, this section presents a
description of the major applicable or relevant and appropriate requirements (ARARs) and
other standards for components of the remedial alternatives is provided.
Section 7 provides a description of the remedial alternatives and Section 8 provides an
evaluation of the ability of each of the remedial alternatives to satisfy the RAOs and ARARs.
6.1 Remedial Action Objectives
The following site specific remedial action objectives (RAOs) were developed to describe how
protection of human health and the environment would be achieved through the cleanup. The
contaminants of concern (COC) and the media affected, for which the RAOs apply are included
in Tables 6-1 and 6-2.
The RAOs for groundwater, surface water and soil are as follows.
(a) Restore the TGA to background or the lowest protective concentrations, if feasible, in a
reasonable time. If this is not feasible, minimize the area! extent of the TGA that contains
contaminants above maximum contaminant levels (MCLs), 1 x 10*6 excess cancer risk,
or a hazard quotient of 1.0 (whichever is more protective), and provide long-term
containment for areas where concentrations are above MCLs or risk-based levels.
(b) Prevent ingestion of TGA groundwater or surface water that contains contaminants at
concentrations above MCLs or acceptable risk-based cleanup levels.
(c) Protect environmental receptors by preventing discharge of TGA groundwater to surface
water at VOC concentrations that may exceed ambient water quality criteria.
(d) Prevent the further spread of contamination in the TGA to the extent practicable.
(e) Protect groundwater quality in the TSA.
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(f) Allow existing uses of groundwater resources in east Multnomah County.
(g) Prevent direct contact with unsaturated soil that has contaminant concentrations
exceeding risk-based protective cleanup levels.
(h) Reduce contaminant concentrations in, and prevent contaminant migration from,
unsaturated soil, to the extent necessary to achieve the groundwater RAOs defined above.'
6.2 Cleanup Levels
This section summarizes the numerical risk-based cleanup levels for soil and groundwater to
satisfy the remedial action objectives described above. Cleanup levels for surface water in
Shepard Spring are the same as the groundwater cleanup levels because groundwater is the
6.2.1 Groundwater Cleanup Levels
The cleanup goals for the chemicals of potential concern in groundwater (TCE, PCE, cis-1,2-
DCE, vinyl chloride and chromium) are the drinking water standards, which are referred to as the
Maximum Contaminant Levels (MCLs). MCLs are federally promulgated standards for the
protection of human health from use of contaminated drinking water. They are promulgated
under the Safe Drinking Water Act (SDWA) and are the maximum concentrations of
contaminants allowed in water used for drinking (40 CFR 141.1 1-141.16). Oregon has adopted
the federal regulations as state water regulations (OAR Chapter 333 Division 61). The current
MCLs for the VOCs and chromium, 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 chemicals volatilizing from groundwater during normal
household use.
The excess cancer risk corresponding to the MCLs for vinyl chloride and PCE exceed 1x10"*.
However, the expected residual concentrations of these chemicals after cleanup will be much less
than their respective MCLs, if the MCL for TCE is obtained. The vinyl chloride and PCE
plumes are encompassed by the TCE plume, with the vinyl chloride hot spot in Area 1 and the
PCE hot spot in Area 3. To illustrate, a remediation of groundwater in Area 1 where TCE
concentrations are reduced from their current maximum level (5,000 to 10,000 ppb) to the MCL
(5 ppb) represents a 1,000- to 2,000-fold reduction in concentrations. If this 1000-2000 fold
factor is similarly applied to the maximum vinyl chloride concentrations (less than 10 ppb), it is
anticipated that the concentrations will be proportionally reduced to 0.01 ppb. This
concentration corresponds to an estimated cancer risk levels less than 1x10 for vinyl chloride
(based on residential exposure via ingestion, dermal contact* and inhalation). Similarly, analysis
for PCE indicates that PCE concentrations would be expected to be below the 1 x 10"* risk based
concentration in most, if not all, of the TGA.
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6.2.2 Soil Cleanup Levels
The primary cleanup- goals for soil are to prevent exposure to contamination exceeding
acceptable risk-based concentrations under existing and future industrial site uses, and to prevent
continued release of contaminants from the unsaturated soil zone resulting in groundwater
contaminant concentrations exceeding groundwater cleanup levels. Table 6-2 presents the soil
cleanup levels for direct contact and groundwater protection. Background concentrations for
VOCs, carcinogenic PAHs and TPH are assumed to be zero. Background concentrations for
chromium are generally less than 70 mg/kg.
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 Cascade are described
below.
6.3.1 Resource Conservation and Recovery Act (RCRA)
Regulations implementing the Oregon Hazardous Waste Management Act (OAR 340-100-
OQlet.sec.) generally adopt the federal RCRA regulations. These regulations are applicable to
cleanups involving "hazardous wastes" as defined in these rules. 40 CFR Part 261 contains
definitions and criteria for identifying RCRA hazardous wastes. As noted in Section 4, several
of the source areas to be addressed in this cleanup involved disposal of spent solvents and
sludges from the former vapor degreaser, which are F001 listed hazardous wastes. Wastes
consisting of soil cuttings from drilling activities, soil removal, or extracted groundwater that
contain the F001 hazardous waste constituents would have to be managed, treated, and disposed
of as hazardous waste, unless the agency determines through a "contained in" determination that
the constituents are below health-based levels. Listed wastes which are found to be below
health-based levels may still be hazardous waste, based on the toxicity characteristic leaching
procedure (TCLP). Potential characteristic waste codes for wastes at the Cascade site include
D007, D039, D040, and D043.
Wastes that are determined to be hazardous waste 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 ORS
465.315, or determined to be procedural requirements. 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.
Table 6-2 includes the universal treatment standards specified in Section 268 of RCRA, which
must be met prior to land disposal of waste determined to be hazardous waste under Section 261
of RCRA. Wastes determined to be non-hazardous pursuant to Section 261, must be managed in
accordance with the substantive requirements for solid waste described in Section 6.3.2 below.
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Wastewater (e.g. groundwater treated through air stripper) discharges that are point source
discharges subject to regulation under Section 402 of the Clean Water Act are excluded as
hazardous waste at the point of discharge under Section 261.4(a)(2) of the RCRA rules.
However, these wastewaters must be managed in accordance with applicable hazardous waste
regulations until the point of discharge. Wastewaters generated during drilling activities which
are temporarily stored in tanks or drums, however, must be managed in accordance with
applicable hazardous waste requirements.
6.3.2 Solid Waste Management Regulations
The Oregon Solid Waste Management Regulations (OAR 340-93 through 97) regulate the
management of nonnazardous solid wastes. Soil exceeding the site specific risk based
concentrations in Table 6-2 would be disposed off-site in accordance with these regulations. Soil
which is treated to soil cleanup levels for protection of groundwater in Table 6-2 may be used as
fill at the site.
6.3.3 Clean Air Act
Oregon Air Pollution Control Laws (OAR 340-20 and 28) regulate operations of air pollution
stationary sources. These regulations are applicable to air stripping or soil vapor extraction units.
6.3.4 Drinking Water Quality Act
The Oregon rules for public water systems (OAR 333-61) implement the Oregon Drinking Water
Act (ORS 448.115 through 990). These regulations 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. The MCLs are also relevant and appropriate standards for cleanup of the
TGA, because they are assumed to be protective.
6.3.5 Clean Water Act
The federal Clean Water Act administered under Oregon Water Pollution Laws regulate the
discharge of pollutants to surface waters of the State and are applicable to the discharge of
treated groundwater.
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7. DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES
This section describes the remedial action alternatives developed by Cascade in the FS Report
The alternatives were developed to satisfy the RAOs described in the previous section. The
range of remedial alternatives addressed the requirements of OAR 340-122-080(3)(a).
7.1 Areas and Volumes
This section summarizes the areas and volumes of contaminated soil and groundwater that are
subject to the remedial action alternatives.
7.1.1 Groundwater
Figure 5-3 illustrates the areal extent of TGA groundwater contamination exceeding at least one
of the risk-based cleanup levels presented in Table 6-1. The extent of the plume covers
approximately 10 acres. The estimated volume of contaminated groundwater is 20 million
gallons.
7.1.2 Soil
The volume of impacted soil (exceeding background) in all 6 source areas is estimated to be
6000 cubic yards.
7.2 Common Remedial Components
This section describes the remedial actions common to the five alternatives evaluated in
Cascade's FS for the TGA.
7.2.1 Existing Hydraulic Control Systems
As summarized in Section 4, there are two systems (on- and off-site) currently operating to
provide hydraulic control of contaminated groundwater at the site. Each alternative developed in
the FS includes continued operation of these systems.
On-site Hydraulic Control. The existing on-site hydraulic control system is a groundwater
pump-and-treat system that collects groundwater from five extraction wells located along the
north boundary of the site, downgradient of the soil source areas and the production facility
(Figure 7-1). The on-site system is effectively controlling further off-site migration of TGA
contaminated groundwater. Extracted groundwater is treated with a packed-tower air stripper,
discharged to the north ditch, and then conveyed to the east ditch under a National Pollution
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Discharge Elimination System (NPDES) permit previously issued by DEQ. Treated
groundwater is commingled with noncontact cooling water from Cascade's manufacturing plant
before flowing into the east ditch.. The treatment system capacity is approximately 20 gallons
per minute (gpra) and has a VOC removal efficiency of approximately 99 percent.
Off-site Hydraulic Control. The current off-site hydraulic control system is a 420-ft
interceptor trench located north of the site and just upgradient of Shepard Springs (Figure 7-1).
The trench extends to the base of the TGA (average depth of 26 ft below the ground surface), and
is keyed into GUI. Water is extracted from nine sumps with variable-speed submersible pumps.
Trench operations appear to be effectively controlling horizontal TGA groundwater flow, based
on elimination of groundwater discharge to Shepard Spring and water level monitoring.
Extracted water is piped to an air stripper capable of treating 100 gpm at a 99.5 percent VOC
removal efficiency. Treated groundwater from the TGA trench is discharged by gravity flow
through a 6-inch diameter pipeline to the storm sewer. NPDES conditions for this discharge are
specified in the Cascade consent order.
VOC emissions from the on- and off-site groundwater treatment systems are below DEQ
significant emission rates and treatment of off-gasses containing VOCs is not required.
7.2.2 Additional Source Area Characterization
Each of the alternatives, except for Alternative 1, includes additional characterization of the north
ditch (Area 4), the hydraulic line trench (Area 5), and the vapor degreaser sludge and coolant
disposal areas (Area 6) source areas. The characterization would include soil gas monitoring for
VOCs in all areas, and near-surface soil characterization for chromium and TPH in Area 4.
An option for the north ditch is to cap soil in the ditch to reduce the potential for direct contact
with contaminated soil. A culvert would also be installed to direct surface water drainage to the
storm sewer. If additional characterization shows concentrations of VOCs in unsaturated zone
soil that might result in a long-term contaminant source to groundwater, then soil vapor
extraction (SVE), included as a remedial component in Alternatives 2 through 5, will be
expanded-.to include.the-aorth ditch area:
Remedial action for Area 5 and Area 6 will be evaluated after additional VOC soil gas
monitoring.
7.2.3 Cap Maintenance
All the source areas, except the north ditch, are now covered by buildings, asphalt, or concrete.
Each remedial alternative includes resurfacing and maintaining the asphalt pavement covering
Areas 1 and 6, to prevent future exposure to residual soil contamination by site workers. The
other source areas are covered by concrete and should not require resurfacing, but would also be
maintained.
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7.2.4 Groundwater Monitoring
All alternatives include groundwater monitoring to evaluate performance of remedial systems.
Details on the monitoring program will be developed during remedial design. The groundwater
samples would be analyzed for VOCs on all wells, and chromium on selected wells.
7.2.5 Institutional Controls
In each alternative, a notice of the potential that contaminants will remain on site above the
cleanup levels would be filed in the deed records of Multnomah County. This notice would
identify areas where subsurface activities (e.g., excavation) might require special precautions to
prevent exposure to the residual contaminants.
7.3 Description of Alternatives
This section discusses the five remedial alternatives that were evaluated in Cascade's FS for the
TGA, including technological components, estimated cleanup times, and permitting
requirements. The estimated implementation timeframes and total capital and operation and
maintenance costs for each of the five remedial alternatives is summarized in Table 7-1.
7.3.1 Alternative 1
Description. Alternative 1 would continue implementation of existing on- and off-site
hydraulic control systems and groundwater monitoring to assess remediation performance. A
deed notice would be filed with Multnomah County, and regular maintenance of existing paved
areas would also be implemented.
Estimated Implementation and Cleanup Timeframes. The estimated time to achieve the
groundwater cleanup levels is 33 years for the on-site portion of the contaminant plume and 14
to 30 years for the off-site component of the plume. The estimates are based on predicted
contaminant mass removal rates of 8 pounds per month and the contaminant mass estimates
summarized in Table 8-1.
Factors such as contaminant adsorption to soil, heterogeneities in contaminant distribution and
site conditions, presence of nonaqiieous phase liquid (NAPL), and contaminant transport to
groundwater from persistent contaminant sources within the unsaturated zone would probably
prolong cleanup beyond 33 years for the on-site portion of the plume. Cleanup times for the off-
site portion of the plume could increase, if the on-site hydraulic control system is not completely
effective in preventing transport of contaminated groundwater off-site.
Permitting Requirements. Discharge of treated groundwater from the on-site treatment system
would continue under the existing NPDES permit for the Cascade facility. For the off-site
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system, the existing NPDES discharge limits and requirements specified in the consent order
would either be continued under the consent order for remedy implementation or under a NPDES
permit. Contaminant discharge limits for the NPDES are presented in Section 9.
7.3.2 Alternative 2
Description. This alternative includes all the components of Alternative 1 and adds additional
source area characterization, soil vapor extraction (SVE) and passive product recovery for
increased mass removal. These remedial components are described below.
Two wells equipped with bailers would be installed for passive recovery of light nonaqueous
phase liquid (LNAPL) in Area 1. Recovered LNAPL would be temporarily stored on-site in an
above-ground storage tank, characterized and transported off-site for treatment and disposal, in
accordance with applicable RCRA regulations.
Unsaturated soil in Areas 1, 2, and 3 would be treated by SVE. The conceptual design for the
SVE system includes 20 wells in Area 1, nine within and downgradient of Area 2, and four wells
in Area 3. The SVE systems would operate until the VOCs in the extracted vapor from each
source area attain a performance-based concentration below 5 parts per million by volume
(ppmv) total VOCs. The 5 ppmv cleanup level for soil vapor VOCs is based on calculated
equilibrium concentrations for VOCs adsorbed to soil and partitioning to soil gas or
groundwater. The 5 ppmv soil vapor should result in residual VOC concentrations in soil below
the soil cleanup levels for protection of groundwater presented in Table 6-2.
SVE pilot test data from the site indicate that emissions from the full scale SVE system would
exceed significant emission rates for one or more contaminants in Table 6-2 (e.g., vinyl
chloride), and that treatment of VOC air emissions from the system will be required. SVE off-gas
will be treated with a catalytic oxidation unit or equivalent system to meet applicable discharge
requirements.
Estimated Implementation and Cleanup Timeframes. The estimated time to achieve cleanup
is the same as for Alternative 1. The inclusion of passive product recovery and SVE in this
alternative is not expected to reduce the overall cleanup time for groundwater to less than
30 years, although it is more likely that cleanup would actually be attained as compared to
Alternative 1.
Passive LNAPL Recovery. The volume of LNAPL was not estimated because it has been
detected only in two adjacent wells. The time required for passive product recovery is, therefore,
difficult to estimate. The passive LNAPL recovery system was assumed to operate for up to five
years.
SVE. The predicted time frame to reach the performance-based goal of 5 ppmv total VOCs in
unsaturated soil is 10 years. The timeframe is based on the estimated mass of VOCs in the
unsaturated zone soil, an initial mass removal rate of 240 pounds per month and an assumed
30 percent reduction in this initial rate each year.
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Permitting Requirements. The NPDES requirements for groundwater discharge would be as
described for Alternative 1. A Notice of Intent to Construct would be submitted to DEQ's Air
Quality Division for discharge of VOCs from the SVE treatment system, as prescribed by
OAR 340-28-1720 and 1750. Permitting requirements for RCRA are discussed in Section 9.
7.3.3 Alternative 3
Description. This alternative includes the technologies described for Alternative 2, with the
addition of active LNAPL recovery, and both air sparging and groundwater extraction in Source
Areas 1, 2, and 3. These additional mass removal technologies within targeted source areas
would accelerate cleanup and reduce the overall operation and maintenance time frame for the
groundwater extraction and treatment systems. The additional remedial components for
Alternative 3 are described below.
Nine groundwater extraction wells would be used in Source Areas 1, 2, and 3 for combined
groundwater extraction and SVE. Extracted water would be treated by air stripping. The
existing on-site air stripper would be replaced with a 50-gpm system to accommodate the
increased volume of extracted groundwater. Groundwater extraction in the source areas would
lower the groundwater table and increase the volume of soil that could be treated by SVE.
Two wells in Area I would also be used for active LNAPL recovery. The LNAPL recovery
system will likely include pneumatic skimmers. Management and disposal of recovered LNAPL
would be the same as for Alternative 2.
Air sparging involves injection of air into the saturated portion of the aquifer to facilitate
biodegradation and volatilization of VOCs from groundwater. The conceptual design of the air
sparging system consists of 25 sparging wells installed in Areas 1, 2, and 3. Contaminants
volatilized from groundwater to the unsaturated zone soil would be recovered by the SVE
treatment system. Increased air flow to the unsaturated zone soil may also have an added benefit
of promoting biodegradation of TPH contamination.
Estimated Implementation and Cleanup Timeframes. The estimated time to achieve
cleanup levels with Alternative 3 is expected to be less than for Alternative 2. Based on the
anticipated increased mass removal rates, operation of the air sparging and SVE system would
continue for approximately seven years, and additional groundwater extraction from source area
extraction wells for approximately-15 years. Active product recovery was assumed to be
accomplished in two years. Because of the uncertainty in the effectiveness of air sparging and
SVE, it was assumed that the on-site hydraulic control system would operate for at least 30 years
(the maximum time used for costing purposes).
Permitting Requirements. The permitting requirements are the same as described for
Alternative 2, except the existing permit for the on-site system would be modified by DEQ to
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account for the increased flow rate and addition of contaminant discharge limits and monitoring
for chromium. _
7.3.4 Alternative 4
Description. Alternative 4 is the same as Alternatives, with the addition of in-situ
groundwater bioremediation. This technology involves the injection of nutrients and oxygen to
enhance aerobic degradation of VOCs in saturated soil and groundwater. The application of this
technology at the site is described below.
The bioremediation system would consist of aboveground components for delivering nitrogen,
phosphorus, a cometabolite (phenol or toluene), and oxygen to the saturated zone via injection
wells. Five SVE wells in Areas 2 and 3 would be periodically used as injection wells. During
each injection, the air-sparging system, parts of the SVE system, and portions of the source area
groundwater extraction system would be inactive. Treated effluent from the on-site hydraulic
control system would be used as a source of water for reinjection. A pilot test would be required
to determine cometabolite amendment levels, injection flow rates, and system configuration.
Estimated Implementation and Cleanup Timeframes. In-situ bioremediation could
increase initial mass removal rates, but, without a field-scale pilot study, it was difficult to
determine how effective bioremediation would be in reducing VOC concentrations in
groundwater. A five-year duration for biotreatment system operation was assumed for
cost-estimating purposes. The estimated time for operation of other remedial components are as
described for Alternative 3. Because of uncertainties in estimating remedy performance, the FS
assumed that the on- and off-site hydraulic control system would operate for 30 years.
Permitting Requirements. The NPDES requirements would be addressed as described for
Alternative 3. DEQ Water Quality Division approval would be obtained for nutrient and
chemical injection for in-situ bioremediation.
7.3.5 Alternative 5
Description. This alternative is similar to Alternative 4, with the addition of soil excavation
in Area 1. This technology is described below.
Contaminated unsaturated soil would be removed from the area of the former waste coolant
USTs (Area 1), and the oil-water separator north of Cascade's production facility would be
removed and replaced. Approximately 6,200 cu yd of soil would be removed.
The excavated soil will be characterized to determine whether it is a RCRA hazardous waste.
Based on the characterization, the excavated soil would be disposed off-site in accordance with
applicable hazardous or solid waste regulations.
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During excavation, LNAPL/groundwater would be pumped out and managed as described in
Alternative 2. Before the excavation was backfilled, SVE piping and air sparging wells would be
installed.
The bioremediation system would be the same as that described for Alternative 4, with additional
injection capabilities due to the vapor extraction lines installed in the excavation. These lines
would be used periodically for injecting nutrient- and substrate-amended water to enhance in-situ
bioremediation of the underlying soil.
Estimated Implementation and Cleanup Timeframes. The estimated remedy
implementation timeframes and time to achieve cleanup levels with Alternative 5 were assumed
to be the same as for Alternative 4.
Permitting Requirements. The permitting requirements are as described for Alternative 4.
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8. EVALUATION OF REMEDIAL ACTION ALTERNATIVES
This section discusses the comparison of the remedial action alternatives, with respect to the
remedy selection criteria presented in OAR 340-122-090(5) through (9). The purpose of this
evaluation is to consider the relative advantages and disadvantages of each alternative, in order to
select remedies offering the most effective and efficient means of achieving the site remedial
action objectives and cleanup goals described in Section 6. In addition to these five criteria, OAR
340-122-080(3)(b)(B) requires that each alternative be evaluated regarding the extent to which
they comply with the requirements, criteria, or limitations under federal and state environmental
laws. For each criterion, the remedial action that best meets the criteria is presented first. The
other options are discussed in order of ranking.
8.1 Protection and Feasibility Requirements
8.1.1 Overall Protection of Human Health and Environment
Overall protection of human health and the environment addresses whether each alternative
provides adequate protection of human health and the environment and describes how risks
posed through each potential exposure pathway are eliminated, reduced, or controlled through
treatment, engineering controls, and/or institutional controls. The potential exposure pathways
include future ingestion of groundwater as a drinking water supply, direct contact with
contaminated soil in source areas, and direct contact with contaminated surface water in Shepard
Spring.
Background. None of the alternatives will restore the site to background conditions. At least
two soil source areas have physical constraints that prevent direct removal of contamination.
Restoration of groundwater to background concentrations is considered unlikely, due to technical
limitations of available technologies,, heterogeneity of the TGA, and the presence of LNAPL in at
least one source area.
Lowest Concentration Feasibfe and Protective. Based on existing data, soil
contamination exceeding risk-based protective levels for direct contact presented in Section 6.2
is limited to Area 1 (former UST location). Alternatives 2 through 5 include treatment to protect
against further degradation of groundwater. Soil contamination in those source areas has resulted
in contamination of TGA groundwater exceeding groundwater cleanup levels. Alternative 5 will
likely result in the lowest concentration feasible for Area 1, as compared to in-situ treatment
options, and therefore ranks slightly higher in protectiveness than Alternatives 2 through 4.
Alternative 1 ranks the lowest, because it is unlikely that on-site groundwater restoration to
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protective levels could be achieved, due to long-term releases of contaminants from the
unsaturated zone soil.
Alternatives 3 through 5 were equally rated for restoration of groundwater to protective levels,
because of the uncertainties on the relative effectiveness of various remedial technologies.
Alternative 2 ranks slightly less protective than Alternatives 3 through 5, because passive
LNAPL recovery will likely be less effective than enhanced recovery and it does not include
groundwater extraction at the source areas. Alternative 1 ranks lowest, because it is highly
unlikely that groundwater would be restored to protective levels.
All of the alternatives are equally protective for the surface water exposure pathway, because the
off-site hydraulic control system has eliminated discharge of contaminated groundwater to
Shepard Spring.
8.1.2 Use of Permanent Solutions and Alternative Technologies
Each of the five alternatives provided some degree of a permanent solution, used one or more
technologies, and are estimated to remove different quantities of contaminant mass from soil and
groundwater. Alternatives 3, 4, and 5 used the most alternative technologies to permanently
remediate the site. Alternative 5 ranks slightly higher than Alternatives 3 and 4, because soil
contaminated with TPH is removed from the site.
8.1.3 Cost-Effectiveness
To evaluate the cost-effectiveness of one alternative relative to another, the benefits of the least-
expensive alternative were compared with a more-expensive alternative. Because mass removal
was-a primary benefit of the remedial actions evaluated; the ratio of the cost of the alternative to
the total VOC mass removed during the first five years of operations was used as one measure of
cost-effectiveness. In addition to a quantitative comparison based on mass removal rates, a
qualitative evaluation for the other evaluation criteria (e.g., attainment of RAOs, and
protectiveness) was done in the FS.
Table 8-1 shows the mass removal rate for each alternative, the estimated mass of VOCs
removed during the first five years of operation, the total cost of the alternative, and the ratio of
the total cost to total mass removed. Costs considered in comparing the alternatives included
capital costs and the net present value of operation and maintenance costs over the predicted
duration of system use. Costs are summarized in Table 7-1. The total cost for Alternative 1 is
almost entirely for O&M for the existing hydraulic control system with a normalized cost of
$4,170/lb of VOC removed. The capital costs investment associated with the addition of SVE
and air sparging in Alternatives 2 and 3, respectively, results in proportional benefits in terms of
mass removal in the first 5 years, as evidenced by the decrease in the cost per pound of VOC
removed to $440/lb for Alternative 2, and $414/lb for Alternative 3. The capital investment for
in-situ bioremediation in Alternative 4, however, results in only minimal increased mass removal
compared to Alternative 3, resulting in an increase in the cost per pound of VOCs removed to
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$465. The cost per pound of VOCs removed by Alternatives increased to $527/lb. On the basis
of this analysis, Alternative 3 was found to be the most cost-effective.
8.1.4 Effectiveness
The effectiveness criterion evaluated the overall performance of an alternative, including the
extent to which it would reduce the toxicity, mobility, and volume of hazardous substances.
Attainment of the RAOs, potential short-term risks, operational reliability, and time required to
achieve full protection were also considered.
Magnitude of Residual Risk. Alternative 3 was rated slightly higher in effectiveness (i.e. less
residual risk) than Alternatives 4 and 5, due to potential failure of the in-situ bioremediation
process which could result in phenol or toluene co-metabolite remaining in the aquifer.
Alternative 2 rated lower in effectiveness than Alternative 3, based on an assumed increase in
VOC removal efficiency with air sparging provided with Alternative 3, which should result in
lower residual contaminant concentrations in groundwater at the site. Alternative 1 would likely
result in the highest residual groundwater contaminant concentrations of the 5 alternatives
evaluated, and therefore, rated lowest in effectiveness.
Reduction of Toxicity, Mobility, and Volume. Alternative 5 would result in the greatest
reduction of TPH contamination in soil. Alternatives 4 and 5 have the potential to produce
significant reductions in toxicity through in-situ biodegradation of VOCs in groundwater, but the
reliability of this technology has not been demonstrated at this site. Alternatives 2 and 3 should
result in significant reduction in the volume of contaminated groundwater exceeding cleanup
levels. Alternative 1 should restore off-site groundwater to cleanup levels, but probably would
not restore or minimize the extent of groundwater contamination on-site to cleanup levels.
Time until Remedial Objectives Are Achieved. The FS assumed that the groundwater
cleanup would take 30 years, based on the presence of LNAPL in at least 1 source area.
Alternatives 3, 4, and 5 would increase contaminant removal rates and would be expected to
provide the shortest overall time required to clean up groundwater on-site. Alternative 2 would
likely take longer than Alternative 3, because enhanced LNAPL recovery should be more
effective than passive recovery methods. Alternative 1 would take decades to achieve
groundwater cleanup levels.
8.1.5 Implementability
Alternative 1 has already been implemented and, therefore, rates highest under this criterion.
Alternatives 2 and 3 would use proven technologies that are relatively easy to implement, and the
necessary permits and/or DEQ approvals could be readily obtained. Alternatives 4 and 5 would
be somewhat more difficult, because they use in-situ biological treatment, which is an innovative
technology that would require field testing for injecting nutrients and cometabolites (phenol or
toluene) into the groundwater.
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8.1.6 Compliance with Other Regulatory Considerations (ARARs)
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. Alternative 1 was the only alternative that did not satisfy the
CERCLA statutory preference for treatment, because some form of treatment for the soil source
areas to reduce or eliminate long-term contaminant impacts to groundwater is not included.
8.2 Evaluation Summary
DEQ believes Alternative 3 best satisfies the remedy selection criteria specified in OAR 340-
122-090 (5) through (9). Alternative 2 is the next best rated alternative. Alternatives 4 and 5
were rated lower, because in-situ groundwater bioremediation has not been demonstrated beyond
bench scale treatability studies and there are potential detrimental effects to cleanup should
bioremediation fail and the co-metabolites injected into the aquifer remain. Alternative 1 rated
the lowest of the 5 alternatives.
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9. THE SELECTED REMEDIAL ACTION
DEQ has selected Alternative 3 as the remedial action for the site. The estimated cost of the
selected remedial action is S3.9 million. The estimated capital cost and long-term operation and
maintenance costs are $800,000 and $3.1 million, respectively.
9.1 Description of Selected Alternative
The selected remedial action is described in separate sections below and includes modifications
of Alternative 3 described in the Cascade FS Report Modifications to Alternative 3 include the
approach to source area characterization described in Section 7.2.2, and the timing and decision
criteria for institutional controls discussed in Section 7.2.5. In addition, the contingency
measures described in the recommended remedial action have been expanded to address
uncertainties in the on-site source area characterization and in the effectiveness of controlling
the migration of groundwater contamination between the TGA and TSA off-site.
The description includes the identification of the cleanup goals, the elements'of the alternative
addressing soil source areas and groundwater, and other regulatory requirements to be addressed
in the cleanup. Figure 9-1 shows the locations for the remedial components.
9.1.1 Soil Source Areas Remediation
Soil source area remediation includes: soil vapor extraction to remove the VOCs from the
unsaturated zone soil which serve as an on-going source to groundwater contamination;
additional characterization of source areas to determine the scope of SVE or containment;
containment of residual source area contamination; and institutional controls. • Each of these
components is described below.
*
Soil Vapor Extraction. Soil vapor extraction will be conducted in Areas 1, 2 and 3 to remove
VOCs from the unsaturated zone soil. The system will include approximately 20 SVE wells in
Area 1 (4 existing and 16 to be installed), 9 existing SVE wells in Area 2, and 4 wells (2 existing
and 2 to be installed) in Area 3. Based on the additional characterisation of Areas 4, 5 and 6, the
SVE may be expanded, as necessary, to address VOC sources in these areas. The final number,
configuration, and design of the SVE wells will be determined during remedial design.
Soil gasses removed from the SVE well network are projected to contain significant
concentrations of VOCs. The SVE system, therefore, will include a treatment system designed
to meet air quality discharge requirements. A catalytic oxidation unit with a VOC destruction
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efficiency of at least 95 percent, or an equivalent technology developed during remedial design,
will be used for soil gas-treatment prior to discharge to the environment.
The SVE system will be operated until soil gas VOC concentrations are reduced to a
concentration of 5 parts per million by volume (ppmv) in each source area. Soil gas monitoring
will be performed after achieving 5 ppmv and SVE restarted, if soil gas VOC concentrations
rebound above the soil vapor cleanup level.
Additional Source Area Characterization. Additional characterization of Areas 4, 5 and 6,
and soil contamination areas identified during plant expansion construction will be conducted to
determine whether these areas contain significant levels of VOCs. The characterization will
include a soil gas survey.in Areas 4 and 6, and along, the south side of the production building,
andysoitigasimonitoring^omsoi^^^
within the production buildihgi If additional characterization shows concentrations of VOCs in
unsaturated zone soil that might serve as a long-term source to groundwater contaminant
releases, then soil vapor extraction (SVE) will be expanded to address these areas.
Confirmation soil samples will be collected from the north ditch, to verify that no residual
contamination exists in the upper 4-foot soil interval. This sampling will be limited to the metals
and semivolatile organic chemicals presented in Table 6-2. If the additional characterization
determines that these contaminants exceed applicable cleanup levels, then the soils will either be
excavated for treatment/disposal or capped in place.
Cap Maintenance. Based on existing information, all the source areas with residual soil
contaminant concentrations exceeding the direct contact, risk-based concentrations in Table 6-2
are currently covered by buildings, asphalt, or concrete. The asphalt paved parking lot will be
resurfaced after completion of drilling activities associated with SVE, air sparging and well
installations. All asphalt pavement covering Areas 1 and 6, and the contingent cap in Area 4 will
be maintained and resurfaced as necessary. Concrete surfaces covering other source areas will
also be maintained as necessary.
Institutional Controls. A DEQ-approved notice will be recorded in the deed records of
Multnomah County. This notice will identify areas where soil contamination above cleanup
levels exists and identify special precautions to be undertaken during any future subsurface
excavation. The geographic scope of the deed notice will be determined at the completion of the
soil remediation.
Remedial Action Duration. Implementation of the SVE system is projected to continue for 7
years. The actual timeframe will be based on achieving and maintaining the 5 ppmv VOC soil
gas concentration action level. Completion of the additional source area characterization is
expected to take less than 1 year. Cap maintenance and institutional controls will be evaluated
periodically, for those areas where residual contaminant concentrations exceed risk-based
cleanup levels.
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9.1.2 Ground water Remediation
Groundwater remediation includes: continued operation of the on- and off-site hydraulic control
systems described in Section 7.2; LNAPL extraction in Area 1; additional groundwater
extraction and air sparging from Source Areas 1, 2, and 3; groundwater monitoring; and
contingency measures. Each of these remedial components are described below.
LNAPL Recovery. Two wells will be installed in Area 1 to remove the floating product
(LNAPL) in this location. The LNAPL will be removed by co-pumping of groundwater and
product. The recovered product will be separated from groundwater and contained in an above
ground storage tank, to be located within a hazardous waste storage area to be constructed. The
storage area will be equipped with secondary containment, in accordance with hazardous waste
regulations. The LNAPL has been characterized as an F001 listed hazardous waste and will be
transported off-site for treatment and disposal, in accordance with applicable RCRA regulations.
Additional Groundwater Extraction, Treatment and Disposal. Groundwater will be
extracted from Areas I through 3, using 8- existing and I new well. Additional extraction may be
implemented in Areas 5 and 6, based on additional investigations to be performed to assess VOC
releases in these areas. The source area groundwater extraction is expected to increase on-site
groundwater extraction rates from the current rate of 7-10 gpm to 30-40 gprn. To accommodate
the additional flow, the existing air stripper will be replaced with a larger packed air stripper
with a 99 percent VOC removal efficiency. No treatment of VOC emissions from the air stripper
witt ;be required,- because -VOG emissions will not exceed DEQ significant enrissiorrrates. For-
the on-site actions, treated groundwater will be discharged to surface water, under the existing
NPDES permit. The existing permit will be modified by DEQ to incorporate the increased flow,
and add monitoring and discharge limits for chromium and other constituents such as nitrate,
orthophosphate and total phospate identified by DEQ's Water Quality Source Control Section.
For the off-site system, NPDES discharge requirements will be specified in the consent order for
implementation of the selected remedy, pursuant to OAR 340-45-062, or in an NPDES permit
Contaminant discharge limits for VOCs will be established at the MCLs shown in Table 6-1.
Monitoring and reporting requirements for other constituents such as nitrate, orthophosphate and
total phospate identified by DEQ's Water Quality Source Control Section will be specified in the
NPDES discharge requirements of the consent order or NPDES permit
Air Sparging. Approximately 25 air-sparging wells will be installed in Areas 1, 2 and 3, to
increase VOC removal from groundwater. The air sparging will volatilize VOCs from
groundwater to the vapor phase, where they will be removed with S VE, and will promote natural
degradation of VOCs and TPH in soil and groundwater through the addition of oxygen to the
subsurface. The final number, configuration and design of the air sparging wells will be
determined'during remedial design.'
Remedy Performance Monitoring. Groundwater will be monitored to assess the effectiveness
of the remedial actions in hydraulic capture and restoration of groundwater to the cleanup levels.
The specifics of the monitoring program will be defined during remedial design. The
groundwater monitoring network may be expanded, as necessary, to assess impacts to
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groundwater from additional source areas or to assess remedy performance. Performance
evaluation reports will he submitted anually. Detailed performance evaluations will be prepared
at a minimum of every five years during remedy implementation.
Cleanup Levels. The goal of the selected remedial action is to restore groundwater to its
beneficial use, which is, at this site, a potential drinking water source. The groundwater cleanup
levels for the site are the MCLs listed in Table 6-1.
Remedial Action Duration and Contingency Measures. The selected remedy will include
groundwater extraction for an estimated period of 15-30 years, during which time the system's
performance will be carefully monitored on a regular basis and adjusted as warranted by the
performance data collected during operation. Modifications are subject to DEQ approval and
may include any or all of the following:
1. Expansion of the off-site hydraulic control trench, if monitoring data indicate that
contaminated groundwater is migrating laterally around the trench;
2. At individual wells where cleanup goals have been attained, pumping may be
discontinued;
3. Alternating pumping at wells to eliminate stagnation areas; and
4. Pulse pumping to allow aquifer equilibration and to allow adsorbed contaminants to
partition into groundwater;
To ensure that cleanup levels continue to be maintained, the aquifer will be monitored at least
every 2 years, for a 10-year period following discontinuation of groundwater extraction.
The following contingency measures will be implemented if it is determined that certain portions
of the aquifer cannot be restored to the cleanup levels:
1. Hydraulic control of these areas to prevent recontamination of portions of the aquifer
previously restored to MCLs;
2. Institutional controls in a form deemed necessary by DEQ to restrict use of
groundwater as a drinking water supply;
3. Continued monitoring of specified wells; and
4. Re-evaluation of remedial technologies, such as in-situ bioremediation, for
groundwater restoration.
The decision to invoke any of these measures may be made during periodic reviews of the
remedial action, which will occur at 5 year intervals, beginning when the remedy is determined
to be operational and effective, in accordance with the requirements specified herein.
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9.2 Satisfaction of Protection and Feasibility Requirements
9.2.1 Overall Protection of Human Health and Environment
The selected remedy is protective of human health and the environment. There are no current
users of TGA groundwater for drinking water supply. Future use of TGA groundwater during
remediation can be controlled by Cascade, who owns most of the affected property, with the
exception of the land for 1-84 and Union Pacific Railroad transportation arterials, which are not
considered areas feasible for groundwater use development. Restoration of the TGA to the MCL
for TCE is expected to result in residual concentrations for the other VOCs well below MCLs or
equivalent risk-based concentrations.
9.2.2 Permanent Solutions and Alternative Technologies
The selected remedy includes SVE and air sparging technologies which, combined with
groundwater extraction, will permanently remove contaminants from soil and/or groundwater
beneath and downgradient of the site. After completion of all active remedial actions, soil and
groundwater contamination is predicted to approach cleanup levels. Cap maintenance, notices in
the deed records, and groundwater monitoring will be maintained until cleanup levels are
achieved.
9.2.3 Cost-Effectiveness
As discussed in Section 8.1.3, the selected remedial action alternative is cost-effective, because
the incremental and total costs are proportionate to the incremental and total results.
9.2.4 Effectiveness
Reduction in Toxicity, Mobility, and Volume. The selected remedy is expected to remove
a significant mass of VOCs from soil and groundwater, and to significantly reduce the areal
extent of groundwater contamination above cleanup levels. Groundwater hydraulic controls will
reduce, if not eliminate, further migration of contamination from the TGA to the underlying
TSA. VOCs removed by the SVE system will be destroyed through catalytic oxidation. Product
recovery in Area 1 will remove an on-going source of contamination to shallow groundwater.
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 and SVE systems. However, VOC emissions from groundwater treatment systems
will be minimal and will not pose a significant risk to neighboring residents. Treatment of air
Cascade Corporation Record of Decision 12/18/96 9.5
-------
emissions from the SVE system will protect the community from significant VOC emissions
during system operation.
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 various remedial systems. Operation,
maintenance, and monitoring of these systems will pose only minimal risks to remediation
workers.
Environmental Impact The off-site IRAM, which is a component of Alternative 3, has
stopped the discharge of contaminated groundwater to Shepard Spring, eliminating the primary
exposure pathway to ecological receptors in this area. Alternative 3 will not cause significant
adverse impacts to the environment from discharge of VOCs from groundwater treatment
systems or discharge of treated groundwater to surface water bodies.
Time Until Full Protection Is Achieved. Full protection of human health through
groundwater restoration may take up to 30 years. Restoration of soil source areas to levels
protective of groundwater is projected to take 7 years. Protection of on-site workers from direct
contact soil contamination currently exists, because all on-site source areas are paved.
Additional investigation and remedial measures for the north ditch can be completed within 6-12
months.
Magnitude of Residual Risks After Implementing Remedial Action. The selected
remedy will result in reduction of contaminant concentrations in soil to 1 x 10"* excess lifetime
cancer risk levels for carcinogens and a hazard index of less than 1 for non-carcinogens. Based
on existing information, soil contaminant concentrations for PAHs and metals are below
protective levels presented in Table 6-2. Cleanup of VOCs in soil to the 5 ppmv total VOC
concentration''in •sbrl"vapxn7"will"TCsnlti*iri resrdTM"VOCTxohcentrations:"in soft"belcfw"-the
groundwater protection levels presented in Table 6-2. Although the soil remedy will result in
containment of TPH contaminated soil above 500 mg/kg, TPH itself will not pose a threat to
human health and the environment, because the hazardous constituents (VOCs) should be
effectively removed by SVE/air sparging.
Based on the information obtained during the remedial investigation, and the analysis of all
remedial alternatives, DEQ believes that the selected remedy may be able to attain the MCLs
presented in Table 6-1.
Type and Degree of Long-term Management, including Monitoring and Operation
and Maintenance. Groundwater contamination may be especially persistent in the immediate
vicinity of the contaminant source areas, where concentrations are relatively high. The ability of
the remedial alternative to achieve cleanup of groundwater throughout the plume area cannot be
determined, until the remedy has been implemented, modified as necessary, and plume response
monitored over time. Alternative 3 will require intermediate to long-term groundwater
monitoring. Long-term operation and maintenance and performance monitoring of the on- and
off-site hydraulic control and source area groundwater extraction systems, and maintenance of
Cascade Corporation Record of Decision 12/18/96
-------
the existing cap will also be required. The SVE and air sparging systems will require
maintenance and performance monitoring for the duration of their operation, which is currently
estimated at 7 years.
Long-term Potential for Exposure of Human and Environmental Receptors to
Remaining Contaminants. There is a low potential for exposure of receptors to remaining
contaminants after completion of Alternative 3. The selected remedy includes contingencies for
groundwater use restrictions, for those areas which cannot be restored to protective levels.
Potential for Failure of Remedial Action or for Need to Replace Remedy. The use of
proven or demonstrated technologies will limit the potential for failure of the remedial actions
included in Alternative 3.
9.2.5 Implementability
Degree of Difficulty. The mass removal and treatment technologies to be used are proven
technologies and are readily implementable. The institutional controls (placing notice in deed
records), groundwater monitoring, and cap maintenance are also easy to implement.
Expected Operational Reliability. The mass removal and treatment technologies that will
be used by Cascade are commonly used, proven, and generally reliable.
Need to Coordinate with and Obtain Approval from Other Agencies. Implementation
of the selected remedy will primarily involve the DEQ for permit revisions/waivers. The
existing NPDES permit will require modification to increase the rate of groundwater discharge
from the source area extraction wells, and to add discharge requirements for metals and possibly
other constituents such as nutrients. Authorization from Multnomah County will be needed for
increasing the discharge volume to the storm sewer. NPDES discharge requirements for the off-
site hydraulic control system will either be issued as part of the consent order for remedy
implementation, or issuance of an NPDES permit by DEQ. An air emissions permit from the
DEQ, for the discharge of VOCs from the SVE and groundwater treatment systems, will not be
required. DEQ will approve the design and construction of the hazardous waste storage facility,
to be used for storage of LNAPL product and other wastes generated during remedial action
construction activities.
Availability of Equipment and Specialists. Equipment for the on- and off-site hydraulic
control systems, and source area groundwater extraction has either been installed or can easily be
acquired. Equipment and personnel to operate the SVE, air sparging, and active product
recovery systems are also readily available.
Available Capacity and Location of Treatment, Storage, and Disposal Services.
Recovered product will be temporarily stored on site before it is transported to an off-site
treatment, storage, and disposal facility for treatment. A permitted facility for acceptance for this
material has been identified.
Cascade Corporation Record of Decision 111 \ 8/96 n 7
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Ability to Monitor Effectiveness of Remedy. Periodic inspections of the capped area and
extraction and treatment systems, plus groundwater monitoring, will provide the information
required to evaluate the effectiveness of the selected remedy.
9.2.6 Compliance with Other Regulatory Requirements
Alternative 3 will comply with the regulatory requirements described in Section 6.3. In addition,
the recommended remedy satisfies federal requirements in CERCLA and the NCP.
9.2.7 Consistency with Revised Oregon Environmental Cleanup Statutes
The State of Oregon Environmental Cleanup Statutes (ORS 465.315 through 465.325) were
amended in 1995 by the 68th Oregon Legislative Assembly (House Bill 3352). 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 1995 Cleanup Law, to the maximum extent
practicable within the bounds of existing cleanup rules. This section evaluates consistency of the
selected remedial action with the amendments in the statute.
Protect!veness. Under the 1995 Cleanup Law, the protectiveness of a remedial action is
determined by application both of 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
rulemaking is completed. The selected remedial action is nonetheless consistent with this
provision of the revised statute and the current rules.
The acceptable risk levels for human health prescribed by the revised statute are 1x10"* excess
lifetime cancer risk for individual carcinogens and a hazard index of one for non-carcinogens.
The selected remedy is expected to achieve these standards in soil, and to restore the TGA
aquifer to MCLs for drinking water.
Treatment of Hot Spots. Once the 1995 Cleanup Law becomes fully operative, the treatment
of hot spots of contamination will be required to the extent feasible. The selected remedy
requires treatment of groundwater contamination Source Areas 1, 2 and 3 using SVE, air
sparging and groundwater pump and treat technologies, and utilizes containment for those source
areas which pose a low level risk (at or below 10"6 excess cancer risk). Although there are no
existing beneficial uses of TGA groundwater within 1 mile of the site, the TGA groundwater
contaminant plume is considered a hot spot, because it is hydraulically connected to the
underlying TSA aquifer, which is currently used as a source of residential drinking water supply.
Remedial Methods. The selected remedy is consistent with the remedial methods described
in the 1995 Cleanup Law, in that it includes a combination of containment, removal, treatment
using "presumptive or generic" remedies such as SVE, institutional controls, and other measures
such as monitoring and maintenance.
Cascade Corporation Record of Decision 12/18/96
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Balancing Factors. .Under the 1995 Cleanup Law, remedial actions selected by DEQ 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 3 provides the best balance against these criteria. As shown in
Table 8-1, the increase in cost for Alternative 3, as compared to less expensive Alternatives 1 and
2, is reasonable, because the benefits (e.g. mass removal/risk reduction) are proportionate to the
increase in cost. Alternative 4 and 5, however, would not satisfy this criteria in comparison with
Alternative 3.
Land Use and Beneficial Groundwater Use. The 199S Cleanup Law requires DEQ to
consider current and reasonably-anticipated future land uses at the facility and surrounding
properties, when selecting a remedial action. DEQ considered present and potential future land
uses at the facility in determining risk-based cleanup levels for soil (Table 6-2). DEQ has
determined that continued industrial use of the Cascade facility is a reasonably likely future use,
and has selected soil cleanup levels for direct contact based upon an industrial exposure
scenario.
The selected cleanup levels for groundwater are based on potential future use of the TGA aquifer
as a source of residential drinking water supply. This determination is based on the hydraulic
connection between the TGA and die underlying TSA, which is currently used as a residential
drinking water source.
Cascade Corporation Record of Decision 12/18/96 9.9
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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 and 15, 1996, respectively. On September 1,1996, DEQ also mailed copies of a fact sheet
and proposed plan (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 DEQ's recommended remedial action for the Cascade Corporation 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 Cascade site. DEQ issued press releases to the news
media several days prior to the public hearings, to remind the public of the scheduled 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 recieved on the proposed cleanup plan for the Cascade site.
Cascade Corporation Record of Decision 12/18/96 10-1
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11. CONSIDERATION OF PUBLIC COMMENTS
This section summarizes the verbal and written public comments received by DEQ concerning
the recommended remedial action for the Cascade site. Written comments were received from
Cascade Corporation, the City of Portland, and Friends of Blue and Fairview Lake.
Comment: The staff report states that discharge requirements for treated groundwater from the
off-site trench will be specified in the consent order, and will be established at MCLs. This is an
order of magnitude lower than the current discharge limit of 50 ppb for the trench and the on-site
remedial system.
Response: Effluent monitoring from the existing trench treatment system has shown non-
detection of VOCs, since operations began. Therefore, establishing discharge limits consistent
with those included in related NPDES permits (e.g. Boeing Portland and for the TSA remedy) is
feasible, and readily attainable with the existing air-stripping treatment systems, or the new on-
site system to be installed for the final remedy.
Comment: Cascade Corporation does not support continued characterization of Area 6 as a
significant long-term source of VOC impacts to groundwater. Past characterization in Area 6 has
shown no indication of VOC impacts.
Response: DEQ has determined that additional characterization is necessary for Area 6, as well
as for newly identified contamination along the south side of the production building for several
reasons. First, soil sampling at the site has rarely shown significant VOC concentrations in soil,
due either to the soil matrix (gravels) or to sample collection, preservation and analysis methods.
At the Cascade site, soil gas monitoring has been demonstrated to be more reliable in identifying
VOC soil source areas at the site than direct soil sampling and analysis methods. Second, the
documentation provided by Cascade for the test pits installed in this area is limited and does not
define zones of contamination relative to the soil sample collection points. Finally, VOC
concentrations have continued to increase in extraction well RW-3 with time. This has not been
explained by Cascade, and is difficult to understand with the low sustainable groundwater
extraction rates (less than 1 gpm) of the newly installed extraction well RW-4, which suggests
the source of the VOCs in RW-3 are not from Area 1. Further investigation is needed to
determine whether Area 6 is the source of VOCs in RW-3, and whether other recently discovered
soil contamination is a source to groundwater contamination at the site.
Comment: The City of Portland is concerned that the proposed on-site and off-site extraction
systems for the TGA at the Cascade site, will not stop the downward leakage of contaminants
through CU1 into the TSA, especially in the area north of the Cascade site where GUI thins. The
Cascade Corporation Record of Decision 12/18/96 11-1
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City believes that Cascade must be required to implement a monitoring program to ensure that
migration from the TGA to the TSA is halted, and be required to enhance the remedy, as
necessary to protect the TSA.
Response: DEQ understands the City's concerns and believes that actions have been taken to
address those concerns. The off-site trench was designed to hydraulically control the horizontal
flow of groundwater across the GUI outcrop north of the site. The control of the potential
vertical seepage of groundwater through CU1 is being accomplished by maintaining water levels
within the trench below the TGA/CU1 contact With the preferential flow in the TGA north of
Cascade documented during trench construction, it is difficult to identify what more can be done
to control vertical migration. However, the final remedy does include contingencies to expand
the trench, and requires additional groundwater monitoring to assess remedy performance.
Comment'. The City is concerned about the proposed discharge of treated TGA water to the
Columbia Slough. DEQ's Water Quality's Division has determined that the Sough is water
quality-limited water body for toxics (including metals), and eutrophication factors such as low
dissolved oxygen, elevated levels of nutrients, and biochemical oxygen demand. As a
consequence, DEQ is developing total maximum daily loads (TMDLs) for some pollutants
discharged to the Slough. Until TMDLs are established, state regulations do not allow new
discharges of contaminants contributing to water quality violations. DEQ appears not to have
assessed the effects on the Slough of plume co-contaminants, such as metals, 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 levels
exceed TMDLs or other established limits.
Response: Based on exisiting information, nitrates are not elevated in the TGA on-site, but are
elevated in the off-site TGA remediation area. However, concentrations are below the drinking
water standard of 10 mg/L. The presence of elevated nitrates in off-site remediation area is
presumably related to historical agriculture practices there. Effluent from the trench sytem was
tested for nitrate and phosphate near the end of the public comment period. Nitrate
concentrations in the trench water are approximately one sixth the concentrations detected in
Taggart spring located west of the trench; phosphate levels were essentially the same. Taggard
spring and the trench efflfuent both discharges to the Slough through the same storm water
drainage system. Flow rates from Taggart spring typically exceed the extraction rate for the
trench.
Summer dry periods is when low dissolved oxygen (DO) occurs in the Slough due eutrophication
factors elevated levels of nutrients, biochemical oxygen demand. During this time, groundwater
extraction rates are 5 gallons per minute or less. The nutrient loading from discharge of effluent
from the trench is deminimus in comparison to loading from surface water discharges (e.g.
Taggart Spring), or natural groundwater discharge. Because the groundwater is being treated by
air stripping, the effluent would contain high levels of oxygen, not low levels as indicated in the
comment.
Cascade Corporation Record of Decision 12/18/96 11-2
-------
The final remedy will involve an increase in the rate of discharge of treated groundwater to
Fairview Lake, via the east ditch and Osboume Creek, under the existing NPDES permit
covering the existing on-site IRAM. The final remedy specifies that DEQ will modify Cascade's
existing NPDES permit to include monitoring for chromium or other constituents identified by
DEQ's Water Quality Program.
Comment: Monitoring for chromium and other known heavy metal contaminants should be
required for treated effluents from the TGA remediation effort at Cascade, and plans for heavy
metal removal prior to discharge into nearby surface waters should be developed.
Response'. The final remedy requires modification of the existing NPDES permit for Cascade's
on-site remediation system, to include monitoring for chromium and other constituents identified
by DEQ's Water Quality Program.
Cascade Corporation Record of Decision 12/18/96 11-3
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12. DOCUMENTATION OF SIGNIFICANT CHANGE
No significant changes were made in the final remedial action selected by DEQ as a result of
public comment. However, DEQ expanded the scope of the additional source area
characterization to be performed during remedial design, due to the discovery of additional soil
contamination at the Cascade plant site during the public comment period. Additional soil and
gioundwater remediation, using the remedial technologies specified in the selected remedy may
be required based on the additional characterization. DEQ also made minor modifications of the
NPDES discharge limits and monitoring, to assess nutrient loading to Fairview Lake and the
Columbia Slough.
Cascade Corporation Record of Decision 12/18/96
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13. FINAL DECISION OF THE DIRECTOR
The selected remedial action for the Cascade Corporation 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 9.3.
13.1 Director's Signature
Lang<{onyMarsh, Director Date
Department of.Environmental -Quality..... -
Cascade Corporation Record of Decision 12/18/96 13-1
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TABLES
Cascade Corporation Record of Decision 12/18/96
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Table 3-1
Correlation of Geologic & Hydrogeolgic Units
System
Quaternary
Tertiary
Series
Holocene/
Pleistocene
Pliocene
Miocene
Geologic Unit (after
Tolan and Beeson, 1984)
Alluvium/Unconsolidated Sand and
Gravel
Upper Member
Troutdale Formation
Lower Member
Troudale Formation
Sandy River Mudstone
Hydrogeologic Unit (after
Hartford and McFarland, 1989)
TGA
GUI
ISA
CU2
SGA or SRMA *
' SRMA - Sandy River Mudstone Aquifer.
Cascade Corporation Record of Decision
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Table 5-1
Cascade Corporation Site
Summary of Compounds Detected in Soil(a)
Compound
No. of
Samples
Volatile Organic Chemicals
Tetrachloroethene
Trichloroethene
1-2-Dichloroethene
Benzene
Toluene
Ethyl Benzene
Xylenes
55
60
53
56
60
60
55
No. of
Detects
2
5
7
1
13
5
12
Range (mg/kg)""
Min.
0.0008
0.002
0.05
0.3
0.0004
0.0063
0.01
Max.
0.09
5.5
10
0.3
4.5
I
4.5
Location of Maximum
Concentration.
Area 4 - North Ditch
Area 1 -Former Ust Location
Area 1 -Former Ust Location
Area 1 -Former Ust Location
Area 1 -Former Ust Location
Area 1 -Former Ust Location
Area 1 -Former Ust Location
Semi-Volatile Organic Chemicals
TPH
PAHsw
52
39
52
5
5
0.01
35,164
0.21
Area 1 - Former UST Locations
Area 6 - Sludge Disposal Area
Metals
Arsenic
Chromium
Copper
Lead
Nickel
15
39
15
4
39
15
39
15
4
39
0.35
1.2
9.6
140
62
37
1,430
1,300
200
170
Area 4 - North Ditch
Area 3 - Chrome Plating Area
Area 4 - Norm Ditch
Area 4 - North Ditch
Area 4 - North Ditch
Notes:
a. Includes data from RI and Supplemental Investigation
b. Includes detected sample results only.
c. Polynuclear aromatic hydrocarbons
Cascade Corporation Record of Decision
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Table 5-2
Cascade Corporation
Summary of VOCs Detected in Soil Vapor Samples'*'
Sample I.I>. -
C-106V
SV-6
C-103V
SV-1
... : .•: , Concentration: (mj^n^;® 1:
PCE
ND
8
8.9
2
iTCgY:^=:
584
86
10.6
15
.1,2-DCE;>X
554
92
12.4
2
Source Area
Area 1 - Former UST Location
Area 2
Area 3
AreaS
Note: No soil vapor samples collected from Areas 4 and 6.
Table 5-3
Cascade Corporation
Summary of Groundwater Contaminant Concentrations
Compound
No. of
Samples
Volatile Organic Chemicals
Tetrachloroethene
Trichloroethene
1-2-Dichloroethene
Vinyl Chloride
Benzene
397
397
384
397
43
No. of
Detects
208
315
27}
45
3
Range (ug/L)w
Min.
0.6
0.5
0.5
0.6
2
Max.
920
11,000
13,000
106
3
Location of Maximum
Concentration.'
Area 3 (MW-7s)
Area 1 (MW-5a)
Area 1 (MW-5a)
Area 1 (MW-28s)
Area 1 (MW-5a)
Metals
Chromium
Iron
Lead
Manganese
187
37
170
37
24
7
6
' 15
6
25
2
7
172
9,690
7
811
Area 3 (MW-7s)
Area2(MW-15s)
MW-8i (next to 1-84)
Area 1 (MW-5a)
Notes:
a. Includes data through May 1994; max. concentrations lower since ERAM implementation
b. Includes detected sample results only.
Cascade Corporation Record of Decision
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Table S-H
Cascade Corporation
Chemicals Detected in Surface Water
IPPb)
Chemical
Mclals
Chromium
Lead
Iron
Manganese
VOCi
1.1 -DCE
trans -1,2-DCE
cis-l,2'DCE
Chloroform
1,2-DichJorocUianc
TCE
1,1.2-TCA
PCE
Shepard Spring
Number
Delected
1
»
2
2
1
I
14
22
1
0
22
1
20
Number
Analyzed
13
12
2
2
22
22
22
22
22
22
22
22
Concentration
Minimum
6
3
64
6
1.7
2
260
12
-
310
17
9.8
Maximum
6
28
192
6
1.7
14
1,200
12
—
1,000
. l7
23
Taggart Spring
Number
Detected
2
1
1
0
0
1
3
0
1
7
0
2
Number
Analyzed
*,
11
10
2
2
20
20
20
20
20
20
20
20
Concentration
Minimum
6
5
47
»•
.
1.2
0.5
• —
0.8
0.6
-
1
Maximum
6
5
47
—
1.2
1
-
0.8
2.3
-
1.2
NOTE: Mcthylene chloride. * common Ubonlory contunintnl, U excluded from Ihii Ublc. DiU Tor mclhylcne chloride ut included in Appendix C.
H/CAS/HD/TAIJM I6.]03-¥S/TC:IX
061)001.01
Part 1
Rev. 1,3/6/Vi
-------
TABLE 5-5
CASCADE CORPORATION SITE
SUMMARY OF POTENTIAL SITE RISKS
Future Groundwater Ineestion-
Average Case
Reasonable Maximum
Future Surface Water Ingestion6
Average Case
Reasonable Maximum
Hazard Index
9.4
18.4
0.8
1.8
Excess Cancer Risk
4 x 10'5
3 x 10"4
5 x 10~7
5 x 10"6
NOTES:
alncludes consideration of ingestion and inhalation of contaminants in groundwater from upper TGA
aquifer through household use.
"Includes consideration of ingestion and inhalation of contaminants hi water from Shepard Spring
through household use.
Cascade Corporation Record of Decision
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TABLE 6-1
CASCADE CORPORATION SITE
GROUNDWATER CLEANUP LEVELS FOR THE TG A
Chemical of
Potetial Concern
Groundwater
Cleanup Level
Corresponding
Excess Cancer Risk
Levels
Corresponding
Noncancer Hazard
Quotient^)
TCE
PCE
cis-l,2-DCE
vinyl chloride
Chromium (VI)
5
5
70
2
100
1x10*
5x10*
NC
7x10*
NC
0.03
0.02
0.2
NC
0.6
Total Estimated Risk at MCLsW
7x10-4
0.9
Notes: NC Not considered carcinogenic or not calcuable due to lack of reference dose.
(a) Based on Federal MCL.
(b) Based on RME exposure for residential ingestion of, inhalation of, and dermal
contact with drinking water.
(c) Cleanup of TCE to MCL should reduce other chemicals of potential concern to
levels well below the MCL.
Cascade Corporation Record of Decision
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Table 6-2
Cascade Corporation Site
Soil Cleanup Levels
Potential Chemical of
Concern
VOCs
cis- 1 ,2-Dichloroethene
Trichloroethylenc
Vinyl chloride
Tetrachlorocthylene
Benzene
Toluene
Ethylbenzenc
Xylenes
Carcinogenic PAHs
Benz(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Chrysene
Dibenzo(a,h)anthracene
Indeno( 1 ,2,3-cd)pyrene
TPHC
Chromium (TV)
Industrial Direct Contact
(mg/kgP
20.000
20
0.05
10
2
6.000
20.000
2,500
1
1
1
1
1
1
1
NA
1.500
Protection of Groundwater
(mg/kg)b
4
0.4
0.008
0.3
0.1
80
100
800
NA
NA
NA
NA
NA
NA
NA
500
NA
ARAR Based
Standard0 (mg/Jcg)
NA<1
6.0
6.0
6.0
10.0
10.0
10.0
30.0
3.4
6.8
6.8
3.4
3.4
8.2
3.4
NA
0.86f
a From OAR 340-122-045 (Environmental Cleanup Rules Soil Cleanup Table • Appendix I).
b From OAR 340-122-045 (Environmental Cleanup Rules Soil Cleanup Table).
c Source: 40 CFR 268.48 Table UTS (Universal Treatment Standards), and 40 CFR 268 Subpart D, Treatment
Standards for Hazardous Waste.
d No toxicity data available or chemical not toxic.
« From OAR 340-122-335, Matrix Score Level 2
f mg/LTCLP. ' .
Cascade Corporation Record of Decision
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Table 6-3
Cascade Corporation
Surface Water Protection Criteria
Chemical of Concern
cu-1,2 Dichloroethene
Trichloroethene
Vinyl chloride
Tetrachloroethene
Fresh Water Acute
(ug/L)
11,600W
45,000
(b)
5,280
Fresh Water Chronic
(ug/L)
(b)
21,000
(b)
840
' Value is for total DCE isomers.
b No Chronic Value established.
Notes: Surface Water Protection Criteria Listed only for those contaminants which could result in exceedance of
regulatory standards in the absence of remedial action.
Cascade Corporation Record of Decision
-------
Table 7-1
Cascade Corporation - Remedial Alternative Cost Summary
Alternative 1
On- & Off-Site Hydraulic Control Systems
GW Monitoring
Paved Area Maintenance & Deed Notice
Engineering & System Install 20%
Total!
Yean
Operation
30
30
30
—
Capital
$34,000
SO
$43,000
SI 5.400
$90,000
O*M
$1,341,000
$651,000
$44,000
—
$1,950,000
Totals
S1J44.000
$651,000
$87,000
$15,400
$2,040,000
Alternative 2
On- & Off-Site Hydraulic Control Systems
GW Monitoring
Cap Resurfacing and North Ditch Cap
Record Notice
SVE System
Air Emissions Control
Passive Product Recovery System
Engineering & System Install 20%
Totals
30
30
30
30
10
10
5
—
$34,000
SO
$58,000
$5,000
$122,600
$122,500
$33,800
$75.200
3450,000
SI 44 1,000
$65 1.000
$44.000
SO
$429,000
$267.000
$70,000
—
$2,710.000
$1,344,000
$651,000
$102.000
$5.000
$551,600
$389400
$103,800
$75.200
$3,160,000
Alternative 3
On- & Off-Site Hydraulic Control Systems
GW Monitoring
Cap Resurfacing and North Ditch Cap
Record Notice
SVE System
Air Emissions Control
Active Product Recovery System
On-Site Treatment System Upgrade
Air Sparging System
Source Area GW Extraction System
Engineering & System Install 20%
Totals
30
30
30
30
7
7
2.
7
IS
—
$34.000
SO
$58,000
S5.000
$122.600
$122.500
$33.100
$50.400
SI 66.600
$72.700
$133,000
$800,000
$1,341,000
$65 1,000
$44,000
SO
$333,000
$202,000
$21,000
SO
$168,000
$420,000
—
£3,090,000
$1.344,000
$651,000
$102.000
$5.000
$455,600
$324400
$54,100
$50,400
$334,600
$492,700
$133,000
S3 ,890,000
Alternative 4
On- & Off-Site Hydraulic Control Systems
GW Monitoring
Cap Resurfacing and North Ditch Cap
Record Notice
SVE System
Air Emissions Control
Active Product Recovery System
On-Site Treatment System Upgrade
Air Sparging System
Source Area GW Extraction System
In-Situ Bioremediation System
Engineering & System Install 20%
Totals
30
30
30
30
7
7
2
7
15
5
—
$34,000
SO
$58.000
$5.000
$122.600
$122,500
$33,100
$50.400
$166.600
$72.700
$125,000
$158,000
$950,000
SI .34 1.000
$65 1,000
$44,000
$0
$333.000
$202.000
$21.000
SO
$168,000
$420,000
$452.000
—
$3340,000
$1,344,000
$651,000
$102,000
$5,000
$455,600
$324400
$54,100
$50,400
$334,600
$492,700
$577,000
$158.000
$4,490,000
Alternative 5
On- & Off-Site Hydraulic Control Systems
GW Monitoring
North Ditch Cap
Record Notice
SVE System (Following Excavation)
On-Site Treatment System Upgrade
Air Sparging System
Source Area GW Extraction System
In-Situ Bioremediation System
Soil Excavation & Disposal
Engineering & System Install 20%
Totals
30
30
30
7
7
15
5
$34.000
$0
$20,000
$5,000
$99.300
$50,400
$166.600
$72,700
$125,000
$928,600
$300.400
$1.800,000
S 1,34 1.000
$651,000
SO
SO
$333.000
SO
$168.000
$420.000
$452,000
$0
—
$3,270,000
S 1.344,000
$651,000
$20,000
$5.000
$432400
$50,400
$334,600
$492,700
$577.000
$928,600
$300,400
$5,070.000
Cascade Corporation Record of Decision
-------
Table 8-1
Cost-Effectiveness Evaluation
Alternative
1
2
3
4
5
General approach u
Calculated assumin
Calculated **«»**"*
Calculated using in
Removal rate based
Calculated assumin
* Based on assumptic
Removal rate based
Assumes mass rem
VOC Mass Removed in 5 years (Ib)'
Remedial Component
On-site hydraulic control*
Off-site hydraulic control*
Total mass removed
On-site hydraulic control
Off-site hydraulic control
SVEa
Passive product recovery'
Total mass removed
On-site hydraulic control
Off-site hydraulic control
Source area extraction'
SVE
Air sparging*
Active product recovery*1
Total mass removed
Components from Alt 3
In-situ bioremediation1
Total mass removed
Same as Alternative 4
sed to calculate mass removal rates del
g initial mass removal rate of 5 Ib/tno i
g initial mass removal rate of 3 Ih/mo i
itial mass removal rate of 240 Ib/mo an
on best professional judgment. Mass
g initial mass removal rate of 7 Ib/mo i
>n that 90 percent of mass removal attn
on best professional judgment Mass >
jval rate of approximately 4 Ib/mo, tpf
Mass Removed in
5 years (Ib)
300
180
480
300
180
6,520
50
7,050
300
180
420
7,820
450
250
9,420
9,420
250
9,670
9,670
Alternative Cost
S2.0 million
S3.1 million
S3. 9 million
S4.5 million
S5.1 million
Cost per pound
removed (S/lb VOCJ
S4.no/lb
S440/lb
S414/lb
S465/lb
S527/lb
fined in Section 6.1.6 of FS. All calculations based on total mass of 10,000 Ib.
tmains constant over 5 year period.
vmains constant over 5 year period.
d that this rate declines 30 percent per year (see Section 622 of FS).
refers only to VOCs contained in LNAPL, not total mass of LNAPL removed.
vmains constant over 5 year period.
butable to air sparging (500 Ib) will occur in first S yean.
cfers only to VOCs contained in LNAPL, not total mass of LNAPL removed.
iroximately half the predicted maximum removal rate.
Cascade Corporation Record of Decision
-------
FIGURES
Cascade Corporation Record of Decision 12/18/96
-------
McGjjfre
^ I v iJt^Tfc ;-!*,«*.,*
*3[ C^Jj wj 3|i)Hi«ks«i,
>.^yv.q ^n'.rf-"— •
I \Ur- :J;.L-;HU--nr-
Base Map From: USGS 7.5' quad. CAMAS, WASH.-OREG. (1975)
Figure 3-1
CASCADE CORPORATION
TROUTDALE. OREGON
erncon
PROJECT NC
0683003.13 J
-------
EXPLANATION
Oracle Coscode Property Off«te Cascade Property
——— Ground Surface devotion Contours
(Fed. USL) (Contour Interval 5 re«t)
300
SCALE IN FEET
600
o
Violation
Fence
OAH 9/98
0*N. UK 'I
APP*. A«ar
news.
PROJECT NO.
068JCKX3.I3
Flqure S-2
CASCADE CORPORATION
TROUTOALE. OREGON
SITE FEATURES
-------
.iti— OKUBMIO uva coMraui (n. usu
cacxT or voc PUMC M TOA.
B«SCD ON MAT IMa DATA. PUMC UMTS
AME OOVCD AS s PM TOTAL
cmcon
OAtt "'/»«
Otm.
PROJECT WO.
406UOOJ.01
' Figure 3-3
CASCADE CORPORATION
TOOUTDALE. OREGON
TOA OROUNOWATIR QfVATMM CONTOURS.
MAY JO. I9»8
-------
PRODUCTION
FACILITY
EXPLANATION
O MAU Extraction
0 TCA Wtl
» SVC W.I
Owommioioncd (ndmtnol Wol
Arto Around Wait* Coolant
UST»
Former Vapor Ocqrtattr
(U«d I96J-I97S)
Former Ovonu Plalinq
Tank* (Uwd 1864-1976)
North Ditch
Hydraulic UM Tr«nche<
(rPH only)
Coolant and Sudg* Di«po«ol
ATM
0 100 200
/^N cmcon SCAI£ IN raT
OAlt »/l^
OHM. RJ
QfPH./AK"
REVIS.
PMOJtCT NO
068J003.U
Fi9ur« S-|
CASCADE CORPORATION
TROUTOALE. OREGON
APPROXIMATE JOUHCE AREA LOCATIONS
C \(««C\06»J\OOJ\lV2-« 9/JO/9J 10 PlOl 1-100
-------
UW-tfto
1 OUTCROJf
PPROXJ.
— — ~-o-ir«*
•••—T^"^** '" •_ ' • ^fMt
EVIANATION
© re* M 9 is*
A •*
• Figure J-2.
CASCADE CORPORATION
TROUTOALE. OREGON
T9A HUM tXnUCTMN AMD UOKITORWD LOCAHOW5
cmcon
-------
GROUNOWATER
TREATMENT :
©
•-« I
I-
EXISTING TCA
CUTOrT TRENCH
(OfT-STC IRAM)
1 I "
| \MW-t7oi
100 ZOO S
===
SCALE IN rEET .'
-*^~ "
1
»-a
J
i
c
•^
1
IW-
*.«- 1 UL l!
• c-itr i {>
S-H6V* j ll
«»C-t1IV ',
C-114V i ;
PRODUCTION rj '• \
FACILITY M ! 1
i ^
• }
^ — **•£ i"** — ^
EXPLANATION
< OlUUMl 1*1 IMPM
ff-1 -t- PI«iom.t«r ""-1 * O"'511* «*
(Contour inUrvol • 5 «)
Potato
NOTE: SW-2. 3, AND 4 NOT SHOWN
M Extraction W«l ((€Afi TACcm sf)R(NC)
UVMl 0 TCA «M
C-TUV « Vapor Extraction Wrt
— Exating TCA Cutoff Trench
MW-4 -$- PropOMd On-Ste HUM Extraction Well
cmcon
CASCADE CORPORATION
TROUTDAUE. OREGON
WELLS
-------
Ifi I-"
0 TCA WOO.
+ TCA PIEZOMETER
• RECOVCKr SUMP
. EXPLANATION
® TS» MIL
A KM
i--^
(iJi^ TCE ooNcixnunoNS (ope). AS MEASURED "•••
IN CKOUNMMIJt COLLtCTED 8ET«CEX UAT
1 AND JUNE S
NOT ULILCIU)
(HO)
— '0
ISOCOMCENnUJIOH CONTOUR
TOTAL TC£ (p*e)
• *••"» <«^ vrr*/
MOTT_ M THE CASE OF OUPUCATC SAMPLES THE HOCR CONCEMTKAnON RESULT IS SHOWN.
•$£-& -
@cmcon
0*tt .7-88
0«K »"<
K.
ntoccT no.
40543003.01 7
Figure 5 '3
CASCADE CORPORATION
TFOLTDALE. OREGON
TOA TCE CONCENTRATION
-------
/ EXnANAIION
TAL *XT« (M»). 08 yCAS
CAOUNOWMIR oxurrn)
G TCA WEU.
TO* RBOUCTER
• HECOvorr sun?
NOTE: w me CASE of
MAT J /WC JUNC 5
NOT OCItCTD
'" — ^ isocoNcomunaN axroun
^ TOT*. VOC« (p»»)
.
COMXHDUnON WSULT IS SHO*K.
S«M>LB T>C MCMOt
r,gure -5-
CASCADE- CORPORATION
TROUTDAi£. OREGON
T&A VOC, COHCEXTRAT10N
y*Y, 109«
-------
A
NORTH
KO
M-
PRODUCTION
FACILITY
EXPLANATION
Croundwoter Row Direction
A*
SOUTH
HORIZONTAL SCALE IN FEET
,0 200 400
0 100 200
VERTICAL SCALE IN FEET
Soil Vopor
Projected leokoge
Water
• iso
out
-100
-m
DATE 3/95
OWN. PJF
APPR./4D-
REVJS
PROJECT NO.
0683003.09
Figure S - 5
CASCADE CORPORATION
TROUTDALE, OREGON
CONCEPTUAL SITE MODEL
-------
GROUND WATER ,
TREATMENT
© •
COSTING TCA
CUTOFF TRENCH
(OrT-STC IRAM)
PRODUCTION
FACILITY
o too aoo
^
SCALE IN FEET
O Sprir»9
3W-1 -f Pieromtttr
flfoiiidw«t«f
PotoU
(Contour interval - 5 (I)
RW-1 O On-SU BMW Extraction W.fl NOTE: SW-2. 3. AND 4 NOT SHOWN
0 TGA Wed
(NEAR TACCART SPRING)
Apprexunoti Croundwottr C-114V 9) Vapor Extraction Wtl
Coptur. 2on« from On-SH. ElifUn^ ^ ^ Tfw)Ch
ond Off-SA* RAW
RW-4 4- PropoMd On-SH» IRAU Extraction W.II -
®emcon
OATt
PWOJCCT Na
CASCADE CORPORATION
TROUTDAU. OREGON
-------
CROUNDWATEF
TREATMENT
0
EXISTING TGA
CUTOFF TRENCH
(OFF-SITE IRAM)
too zoo
SCALE IN FEET
Appronmate ATM of
SVC Influence
(Contour interval -
Prapoitd SVC Wen
Propo*«d Product
_2> 3
-------
APPENDIX A - CASCADE CORPORATION
ADMINISTRATIVE RECORD INDEX
Site-Specific Documents
Date Author
14 Jul 88 DEQ
25 Aug 88
3 Feb 89
31 Mar 89
15Jun89
28 Aug 89
19 Oct 89
Dec 89
6 Mar 90
Dames & Moore
Oregon DEQ
Dames & Moore
Century West
DEQ
Century West
Century West
Century West
Document
Order on Consent No. ECSR-NWR-88-01,
Cascade Corporation.
Preliminary remedied investigation plan for
Cascade Corporation Troutdale facility.
Preliminary assessment, Cascade
Corporation (ORD 009031378).
Final preliminary remedial investigation
report: Cascade Corporation, Troutdale
facility.
Excavation plan, north drainage ditch.
Cascade Corporation.
Order on Consent No. ECSR-NWR-89-11,
Cascade Corporation.
Letter (re: Results of north receiving ditch
excavation and soil analysis, Cascade
Corporation facility) to P. Burnet, DEQ, from
J. Snell.
Final work plan, remedial
investigation/feasibility study for Cascade
Corporation Troutdale facility.
Letter (re: Hydraulic system upgrade) to A.
Pollock, DEQ.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-l
-------
!Feb91
1 Feb 91
29 Mar 91
15 May 91
4Jun91
21 Jun91
7 Aug 91
27 Sept 91
Oct91
8Nov91
11 Dec 91
Century West
Century West
Century West
Century West
Century West
Century West
Century West
Century West
E&E
Century West
NeoMedia/SE/E
Phase 1 interim data report, remedial
investigation/ feasibility study. Cascade
Corporation Troutdale facility.
Phase 2 work plan amendments, RI/FS
Cascade Corporation.
Phase 2 unknown source investigation: soil
vapor survey report of findings, remedial
investigation/feasibility study, Cascade
Corporation Troutdale facility.
Revised aquifer test report, Troutdale
Gravel Aquifer, Cascade Corporation,
Troutdale, Oregon.
Industrial well abandonment plan, remedial
investigation/ feasibility study, Cascade
Corporation, Troutdale, Oregon.
Phase 2 Troutdale Gravel Aquifer plume
characterization report, remedial
investigation/feasibility study, Cascade
Corporation Troutdale facility.
Phase 3 unknown source investigation soil
vapor survey report, remedial
investigation/feasibility study, Cascade
Corporation Troutdale facility (draft report).
Interim removal action measures report:
remedial investigation and feasibility study,
Cascade Corporation.
Site inspection report for Cascade
Corporation site, Troutdale, Oregon.
Industrial well abandonment report,
remedial investigation /feasibility study,
Cascade Corporation, Troutdale, Oregon.
Interim . removal action measures
implementation workplan, Cascade
Corporation.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-2
-------
23 Mar 92
23 Mar 92
2 Feb 94
16Feb94
18 Feb 94
26 Apr 94
EMCON/NeoMedia P/uue J remedial investigation and
feasibility study \vorkplan for the Cascade
Corporation facility, Troutdale, Oregon.
EMCON
2 Oct 92
30 Jul 93
5 Nov 93
23 Nov 93
12 Jan 94
EMCON
EMCON
EMCON
EMCON
DEQ
EMCON
EMCON
DEQ
EMCON
Letter (re: IRAM implementation workplan
amendment, Cascade Corporation,
Troutdale, Oregon) to B. Gilles, DEQ, from
D. Mills.
Off-site source receptor survey. Cascade
Corporation, Troutdale, Oregon.
IRAM performance evaluation, Cascade
Corporation (draft report).
Feasibility study workplan, Troutdale
facility.
Preliminary remediation goals, Troutdale
facility.
Letter (re: DEQ comments to Cascade
Corporation Rl/FS preliminary remediation
goals) to J. Miller, Cascade, from B. Gilles.
Letter (re: Final workplan, on-site source
investigation, Cascade Corporation) to
B. Gilles, DEQ, from D. Mills.
Letter (re: Response to DEQ comments on
the Cascade Corporation Troutdale facility
preliminary remediation goals [PRGs]) to
B. Gilles, DEQ, from T. Foster and D. Mills.
Letter (re: Cascade Corp. RI/FS, preliminary
remediation goals) to J. Miller, Cascade,
from T. Foster and D. Mills.
Letter (re: Revised workplan, evaluate
off-site TGA control options: Cascade
Corporation) to B. Gilles, DEQ, from
L. Downs.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-3
-------
21 Jun94
. EMCON
19 Jul 94
24 Aug 94
EMCON
EMCON
21 Dec 94
EMCON
23 Feb 95
EMCON
10 Mar 95
10 Mar 95
EMCON
EMCON
Letter (re: Phase 3 RI/FS workplan
amendment, final workplan for the
endangerment assessment: Cascade
Corporation) to B. Gilles, DEQ, from
D. Mills and T. Foster.
Bench testing for in situ bioremediation,
Cascade Corporation, Troutdale, Oregon.
Letter (re: Amended groundwater tracer
study workplan, Cascade Corporation) to
B. Gilles, DEQ, from T. Todd and
L. Downs.
Letter (re: Workplan for the installation of
additional on-site TGA monitoring wells
near the former vapor degreaser) to
B. Gilles, DEQ, from D. Mills and
L. Downs.
Letter (re: Installation and sampling of
additional on-site TGA monitoring wells
near former vapor degreaser at Cascade
Corporation) to B. Gilles, DEQ, from
A. SL John and L. Downs.
Phase 3 remedial investigation and
feasibility study, Troutdale Gravel Aquifer.
Part 1: remedial investigation (final report).
Phase 3 remedial investigation and
feasibility study, Troutdale Grave. Part 2:
endangerment assessment (final report).
10 Mar 95
EMCON
Letter (re: Response to DEQ comments on
the draft Phase 3 remedial investigation
report dated December 2, Cascade
Cascade Corporation Remediil Action Record of Decision
A-4
Appendix A - Administrative Record Index
-------
13 Apr 95
23 May 95
7Jun95
14 Aug 95
24 Aug 95
24 Oct 95
15 Jan 96
25 Jan 96
EMCON
EMCON
EMCON
EMCON
EMCON
DEQ
EMCON
EMCON
28 Feb 96
DEQ
Corporation) to B. Gilles, DEQ, from
D. Mills.
Groundwater tracer study. Cascade
Corporation, Troutdale, Oregon (interim
technical memorandum).
Pilot test for Troutdale Gravel Aquifer
control.
Letter (re: Amendments to test pitting
program and monitoring well abandonment
and replacement workplan, Cascade
Corporation) to B. Gilles, DEQ, from
L. Downs.
Revised workplan, expansion of off-site TGA
control trench recovery system, Cascade
Corporation, Portland, Oregon.
Letter report: Test pitting program and
monitoring well abandonment and
replacement, Troutdale Gravel Aquifer.
Addendum to order on consent, DEQ
No. ECSR-NWR-89-11, with
attachment AA: NPDES discharge
limitations, monitoring, and reporting
requirements. Issued for TGA control trench
operation.
Phase 3 remedial investigation and feasibility
study. Troutdale Gravel Aquifer. Part 3:
feasibility study (final report).
Letter (re: Modify phase 3 RJ/FS workplan:
decommission MW-28i and . install
additional on-site TGA recovery well) to B.
Gilles, DEQ, from L. Downs and D. Mills.
Letter (re: Comments on final RI/FS reports)
to J. Miller, Cascade, from B. Gilles.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-5
-------
1 Mar 96
29 Mar 96
EMCON
EMCON
Cascade TGA Control Trench Construction
Report - Troutdale, Oregon.
Letter (re: Technical memorandum
responding to DEQ comments on Cascade
site-specific Rl/FS) to B. Gilles, DEQ, from
E. Tuppan and L. Downs.
Guidance Documents and Technical Literature
Apr 88
Oct88
USEPA
USEPA
Mar 89
M89
M89
USEPA
USEPA
USEPA
Sept 89
USEPA
Superfund exposure assessment manual.
Office of Solid Waste and Emergency
Response. OSWER Directive 9285.5-1.
Guidance for conducting remedial
investigations and feasibility studies under
CERCLA. Interim final. Office of
Emergency and Remedial Response.
EPA 540G-89-004.
Risk assessment guidance for Superfund.
Vol. 2: environmental evaluation manual.
Interim final. EPA 540/1-89/OQ1.
Exposure factors handbook. Office of
Health and Environmental Assessment.
EPA/600/8-89/043.
Risk assessment guidance for Superfund.
Vol. 1: human health evaluation manual
(part A). Interim final. Office of Emergency
and Remedial Response. EPA/540/1-89/002.
Physical processes controlling the transport of
non-aqueous phase liquids in the subsurface.
By C. D. Palmer and R. L. Johnson. In Fate
and transport of contaminants in the
subsurface. Technology Transfer Seminar
Publication, Center for Environmental
Research Information, Cincinnati, Ohio, and
Robert S. Kerr, Environmental Research
Laboratory, Ada, Oklahoma. EPA/625/4-89-
019.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-6
-------
90
J. B. Andelman
Mar 91
USEPA
Dec 91
USEPA
Mar 91
USEPA
91
22 Dec 92
C. Zheng,
G. D. Bennett,
Water
C. B. Andrews
USEPA
Sept 93
USEPA
93
USEPA
Total exposure to volatile organic chemicals
in potable water. Eds. N. M. Ram,
R F. Christman, K. P. Cantor (Boca Raton,
Fla: Lewis).
Human health evaluation manual,
supplemental guidance: standard default
exposure factors. Office of Solid Waste
and Emergency Response. OSWER
Directive 9285.6-03.
Risk assessment guidance for Superfund.
Vol. 1: human health evaluation manual (part
B, development of risk-based preliminary
remediation goals).
Ground water issue, dense nonaqueous phase
liquids. By S. G. Ruling and J. W. Weaver.
Superfund Technology Support Center for
Ground Water, Robert S. Kerr Environmental
Research Laboratory, Ada, Oklahoma.
EPA/540/4-91-002.
Analysis of ground-water
alternatives at a Superfund site.
29(6)838-848.
remedial
Ground
40 CFR part 131. Water quality standards:
establishment of numeric criteria for
priority toxic pollutants; states' compliance.
Final rule.
Presumptive remedies: site characterization
and technology selection for CERCLA sites
with volatile organic compounds in soils.
Office of Emergency and Remedial
Response. EPA 540-93-048.
Wildlife exposure factors handbook. Office
of Research and Development.
EPA/600/R-93/187a.
Cascade Coiponiion Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-7
-------
93
M93
.Mar 94
May 94
Jun94
JuI94
95
R. M. Cohen,
J. W. Mercer
G. D. Hopkins,
L. Semprini,
P. L. McCarty
USEPA
USEPA
DEQ
USEPA
USEPA
DNAPL site evaluation (Boca Raton, Fla:
CRC Press).
Microcosm and in situ field studies of
enhanced biotransformation of
trichloroethylene by phenol-utilizing
microorganism. Applied and Environmental
Microbiology
Health effects assessment summary tables.
Annual update. EPA 540/R-94/020.
Drinking water regulations and health
advisories.
Environmental cleanup manual.
Integrated risk information system (IRIS).
Database.
Risk-based concentration table,
January-June 1995. Technical Support
Section, EPA region 3, Philadelphia.
East Multnomah County Groundwater Investigation
Oct91
Oct91
Jul91
11 Dec 92
E&E
E&E
Parametrix
DEQ
East Multnomah County groundwater study,
Gresham, Oregon. Prepared for EPA
region 10, Seattle.
East Multnomah County vadose zone gas
survey, Portland, Oregon. Final report.
Prepared for EPA region 10, Seattle.
East Multnomah County database and
model: final geologic interpretation, detailed
modeling area. Prepared for DEQ.
East Multnomah County regional
groundwater project, DEQ master plan.
Environmental Cleanup Division.
Cascade Corporation Remedial Action Record of Decision - Appendix A • Administrative Record Index
A-8
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Jun93
SSP&A/Parametrix
East Multnomah County database and model:
groundwater flow model report. Prepared for
DEQ.
Remedy Selection Public Notice and Comment
Aug96
Aug96
Oct96
DEQ
DEQ
Scott A. Wells
Oct96
Staff Report DEQ Recommended Remedial
Action for the Cascade Corporation Site.
i
Proposed Cleanup Plan for the Cascade
Corporation Site, Gresham, Oregon.
Letter of comment on DEQ Recommended
Remedial Action for Cascade Corporation
Site from Scott Wells, Portland State
University, to Bruce Gilles, DEQ Project
Manager, dated October 28, 1996. Prepared
on behalf of Friends of Blue and Fairview
Lake.
Terrence L. Thatcher Letter of comment on DEQ Recommended
Remedial Action for Cascade Corporation
Site from Terrence Thatcher, City of Portland
Deputy City Attorney, to Bruce Gilles, DEQ
Project Manager, dated October 30, 1996.
Prepared on behalf of the City of Portland.
Oct96
David L. Blount
Nov 1996
DEQ
Letter of comment on DEQ Recommended
Remedial Action for Cascade Corporation
Site from David L. Blount, Copeland,
Landye, Bennett and Wolf, LLP, to Bruce
Gilles, DEQ Project Manager, dated October
30, 1996. Prepared on behalf of Cascade
Corporation.
Memorandum to East Multnomah County
Project File from Bruce Gilles, Project
Manager, dated November 21, 1996.
Memorandum summarizes public hearings
held on the DEQ Recommended Remedial
Action Plans for the Cascade Corporation
Site and the East Multnomah County
Troutdale Sandstone Aquifer Site.
Cascade Corporation Remedial Action Record of Decision
A-9
Appendix A - Administrative Record Index
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Nov 96 DEQ Memorandum to Bob Baumgartner and Neil
Mullane, DEQ Northwest Region Water
Quality Program, from Bruce Gilles, DEQ
Project Manager, dated November 25, 1996.
Memorandum summarizes NPDES issues
related to permitting of discharge of treated
groundwater in preparation of the final
remedy Record of Decision.
Century West = Century West Engineering Corporation, Portland, Oregon.
Dames & Moore = Dames and Moore, Inc., Portland, Oregon.
DEQ = Oregon Department of Environmental Quality.
E&E = Ecology and Environment, Inc., Seattle, Washington.
NeoMedia = NeoMedia, Beaverton, Oregon.
Parametrix = Parametrix, Inc., Kirkland, Washington.
SE/E = Sweet Edwards/EMCON, Portland, Oregon.
SSP&A = S. S. Papadopulos and Associations, Bethesda, Maryland.
USEPA = U.S. Environmental Protection Agency.
Cascade Corporation Remedial Action Record of Decision - Appendix A - Administrative Record Index
A-10
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