United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R10-93/054
December 1992
c/EPA Superfund
Record of Decision:
-------
REPORT DOCUMENTATION '1. REPORT NO. 2. 3. Recipient's Accession No.
PAGE EPA/ROD/R10-93/054
4. Title and Subtitle 5. Report Date
SUPERFUND RECORD OF DECISION 12/31/92
Queen City Farms, WA 6.
Second Remedial Action - Final
7. Author(s) 8. Performing Organization Rept. NO'
9. Perfonnlng Organization Name and Address 10 Project TaskIWork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Address 13. Type of Report & Period Covered
U.S. Environmental Protection Agency
401 M Street, S.w. 800/800
Washington, D.C. 20460 14.
15. Supplementary Note.
PB94-964617
16. Abstract (Limit: 200 words)
The 320-acre Queen City Farms site is a former pig farm located in Maple Valley, King
County, Washington. Land use in the area is predominantly rural and residential.
Adjoining the site to the north is the Cedar Hills landfill, a municipal landfill
operated by King County. The Queen City Farms (QCF) site is bounded to the west by
woodlands, a gravel sorting facility, and private residences; and to the south by
undeveloped marshy areas, which extend partially within the site boundary. The Cedar
River is located approximately one mile to the west of the site. The QCF site overlies
five saturated hydrogeologic units, including Aquifer 1 and Aquifer 2. Aquifer 1 is a
perched sand and gravel aquifer in the area of the IRM; and Aquifer 2 is unconfined and
extends throughout the site and beyond site boundaries. The private residents who live
in the vicinity use Aquifer 2, which appears to be recharged by Aquifer 1 and is
located downgradient of the site to the south and southwest, to obtain their drinking
water supply. Current land use at the site consists of 2 major commercial operations:
yard-waste composting and sand and gravel mining. Past waste disposal practices at the
QCF site are documented poorly. From 1955 until the late 1960s, local industry used
the site to dispose of industrial waste liquids, including paint, petroleum products;
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Queen City Farms, WA
Second Remedial Action - Final
Contaminated Media: soil, debris, gw, sw
Key Contaminants: VOCs (PCE, TCE, toluene, xylenes), other organics (PAHs, PCBs,
pesticides), metals (chromium, lead), inorganics (cyanide)
b. Identifiers/Open.Ended Terms
c. COSATI FleldlGroup
18. Availability Statement 19. Security Class (This Report) 21. No. of Pages
None 128
20. Security Class (This Page) 22. Price
None
50272-101
(See ANSI-Z39.18)
Sse Instructions on Reverse
OPTIONAL FORM 272 (4.77)
(Formerty NTIS-35)
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EPA/ROD/R10-93/054
Queen City Farms, WA
Second Remedial Action - Final
Abstract (Continued)
organics, solvents, and oils. Primarily, the wastes were disposed of in three unlined
ponds (Ponds 1, 2, and 3) located in the northeast portion of the site, which were closed
under another IRM in 1986. Ponds 4, 5, and 6 were used to dispose of whey and animal
waste from a hog farming operation conducted onsite from the mid-1950s until 1964. A
building in the western portion of the site was leased by 4-Tek Industries (4-Tek) and
used to repackage and recycle solvents until 1986. Bulk chemicals were stored and mixed
in the storage area, and surface water runoff from the area was drained into a sump that
eventually drained to an outlet west of the pad area. In 1980, EPA and the State
identified elevated levels of VOCs in soil in the vicinity of the 4-Tek facility that may
be attributed to spillage during plant operations. Later in 1980, EPA ordered QCF to
complete a well restoration program and, in 1984, to conduct additional site
investigations. These studies documented elevated levels of VOCs, PAHs, and PCBs in the
sludge ponds and in underlying soil, which have migrated into and contaminated onsite
ground water. In addition, LNAPLs, determined to be primarily a mixture of fuel oils,
were found to be a source of ground water contamination in Aquifer 1, in the vicinity of
the IRM Area. In 1985, QCF implemented an IRM for Ponds 1, 2, and 3, which included
separation, onsite stabilization, and offsi'te disposal of sludge; capping associated soil;
and implementing engineering controls and ground water monitoring. In 1988, after sand
and gravel excavation activities uncovered 32 buried crushed drums, contaminated soil, and
other materials, EPA ordered these removed and disposed of offsite. In 1990,
approximately 170 yd3 of soil containing VOCs and 40 yd3 of concrete were excavated and
removed offsite. For the purpose of remediation, the site has been divided into three
study areas: the IRM and associated ground water contamination, the Buried Drum Area
(BDA), and the 4-Tek Industries areas. This ROD addresses soil, debris, and onsite/offsite
ground water contamination at these three areas. The primary contaminants of concern
affecting the soil, debris, ground water, and surface water are VOCs, including PCE, TCE,
toluene, and xylenes; other organics, including PAHs, PCBs, and pesticides; metals,
including chromium and lead; "and inorganics, including cyanide.
The selected remedial action for this site includes isolating contaminated soil by
constructing a vertical barrier system/slurry wall around the IRM to contain 280,000 yd3
of contaminated soil onsite; excavating and treating 10,000 yd3 of contaminated soil and
debris from the BDA offsite, with disposal of soil with high levels of contamination
offsite at a permitted hazardous waste landfill; removing and pretreating onsite, if
necessary, approximately 100 yd3 of debris containing metals and organics, with subsequent
offsite treatment or off site disposal at a solid waste or hazardous waste landfill;
placing approxlmately 4,000 yd3 of soil with low levels of metal, PAH, and PCB
contamination below an extension of the existing IRM cap, and backfilling the excavated
area with clean soil; dewatering and onsite treatment of ground water recovered within the
IRM area using a treatment system that may include oil and water separation, filtration,
air stripping with air emission controls, and carbon adsorption treatment, with offsite
discharge to a POTW; providing a contingent remedy for extraction and onsite treatment of
Aquifers 1 and 2 using air stripping, with discharge of the treated ground water onsite to
surface water and provision of an alternate water supply, if ground water monitoring
indicates that cleanup levels are exceeded at the offsite areas; removing the LNAPLs, from
within and adjacent to the IRM, and incinerating them offsite; conducting treatability
studies during the RD to determine the effectiveness of venting, and providing a
contingency for venting of IRM soil, based on study results; constructing a surface water
diversion system to prevent infiltration of water into the IRM BDA cap; monitoring onsite
and offsite ground water, surface water, and private drinking water wells; and
implementing institutional controls, including deed, land, and ground water use
restrictions. The estimated present worth cost for this remedial action is $50,011,000,
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EPA/ROD/R10-93/054
Queen City Farms, WA
Second Remedial Action - Final
Abstract (Continued)
PERFORMANCE STANDARDS OR GOALS:
Soil and ground water cleanup goals are based on SDWA MCLs and cancer and Model Taxies
Cleanup Regulations (MTCA) risk data. Chemical-specific ground water cleanup levels for
Aquifer 1 are based on a cancer risk of 10-5, and include total chromium 80 ug/l; 1,2-DCE
70 ug/l; trans-l,2-DCE 100 ug/l; carcinogenic PAHs 0.01 ug/l; PCBs (total) 0.01 ug/l; PCE
1 ug/l; TCE 5 ug/l; and vinyl chloride 0.02 ug/l. Chemical-specific soil cleanup goals
are based on MTCA, and include arsenic 20 mg/kg; cadmium 40 mg/kg; chromium 400 mg/kg;
-------
.$>'<.«..0 ST'I~~
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"'..,., PRO'\:'V""
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 1 0
1200 Sixth Avenue
Seattle, Washington 98101
RECORD OF DECISION
DECLARATION, DECIS~ON SUMMARY,
AND
RESPONSIVENESS SUMMARY
FOR
FINAL REMEDIAL ACTION
QUEEN CITY FARMS SUPERFUND SITE
MAPLE VALLEY, KING COUNTY, WASHINGTON
DECEMBER 1992
o Printed on Recycled Paper
CI..~, .
.) ," "">-~~~~"-:,,,,,,~,~~~~~;':,,".~,-': -~- .
-------
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S~TE NAME AND LOCAT~ON
Queen city Farms
Maple Valley, King county, Washington
STATEMENT OF BAS~S AND PURPOSE
This decision document presents the selected remedial
actions for the Queen city Farms site (site or QCF site), in
Maple Valley, King county, Washington, which were chosen in
accordance with the requirements of the comprehensive
Environmental Response, compensation, and Liability Act of 1986,
42 U.S.C. SS9601 et. sea., pub. L. 99-499 (CERCLA), and, to the
extent practicable, the National oil and Hazardous substances
Pollution contingency Plan, 40 C.F.R. Part 300, published in 55
Fed. Rea. 8666, et. sea., on March 8, 1990 (NCP). This decision
is based on the administrative record for the site.
The state of Washington concurs with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response actions
selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or the environment.
DESCR~PTION OF THE SELECTED REMEDY
The remedial actions described below are the final response
actions planned for the site. An Initial Remedial Measure (IRM)
was performed at the site in 1986 that included removal and
containment measures which addressed sludge and liquid
contamination at the site. The IRM only partially addressed soil
contamination, and did not deal with ground water contamination
at the site. The cleanup actions described in this ROD address
the threats to ground water and soils posed by trichloroethene
(TCE) and other contaminants at the site. Long-term management
controls are necessary to maintain the integrity of the cleanup.
For purposes of the evaluation and selection of cleanup
alternatives, the site was divided into the following three study
areas: (1) the IRM and associated ground water contamination, (2)
the Buried Drum Area (BDA), and (3) 4-Tek Industries.- The
selected remedy addresses all three study areas.
The major components of the selected remedy are:
For the ~RM and associated around-water contamination:
.
Isolation of contaminated soils by construct-ion of--a --.-
-------
.
Dewatering, treatment and off-site discharge of the
water within the IRM.
.
Contingent extraction and treatment of Aquifer 1 ground
water outside the IRM. On-Site discharge of treated
ground water to the Main Gravel Pit Lake or equivalent
surface water body.
.
Removal and off-site incineration of LNAPL from within,
and adjacent to, the IRM.
.
Contingent venting of IRM soils. The effectiveness of
venting will be determined by treatability studies to
be conducted during remedial design.
.
contingent extraction and treatment of contaminated
Aquifer 2 ground water. Discharge of-extracted ground
water to the Main Gravel Pit Lake or- equivalent surface
water body.
For the BDA:
.
Excavation of approximately 10,000 cubic yards of soil
and debris from the BDA. Off-site treatment and
disposal of the soils with high levels of contamination
at a permitted hazardous waste landfill. On-site
treatment of debris prior to recycling or aisposal of
debris at a solid waste or hazardous waste landfill.
Placement of soil with low levels of contamination
below an extension of the existing IRM cap.
Backfilling of the uncontaminated soil.
.
Construction of a surface water diversion system, to
prevent infiltration of water into the IRM/BDA cap.
For 4-Tek Industries:
.
sampling and analysis of the shallow ground-water zone,
and Aquifer 2, at the 4-Tek facility at least twice per
year for 5 years. Should contamination be found above
cleanup levels, then the ground water would be
extracted and, if necessary treated on site. Treated
ground water would be discharged to the Main Gravel Pit
Lake or equivalent on-site surface water body.
site-Wide Actions:
.
Deed restrictions and institutional controls on land
and ground-water use.
Long-term ground-water and surface water monitoring.
.
-------
.
Long-term monitoring of private drinking water wells,
with a contingency for providing an alternative water
supply, should site-related contaminants exceed cleanup
levels.
.
continued long-term monitoring of surface water and
ground-water in the southern portion of the Cedar Hills
Landf ill.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment or resource
recovery technologies to the maximum extent practicable,. and
satisfies the statutory preference for remedies that employ
treatment that reduces, toxicity, mobility, or volume as a
principal element. .
Because this remedy will result in hazardous substances
remaining on site above health-based levels, a review will be
conducted within five years after commencement of the remedial
action to ensure that the remedy continues to provide adequate
protection of human health and the environment.
(2-{?>l ! q7-
Date
~Q~
Regional Administrator
Environmental Protection Agency
-------
~ -"' () " "Q9'-'
iJ!:..... ..,.. I", !..
OFF:CE 0::
REGiOrJl\.L i\J~'.'~!i\~; .3TP.~..:~:~~
STATE OF WASHINGTON
DEPARTMENT OF ECOLOGY
Mail Stop PV-11 . Olympia, Washington 98504-8711 .
(206) 45%000
December 23, 1992
Ms. Dana Rasmussen
Regional Administrator
U.S. EPA, Region 10
1200 Sixth Avenue
Seattle, WA 98101
Dear Ms. Rasmussen:
Re:
Record of Decision for the Queen City Farms Superfund Site
The Washington State Department of Ecology has reviewed the Record of Decision for
the Queen City Farms Superfund Site near Maple Valley, King County. We concur with
the following selected remedies, described in chapter ten of the document:
To isolate and consolidate contaminated soils with a slurry wall/cap and
passively vent their main portion;
to extract and treat, if necessary, contaminated ground water from
within the containment structure plus various aquifers outside this and
another operable unit;
to dispose off-site of the most contaminated, excavated materials;
to monitor ground water extensively on and off-site;
and to apply and maintain comprehensive administrative controls.
We recognize contaminants will remain on-site, because
and some contaminants cannot be effectively treated or
selected remedies are consistent with the Model Toxics
(Chapter 173-340 WAC).
removal is not practicable
completely destroyed. The
Control Act Regulations
We are looking forward to the cleanup activities at this site.
Sincerely,
f, . .~J
l,l.V'L<.".-t., ..7--, .
1: '1 j.' /
- '...,;--'
.:, ..-Lt -<.L.' .,:,(. ,
Carol L. Fleskes
Program Manager
Toxics Cleanup Program
CLF:MHR:jw
cc:
Howard Or1ean, EPA
Timothy L. Nord, Ecology
Michael Ruef, Ecology
~3
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DECISION SUMMARY
FINAL REMEDIAL ACTION
QUEEN CITY FARMS SUPERFUND SITE
MAPLE VALLEY, KING COUNTY, WASHINGTON
- -.---.. -_.
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TABLE OF CONTENTS
Page
Decision Summary
1.0
2.0
3.0
4.0
5.0
6.0
site
site Name
2.1
2.2
2.3
and Location........................... 1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
setting................................ .'.... 1
Topography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
Land Use.................... . . . . . . . . . . . . . . .. 4
site History and Enforcement Activities........... 6
3.1
3.2
3.3
3.4
Past Disposal
Activities .................... 6
Past Remedial and Removal Activities ........ 6
3.2.1
Ponds 1, 2,
and 3 .................... 8
3.2.2
Buried Drum Area
. . . . . . . . . .'. . . . . . . . . .. 9
3.2.3
4-Tek Industries
. . . . . . . . . . . . . . . . . . . .. 9
Off-site Studies ............................ 9
3.3.1
Cedar Hills Landfill................. 10
3.3.2
Off-Site Domestic Well Study......... 10
Enforcement Activities ...................... 10
3.4.1
Reports Produced by Potentially
Responsible Parties Under Consent Orders
with EP A ..................................... 12
3.4.2
Major Reports Prepared and/or Issued
Community Relations.............................. 14
by EPA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
Scope of Response Actions Within site Strategy... 17
6.1
site Character~stics ............;................ 18
Geology and Soils ........................... 18
6.2
Surface Water Hydrology
-------
7.0
8.0
6.3 Ground
6.4 Extent
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
Water Hydrology ...................... 23
of Contamination ..................... 25
So i 1 ........ e.. . . . . . . . . . . . . . . . . . . . . . .. 25
Surface Water........................ 29
Sediment. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34
Light Non-Aqueous Phase Liquid (LNAPL) 34
Ground Water ......................... 34
6.5
Routes of contaminant Migration
. . . . . . . . . . . .. 39
6.6
Characteristics of Contaminants Found at the
QCF site............................. ~ . . . . .. 46
Summary of
site Ri sks ............................ 50
7.1
Human Health Risks .-......................... 50
contaminants of Concern .............. 50
7.1.1
7.1.2
7.1.3
7.1.4
Toxicity Assessment
. . . . . . _8 . . . . . . . . . .. 52
Exposure Assessment
. . . . . . . . . . . . . . . . .. 55
Environmental Assessment .................... 60
Risk Characterization ................ 55
7.2
7.3
Uncertainty in the Risk Assessment .......... 61
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 62
7.4
Conclusions
Description of Alternatives ...................... 64
8.1
IRM and Associated Areas .................... 64
8.2
Bur ied Drum Area...... . . . . . . . . . . . . . . . . . . . . .. 73
8.3
4 -Tek ....................................... 75
9.0
Comparative Analysis of Alternatives ............. 77
. . . . . . . . . e.. . . . . . . . . . . . . . .. 77
9.1
Threshold criteria
9.1.1 Overall Protection of Human Health
and the Environment ...:..................~.. 7/
9.1.2
-------
10.0
9.2
Primary Balancing criteria .................. 80
Long-Term Effectiveness and
9.2.1
Permanence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 81
9.2.2 Reduction of Toxicity, Mobility or
Volume through Treatment .................... 81
9.2.3
9.2.4
9.2.5
Short-Term Effectiveness ............. 82
Implementability ..................... 82
Projected Costs ...................... 84
9.3
Modifying criteria .......................... 84
State Acceptance ..................... 84
9.3.1
9.3.2
The Selected Remedy.............................. 87
community Acceptance ................. 86
10.1 IRM Area and Associated Ground-Water
contamination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 88
10.1.1
10.1.2
10.1.3
10.1.4
10.1.5
10.1.6
vertical Barrier System ......~...... 88
Dewatering of IRM ................... 89
contingent Extraction and Treatment
of Aquifer 1 Ground Water Outside
Barr ier System...................... 89
LNAPL Remova 1 ....................... 91
Venting of IRM Soils
................92
Aquifer 2 Extraction and Treatment .. 92
10.2 Buried Drum
Area. . . . . . . . . . . . . . . . . . . . . . . . . . .. 96
10.2.1
10.2.2
BDA Excavation/Off-Site Treatment/
Disposal/Onsite Consolidation ....... 96
10.3 4-Tek Industries............................ 98
IRM/BDA Surface Water Drainage System 98
10.4 site-Wide Actions ...........:................99
10.4.1
10.4.2
Deed Restrictions qnq Institutional
Contro 1 s ............................ 99
Long-Term Monitoring
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10.4.3
CERCLA Five Year Review............. 99
10.5 Off-site Areas
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 99
10.5.1
Monitoring of Off-site Drinking
Water Wells ................."........100
10.5.2
Monitoring of Cedar Hills Landfill.. 100
11. 0
Remedial Action Objectives ...................... 101
. . . . . . . . . . . . . . . . . . . . . . .. 103
12.0
statutory Determinations
12.1
12.2
12.3
12.4
12.5
Protection of Human Health and the
Env ironment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 103
Compliance with Applicable or Relevant
and Appropriate Requirements ............... 104
Cost Effectiveness ......................... 107
utilization of Permanent Solutions and
Alternative Treatment Technologies to the
Maximum Extent practicable ................. 107
Preference for Treatment as a Principal
E 1 em e n t """"""",""""":.""""" 1 0 9
13.0
Documentation of Significant Differences ........ 110
13.1
13.2
13.3
13.4
13.5
13.6
Appendices
Appendix A:
Appendix B:
Appendix C:
Cleanup Goals for Soils at the QCF Site .... 110
venting of IRM Soils ....................... 110
Aquifer 2 Extraction and Treatment ......... 111
4-Tek Industries ........................... 112
On-site Surface Water Discharge of
Extracted Ground Water ..................... 112
Off-site Drinking Water Wells .............. 112
Responsiveness Summary
Administrative Record Index
Key to Abbreviations
-------
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
LIST OF FIGURES
Page
site Location
. . . . . . . . . . . . . . ... . . . . . . . . .8 . . . . . . . . . . . . . . .. 2
General site Plan
.....................................3
Location of Wells Sampled During Off-Site Study....... 5
Schematic Diagram of 4-Tek Portion of Site ............ 7
stratigraphic units Beneath QCF ....................... 19
Geologic Cross section Through IRM Area ............... 20
Surface Water in the Vicinity of Queen City Fa~ms ..... 21
Drainage Basins in the Vicinity of Queen City Farms ... 22
North-South Hydrogeologic Cross
section ............... 24
Areal Extent of LNAPL ("Oil") ......................... 35
Areal Extent of Aquifer 1 ............................. 41
Distribution of DCE in Aquifer 2
. . . . . . . . . . . . . . . . . . . . .. 42
Distribution of TCE in Aquifer 2 ...................... 43
Conceptual Model of Historical and Existing Aquifer ,2
Groundwater Flowpaths ................................. 45
Conceptual Model of Surface Water and Groundwater
Interactions and Flow................................. 47
Preliminary Barrier Wall Construction Concept
. . . . . . . .. 67
Conditional Point of Compliance for Aquifer 2
-------
1.
2.
3.
4.
5.
6.
7 .
8.
9.
9A.
LIST OF TABLES
Page
summary of subsurface Soil contaminants in Former
Ponds 1, 2, and 3 (IRM Area) ............'.........'.... 26
Summary of contaminants Detected in Buried Drum Area .. 28
contaminants Detected in RI soil Samples Collected
from Ponds 4, 5, and 6 ..................~............. 30
contaminant concentrations in subsurface Soil at 4-Tek
32
contaminant Concentrations in
LNAPL ................... 36
contaminant concentrations in the Near-Surface Water-
Bear ing Zone..........'."'..'.....'...""..'.""... 3 7
Ground Water contaminant Concentrations at 4-Tek ...... 38
contaminant Concentrations in Aquifer 1
. . . . . . . . . . . . . .. 40
Summary of Volatile Organics Detected in Aquifer 2 .... 44
Unfiltered and Filtered Metal concentrations in
Aqu i fer 2 ............................................. 44A
10.
Chemicals of potential Concern at the QCF site ........ 51
11.
Human Toxicity Factors of Chemicals Retained for Risk
Quantification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53
12.
Reasonable Maximum Exposure (RME) and Average Exposure
Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 56
13.
Total Non-Cancer Risks at QCF site .................... 58
14.
Total Cancer Risks at QCF
site. . . . . . . . . . . . . . . . . . . . . . .. 59
15.
Elements of IRM Area Remedial Alternatives ............ 65
16.
Glossary of Evaluation criteria ....................... 78
17.
Estimated Costs for Evaluated Alternatives ............ 85
18.
Cleanup Levels for Aquifer 1 Ground Water ............. 90
Cleanup Levels for Aquifer 2 Ground Wat.er ............. 93
Cleanup Levels for BDA soil Left in Place ............. 97
- ---.- ----. .
19.
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1.0 SITE NAME AND LOCATION
Queen City Farms
Maple Valley, King County, Washington
2.0 SITE DESCRIPTION
2.1 settinq
The 320-acre Queen City Farms site (Site or QCF site) is
located adjacent to Cedar Grove Road, approximately three miles
northwest of Maple Valley, King County, Washington (Figure 1).
It is situated in a predominantly rural, wooded, residential
neighborhood. The site was the location of a former pig farm and
is owned by Queen City Farms, Inc (QCF, Inc).
Adjoining the QCF Site to the north is the Cedar Hills
Landfill, a municipal landfill, which is operated by King County
(Figure 2). The Site is bounded to the west by wooded land owned
by Plum Creek Timber Company, and a gravel sorting facility
operated by Stoneway Concrete Inc (stoneway). The south side of
the site is also partially bounded by the Stoneway gravel sorting
facility and by private residences. Across Cedar Grove Road to
the south is an undeveloped marshy area. Some of this marsh is
within the.QCF property boundary and the remainder is privately
owned. The eastern side of the site is bounded by 22Sth Avenue
SE which provides access to Cedar Hills Landfill. Private
residences are located to the east of 22Sth Avenue SEe
2.2
TopoqraphV
The QCF site is located on a rolling upland area on the
north side of a broad northeast-southwest trending valley (Cedar
Grove Channel). The southwestern third of this valley drains
into the Cedar River, approximately 1 mile to the west of the
site. The central and northeastern portions of the channel drain
into the Issaquah Creek Basin.
The QCF site slopes from an approximate elevation of 535
feet above mean sea level (MSL) near the northeast and northwest
corners to an approximate elevation of 360 MSL along Cedar Grove
Road to the south. Gravel mining operations in the south-central
portion of the Site have also lowered the surface topography to
an approximate elevation of 360 MSL. The Cedar Grove Channel in
. the southeast portion of the QCF property is slightly lower than
Cedar Grove Road.
The site topography is characterized by varied glacial
terrain that includes rolling upland, a seasonal kettle lake
(Queen City Lake), delta and kame terraces, and a steep
de$cending slope in the floor of Cedar Grove Channel. Sand' and
gravel mining of the glacial outwash deposits has significantly
-------
. - .. .
- ..-.-. ..---.
..-. - ...-
ro, SOUTH
480
I 470
I
I, 460
450
:J' 440
~
E.
c 430
,2
! 420
W
410
400
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390
380
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NORTH I
480 II
470
460 :
I
450
440 'i
E.
430 .ti
420 I
w
410
400 N
CO°
o
Openwoo< Gravels
. -.- ..-.----.-
FIGURE 6
GEOLOGIC CROSS-SECTION THROUGH IRM AREA
(
~.,..""~,"",,..
Dip 01 Bedding
. . . '9. . .. High Water Level
.--- ---'.'---'---."'.
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-. ~ . "1"9 (Hoy
- General Sile Plan .
FIGURE 2
01
1992)
POOR QUALITY
-------
.-.-- --.-----..'
seasonal lake has formed in the south-central portion of the
in a depression left by extensive gravel mining (Main Gravel
Lake). Construction of a yard waste composting facility has
altered the topography in the northwest portion of the site.
site
pit
also
2.3
Land Use
piqure 2 shows the general plan of the QCF site. The QCF
site includes six former waste ponds, a now closed and reclaimed
sand and gravel pit which was operated by ~toneway, the former
Queen city airstrip, the former 4-Tek Industries facility and
Queen city Lake. A yard waste composting facility, operated by
Cedar Grove composting, Inc. is located in the northwest corner
of the site..
Current land use at the QCF site is consistent with King
county zoning, and consists of two major commercial operations:
1) sand and gravel mining, and 2) yard-waste composting. Mining
operations began in the southwest corner of the QCF site in the
mid-1970S and expanded across the southern portion of the site
and then northward until sand and gravel resources were depleted
in 1992. Currently, stoneway has implemented a Reclamation plan
which has been approved by King' County, .and required slope
regrading, stabilization and hydro-seeding.
Yard-waste composting is currently being conducted at a
facility, owned and operated by the QCF site property owners,
which is located on approximatelY 26 acres in the northwest
portion of the site. The Cedar Grove Composting facility accepts
compostable yard-waste collected as part of the city of seattle's
and King County's recycling programs. composted product from
this facility is sold commercially for use as a soil amendment.
Immediately south of the composting facility is a building
which was used by 4-Tek Industries for repackaging of various
chemicals and solvents. This building is now used by Cedar Grove
composting Company. The west-central portion of the site
contains a fenced storage yard which is used by the property
owners to store heavy equipment related to current and past
commercial operations at the site.
The north-central and northeastern portions of the site are
not currently used for commercial purposes. Queen city Lake, a
seasonal lake with no surface outlet, occupies much of the north-
central portion of the site. The Initial Remedial Measure (IRM)
area, location of a 1986 remediation activity, is located on
approximately 4 acres in the northeastern portion of the Site.
currently, there is no residential use.of the QCF site. One
abandoned residence is located immediately east of the IRM area.
Private residences, located down-gradient to ~e south and.
southwest of the QCF site use ground water for drinking water.
pigure 3 shows the locations of the off-site drinking water
wells.
-------
. .
.
.
FIGURE 3
LOCATION OF WELLS SAMPLED DURING OfF-SITE STUDY
POOR QUALITY
-------
3.0
S~TE H~STORY AND ENFORCEMENTACT~V~T~ES
b..!
Past DisDosal Activities
Past waste disposal practices at the QCF site are poorly
documented. From approximately 1955 until the late 1960'S, local
industry used the QCF site for disposal of industrial waste
liquids. These wastes included paint and petroleum products,
organic solvents, and oils. Most records available indicate that
the wastes were primarily disposed of in three unlined ponds
located in the northeast portion of the site. These ponds, known
as Ponds 1, 2, and 3 (Fiqure 2), were closed as the focus of the
IRM in 1986.
Wastes were transported to the ponds in tanker trucks and
subsequently discharged directly to the ponds. Wastes were also
poured into the ponds from drums and, on occasion, the drums
themselves were'placed into the ponds. Ponds 1, 2, and 3 were
reportedly burned periodically by the operators, Seattle Disposal
Company, in order to reduce waste volume.
Ponds 4, 5, and 6, located immediately to the south of Queen
City Lake, are believed to have been used for disposal of whey
and animal waste produced by a hog farming operation conducted on
site between the mid-1950's and 1964.
4-Tek Industries (4-Tek) leased a building in the western
portion of the site for the purpose of recycling-solvents. The
company purchased degreasers and surfactants in bulk and
repackaged them into smaller containers. 4-Tek then sold the
repackaged chemicals to the government and to oil recovery
companies. The plant operated until 1986.
A schematic of the 4-Tek portion of the QCF site is shown in
Fiqure 4. Bulk chemicals were stored and mixed in a storage
area, located south of the plant offices. Surface water runoff
from the chemical storage and mixing area drained through an 8-
inch vertical pipe to a sump located below the retaining wall
west of the plant buildings. The sump was located in the middle
of a concrete pad with approximately 3 feet of soil covering the
pad. A second 8-inch pipe drained to an outlet west of the pad
area. In 1980, the United states Environmental Protection Agency
(EPA) and the Washington Department of Ecology (Ecology) sampled
soils in the vicinity of the 4-Tek facility. These soils
contained detectable levels of volatile organic compounds that
were probably due to spillage which occurred during 4-Tek
operations.
3.2
Past Remedial and Removal Activities
Past remedial and removal activities have addressed three
areas of the site: (1) Ponds 1, 2, and 3 (2)' the 'Bur iEid--Drum
Area (BDA) and (3) the area of 4-Tek Industries operations.
~~._-_. ..-."-..
-------
-------------
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---------------
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I FORMER
\ LOCATION
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VEGETATION
CEDAR GROVE COMPOSTING FAC'UTY
HW-,t .
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.:;: LOCATION OF
'.' FORMER CHEMICAL'
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I I
1_____...1
FORMER LOCATION OF
8~; VERTICAL PIPE
II
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RETAINING
WALL
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tt-.>a 1i.~;'hr'4\' tJ.."
. . . .
Aerial extent of soil excavation
ParCImetrfx. Inc.
Former sump location
Figure .4
Schematic Diagram' of 4- TEK Site
7
\
!
-------
3.2.1
Ponds 1. 2. and 3
In 1980 the six waste ponds were first sampled by EPA. The
analyses of water, sludge and sediment samples taken from the
ponds identified 44 contaminants including metals, volatile and
semi-volatile organics, and PCBs. . In May 1983, EPA began a test
well drilling program to investigate the extent of soil and
ground-water contamination around the ponds. In August 1983,
QCF, Inc. signed a Consent Order pursuant to section 106 of
CERCLA, 42 U.S.C. S9606 to complete the well drilling program.
The analyses of soil and ground-water samples taken during these
field investigations confirmed the presence of 24 of the original
44 contaminants.
In August and September 1984, QCF conducted an additional
field investigation in the immediate vicinity of Ponds 1, 2, and
3. The purpose of this investigation was to determine the volume
of the industrial waste sludges in the ponds, and th~ volume of
contaminated soil adjacent and beneath these ponds. This
investigation determined the volume of industrial waste sludge in
Ponds 1, 2, and 3 to be approximately 5200 cubic yards. The
volume of the contaminated soil immediately beneath and adjacent
to the ponds was estimated to be 16,800 cubic yards. samples
taken from the sludge and soils confirmed the presence of
significant concentrations of heavy metals, volatile organics,
semi-volatile organics, polyaromatic hydrocarbons (PARs), and
PCBs.
Subsequent to this second investigation, QCF, Inc. began
work on a Focused Feasibility Study (FFS) to examine possible
initial remedial measures for the removal and/or containment of
the wastes in Ponds 1, 2, and 3, and in the underlying and
adjacent soils. In June 1985, QCF, Inc. submitted the FFS to
EPA. The FFS evaluated eleven initial remedial alternatives
under the broad categories of infiltration prevention, ground-
water diversion, contaminated soils isolation or removal and
chemical sludge stabilization, solidification, isolation or
removal, and incineration.
In October 1985, QCF, Inc. signed a Consent Order pursuant
to section 106 of CERCLA 42 U.S.C. S9606 for implementation of
Initial Remedial Measures (IRM) for Ponds 1, 2, and 3. The
evaluation conducted in the FFS, and the selected alternative for
the IRM were documented in an Enforcement Decision Document
issued by EPA on October 24, 1985.
The IRM was constructed at Ponds 1, 2, and 3 in late 1985
and in 1986 and included the following:
.
.
separation of chemical sludge into liquid and solid phases;
staQilization of the liquid portion of the sludge with
limestone flour and/or kiln dust"; . - -------.-----.--
disposal of the stabilized sludge at an off-site hazardous
waste landfill;
.
-------
.
installation of a ground water/surface water diversion
system to prevent surface water and near-surface ground
water from migrating through the contaminated soil left in
place beneath the former pond~;
installation of a multi-layered cap over the contaminated
soils; and,
installation of a ground-water monitoring system.
.
.
3.2.2
Buried Drum Area
During sand and gravel excavation activities conducted by
Stoneway in March and April.:of 1988, buried crushed drums,
contaminated soils, liquid wastes and other materials were
discovered in an area approximately 400 feet south of Queen .city
Lake and 750 feet west of the IRM. Samples taken of these waste
materials contained polyaromatic hydrocarbons (PARs),
pentachlorophenol (PCP), toluene, ethylbenzene, tetrachloroethene
(PCE), xylenes, and heavy metals. On August 15, 1988, a work
plan was submitted by QCF, Inc. to EPA and Ecology for removal of
all exposed drums and drum pieces. Upon EPA and Ecology approval
of the work plan, the removal was accomplished during August and
September, 1988.
Thirty-two over-pack drums were used to contain recovered
crushed drums. One drum was used to contain recovered liquids
and three roll-off truck boxes were used to contain heavily
contaminated soils and recovered crushed drums. " These materials
were transported off Site and disposed of in accordance with
section 121(d) (3) of CERCLA, 42 U.S.C. S9621(d) (3), sections 3004
and 3005 of the Resource Conservation and Recovery Act (RCRA), 42
U.S.C. SS9624 and 9625, and all other applicable State and.
Federal regulations.
3.2.3
4-Tek Industries
Soil sampling conducted by QCF, Inc. at 4-Tek in 1985 and
1987 confirmed the presence of volatile organics including PCE,
trichloroethene (TCE), toluene and methylene chloride. In May
1990, QCF, Inc. signed a Consent Order pur$uant to Sections 104
and 122 of CERCLA, 42 U.S.C. SS9604 and 9622 to conduct removal
cleanup activities at the 4-Tek property. In May and June 1990,
under EPA oversight, excavation, soil removal", confirmatory soil
sampling and water sampling from the sump were conducted by QCF,
Inc. Approximately 170 cubic yards of soil containing volatile
organics and"40 cubic yards of concrete were excavated and
removed to an off-site hazardous waste landfill.
3.3
Off-site studies
In addition to the three on-site ~tudy areas, two investigations
were conducted off site in localities adjacent to the QCF-Site.-
-------
3.3.1
Cedar Hills Landfill
. In order to determine whether the Cedar Hills Landfill,
which is adjacent to, and lies north of the site, was
contributing ground water or surface water contamination to the
QCF site, King County signed a CERCLA section 106 Consent Order,
pursuant to 42 U.S.C. S9606, with EPA to conduct a Remedial
Investigation and Feasibility Study (RIfFS) for the southern
portion of the landfill. The RI was completed in January 1991.
The results of the RI are summarized as follows:
.
No evidence was found of contamination in excess of
regulatory standards migrating from Cedar Hills
Landfill to the QCF site due to ground-water transport.
.
surface water that flows across the property line from
Cedar Hills Landfill to Queen City Lake does not appear
to have any impact on the chemical water quality in the
lake.
3.3.2
Off-site Domestic Well study
EPA, Ecology, and the King county Health Department sampled
off-site domestic drinking water wells in 1981, 1984, and 1986 to
determine whether ground-water contamination related to QCF was
migrating off-site. Results of these studies indicated that no
contamination related to the QCF site was found in these off-site
wells. In December 1991, EPA sampled 12 private-drinking water
wells in the vicinity of the Site. One of the off-site domestic
water wells contained detectable levels of TCE which were below
health-based standards. The source of this contamination has not
been identified, but may be related to the QCF site.
3.4
Enforcement Activities
In October 1980, EPA and Ecology conducted a site
Investigation (SI) of the soil, water ~nd sediment from the six
former waste ponds at the QCF site. Results of the SI revealed
the presence of heavy metals and organic compounds in water and
sludge samples collected from Ponds 1, 2, and 3. Ponds 4, 5, and
6 contained agricultural waste.
In August 1983, EPA and QCF, Inc. signed a Consent Order
requiring QCF, Inc.to conduct a shallow ground water
investigation pursuant to section 106 of CERCLA, 42 U.S.C. S9606.
The QCF site was proposed for inclusion on the National
Priorities List (NPL) in september 1983. In september 1984, the
QCF site was placed on the NPL.
In September 1985, EPA issued information request letters,
pursuant to section 104(e) of CERCLA, 42 U.S'-C. S9604(e), to.-4S.
potentially responsible parties (PRPs), including QCF, Inc., and
The Boeing company.
-- ---- _0-
-------
Pursuant to Section 106 of CERCLA, 42 U.S.C. S9606, E~A,
QCF, Inc., and The Boeing Company signed a Consent Order in
October 1985 for implementation of the IRM source control
measures at Ponds 1, 2, and 3. This Consent Order was amended in
July 1986 to extend the milestone dates of implementation of the
source control measures. . Subsequently, QCF, Inc. signed a
Consent Order with Ecology in January 1986, to implement the
source control measures under the authority of Revised Code of
Washington (RCW) 90.48.120.
In March 1986, in No' Damaqinq or Unsiqhtlv Municipal .
Pollution. Inc. v. Kinq Countv, No. C82-186V, the U.S. District
Court held that Queen City Lake receives surface water runoff
from the Cedar Hills Landfill. This decision proved important in
later enforcement actions regarding coordination. of activities at
th~ QCF site with activities at Cedar Hills Landfill.
In July 1987, pursuant to Sections 106. and 122(d) (3) of
CERCLA, 42 U.S.C. SS9606, 9622(d) (3), EPA and Ecology notified 25
PRPs of their intent to conduct a Remedial Investigation and
Feasibility Study (RIfFS) of the QCF site.
In November 1987, EP-A issued Special Notice Letters to QCF,
Inc., The Boeing Company, the Washington Department of Natural
Resources, and King County. The special Notice Letters invoked a
60 day negotiation moratorium for the financing and
implementation of RIfFS activities at the site pursuant to
section 122(e) (2) of CERCLA, 42 U.S.C. S9622(e) (2). In addition,
in accordance with section 107 of CERCLA, 42 U.S.C. S9607, the
Special Notice Letter demanded reimbursement of past EPA costs,
including all future EPA costs at the Site, as well as payment of
interest on these costs.
The Boeing Company, QCF, Inc., and EPA signed a Consent
Order in May 1988 requiring The Boeing Company and QCF, Inc. to
undertake the RIfFS pursuant to section 106 of CERCLA, 42 U.S.C.
S9606.
Under the
S9606, EPA and
requiring King
portion of the
authority of Section 196 of CERCLA, 42 U.S.C.
King County signed a Consent Order in June 1988
County to undertake an RIfFS on the southern
Cedar Hills Landfill, adjacent to the QCF site.
In May 1989, EPA issued a Unilateral Order (Order) to
Stoneway and QCF, Inc., pursuant to section 106 of CERCLA, 42
U.S.C. S9606. This Order called for Stoneway and QCF, Inc. to
cease and desist from conducting any excavation activities in
designated areas of the QCF site due to the presence of buried
crushed drums, drum remnants, contaminated soils, liquid wastes
and other materials. .
Under the authority of section 122 of CERCLA, 42 U.S.C.
S9622, EPA issued a special Notice Letter to QCF, Inc. in July
1989. The Special Notice Letter invoked a_60 day negotiation
-------
moratorium for the financing and implementation of response
activities at the 4-Tek portion of the QCF site.
In May 1990, EPA and QCF, Inc. signed a Consent Order
requiring QCF, Inc. to undertake removal activities at the 4-Tek
portion of the QCF site pursuant to sections 104 and 106 of
CERCLA, 42 U.S.C. SS9604 and 9622. In addition, under the
authority of Sections 104 and 122 of CERCLA, 42 U.S.C. SS9604 and
9622, EPA, QCF, Inc., and Stoneway signed a Consent Order which
prohibited stoneway and QCF., Inc. from excavating in certain
areas of the site. This Consent Order between EPA, QCF Inc., and
Stoneway superceded the May 1989 Unilateral Order. .
In May 1992, EPA and King county. signed a Consent Order
pursuant to Section 106(a) of CERCLA, 42 U.S.C. S9606(a),
requiring King County to undertake a long-term surface water and
ground-water monitoring program on the southern portion of the
Cedar Hills Landfill.
3.4.1 Reports Produced bv potentia11v Responsible Parties
Under Consent Orders with EPA
8
February 7, 1985, Hart Crowser & Associates On Behalf
of QCF, Inc., "Focused Remedial Investigation, Queen
City Farms, King County, Washington"
8
June 28, 198?, Hart Crowser & Associates, On Behalf of
QCF, Inc., "Focused Feasibility study -for Remedial
Action, Queen city Farms, King County, Washington"
8
January 29, 1987, Hart Crowser & Associates On Behalf
of QCF, Inc., "Site Remediation Documentation Report,
Source Control Remedial Action, Queen city Farms,
Washington"
8
February 24, 1988, Landau Associates Inc. On Behalf of
The Boeing Company and QCF, Inc., "Queen City Farms,
Initial Remedial Measures, First Year Performance
Monitoring Report"
.8
April 20, 1990, Landau Associates Inc. On Behalf of The
Boeing Company and QCF, Inc., "Remedial Investigation
Report, Queen city Farms, King County, Washington" (RI)
8
April 20, 1990, Landau Associates Inc. On Behalf of The
Boeing company and QCF, Inc. "Baseline Risk Assessment,
Queen city Farms, King County, Washington" (BRA)
8
January 31, 1991, King County Solid Waste Division,
"Cedar Hills Regional Landtill, South Cedar Hills.
Remedial Investigation"
8
July 31, 1992, Landau Associates Inc. On Behalf of The
Boeing company and QCF, Inc., "Supplemental Remedial
-------
Investigation Report, Queen City Farms, King County,
Washington" (SRI) .
.
July 31, 1992, Landau Associates Inc. On Behalf of The
Boeing Company and QCF, Inc., "Baseline Risk Assessment
Addendum" Queen City Farms, Remedial Investigation"
(BRAA)
.
July 31, 1992, Landau Associates Inc. On Behalf of The
Boeing Company and QCF, Inc. "Draft Feasibility Study
Report, Queen City Farms, King County, Washington"
(Draft FS)
3.4.2
Ma;or Reports Prepared and/or Issued bv EPA
.
October 24,1985, "Enforcement Decision Document,
Initial Remedial Measure Alternative Selection"
.
July 1992, ICF Technology Incorporated On Behalf of
EPA, "Summary Data Report, Queen City Farms Sampling of
Off-Site Water Supply Wells"
.
September 1992, "Data Summary Report, Four-Tek Portion
of Queen city Farms Superfund Site, Maple Valley, King
County, Washington"
.
September 1992, " Feasibility Study Addendum, Queen
city Farms Superfund Site, Maple Valley, King County,
Washington" (FS Addendum)
.
September 30, 1992, "Superfund Fact Sheet, The Proposed
Plan, Queen City Farms Superfund site, Maple Valley,
Washington" (Proposed Plan)
. .-.-- - --".--. - - . .
-------
4.0
COMMUNXTY RELATXONS
The RI, BRA, SRI, BRAA, Draft FS, FS Addendum, and the
Proposed Plan were released to the public for comment on
september 30, 1992. The public comment period extended from
October 2, 1992 to November 2, 1992. The RIfFS and supporting
documentation were made available to the public in both the
administrative record and information repositories maintained at
the Superfund Records Center in Region 10, the Issaquah Public
Library and the Maple Valley Public Library. The notice of
availability of the RIfFS documents was published in the "voice
of the Valley" and in the "Issaquah Press" on October 14, 1992.
A public meeting was held at the Lake wilderness Elementary
School in Maple Valley on October 21, 1992. The meeting was
attended by seventeen people which included four representatives
of the PRPs. At this meeting, representatives from EPA presented
the results of the RIfFS and EPA's preferred remedial
alternative. In addition, EPA answered questions about the
preferred alternative and about problems at the site. A
transcript of the meeting is available at the information
repositories listed above. Response to comments received at the
public meeting and during the public comment period is included
in the Responsiveness summary, which is part of this ROD.
EPA Region 10 community relations activities at the site
included the following:
.
April 1981: EPA samples five drinking water wells from
residences located adjacent to the site.
.
November 1983: The Seattle-King County Department of
Public Health (SKCDPH), EPA, Ecology, and the
washington State Department of social and Health
Services jointly conduct a drinking water survey of 105
residences that draw water from wells in the area of
the site.
.
January 1984: Based on the survey results, EPA,
Ecology and SKCDPH jointly sample 46 drinking water
wells within a 3.2 mile radius of the site.
.
April 1984: EPA, Ecology and SKCDPH jointly issue a
press release describing the final results of the
drinking water sampling program.
.
August 1, 1984: Draft community Relations Plan is
released to the public.
.
october 10, 1985: EPA conducts a public meeting
regarding the work plan and Consent Order ~or the
surface cleanup of Ponds 1, 2, and "3. .
-------
.
April 1986: EPA samples 11 SKCDPH designated potable
water supply wells in the vicinity of the QCF site.
August 22, 1986: EPA and SKCDPH release the results of
the potable water supply well study to residents. The
results of this study indicate that contaminants from
the QCF Site have not migrated to potable water
supplies.
.
.
January 1989: The Community Relations Plan is revised
and released. A Fact Sheet is released updating the
community on site activities.
.
October 18, 1989: EPA publishes a Notice of Public
Availability in the Issaquah Press which announces the
availability of the administrative record for the QCF
site at the Issaquah Public Library.
.
February 7, 1990: EPA issues a Fact Sheet describing
RIfFS activities at the site.
August 1990: EPA representatives meet with local
officials and members of the community to discuss their
concerns about the site and to review the progress of
the RIfFS, prior to updating the community Relations
Plan.
.
.
september 14, 1990: EPA issues a Fact Sheet updating
the community on the Community Relations Plan and on
the need for additional work at the IRM and 4-Tek study
areas.
.
.October 1990: The revised Community Relations Plan is
published and distributed to the information
repositories.
.
November 1990: EPA identifies the need to sample off-
site private drinking water wells to ensure that
ground-water contamination from the site had not
spread. Information was coordinated with the Seattle-
King Coupty Department of Public Health (SKCDPH),
Ecology and The Boeing company.
.
March - June 1991: community participants in the off-
site drinking water well study are contacted, and
interviewed by representatives of EPA.
.
April 9, 1991: EPA issues Fact Sheet on results of the
renedial investigation of the southern portion of the
Cedar Hills Landfill, and the start of the off-site
. drinking water well monitoring program.
-------
.
December 1991:
wells.
EPA samples 11 off-site drinking water
-------
.
January 22, 1992: EPA issues a Fact Sheet updating
community on status of work on-site and off-site.
.
April 14, 1992: EPA sends letters to residents whose
wells were sampled to inform them of the results.
.
April 20, 1992: EPA issues Fact Sheet updating
community on results of off-site drinking water well
sampling study.
.
May 12, 1992: EPA representatives meet with members of
the Cedar Hills citizen Review committee to discuss the
progress of the RIfFS and off-site drinking water well
study.
.
June 1, 1992: Representatives of EPA meet with the
Maple Valley Area council. to discuss the progress of
the RIfFS. .
.
July 1992: The Summary Data Report describing the
results of the off-site drinking water well study is
completed and placed in the administrative record.
.
September 30, 1992: EPA distributes copies of the
Proposed Plan to community members.
.
October 21, 1992: Public Meeting to take comments and
answer questions regarding the Proposed Plan.
-------
5.0
SCOPE AND ROLE OP RESPONSE ACTION WITHIN SITE STRATEGY
The remedial actions addressed by this Record of Decision
are the final remedial actions planned for the QCF site.
Residual waste in subsurface soil which is associated with
past disposal activities around Ponds 1, 2, and 3 is the most
significant existing contaminant source area at the QCF site.
Subsurface soil is contaminated with chromium, PCBs, PARs, and
volatile organics.
The presence of ground water in contact with contaminated
soil below the IRM area have caused contaminants to migrate from
the subsurface soils to the ground water. A volatile organic
contaminant plume has developed in the ground water which
threatens off-site drinking water supplies.
Heavy metal, PCB, PAR, volatile, and semi-volatile
contamination remaining in soil from the Buried Drum Area, may
serve as a continual source to ground-water contamination.
Volatile organic contamination in shallow ground water which
may be associated with past activities at the 4-Tek property may
serve as a continual source of deep ground-water contamination.
The remedial actions described in this ROD will address the
presently known remaining threats to human health ana the
environment posed by contaminated soils and ground water at the
QCF site. ..
..____n_- -
-------
6.0
SITE CHARACTERISTICS
6.1
Geoloav and soils
The QCF site is underlain by glacial deposits from the most
recent period of glaciation known as the Vashon Stade of the
Fraser glaciation (Vashon). These sediments overlie pre-Vashon
soils and sediments which were deposited by streams and lakes.
Twelve stratigraphic units were identified on the site (Figure
5), consisting of six pre-Vashon units, five Vashon units, and
recent deposits. stratigraphic units of Vashon age include till,
ice contact, and outwash deposits which can be correlated to
similar geologic units throughout the puget Sound Basin. Pre-
Vashon deposits have not been correlated outside the Cedar River
Valley.
In general, stratigraphic relationships between Vashon
deposits are complex, pinching out or grading laterally into
other units or soil types over relatively short distances within
the QCF site boundary. Pre-Vashon deposits conversely are
generally continuous laterally at the QCF site, however geologic
data collected off-site indicate that these deposits may be of
limited regional extent. A north-south geologic cross section
through the IRM Area showing the relationship of some of these
stratigraphic units is shown in Figure 6.
The well-sorted Vashon sands and gravels have been mined
extensively in the central portion of the site by Stoneway. This
portion of the site is currently dominated by a gravel pit face
which in the past has served as a valuable tool for correlating
stratigraphic units across the site. The gravel pit face is
currently undergoing reclamation and will be regraded to a 2:1
slope and then hydro seeded with grass.
L.£
Surface Water Hvdroloav
Major surface water features in the vicinity of the QCF site
are shown in Figure 7. The upland area encompassing the QCF site
and Cedar Hills Landfill is bounded by major surface water
drainage channels; to the north by Mason Creek, to the east by
Issaquah Creek, and to the west by the Cedar River. Cedar Grove
Channel, a northeast-southwest trending drainage swale, occupies
the area directly south of the QCF site. Surface water on the
drift plain north and south of the QCF site includes a number of
small lakes and streams. streams draining to the south, towards
Cedar Grove Channel, discharge into seasonal lakes with no
surface outlet or infiltrate directly into the ground. other
streams discharge directly into the major dr~inage channels.
Seven drainage basins have been delineated in the vicini~y__-
of the QCF site (Figure 8). The Queen city Lake Basin, the Main
Gravel pit Lake Basin, and the stoneway pit Sub-Basin drain into
seasonal lakes that have no surface outlet. Surface water in the
n_.'- ---
-------
AGE
.---.-
-.- -- --;. .
RECENT
~~%~~
.::~~~:A,\;
~
ii:
S
£
i
i
VASHON
STADE
T
PRE-VASHON
UNDIFFERENTIATED
DRIFT
'f'
STRA11GRAPHIC
UNIT
-0-
@
@
@
@
@
o
@
@-
o
o
@
:~
DESCRIPTION
Clayey SLT. SIlT. silty rIM SAND
. .
.:
Poorly- to W8korted ClAY, SIlT, SAND, and GRAve.
(Ice contact deposit) (locally wat8r~ within Aquler 1 and
Aquller 2)
Strallfied., poorty to wekoned SAND and GRAVEL with occasional
Interbedded clayey Su.. T and 1=Iow 1'1Ir (r8C8SSionaI outwash and
deltaic deposits) {locally water-bearing wtthin AquIfer 1 and
Aquifer 2)
Unsorted ClAY. SILT. SAND. and GRAVEL (118 deposiIed during
f8C8SSlonai phase) (T1II AquJtard)
Unsorted ClAY. SILT. SAND. and GRAYa (lodgement 1111. TDi "..-.. .
Aqultard) .
Stratified poorty to well-soned SAND and GRAYa with ocCasional
silty GRAVEllntetbeds (advance outwash) (locally water-beartng
within Aquner 2)
WeD-sorted. slightly silty to silty. very fine. fine and medium SAND
with Occasional clayey SILT to silty etA Y Interbeds. (upper l8Ction is
d2rt( red-brown to orange-brown color; occasional wood fragments.
water-bearing within Aquifer 2)
SILT. clayey SILT. line sandy SILT. and silty fine SAND (oc::asional
wood fragments) (Aqultard 2)
.:s.'
Well-sorted very fine to medium SAND with sandy GRAVEL and
gl'aV6Dy SAND Interbeds (oc:casIonai wood fragments)
(water-bearing within Aquifer 3)
SILT and fine sandy SILT (containing abundant wood fragments)
to gravelly SilT with occasional SAND and sandy GRAVEl
interbed (Woody Aquitard)
,
Interbedded sandy GRAVEL. graveDy SAND. silty sandy GRAVEL.
sandy SilT. and SAND (Deep Water-Bearing Zone)
CLAY. with closely spaced slickensides with interbedded SILT
and very fine SAND (Undifferentiated Pr&-Vashon Quaternary
lacustrine sediments) .
NOID: Snligraphic Units I and J - baled in part on Wlterpretallon
. and generalization of boring log daI:a for monIIDring weIs
MW-24. MW-53. and MW-S4 at Cedar Hills Landfill.
.S:!
. ,.;
:b
...
Ii)
. .
~
Stratigraphic Units Beneath aCF
FlQUre, 5
-------
N
o
-----....
SOUTH
480
470
I 460
450
:::; 440
~
€.
c 430
o
';
>
CD 420
iii
410
400
390
380
Nole: This aosl s«:don has boon
genorallzed 110m ploJoct nold dala.
V31Iadons between It'III CI068 locUon
and aellla/loIl condldonl may be
encountered. The plOJecI boIlng logs
and wlillen reporlll musl be
relerenood lor a ploper understanding
011110 nalure 01 lubsurlaoo malO/lals.
)
F(2)
W.2
W-4 MW.9
-........
""'''''''
'''''''''..............
.. ,..,
UnltC
""''"................
........~
",.
'.
o 125
~.-
,Morlzontal ~aleJn Fe,el,
Ver1lCalExaggeralion . 5x
KEY
B-6 .- Approximate Boring location
1 and Identification
? ~ - Screened Interval
"-1";'-.... Approximate Geologic Cpntacl
I 1
- Boltorn 01 Boring
NORTH
<480
<470
460
<450
440 :::;
~
€.
430 .8
<420 I
w
410
400
Unll E
390
380
250
I
~
Silt .
. . . 'Sl. . .. High Water level
Dip 01 Bedding
t:~:~:~~ TIll
~ Openwor1< Gravels
.- .-..----.-
.-.- ---"'- -'-""'-'
FIGURE 6
GEOLOGIC CROSS-SECTION THROUGH IRM AREA
)
',....",,""'..
-------
., ---1.-..:.-- :.
..-- ..-------...-
"
;.. ---.-..........--....
t
N
I I:
I ,:
':
"
i'
;i
o
.,~. .
,.'
.'''..' -
u
~~
'.'
'-.
'-
Souroe: Base map after King County (1987) ,
~
o
I
1/2
!
2
I
Property Boundaries
1
1
Scale in Miles
--.2 ! FIGURE 7
SURFACE WATER IN THE VICINITY OF QUEEN CITY FARMS
----
Drainage Courses
'..'
~
Water Bodies
('
21
I
t:
n,
I:
:,
;j
iI
:!
:.
.,
-------
;ij
~~
.,.
.'
. .
~. .
~
~~~~~~
~
---
M'??;;-&N\I
lakes and Ponds
Property Boundaly
-..-
Roads
Streams
F. 'I
tgur~ 8.
Drainage Basins in the Vicinity
of Queen City Farms (Landau 1990)
.-..;
-~: SCAL£ IN FEET
IL.II
t.2S0 2.500
Drainage Basin Boundary
o
22
,.
t
!
~
H.
~
H-
!!
~
>~
g
~!
~
~
""
II!i!'
t
F
-------
--- - .. .-
.- _...' .- .
Cedar Grove Basin appears to infiltrate Cedar Grove creek.
Surface water in the Cedar River Basin, the Mason creek Sub-
Basin, and the Issaquah Creek Basin discharges to the respective
.r i ver or creek. .
Six of the seven drainage basins include portions of the QCF
site. Surface water within these basins is characterized by a
number of seasonal lakes, streams, and springs. Seasonal
precipitation patterns cause lake levels and stream and spring
flows to vary widely. Prior to 1991, surface water flow and
excessive precipitation during the wet season would cause Queen
City Lake to overflow periodically. A culvert (Erosion Control
Measure) was installed by QCF Inc. and Stoneway in 1991 which
diverted water from the outlet of Queen city Lake to the lower
gravel pit (Main Gravel Pit Lake). With the installation of the
Erosion Control Measure, excessive surface water runoff and
flooding has been controlled. with the exception of a few
springs, surface water on the QCF site normally dries up by late
summer.
.!.d
Ground Water Hvdroloqy
The QCF site is located within a regional ground-water
recharge zone. Surface water recharges the shallow water-bearing
zones and hydraulic gradients direct ground-water flow from the
upper aquifers to the lower aquifers.
Twelve hydrogeologic units have been identified at the QCF
site. Hydrogeologic units are grouped into two unsaturated
units, five saturated units, and five aquitards. Unsaturated
units are formations, or groups of formations, that do not have
sufficient water to monitor in a well. A north-south
hydrogeologic. cross-section is shown in Figure 9.
The five saturated units identified at the QCF site include
the following:
1) The Near-Surface water-Bearing Zone (not shown on Figure
9) - This unit comprises ground water in the weathered
glacial till and near-surface deposits, is generally limited
in extent and restricted to the northern portion of the QCF
site and to the Cedar Hills Landfill.
2) Aquifer 1 - This unit is a perche~ sand and gravel
aquifer which is very permeable, is l'imited in extent and
restricted to the northern portion of the QCF site in the
vicinity of the IRM. .
3) Aquifer 2 - This aquifer is unconfined and consists of a
series ot sands and silts which extend throughout the QCF
Site and beyond the site boundaries.
-------
;.',
.;.. . ~ .::.;:;t.t~:~. :J
1~,1..~~~i!~:t~: ,. ;t
NORTH
500
475
450
425
400
375
350
325
J 300
.N
J~
275
250
225
KEY
~
////
I
1:::::::::1
,
li{:\;'""<1
"
HC.~
8131
Till
Aquitard
Aquifer 1
-Clayey-Silt Layer
Vq~:L '2a\;.VO.. "...,
L-
Slit)' Layer 2-A : : .
Slit Layer 2-D:
, ' .
[[[ .
[[[ .
. . . .. . . . . . . . . . . . . , . . . , . , . , , . , , , . . , . , . , , , : : : : : : : : : : :1. : : : : : : : A: ' 'q' , 'U' ',"f' e. , roo '2'" : : : : : : : :: :
.................. ..., . ...................... ......... .
...-.... ...................... .....................
.. ..........
...... . . . . . . . . .. ...... I . . . .
................ . ..........
. ,
..............
....
....
Slit Llyer ~-:<:
[[[ .
[[[ .
.........................................
......
Unit G --
Aqultard
" ...... .
........ . ............. ................................................. .
. . . . . . .... . . .. . . . . . ... [[[ .
. . . . . ... ..... . . . . . . .. .. ... . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ".
. ...................... """""""""""""""""""""'A 'f 3"""'"
[[[ qUI er .........
....................... """1""""""""""""""""'" ........ .
....................... ............................................... ...................
....................... [[[ .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .
....................... [[[ .
.................... ............... .
. " ',' ': . ,"' ...', ,
:::"~"~.. .":... .'....... .t:"':. ~"..........:.. ~:: :': :": f:"; :~'~".':~ I"'" I ~..... ."."... ~......: :::: J':: :":':.. ."."....
: [[[ : Un It J 1:::::::::::::::::::::::::::
-------
4) Aquifer 3 - This aquifer is confined and, is similar to
Aquifer 2, consists of a series of sands and gravels which
extend throughout the site and beyond the site boundaries.
5) Deepwater-Bearing Zone - This sand and silt aquifer is
confined and is most likely of regional extent.
Aquifers 2 and 3 and the Deep Water-Bearing Zone represent a
continuous sequence of sands and silts separated by two
relatively thin clay and silt aquitards.
Ground-water flow direction at the QCF site is generally
from the north to the south, with some important exceptions that
are discussed in greater detail in the section entitled "Routes
of contaminant Migration."
6.4
Extent of contamination
6.4.1
soil
soil contamination on site is generally confined to
identified potential source areas. Soil and sediment sampling
conducted during the RI focused primarily on previously
identified source areas and other potential areas of
contamination.
Although the IRM conducted in 1986 removed m~ch of the
source materials from the QCF Site, soil beneath former Ponds 1,
2, and 3 are contaminated due to years of leaching of the waste
materials. No subsurface soil samples were taken from the IRM
area below former Ponds 1, 2, and 3 during the RI. Previous
sampling, conducted by Hart-Crowser on behalf of QCF Inc. in
1983, 1985, 1986, and 1987, revealed high"concentrations of
metals, volatile organics, semi-volatile organics, and PCBs. The
range and frequency of contaminant concentrations detected in
soils remaining beneath former Ponds 1, 2, and 3 is shown in
Table 1. contaminants Df concern from these soils include
chromium, cyanide, TCE, DCE, toluene, xylene, PAHs, and PCBs.
Because ground water is in contact with these soils, the IRM
soils are still serving as a continuous source to ground-water
contamination at the site.
Contaminants detected in post-removal samples from surface
and subsurface soils of the BDA include arsenic, chromium,
copper, lead, PCBs, PAHs, PCP, 1,2,4-trichlorobenzene,
phthalates, PCE and TCE. The range and frequency of contaminant
concentrations detected in subsurface soils from the BDA is shown
in Table 2. Based on magnetometer studies, five test pits were
excavated to depths ranging from 8 to 15 feet below surface.
Drums and wastes encountered in the test pits indicated that
damaged, empty drums, or drums that would not easily drain were
placed in the burial area. All drums encountered during the RI
contained either a very viscous tar-like material or residual
solid sludge or cake material. Samples of native soil were taken
-------
-,'.
. . ..
-. ,."." '-, ~";'.'~":~""~"7-''''''':''''''. .....'
Page 1 of 2
TABLE 1
SJjMMARY OF.. S.UBSUR;FAC~. SOIL'.CONTOONANTS
. (IRM AREA)
INFORMER PONDS l~ 2 AND 3
Pre-RI Soil Data Subsur1ace Soil at (or Near)
Beneath the IRM (a) Perimeter of IRM (b)
Concentration Frequency of Concentration Frequency of
Consttue:'1t Range Detection (c} Range Deteaion
lnoraanics (~o)
Arsenic 1.1 - 24 19119 1.3 B - 5 27127
Barium 29 - 170 12/12 35.3 - 93.7 27127
Beryllium 0.3 - 0.8 11/12 20.3 1/6
Cadmium 0.08 -38 18/19 0.64 - 7.9 25127
Chromium 16 - 31000 39/39 17.4 - 1320 27127
Cobalt NA 4 B - 9.3 416
Copper 12 - 530 19119 10.9 - 133 27127
Cyanide 02 -38 9123 NO
Lead 1.7 - 510 18/19 1.6 - 3.9 25127
Manganese NA 161 - 452 1 6116
MerOJry 0_3 2/12 0.85 1/18
Nickel 16 - 89 19/19 13 - 43.1 27/27
Selenium 0.6 2/12 NO
Silver 0.2 - 2.9 8/12 NO
Thallium ND 0.34 1.':3
Va.~2diurn NA 37.4 - 4: 6/6
Zinc 26 - 6CO ~ 9/19 25.6 -54 27/27
Oraanics (uo!ko)
Arodor-1016 40010 1/32 NO
ArocIor-1254 850 - 39600 7/32 270 - 7600 7/25
Arodor-1260 92 -862000 26/32 230 - 18000 10/25
beta-BHC 92 1/32 NO
1.2.4- Trichlorobenzene NO 52 J - 2700 6126
2.4-0imethylphenol 8.1 1/12 NO
2-MethyinaphthaJene 7800 - 190000 4/12 610 - 970 3126
Acenaphthene 530 - 11500 1 0133 NO
Acenaphthylene 1890 - 8890 3/33 NO
Anthracene (d) 450 - 30500 9/33 63 J - 70 J 2/26
Benzo(a)anthracene (e) 370 - 1900 3/33 NO
Benzo(a)pyrene 300 -2800 2133 43 1/26
Benzo(b)fluoranthene (I) 2180 - 3270 7133 NO
Benzo(k)f1uoranthene (I) 2180 - 3270 7/33 NO
B'3nzcic 3Cid 360 t/12 ND
bis(2-Ethylhexyl)phthalate 130 - 7200 10/12 39 J - 300 4/26
Chrysene 570 - 96000 5133 61 J -54 J 2/26
Di-n-butylphthalate 60 - 860 5112 110 1/26
Oi-n-octylphthaJate 100 - 690 . 3112 3S J 1/26
Oibenzofuran 82 - 4400 7/12 NO
Fluorene 52 - 19200 10/33 260 J - 320 J 2/26
Ruoranthene 240 - 78700 4/33 NO
Naphthalene 740 - 37000 9133 180 1126
Phenanthrene (d) 80 - 40000 12/33 14 J - 820 4/26
Phenol 190 - 8900. . 4/12 21 J - 30 J 2/26
Pyrene (e) 460 -9800 6/33 51 - 180 J 4126
1.1.1-Trichloroethane 1500 1/12 NO
1.1-Dichloroethane 38 1/12 NO
1.1-Dichloroethene 49 1/12 NO
1,2-0ichtoroethane 43 1/12 NO
.: \ '.~ t ~ \1 ".'>.\;~: \! I '. ;'....,
-------
.' .
..... ..... ...., .. .
. .. . .
-',:. 4 ..~. . '~'.' .~ '"':,""''',-,
'.'~" .~..: ''''':~'':..~r'':'~'',,:~'';';;'''''':._.~;~.. .
Page 2 of 2 .
.:.~~*~~..:..".~.....,.~ '....'
..' .." .,'....: ~ " .
.' ~'~.'''' '.. " ..,.. -I'.A. .~_. .,':' . .
"...'" .~_.,"!'" ~ ~-.~...,;.... ., .~:..... --':" -..'... "C;"".fI-~....._.
.. .-~..~.. -'-"--".
.. ., ,"'f""'
'. '.- '.. .
~
.-..---.- ---
- TABLE 1 (Continued)
SUMMARY OF CONTAMINANTS DEIECTED IN FORMER PONDS 1, 2, AND 3
. . ".:" ".'
'o.:l.:"u': '.
Pre-RI Soa Data Subsur1ace Soil at (or Near)
Beneath the IRM (a) Perimeter of IRM (b)
Concentration Frequency of Concentration Frequency of
Constituent Range Detection (e) Rang a DettoCtion
1 ,2-Dichloroethene (total) NA 2J-3S 5/28
1 ,2-Cichloropro~a 19:> 1'1~ I':D
2-8utanone 150 - 6100 4112 NO
4-Methyl-2-pentanone 31 1'12 NO
Acetone 110 - 18000 2112 4 J - 71 16128
Benzene 380 1'12 NO
Chloroform 290 1"2 NO
Ethylbenzene T - 6200 4112 79 1128
Methylene dlloride T - 180000 8/12 1 J - 31 18/28
Styrene Trace 1'12 NO
T etrachloroethene 1900 "12 2 J - 12 3/28
Totuene T - 40000 5/12 NO
trans-1 ,2-Dichloroethene T - 1300 4112 NA
T richJoroethene T -670000 6/12 3 J - 6 J 4/28
Vil'!yl <:h~!ida TraCE! . 1i12 ND
Xyl6r:a (:otal) T - 38000 5112 210 - 1.128
(a) Data compiled from Hart Crowser (1983, 1985b, and 1987). All data are representative of soil. remaining beneath the
IRM Area. Soil sample locations: HC-10, HA-10, HA-11, HA-12 (Hart Crowser 1983), HC-11, HC-12, HC-13,
P-2. P-3, P-4, P-S, P-6, P-9, P-10, P-14, P-20 (Hart Crowser 1985b), P-1, P-2, P-3, PB-1, PB-2
PB-3 (Hart Crowser 1987). Results of duplicate samples Me a'..eraged
Pond bottom soil samples (P-1, P-2, P-3) are 6:1 composites (Hart Crowser 1987).
(b) Concentration range of detected analytes. Results of duplicate samples ar6 not averaged.
Data indusive of sampling events from September 1990 to March 1991 (Landau Associates 1992a).
Sample Locations MW-9, MW-10, MW-11, W-1, W-2, W-3B, W-4, W-7, andW-9
at 9 to 68 ft below ground sur1aee.
(e) Number of samples in which the chemical was detected/number 01 samples analyzed.
(d) Anthracene and Phenanthrene = co-elutes, Hart Crowser 1985b boring and test pit soil samples.
(e) Benzo(a)anthracene and pyrene = co-elutes, Hart Crowser 1985b boring and test pit soil samples.
(f) Benzo(b)fluoranthene and Benzo(k)f\uoranthene = co-elutes. Hart Crowser 1985b boring and test pit soii samples.
Data Flaas
B = Lab lIag for inorganics: The reported value is less than the Contract Required Detection Limit but greater than
the Instrument Detection Limit.
J co Lab flag for organics: The reported value is less than the Contract Required Detection Limit but greater than
the Instrument Detection Limit.
T = Trace.
NA = Not analyzed.
NO = Not detected.
F:\PROJECTS\SOEING\OCF\FS\SUBSURFA.WK 1
071'22192
-------
TABLE 2
SUMMARY OF CONTAMINANTS DETECTED IN BaRIED DRUM AREA
Concentration Frequency of
Consti11Jent Range (a) Detection (b)
lnoraanics (malka)
Arsenic 0.55 B . 65.7 B 7/8
Barium 60.6 . 488 8/8
Cadmium 1.7 - 53. 618
Chromium 21.5 - 97.2 8/8
Copper 18.1 . 1020 8/8
Cyanide 0.83 . 7.1 SI8
Lead 2.1 . 414 8/8
Nickel 19.4 . 6S 8/8
Zinc 39.8 - 1760 8/8
Oraanics (ualka)
ArocIor-1254 570 - 7200 6/8
ArocIor-1260 220 . 3700 6/8
2-Methylnaphthalene 220 J 1/8
Acenaphthene 270 J 1/8
Anthracene 24 J - 1000 J 218
Benzo(a)anthracene 71 J - 2300 218
Benzo(a)pyrene 54 J - 1800 318
Benzo(b)fluoranthene 39 J . 2100 2/8
Benzo(g,h)perytene 550 J - 1/8
Benzo(k)fluoranthene 47 J - 2100 218
bis(2-ethylhexyl)phthalate 50 J - 1600 J 6/8
Chrysene 82 J . 2200 218
Dibenz(a.h)anthracene 320 J 1/8
Auoranthene 100 J . 2200 218
Fluorene 390 J 1/8
Indeno(1.2.3-<:d)pyrene 18 J - 600 218
Phenanthrene 54 J - 4300 218
Pyrene 90 J . 2900 218
Acetone 21 J 1/8
T etrachloroethene 1 J - 33 318
Toluene 2 J - 10 J 3f7
Trichloroethene 1 J . 13 7/8
Xylene (total) 23 - 41 218
(a) Concentra1ion range of detected analytes. Results of duplicate samples are
not averaged. Data compiled from Landau Associates (1989a).
Sample Locations TP-1 b, TP-1 c, TP-2a. TP-2b, TP-4a, TP-4b, and TP-5a.
(b) Number of samples in which the chemical was detected/number of samples analyzed.
Data Flaas
B = Lab flag for inorganics: The reported value is less than the Contract Required Detection Umit
but greater than the Instrument Detection Umit.
J = Lab flag for organics: The reported value is less than the Contract Required Detection Umit
but greater than the Instrument Detection Umit.
F:\PROJECTS\BOEING\OCF\FS\SOIL-SCA. WK1
07/ZJ192
-------
below visibly discolored soil i~ the test pits. These native
soil samples showed some indications of contamination related to
wastes encountered at higher elevations in the respective test
pits. Heavy metals including chromium, coppe~ and lead were
detected in all 5 test pits. Bis{2-ethylhexyl)ph~halate and TCE
" were detected in most of the test pits. PCBs and cyanide were
detected in 2 of 5 test pits. PAHs were detected in 1 of 5 test
pits. Based on these test pit sampling results, wastes from the
BDA have leached into and contaminated the underlying native
soils.
Heavy metals and organic compounds were detected in soil
samples taken from Ponds 4, 5, and 6. A summary of contaminant
concentrations in samples taken from these ponds is shown in
Table 3. As noted in this table, the concentrations of metal and
organic contaminants g~nerally decrease with depth. Metal
concentrations are at or below background levels at a depth of 10
feet. Organic contaminants are generally not detected below 2
feet. .
Confirmatory surface soil sampling taken after completion of
the 4-Tek soil removal indicated that the surface soils were
clean. post-removal subsurface soil samples taken from three
monitoring wells drilled at the 4-Tek facility revealed the
presence of volatile organic compounds (Table 4). Contaminants
found include DCE, TCE, acetone and 2-butanone. These
contaminants are most likely related to past operational and
disposal practices by 4-Tek Industries. -
Based on the results of the RIjFS, the total volume of
solids which may require remediation at the QCF site has been
estimated at 290,000 cubic yards. An estimated 280,000 cubic
yards of contaminated soil within the IRM would require further
containment. 10,000 cubic yards of soil and debris from the BDA
would be excavated. Of this 10,000 cubic yards, approximately
100 cubic yards of soil and debris may exhibit hazardous waste
characteristics, and would require treatment prior to off-site
disposal. Approximately 4,000 cubic yards of soil and debris
have low levels of PAH and PCB" contamination and may only require
containment to prevent migration of contaminants to underlying
ground water.
6.4.2
surface Water
Surface water investigations included sampling of springs,
Queen city Lake, and the Main Gravel Pit Lake. Some springs that
emerge from Aquifer 1 on the north face of the Main Gravel Pit
contained low levels of volatile organics incl~ding, but not
limited to TCE {1.7-3.8 microgramsjliter (~jl», and DCE (1-46.3
pgjl). These volatile organics are apparently lost through
volatilization within short distances downstream of the springs.
standing water bodies, including Queen City Lake, the Main Gravel
pit Lake and the Interceptor Trench have not been significantly
affected by contaminant source areas.
-------
TABLE 3
CONTAMINANTS DETECTED IN RI SOIL SAMPLES
COLLECTED FROM PONDS 4. 5. and 6 . .
AT QUEEN CITY FARMS
POND 4
. ----- SAMPLE NUMBER P4-0 P4-2 P4-'2 P4-4
.SAMPLE DEPTH 0-1.5Ieet 2-3.5 leat (P4-2 dup) 4 -5.5 leet
CHEMICAL CONCENTRATION
Cyanide (mg/kg) 0.84 0.63 0.67 «a) 0.61
TOTAL METALS (mg/kg)
Arsenic 2.9 2.8 2.9 2.7
Barium 210 N' 130 N 150 N 75 N
Cadmium 1.2 N .:: 0.75 N < 0.77 N < 0.73 N
Chromium 28 N 35 N 39 N 29 N
Copper 76 34 33 26
Lead 79 36 19 6.9
Nickel 19 19 21 21
Zinc ~20 ISO 150 89
PESTICIDES/PCBs (ug/kg)
4,4' -ODD 120 ~2 39 < 7.5
4,4' -DOE 64 23 21 < 7.5
Aroclor- 1 254 590 390 340 < 75
Aroclor-1260 340 < 79 < 77 < 75
Dieldrin 29 11 10 < 7.5
Endosullan II 9.3 < 7.9 <: 7.7 < 7.5
SEMI-VOLATILE ORGANICS (uOlkg)
1,2,4- Trichlorobenzene 56 J < 790 <: 800 < 370
Benzo(b)lIuoranthene 140 J 62 ~ 63 J < 370
BenzO(k)lIuoranlhene 140 J 62 .! 63 J < 370
bis(2-Ethylhexyl)phthalate 1000 B 480 J.B 510 J.B 83 J.B
di-n-Butylphthalale <: 810 < 790 <: 800 170 J
Pyrene 88 J c:;- , 51 J < 370
-, -
SAMPLE NUMBER P4-6 P4-8 P4-10 P4-B-12
SAMPLE DEPTH 6-7.5 feet 8-9.5 feet 10-11.5 feet 121eet
CHEMICAL CONCENTRA nON
Cyanide (mg/kg) <: 0.51 < 0.44 < 0.54 < 0.54
TOTAL METALS (mg/kg)
Arsenic 3.9 4.7 2.9 1.7 B
Barium 78 N 84 N 42 N 34 .N
Cadmium <: 0.83 N < 0.81 N < 0.8 N < 0.74 N
Chromium 35 N 91 N 19 N 20 N
Copper 25 36 19 16
. Lead 4.6 2.3 2 2.1
Nickel 27 41 18 21
Zinc 79 59 49 55
PESTICIDES/PCBs (ug/kg)
4,4'-000 7.1 J < 7.4 < 7.4 < 7.3
4,4'-DDE < 7.6 < 7.4 < 7.4 < 7.3
Aroctor-1254 < 76 < 74 < 74 < 73
Aroclor-1260 < 76 < 74 < 74 < 73
Dieldrin < 7.6 < 7.4 < 7.4 < 7.3
Endosullan II < 7.6 < 7.4 < 7.4 < 7.3
SEMI-VOLATILE ORGANICS (ug/kg)
1,2,4- TrichlorObenzene < 370 < 360 < 360 < 370
BenzO(b)lIuoranthene < 370 < 360 < 360 < 370
BenzO(k)lIuoranthene < 370 < 360 < 360 < 370
bis(2-Ethylhexyl)phthalate 94 J,B 34 J,B 28 J,B 49 J,B
di-n-Butylphthalate < 370 < 360 < 360 370
Pyrene < . 370 < 360 < 360 < 370
-------
P5-0
0-1.5Ieel
TABLE 3 (con't.)
-. POND ')
P5-2 P5-4
2-3.5Ieel 4-5.5Ieel
CONCENTP.A TiON
P5-6
6-7.5 leol
P5-8
8-9.5 leol
SAMPLE NUMBER
SAMPLE DEPTH
CHEMICAL
TOTAL METALS (mg/kg)
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
NIckel
Zinc
PESTICIOES/PCBs (ug/kg)
4,4'-DDD
Aroclor-1254
Aroclor -1260
Dieldrin
Heplachlor epoxlde
SEMI-VOLATILE ORGANICS (oOlkO)
BenZm)IIUOranihene
Benz k)lIuoranihene
Benzo 0 acid
W-SAMPLE NUMBER
.... SAMPLE DEPrn
CHEMICAL
TOTAL f-AETAlS (mg/kg)
Arsenic
BarIum
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
PESTICIDEs/PCBs (ug/kg)
Aroelor-1254
. SEMI-VOLATILE ORGANICS (ug/kO)
. dl-n-Bulylphlhalale
---P5-10
10-11.5 le91
2.2 N. 3.7 N 5.5 3.3 4.7
130 . 110 60 N 63 N 75 N
1.3 N <- 0.98 N c 0.7 N < 0.04 N c 0.68 N
36 34 25 0 29 N 27 N
50 30 16 20 17 N
36 9.4 3.8 2.5 3.3
32 37 19 33 22
190 130 59 52 ~8
12 < 7.1 c 7.5 < 7.4 c 7.3
< 72 140 <. 75 < 74 <. 73
440 < 71 < 75 < 74 < 73
14 < 7.1 < 7.5 < 7.4 < 7.3
9.4 4.1 < 3.7 < 3.7 < 3.7
79 J < 720 < 370 < 370 < 370
79 J < 720 < 370 < 370 < 370
< 3700 110 J .: 1600 -: 1800 < 1700
POND 6
P6-0 P6-2 P6-4 P6.6 P6-8 P6-10
0-1.5 leel 2-3.5 leel 4-5.5 leel 6-7.5 lee I 8-9.5 lelll 10-11.5 leel
, CONCENTRATION
2.7 N 2.5 N 3.3 N 2.3 N 2.7 N 2.7 N
160 120 110 73 77 65
1.1 N <.. 1 N < 1 N < 1 N < 1 N < 1 N
32 25 19 21 16 21
29 24 25 22 20 18
II 6.1 7.6 5.'1 2.2 1.5
36 30 30 30 31 24
260 170 120 100 76 49
71 J
73
76
<
73
73
<
<
<
<
< 370
370
< 370
150 J
< 380
< 370
<
(a) N. Recovery 01 spiked sample was nol wllhln controllimlls.
(b) <. Indlciles analyte was aflalyzed lor. bul nol delecled above Ihe levellndicaled.
(c) B. The reported value Is les!llhan Iht CRDL but grUler Ihan Ihe IOL.
(d) J. A value less Ihan Ihe CROL bul grealer Ihan Ihe IDL.
Relerence: Landau Assoclales (1989c).
-
.:
4.6
71 N
0.8 N
21 N
20
2.4
17
41
<
<
<
<
<
7.4
74
74
7.4
3.7
.:
370
370
1600
<
<
75
CRDL: Contract Required'Detection Limit
IDL: Instrument Detection Limit
-------
TABLE 4
CONTAMINANT CONCENTRATIONS IN SUBSURFACE SOIL AT 4-TEK
..
MW.l
*"'1.SM
Parllmeter Units 7/8 91
Chloromethane ug/Kg. <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Bromometbane ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Vinyl Chloride ug/Kg <3.4 <3.4 <3.3 <3.4 <'.).3 <3.5 <34.
Chloroetbane US/Kg <3.4 <3.4 <3.3 <3.4 <3.3 <3.5 <34
Methylene Chloride ug/Kg 1.58 J.28 1.2B 2.5B 1.2JB 2.4B 15MB
Acetone ug/Kg <5.7 <5.7 <5.5 <5.6 <5.5 270.0 690.0
Carbon Disulfide ug/K.g <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
w 1,1 Dichloroethene ug/Kg <1.1 < 1.1 < 1.1 <1.1 <1.1 <1.2 <11
N
1,1' Dichloroethane ug/Kg < 1.1 <1.1 < 1.1 <1.1 <1.1 150.0 <11
1,2.Dichloroethene (total) ug/Kg < 1.1 42.0 3.4 <1.1 33.0 <1.2 <11
Chloroform ug/Kg < 1.1 <1.1 <1.1 <1.1 <1.1 <;1.2 <11
1,2.Dicbloroethane ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
2.Butanone ug/Kg <8.5 <8.5 <8.2 <8.4 <8.3 26.0 330.0
l,l,i-Trichloroethane ug/Kg <1.1 <1.1 <1.1 < 1.1 <1.1 170.0 <11
Carbon tetrachloride ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Vinyl Acetate ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Bromodichloromethane ug/Ka <1.1 <1.1 <1.1 <1.1 <1.1 <1.2 <11
Trichlorofiuoromethane ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
1,2. Dichloropropanc ug/Ka <1.1 <1.1 <1.1 <1.1 <1.1 <1.2 <11
ds-l,3-DichJoropropcne ug/Kg <2,3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Trichloroethene ug/Kg 1.3 3.2 1.0M < 1.1 4.2 < 1.2 <11
I Dibromochloromethane ug/Ka < l.i <1.1 <1.1 < 1.1 <1.1 <1.2 <11
1,1,2- Trichloroethane ~g/Kg <1.1 <1.1 I <1.1 <1.1 .;1.1 <1.2 <11
Benzene ug/Kg < 1.1 <1.1 <1.1 <1.1 <1.1 < 1.2 <11
Trans-l,3- Dicbloropropenc ug/Kg <1.1 <1.1 <1.1 <1.1 <1.1 <1.2 <11
2-Chloroethylvinylether ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
-------
TABLE 4 (CONTINUED)
Sample Location and Date
MW.l WrY. 1 MW.l MW.1 MW.1 MW.3 MW-3
** 2.5 M 7.5M 12.5M 1.5 M 705M 7.5M 17.5
Parameter Units 7/8/91 7/8/91 7 /8/91 7/8/91 7/8/91 7/8/91 7/8/91
4.Methyl.2.Pentanone ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
2.HexanODt ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Tetrachloroelhene ug/Kg 93.0 31.0 37.0 9.9 1.6 < 1.2 <11
1.1,2,2- Tetrachloroeth ane 'ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
Toluene ug/Kg <1.1 <1.1 <1.1 0.7M <1.1 55.0 540.0
w Chlorobenzene ug/Kg <1.1 <1.1 <1.1 <1.1 <1.1 <1.2 <11
w
Ethylbenzene ug/Kg <1.1 <1.1 <1.1 <1.1 <1.1 1.9 <11
Styrene ug/Kg <1.1 <1.1 <1.1 < 1.1 < 1.1 < 1.2 <11.4
Total XyleDes ug/Kg <2.3 <2.3 <2.2 <2.2 <2.2 3.5 <23
1.1,2- Trichloro.l,2,2.trinuoroethane u K <2.3 <2.3 <2.2 <2.2 <2.2 <2.3 <23
NOTE: B IS Possible/Probable Blank Contamination
J IS Estimated Value (Below Detection Limit)
M = Ldw Spectral Match
-------
6.4.3 - Sediment
Sediment samples taken at depths of 0 - 2 feet from Queen
City Lake during the "RI"""contained low levels of chromium (25 - 51
milligrams/kilogram (mg/kg»,.PCBs (less than 95 to 220
micrograms/kilogram (.jIg/kg», and bis(2-Ethylhexyl)phthalate (860
-1100 jig/kg). No sediment samples were taken from the Main
Gravel Pit Lake. "
6.4.4
Liqht Non-Aaueous Phase Liauid (LNAPL)
An additional source of ground-water contamination is free-
floating light non-aqueous phase liquid (LNAPL) which has been
found in Aquifer 1 in the vicinity of the IRM Area. The extent
of this LNAPL is shown in Figure 10. contaminants detected in
LNAPL samples are summarized in Table 5. The LNAPL was
determined to be primarily a mixture of fuel oils based on gas
chromatograph/flame ionization detector and distillation
analyses. High concentrations of contaminants such as chromium
(740-1400 mg/kg), PCBs (93-280 mg/kg), 2-methylnaphthalene (850-
2000 mg/kg), phenanthrene (220-560 mg/kg) and total xylene (2000-
3000 mg/kg) were detected in LNAPL samples.
Data collected from two monitoring wells on-site indicate
that it may be possible to physically remove some of the LNAPL
from Aquifer 1. The total volume of recoverable LNAPL is
currently unknown. LNAPL thickness has been measured up to 5
feet in one monitoring well; however this data may be of limited
use because the ground-water surface is within the 5-ft long
screened interval of the well for only a short period of the
year. Fluctuations in the Aquifer 1 water level below the IRM
Area have caused LNAPL partic~es to be smeared throughout a much
thicker soil interval. The vertical extent of LNAPL-containing
soil may be as thick as 20 feet.
6.4.5
Ground Water
Monitoring wells in the Near-Surface Water-Bearing Zone
(NWBZ) are defined as hydrologically "upgradient" to Aquifer 1
and are in locations presumably not affected by known contaminant
sources. Low concentrations of metals were detected in the NWBZ
including arsenic, cadmium, copper, nickel and zinc (Table 6).
-'
Upon completion of the removal action at the 4-Tek facility,
EPA required QCF, Inc. to install three shallow ground-water
monitoring wells. Aquifer 1 is not present at the 4-Tek
facility, and these wells were designed to be drilled down to the
water table within the unweathered glacial till above the Lower
Unsaturated Zone. Volatile organic contamination was found in
all three wells. A summary of shallow ground-water contamination
at the 4-Tek facility is shown in Table 7. contaminants found
included, but were not limited to; DCE (2-3731 jlgll), TCE (0.9-65
jig/I), and PCE (1-810 jig/I).
-------
2SOI173 BoonplOCFIfS R""",. 1102
JiE1
Former
Ponds
I. 2. 3
U)
VI
."
o
I
200
.-
Scale in feel
400
I
NOTE
The 'Oi Zone' is the creo wilh evklence 'of
aa. either os residual or free'phose oi.
This zone iIckJdes Ihe residual 01 beneoth
lhe f Orlll9f pondl .hich is obove the hi~
woler level.
"
. MONloring Wel/Boring Wilh
Evidence of Recoverable Oil
o Moniloring Wel/Boring Wilhoul
Evidence or necovcroblc Oil
IE Oi Zone
PIT
/
FIGURE 10
AREAL EXTENT OF LNAPL ("OIL")
-
.;.t:..~.:.
.:?r~
':~~~ii~
:'i~@.
..i~~.~
~
I
~
-------
","'.>., -'-';,""...;,;::;,...;.~;:-::-~~Ii.iQ;-':"-':'-"h'':''~'''';;'''\~~~~~~~;'c~ABLE' ;::,;Z\:."'::~ 1~~"'''','',~',:' .," ''',
CONTAKINANT CONCENTRATIONS IN LNAPL
~
,- ,., ,'", . ~.z.~ Ffequ~at
Ic'--. ~ ~..,.. _""',Ar """R8ng8 (8) ---"."......,~.." ",.," ,. ,._~,. DetecllOR (b) .:-., ~",,;, ",'" .
.'
~ ~. .,.. .
. ":''''..''''~ '!- ;"'. ~. ",';I:''''~~Y~~UabIIs tcnalka)..~.,....,.-..)", '"'~i.'''''~.'~''-'''.''''''''''--'''
~ "
Barium
QIrorrium
Copp8r
Iran
Nid(8I
Zinc
, '; ",,,~, ':"'-''';'..5''''''''~ 1.7'
10 -"12'
740 - 1400
1 -11
53
73 "IJ
1 - 3.9
. " 2/2'
212
212
212
1/1
2.'2
212
Pmici~& (maiko}
Beta-BHC 0.6
Aroc:Iar-1242 3S
Aroc:Iar-1254 170 - 280
Arodof-1260 58 -93
SmniYolab1e Oraanics (malllo}
Naph~ene 220 - 370
2-Methytnaphthalene 850 - 2000
Acenaphthene 110 - 140
Di-n-butylphthalate 96 - 100
Auorene 120 .260
Phenanthrene 220 .. 560
Anthracene 71
?yrena S4 .; - ~OO
f)/K\ZOl-)an:l'lf aca;'lQ 42
Chrysene 55 -80
VoIatlle Oroanics (maIL!
Acetone 690
Toluene 730
Ethytbenzene 490
Xytene (Total) 2000 .3000
Benzene Toluene Elhvtbenzene Xvlene (malka!
Toluene 3.5
Ethytbenzene 2.5
Xytene (Total) 120
Other Parameters
SpecifIC Gravity 0.8911 .0.93
Flash Point (deg.F) 101 . 156
Viscosity @ SO deg.C (cSt) 9.07
Viscosity @ 24 deg.C (cSt) 21.4
pH 6.4 .. 6.6
Total Halogens (mglkg) 770 .. 5000
TPH (mglkg) 4300 .. 530000
1t.2.
1/3
313
2/3
313
313
2/3
212
313
313
1/3
~
.n
..~
2/3-
1/2
1/2
1/2
2J2
111
111
111
212
212
111
1/1
212
212
3/3
(a) Concentrauon range of detected analytes. Results of duplicate samples are nOI averaged,
Data inclusive of sampling events from May 198910 June 1991 (Landau Associates 1992a).
Sample Locations MW-8. MW-12. W4.
(b) Number of sarf"4)les in which the chemical was detected/number of samples analyzed.
Dala Flaas
J = Lab flag for organics: The reported value is less than the Contraa Required Detection Limit
but greater Ihan 1he Insll'Ument Detection Umit.
F:\PROJECTS\90EING'oOCF\FSlLNAPLWK1
23..Jul-92
-------
TABLE 6
CONTAMINANT CONCENTRATIONS' iN .THE NEAR-SURFACE WATER-BEARING ZONE
Chemical
Frequency of
Detection(b)
Range
of Sample
Ouantitation Umits
For Not Detected Analytes
Range
of Detected
Analyte Concentrations
COD (mgtL)
Cyanide (ug/L)
TOTAL RECOVERABLE METALS (ugIL)
0114
0/7
Aluminum
Arsenic
Barium
Chromium
Copper
Iron
Lead
Manganese
Zinc
4/4
1/4
1/4
1/4
1/4
4/4
1/4
414
3/4
0/4
014
3.3
19.5
11.6
4.7
8.9
Cadmium
Nickel
DISSOLVED METALS (ug/L)
Aluminum
Arsenic
Barium
Cadmium
Calcium
Iron
Magnesium
Manganese
Nickel
Potassium
Silicon
Sodium
Zinc
1/7
2114
2/14
1/14
7n
12114
7n
11/14
2/14
3n
4/4
5n
5/14
47.4
1.8
8.5
2.4
16.9
2.7
14.9
7.6
Chromium
Copper
Lead
3.6
8.0
0.9
0114
0114
0114
10.0
10.0
--(d)
3.1
340
(b) Number of samples in which the chemical was positively detected/number of samples analyzed.
(c) ND - Not detected.
(d) . --" Analyte concentrations in all the samples analyzed are above the detection limit.
(e) 8 - Reported value is less than the CRDL but greater than the IDL.
37
34.2
9.2
10.3
1.0
282
8.9 8
7.6
10.7
4.9
25.6
140
3.2
34.2
4.9
32
1.9 S
13.7 8
4800
22 B
740 B
4.0 8
26.6 8
90 8
5800
500 B
4.3 8
9.1
25.5
63
363
15.4
9.3
12.0
2.4
ND(c)
ND
."
:~e):J;'~}~~
1050
74.3 ..
.,..
ND
ND
147B
2.3 8
16.5 8
2.78
17800
1460
3560 B
1370
35.1 B
560 B
9500
4400 B
69.3
ND
ND
-------
TABLE 7
GROUND-WATER CONTAMINANT CONCENTRATIONS AT 4-TEK
Frequency of Range of
contaminant& Detectionsb ConcentrationsC
Acetone 16/36 3. 4Jd - 220
2-Butanone 11/36 28 - 280
Chloroethane 11/36 32 -110
l,l-Dichloroethane 33/36 1 -1300
l,2-Dichloroethane 4/36 3.1 - 7.5
l,2-Dichloroethene (Total) 2/3 51 - 3700
Cis-1,2-Dichloroethene 21/32 15 - 3700
Trans-1,2-Dichloroethene 17/32 0.7J - 34
2-Hexanone 1/36 8.9
Tetrachloroethene 22/36 11-- 810
Toluene 13/36 180 - 860
1, 1, 1-Trichloroethane 14/36 1.5 - 5.1
Trichloroethene 23/36 6.8 - 65
a =
Ground-water. samples were only analyzed for volatile
organic contaminants
Number of detections per number of samples
All concentrations are in ~/l
J = Estimated value, below detection limit
b =
c =
d =
.,
-------
The highest concentrations of ground-water contaminants are
in Aquifer 1 beneath the IRM. A summary of analytical results
for contaminants detected in Aquifer 1 is shown in Table 8.
contaminants detected in Aquifer 1 ,include, but are not limited
to, chromium, DCE, TCE, and vinyl chloride. contaminant
concentrations in Aquifer 1 have varied over several years of
monitoring, appearing to oscillate with changes in piezometric
head levels. Aquifer 1 is limited in areal extent to the
northern portion of the site (Fiqure 11). The Aquifer 1
contaminant plume is therefore confined to the area of the IRM
and from Queen City Lake to the gravel pit face.
Volatile organic contaminants found in Aquifer 2 include DCE
and TCE (Table 9). The extent of the DCE and TCE contaminant
plume and the range of TCE and DCE concentrations found in
Aquifer 2 during sampling conducted in June 1991 are shown in
Fiqures 12 and 13. As can be seen from these figures, the
,greatest concentration of DCE and TCE is close to the southwest
corner of the IRM area. .While the DCE and TCE plumes appear to
be confined to the eastern portion of the site, the extent of TCE
and DCE contamination may reach as close as 200 feet from the
site boundary to the south, and may extend across the northern
site boundary on to the Cedar Hills Landfill. Aquifer 2 serves
as a drinking water source for residences south and southwest of
the QCF site (Fiqure 3).
Heavy metals such as arsenic, chromium, and lead were
detected in low concentrations in some unfiltered ground-water
samples from Aquifer 2. These heavy metals were not detected in
filtered ground-water samples (Table 9A).
Eight heavy metal co~taminants and one semi-volatile
contaminant were detected in low concentrations in samples taken
from Aquif~r 3, and the Deep Water-Bearing Zone.
6.5
Routes of contaminant Miaration
Tpe major source area identified on site which has an
appreciable impact on ground-water quality is contaminated soil
and LNAPL beneath the IRM area. Ground water in Aquifer 1
leaches contaminants from these materials and flows vertically
through the leaky clayey-silt portion of the Aquifer 1 aquitard
and discharges to the underlying sand and gravel unsaturated
zone. In the unsaturated zone beneath Aquifer 1, ground water
moves primarily vertically and discharges to the upper surface of
Aquifer 2. It is estimated that ground water may travel from the
point of recharge in Aquifer 1 to the point of recharge to
Aquifer 2 in less than one year. In Aquifer 2, contaminants
appear to have been transported predominantly to the north and
south (Fiqures 12 and 13): This may be due to radial flow caused
by a ground-water mound which initially developed below the IRM
area, but has recently migrated to the vicinity of the Main
Gravel pit Lake due to the gravel mining operations (Figure 14).
-------
"'''",.,
, ,..', , ..~.-,. 'h~_";,.. :".'"":oCf':~~". 4.''''''''';'''''''':'''';:T.''':":'''''':~'''''.'\:'\ "',',. ...'~" ,
. ~ ' " . , :; " . ....
'.,.. .. '
. . TABLE 8
CONTAMINANT CONCENTRATIONS. IN AOUIFER 1
" ~,
Con~ent
Concentration
Range (a) .
Frequency of
Detection (b)
, ~.',' ..~ c:~~.... ~~~" "";..~~":o'!"'" "
Oissolved Inoraanics (ualL\ . ".'...
Arsenic
. .". Barium',,:- -...:",,~ ,',.:""'-'''-,'" ....,.
Cadmium
Chromium
Copper
Manganese
N"lCkei
Zinc
, .- ~ ""
"'., -... ."'''..''
.. - ','
1.5 8 1/12
. .""""';~~,,,:..:.,~.: ',,,,' :"., "":"""';"~'~ ""'.:.18.1., 8''''''"..69.8:...> 8. .:..,,',.,.;,...., ,.;:.,..,..9f15...~.';,..:.;...,...
. . 5.3 " ~. 71.5 . 5/12' .
18 - 3590 14/15
. 2.1 8 - 272 8/15
346 - 2410 919
4.7 8 . 210 8/15
12.2 /J8 - 234 12/15
..' .~- ,
Orcanics (uaIL)
ArocIor-1254
ArocIor-1260
1.2.4- Tric:hlorobenzene
. 1.3-0ichlorobenzene
2.4-Dimethylphenol
2-Methylnaphthalene
2-Nitrcphenol
Acenaphthene
Benzoic acid
bis(2-Ethylhexyl)phthalate
Di-n-butylphthalate
Di-n-octylphthalate
Auorene
Naphthalene
Pyr~n':!
1 , : ,1- T rictd.)r:>ellt3t14
1 ,1,2. T rich!croethane
. 1 ,1-DicrJoroa!hane
1 ,1-Dichloroethene
1,21Dichloroethene (total)
2-BUtanone
Acetone
Benzene
Carbon disulfide
Chloroform
Ethylbenzene
Methylene chloride
T etrachloroethene
Toluene
T richloroethene
Vinyl chloride
Xylene (Total)
..0
2.5 . 150
23 - 85
2 J - 18
2 J - 3
2 J - 3
1 J - 31
3
1 J . 2
6 J - 16
22
1 J - 3
2
1 J .3
10 J . 27
2
5 - 6
3 J - 4
1 J - 5
1 J - 2
20 - 2400
5 J - 6
5 J - 8
3 J - 22
t
1 J - 15
1 J - 8t
99 - 9500
1 J - 14
4 J - 440
10 . 4400
2 J - 91
2 J . 190
. ..."
J
J
319
219
12/15
2/15
3/15
6/15
1/15
4/15
2/15
1/15
4/15
1/15 .
5/15
5/15
1/1 ~
3i29
2/29
1C129
4/29
29/29
2/29
3/29
10129
2/29
2/29
17129
12/29
24/29
1 3/29
29/29
18/29
1 5/29
J
J
J
J
J
J
J
J
J
J
J
J
J
(a) Concentration range of detected analytes. Results of duplicate samples are not averaged.
Data indusive of sampling events from November 1988 to February 1992 (Landau Associates 1989a.d, 1992a).
Sample Locations MW.6, MW.8, MW-9, MW-11, and 6(1).
(b) Number of samples in which the chemical was detected/number 01 samples analyzed.
Data Flaas
8 = Lab Ilag for inorganics: The reported value is less than the Contract Required Detection Limit but greater
than the Instrument Detection Limit.
J = Lab flag for organics: The reported value is less than the Contract Required Detection Limit but greater
than the Instrument Detection Limit.
JJB = Quality Assurance Coordinator flag meaning the concentration is estimated because 01
blank contamination.
F:\PROJECTS\80EING\OCF\FS\JGWA TEA. WK1
071ZJ192
40
'. .'
"," ".".',','
-------
-
CEDAR HILLS LANDFILL
---------------------------------------------------
.
~
QUEEN CITY FARMS
FACE
~
o
I
300
!
'Scole in feet
600
I
9 Monitored Spring
~ IRM Area Remedial Unit
CSI Buried Drum A"o Remeiiol Unit
o Aquiler I Remedial Unit
FIGURE 11 - AREAL EXTENT OF AQUIFER 1
':::':.~~:.
I
I
~
~
,",f'.J:
:~f~t
:.:&fi
:~!f,9!r
-------
CEDAR HILLS LANDFILL
~~'...
~~":"
l..e"o',
P..d,
(:) CI.I.d $..'" Eod
S.,loe. INP...d..o..
81111-00
NO
,
I~~~ii~,~'~~,; ',H :'~;;; :!,r,
~c ;'; I ..'", .' .;;...
t; "lion 1Iatfr9'OCF1I~ AI 12111 .
'.:" ...~-:-.:. - .~.. ~.:;,.~~~;..~~.t";..;....: ",,-,"r:: "
. ~~.:;'-~''':.;.~~~/ ""
~
N
rUEENCiTYFhRHS
,
i
I
i
,
I
,
i
I
i
L1 ~
. --~--.--'.I
,
i
,
,
C.dar G,n.
C..pa,.I.,
,I
'-:0()
ill
..
Moniloring w.11 Nom.,
Localion and
Conllilu.nl Conc.nlralion
New Monilo,io9 w.11
IOctober 1991 dolO
ore pr.,.nl.d)
Nol Delected
Contour of Consl i,uenl
Concenlrolion IU9/Li
Prop.rly Boundary
Water Bodies
. AI7I
10
o 750
~
Scale i. rot'
NO
'~
......
Q]
~
FIGURE 12
Dislribution 01 DCE in Aquifer 2
-------
: 2501172 8..i>gIOCFtS~I.1 AI 1192 (DRAFT 51921
C"7)C"7)
~~
leochot.
Pond.
CED~R HILLS L~NDFILL
"..
W
r-oUEEN CITY FARMS
I
,
I
I
I
I
I
I
I
I
I
I
i
La2P
---".:_--,
I
,
I
C,dor Oro.,
Co.po" Ing
0°
~
~ Clo,ed Soulh End
Sur /oce 'mpound..ent.
."'.60
ND
"".S6
I NO
--
KEY
IAUI
10
Monitoring W.II Nome,
Local ion ond
Con,litulnt ,Conclntration
NI. Monitoring Well
(October 1991 data
or. prl..nt.dl
Not Delected
Contour 01 Conltltuent
Conc.nlration lug/LI
Prop.rly Boundary
Wat., Boditl
.
o 7S0
~
ND
'<>0
,
Seole in 1081
13
FIGURE 13
Dislribution 01 TeE in Aquiler 2
June 1991
-------
WELL #
A(2)
8(2)
C(2)
E(2)
E(2a)
F(2)
G(2)
1(2)
I (2a)
.:J (2a)
L(2)
L(2a)
M(2)
.
TABLE'
SUMMARY OP VOLATILE ORGANICS DETECTED IN AQUIFER 2
CHEMICAL
CONCENTRATION
RANGE-
Methylene chloride
1.0 - 1.0
1,2-Dichloroethene (total) 32 - 59
Tetrachloroethene 1.0 - 2.0
Trichloroethene 62 - 81
l,2-Dichloroethene (total) 17 - 27
.Trichloroethene 31 45
l,2-Dichloroethene (total) 23 - 45
Trichloroethene 100 - 150
1,2-Dichloroethene (total) 12 - 22
Tetrachloroethene 2.0 - 2.0
Trichloroethene 69 - 77
l,2-Dichloroethene (total) 36 - 65
Tetrachloroethene 2.0 - 3.0
Trichloroethene 84 - 110
1,2-Dichloroethene (total)
Trichloroethene
4 - 14
25 - 45
1,2-Dichloroethene (total) 22 - 27
Trichloroethene 59 - 99
1,2-Dichloroethene (total) 1.0
Tetrachloroethene 1.0 - 2.0
Trichloroethene 4 - 10
Acetone
6
1,2-Dichloroethene (total)
Trichloroethene
3 - 5
37 - 41
1,2-Dichloroethene (total)
Trichloroethene
1 - 10
4 - 14
1,2-Dichloroethene (total)2.0 - 2.0
Trichloroethene 15 - 17
a = all concentrations are in micrograms/liter
44
# OF DETECTIONS
I # OP SAMPLES
2/7
7/7
4/7
7/7
7/7
7/7
9/9
9/9
4/4
4/4
4/4
7/7
7/7
7/7
7/7
7/7
5/5
5/5
1/5
4/5
5/5
1/4
4/4
4/4
4/4
4/4
2/2
-------
-
1I011n ~~"RI7m
. 'p~'~~~"CI'~~' 'Cor'': ii:jci," .a"... ...... ....... ~:;:~;.::;.:::;. .....~.J7." ..r:::., :)....... ... .......
~Still"olol 100 Pood SOU!" 51' 101 loa
............ ...................... BOlin -.
o (] 0 "'''''''''''''''''''''''''''j'''''''''''''' .......,
L.oe"ol. CloI.d Soulh E.d
Pond. Su,'oe. Iftp~undr..."
"""."'"
~
V1
;........
CEDAR HILLS LANDFILL
fOUEEN ci TV FARMS
I C.do, 0'0'. \
: Coapot I i 8'.1
I
,
I
,
i
I
,
G
[ZJ
WOler Bodiu
Stomp
Properly
51'80'"
Boundo,y
o 750
~
SeD!. 10 ,..,
~
FIGURE 14
-------
,.
26013.72 BoftIOIOCF/SuppIemonI8I RI 7/82
. 'p~'~~~"i:,'';i' 'Co;.'r'iiici;.""'" ............ ....... ................... ""J:;lfF'" ~:+)"""'" ''''''''''''''
~ A'p'~oll.1 I..d .
............................~~S.ill."IOIIO. I'ond ~:~:~ Si 1'01 100 ,
£3 0 0 "'''''''''''''''''''''''''''j'''''''''''''' ........
loochal. Cloud Sou.h E.d
Pood. Sur'oc. I~pou.dr..n"
""""""
:........
.".
V1
CEDAR HILLS LANDFILL
roueS:;-ci TV FARMS
,: C.dor 0'0'. \
Cupo,'log
1
1
,
1
1
I
1
1
o 750
~
~ WOler Bodie.
c:J S.omp
--- Properly Boundary
- - Sireami
Scolo 10 r..1
FIGURE 14
Conceptual Model 01 Historical and Existing Aquiler 2 Groundwater Flowpaths
~
. .
. .
-------
..- . '.- .... .
. Although contaminants have not been detected in Aquifer 3
above the.EPA contract laboratory required detection limit, a
downward vertical hydraulic gradient is present across the
aquitard between Aquifer 2 and Aquifer 3. Contaminant
concentrations detected in Aquifer 2 during the 5 years since the
IRK and the 2 years since the formation of the Main Gravel pit
Lake have not shown evidence of attenuation. This suggests that
the vertical travel time through Aquifer 2 is at least 2 years
and possibly longer than 5 years. However, the potential still
exists for contaminant transport to Aquifer 3. Processes that
would tend to retard significant contaminant migration include
sorption and diffusion into the silt aquitard.
No direct evidence of Dense Non-Aqueous Phase Liquid (DNAPL)
has been identified at the site. However, based on the type and
probable quantity of waste solvents disposed at the Site,
residual DNAPL is likely to exist in Aquifer 1. Any vertical
migration of DNAPL would be impeded by the Aquifer 1 aquitard .
system. If DNAPL is present in Aquifer 1, it is very unlikely
that DNAPL has penetrated downward as far as Aquifer 2 based on
the pattern of volatile organic concentrations found in Aquifer
2. TCE and DCE concentrations are relatively uniform over a
large area, suggesting a broad aqueous-phase source.
In addition to the processes described above, migration of
contaminants at the QCF site have probably been influenced by
gravel mining and associated activities. site development
activities changed recharge and discharge relationships for
Aquifer 1 and Aquifer 2. The progressive formation of East
Airport spring due to gravel mining activities has created a
discharge area in Aquifer 1 and substantially reduced discharge
from the west end of the aquifer. The erosion control measure
culvert created a surface water outlet for Queen city Lake and
substantially reduced wet season recharge to Aquifer 1. These
events had a corresponding impact on ground-water levels and flow
within the aquifer including a decrease in maximum and minimum
piezometric head levels, and a steeper ground-water gradient
toward East Airport spring.
A conceptual model of surface water and ground-water
interactions at the QCF Site is shown in Figure 15. The creation
of the Main Gravel pit Lake has impacted Aquifer 2. A.
concentration of recharge to Aquifer 2 in the vicinity of the
Main Gravel Pit Lake has most likely caused the presumed shifting
of the location of the ground-water mound from the IRK area. In
addition, horizontal and possibly vertical ground-water gradients
in Aquifer 2 below the Main Gravel Pit Lake have been increased.
Both the ground-water mound and the increase in recharge through
the Main Gravel pit Lake would have an impact on the contaminant
concentration gradients found in Aquifer 2.
~
Characteristics of contaminants Found at the OCF site
-------
2501173 Booln9o'OC'IFS Roporl 7,g2 (DRAFT 8/02,
NORTH
SOUTH
I
, L Main Gravel
I 1 ~~
~ g _v~ooll1>O::o:cTli " ", ' II . .
. ',,". '".""'''' vuo -...go -WUOo DOO VOoOo 00 0 0000 00 ...f!.!:,."::."':'" ,',':':'..:.','.".',".'" ", 0000' . 000.
. t ) . . . . ,) . , , f f " , '" ~ ' Aquller 3 . . ) . ' . ;.~
~ // //// // / /; / / / t:/ / / / / 0'// lj'/// ;/// // // //// / <;{L/ / // / / // // / // / //7,
Cedar Grove
Channel
"'"
'-I
£
~
777T
Till
'V
Gr oundoo I er 0'
SUrrOCl 1I0ier
lnll
GroUndoOI It
(100 pOIIl
Sur(oce oOlOr
(100 p011I
Sill loyer
..
~
Upper IIqu I rer ,
~
Cf:?J
---- --
Un.OlurOIed
gr oundoo I cr
rlow p011I
Spring
Unll f pOIllon
or IIqul ror ,
0--
FIGURE 15
~
Conceptual Model 01 Surface Waler a'nd Groundwaler Inleractions and Flow
..
-------
Heavy metal contaminants detected in soil, LNAPL and
1 ground water at the QCF site include arsenic, chromium,
and lead. Arsenic is known to cause skin and lung cancer
humans. Chronic arsenic poisoning may result in loss of
appetite, cramps, nausea, constipation, diarrhea, or possible
liver injury. Lead is classified as a probable human carcinogen.
Elevated blood lead levels in children are associated with
encephalopathies and learning disabilities. Acute oral studies
with animals indicate that chromium (VI) compounds are more toxic
than chromium (III) compounds. The RI did not attempt to analyze
chromium (III) separately from chromium (VI). Acute exposure to
chromium (VI) has resulted in kidney and liv~r damage in humans.
There is little info~ation available on copper toxicity in
humans. Copper is exotoxic to many aquatic species. Some of the
metals detected on site tend to be mobile in the environment
(e.g. copper) but significant migration at the QCF site (e.g.
from Aquifer 1 to Aquifer 2) has not been documented.
Aquifer
copper,
in
cyanide was detected in subsurface soil samples from the IRM
area and the BDA. Symptoms of acute exposure to cyanide include
rapid breathing, gasping, tremors and convulsions. If not
treated, death may result. Neurotoxicity has been observed in
humans following both inhalation and ingestion exposure. No
evidence of migration of cyanide from subsurface soils to ground
water has been documented at the site.
PCBs have been detected in elevated concentr~tions in IRM
and BDA soils, and in LNAPL. PCBs are classified as probable
human carcinogens. Non-carcinogenic adverse health effects are
dose-related and may include chloracne, skin rashes, burning of
the eyes and skin, and liver damage. PCBs are persistent
compounds in the environment, exhibiting a high affinity for
particulate adsorption and a resistance to biodegradation.
sorption to organic matter and bioaccumulation in living tissues
are expected to be the dominant environmental fate processes.
sampling at the QCF site indicates that PCBs have not migrated
far from the primary source areas.
PAHs have been detected in soils from the IRM area and the
BDA. Evidence exists that certain PAHs are carcinogenic in
humans and animals. Cancer associated with exposure to PAHs
occurs predominantly in the lung following inhalation and in the
skin following dermal exposure. No evidence of significant
migration of PAHs from source areas to ground water has been
documented at the QCF site.
Xylene was detected in soils from the IRM area and in LNAPL.
If ingested, xylene can cause liver and gastrointestinal distress
in humans. If exposed via dermal .contact defatting of tissue and
skin can occur, and exposure via inhalation. can result in
irritation of both nose and throat and in central nervous system
effects which include headache, narcosis, and dizziness. No
evidence of migration of xylene from IRM soils or LNAPL to ground
water has been documented at the QCF site.
-------
1,2,4-trichlorobenzene (TCB) has been detected in soils from
the IRK area and in Aquifer 1 ground water. Acute exposure by
humans to high concentrations of 1,2,4-TCB is poisonous. 1,2,4-
TCB is a solvent which can be mobile in ground water. While.
1,2,4-TCB has been detected in higb concentrations in Aquifer 1
at the QCF site, the~e is no evidence that it has migrated to
Aquifer 2.
Toluene has been found in IRM soils at the site. Chronic
exposure of humans to toluene is toxic to the central nervous
system. Toluene is a solvent which can be mobile in ground
water, however there is no evidence of significant migration of
toluene from the IRM source area at the QCF site.
Tetrachloroethene (PCE) has been detected in BDA soils and
in shallow ground water in the area of the 4-Tek facility. PCE
has .been classified as a probable human carcinogen. Inhalation
of PCE can effect the central nervous system of humans, and may
cause dizziness, headache, sleepiness, and incoordination. PCE
is a volatile organic which can be mobile in the environment. It
is unknown at this time whether PCE has migrated from the shallow
ground water at 4-Tek to the deeper aquifers.
TCE has been found in soils and ground water throughout the
QCF site. When inhaled TCE may cause headache, vertigo, an~
visual distortion. studies have shown TCE to be carcinogenic in
animals. EPA has previously classified TCE as a pos~ible human
carcinogen. EPA is in the process of reevaluating the evidence
regarding potential for human carcinogenicity of TCE. TCE is a
chlorinated solvent and is very mobile in the environment. At
the QCF Site, TCE has migrated from source areas to Aquifer 1 and
Aquifer 2.. The TCE contaminant plume in Aquifer 2 has migrated
close to the Site boundaries.
Both forms of DCE (cis and trans) have been found in soils
and ground water at the QCF site. Inhalation by humans of large
concentrations of trans-DCE can cause drowsiness, fatigue, and
vertigo. DCE is a volatile organic which is very mobile in the
environment, and at the QCF site, DCE has migrated from source
areas to Aquifer 1 and Aquifer 2 ground water.
vinyl chloride has been detected in Aquifer 1 ground water
at the site. Vinyl chloride is a known cancer causing agent in
humans. Chronic inhalation of vinyl chloride can result in
Reynauds syndrome, dermatitis, hepatitis-like changes, thyroid
insufficiency and acro-asteolysis as well as cancer. Vinyl
chloride has not been found in source areas at the site. A
possible reason for the presence of vinyl chloriqe in Aquifer 1
is that anaerobic biodegradation of TCE to DCE and then to vinyl
chloride may be occurring within the general IRM area.
-------
7.0
SUMMARY OF SZTE RZSKS
,,'CERCLA response actions at the QCF site as described in
ROD are intended to protect human health and the environment
risks related to current and potential exposure to hazardous
substances at the site.
this
from
To assess the risk posed by Site contamination, a Baseline
Risk Assessment was completed by Landau Associates, on behalf of
The Boeing Company and QCF, Inc., 'as part of the Queen City Farms
RI. Based on comments received from EPA, a Baseline Risk
Assessment Addendum was completed by Landau Associates updating
the Baseline Risk Assessment to incorporate additional data,
updated EPA guidance, and amended toxicity criteria.
7.1
Human Health Risks
The QCF site is currently used for a variety of industrial
activities including sand and gravel mining, and yard-waste
composting. The Site is zoned by King County for quarrying and
mining. The Cedar Hills Landfill, which is operated by the King
County Solid Waste Division, is located directly north of the
site. Private homes are located to the east, south and southwest
of the site. Some home owners draw their drinking water from
Aquifer 2 and Aquifer 3. Home owners who draw their drinking
water from Aquifer 2 may be at some risk in the future, should
the TCE and DCE contaminant plume continue to migrate.
While sand and gravel mining operations on the Site property
are winding down, it is expected that the Cedar Grove composting
facility will expand i~s operations on the site as economic
conditions permit. Deed restrictions are currently in effect for
land use of the IRM area, and these deed restrictions will
continue to be in effect, or expanded in the future.
.An assessment of the risks to human health due to existing
conditions at the QCF site involved a 4-step process which
included the identification of contaminants of concern, an
assessment of contaminant toxicity, an exposure assessment of the
population at risk, and a characterization of the magnitude of
risk.
7.1.1
contaminants of Concern
A total of 71 chemicals were detected at the QCF site. Of
these 52 chemicals were identified as chemicals of potential
concern in soils, sediment, surface water or ground water at the
site. A list of these chemicals is shown in Table 10. The number
of detected chemicals evaluated in the Baseline Risk Assessment
and Baseline Risk Assessment Addendum by media are as follows:
-------
TABLE 10
CONTAMINANTS OF POTENTIAL CONCERN AT THE QCF SITE
Acenaphthene
Acetone
Aluminum
Anthracene
Arsenic
Barium
Butylbenzylphthalate
di-n-Butlylphthalate
Cadmium
Chromium
Copper
cyanide
4,4'-DDD
Dichloroethene (DCE; cis and trans)
DDT
Dieldrin
Endosulfan
Ethylbenzene
bis(2-Ethylhexyl)phthalate (DEHP)
Fluorene
Heptachlor epoxide
Iron
Lead
Magnesium (dissolved)
Manganese
Methylene chloride
2-Methylnaphthalene
Nickel
di-n-Octylphthalate
Pentachlorophenol
Phenanthrene
Polychlorinated biphenyls (PCBs) ~ 4 Chemicals
Polynuclear aromatic hydrocarbons (PARs) - 8 Chemicals
Tetrachloroethene .
Toluene .
1,2,4-Trichlorobenzene
Trichloroethene
Vinyl choride
Xylenes
Zinc
-------
Surface water - 18 chemicals
Soil/Sediment - 43 chemicals
Aquifer 1 - 39 chemicals
Aquifer 2 - 13 chemicals
Aquifer 3 - 9 chemicals
7.1.2
Toxicitv Assessment
Toxicity information was provided in the Baseline Risk
Assessment and Baseline Risk Assessment Addendum for the
chemicals of concern. Generally, cancer risks are calculated
using toxicity factors known as slope factors (SFs) , while
noncancer risks rely on reference doses (RfDs).
SFs have been developed by EPA for estimating excess
lifetime cancer risks associated with exposure to potential
carcinogens. SFs are expressed in units of (mg/kg-day)-l and are
multiplied by the estimated intake of a potential carcinogen, in
mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the SF. Use of this approach makes
underestimates of the actual cancer risk highly unlikely. SFs
are derived from the results of human epidemiological studies, or
chronic animal bioassay data, to which mathematical extrapolation
from high to low dose, and from animal to human dose, have been
applied. .
RfDs have been developed by EPA to indicate the potential
for adverse health effects from exposure to chemicals exhibiting
noncarcinogenic effects. RfDs, which are expressed in units of
mg/kg-day, are estimates of lifetime daily exposure for humans,
including sensitive subpopulations likely to be without risk of
adverse effect. Estimated intakes of contaminants of concern
from environmental media (e.g. the amount of a contaminant of
concern ingested from contaminated drinking water) can be
compared to the RfD. RfDs are derived from human epidemiological
studies or animal studies to which uncertainty factors have been
applied.
The Baseline Risk Assessment and Baseline Risk Assessment
Addendum relied on oral and inhalation SFs and RfDs. Because
dermal toxicity factors have not been developed for the chemicals
evaluated, oral toxicity factors were used in estimating
noncancer risks from dermal exposure. The noncancer toxic
endpoints (e.g. the affected organs) are similar for dermal and
eral exposure. Cancer risks from dermal exposure.could not be
calculated. The toxicity factors shown in Table 11, were drawn
from the Integrated Risk Information System (IRIS) or, if no IRIS
values were available, from the Health Effects Assessment Summary
Tables (HEAST). For chemicals which do not have toxicity values
available at this time, other criteria, such as the Maximum
contaminant Level Goal (MCLG) promulgated under the Safe Drinking
Water Act (SDWA) were used to assess toxicity.
-------
COMPOUNO ORAL
Methylene chloride 7.50E-03
Tetrachloroethene 5.10E-02
Trlchloroethene 1.10E-Ol
Vinyl chloride 1.90E+00
DOT 3.40E-Ol
Oleldrln 1.60E+Ol
bls(2-Ethylhexyl)phthalate 1.40E-02
Heptachlor epoxlde 9.10E+00
PAHs 7.30E+00
PC8s 7.70E+00
Pentachorophenol 1.20E-Ol
Arsenic 1.65E+00
Cadmium NA
Chroml um (hexava lent) NO
Nickel NO
SLOPE FACTOR
TA(lLE ;1
HUHAN TOXICITY FACTORS FOR CHEMICALS RETAINEO FOR RISK QUANTIFICATION
CARCINOGENS
b
a
a
a
b
b
b
b
it"
INHALATION
1.60E-03
1.80E-03
1.70E-02
2.95E-Ol
3.40E-Ol
1. 60E+Ol
NO
9.10E+OG
6.10E+00
NO
1. OOE -01
5.00E+Ol
6.10E+00
4.IOE+Ol
8.40E-OI
b
a
a
a
b
b
a
b
~r)
~l f)
a.g)
WEIGHT OF EVIDENCE
CLASSIFICATION
ORAL INHALATION
82 (b) . 82 (bl
82-C (c) 82-C c)
82-C (c) . 82-C c)
A (a) A (a)
82 b :~ I~I
;; ;\ 82 lbl
82 b 82 a
82 b 82 b
82 82
A (b) A (b)
NA 81 (b)
NO A
NA A
a
b
c
d
. e
f
~
Source: EPA. Health Effects Assessment Summary Tables (HEAST)
Source: EPA. Integra~ed Risk Information System (IRIS)
Under revl ew by EPA work group.
Source: Agency for Toxic Substances Disease Registry (ATSOR)
Value Is for benzo(a)pyrene. IRIS
30X absorption used when applying arsenic Inhalation slope factor
Inhalation slope factor specific to refinery dust
Provisional slope factor
NONCARCINOGEIIS
TYPE OF CANCER
ORAL
LIVER IbJ
1I VER a
1I VER a
UING (8)
II VER
HEPATOCELLULAR. HUTAGENIC
LIVER (a)
II VER
STOMACH AT POINT OF CONTACT (d)
HEPATOCELLULAR. DERMAL TOXICITY
HEPATOCELLULAR AOENOHAS AND CARCINOMAS
SKIN (b)
Nr.
NA
INHALATION
LIVER AND LUNG (b)
LEUKEHIA AND LIVER (a)
LUNG (a)
LIVER (a)
LIVER
HEPATOCELLULAR
NA (a)
II VER
LUNG
HEPATOCELLULAR
LUNG (b)
LUNG. TRACHEA. 8RONCHUS
LUNG
RESPIRATORY TRACT
RFO (chronic CONFIDENCE UNCERTAINTY 'lOR
unless Indicated) LEVEl HODIFICATION FACTORS
COHPOUNO ORAL INHALATION ORAL INHALATION ORAL INHALATION CRITICAL EFFECT (Oral; Inhalation)
Acetone (a) 1. OOE-Ol NO U-IOOO NA Increased liver and kidney wel9ht.
8e~zolc acid (a) naphrotoxlclty
4.00E+00 NO U-I NA Irritation. malaise; NO
4.00E+00 IIUb) NO U-I NA
cls-l,2-0Ich10roethene 1.00E-02 gl NO U-3000
trans-l,2-0Ichloroethene 2.00E-02 "0 (b) Low U-IOOO (b) NA (b) No data on developmental or
(sub-I) "0 (I) Hal (b) rproductlve toxicity. Increased
2.00E-OI serum alkaline phosphatase
Ethylbenzene (a) 1.00E-Ol "0 through Ingestion.
U-I000 NA Hepatotoxicity and nephrotoxicity
1.00E+00 (sub-I) NO}I) U.I00 rl
Methylene chorlde 6.00E-02 b) (3mg cubic meter) (a) Hedium (b) U.IOO b U-IOO (a) Liver toxicity; "A (a)
H-I (b
6.00E-02 (Iub-a) (3mg/cllblc meter) (sub-a) U-IOO a)U.IOO \a) Liver toxicity. "A (a)
Tetrachloroethene 1.00E-02 b) NA (b) Hedlum U-IOOO (b NA (b Increased liver and kidney weight
H-l (b) to body rate ratios (b)
1.00E-Ol (sub-a) NO (sub-a) U-IOO (a) NA (a) Hepatotoxicity. "A (a)
.- ......--" ... .
Toluene 2.00E-Ol lb) (0.4mg/cUbIC meterl (sub-b) UalOO U-I00 E~es and nose Irritation:
4.00E-Ol sub-I) 2at/cubiC meter) sub-I) U-I00 U.I00 C S effects
1.2.4-Trlchlorobenzene. 1. 00E-02 b) 3.00 -O~ (a) U-IOOO (a) U-IOOO (a) Increased liver to body weight
(sub-a) 3.00E-02 (sub-a) U.IOO (a)U.I00 (a) ratio; Increased uroporphyrln(a)
2.00E-Ol Same as chronic
Trlchloroethene "0 (c)
Vinyl chloride "A NA Cancer
-------
I
RfO (chronic) CONfiDENCE UNCERTAINTY 'lOR . ..----1"..
unless Indicated) LEVEL HOOlflCATION fACTORS
Compound ORAL INHALATION ORAL INHALATION ORAL INHALATION' CRITICAL EffECT (Oral; Inh4latlon)
Xylenes (total) 2.00E+00 (b) 3.00E-Ol mg/cublc meters (a) U-l00 U'100 Hyperactivity, low body we~~ht
and Increased mortality; C
3.00E+00 mg/cublc meter (sub) effects. nose and throat Irrlt.
.4.00E+00 (sub) U-l00 U-l00 None. CNS effects. nose
and throat Irritation
dl-n-Butylphthalate (a) 1. OOE-Ol b) NO U.l000 NA Effects on body wel~ht gain
1. ODE +00 sub) NO U.l00 NA testes. liver. end Idney.
Butyl benzyl phthal ate (a) 2.00E-Ol b) NO U.l000 NA Effects on body wel~ht geln
2.00E+00 sub) NO U.l00 NA testes. liver. and IdneI'
bls(2-Ethylhexyl)phthalete 2.00E-02 I) NO Ie) U.l000(e) NA la! Increesed liver welght;N la!
2.00E-02 sub-I) NO sub-e) U.l000 (e) NA a Increased liver welghtiNA a
DOT (a) 5.00E-04 b) NO U.l00 NA liver lesions; NO
5.00E-04 sub) NO U=100 NA
Dieldrin 5.00E-05 b) NO (I) Hedium U'100(b) Liver Is target organ for oral
H-l(b) exposure.
5.00E-05 rUb-I) NO (I) U.l00(1)
Endosulfan (a) 5.00E-05 b) NO U-3000 NA Hlld kidney leslons;"NA
2.00E-04 sub) NO U'1000 NA
He~tachlor epoxlde 1.30E-05 b) NO U-l000 NA Increased liver weight: NA
PA s (noncarcinogenic) NA NA Adverse effects at pt. of contact
PCBs NA NA
Pentachlorophenol 3.00E-02 (b) NO Hedlum U.l00(b) NA Liver and kidney damage through
H-l Ingestion; acute polsonlny of
clrc. system thru Inhalat on. (b)
3.00E-02 Isub-e) NO la! U-l00(a) NA la! fetotoxlclty; NA (a)
Arsenic 3.00E-04 b) NO a U.3 NA a Kerotosls and hyperplgmentatlon
U1 Skin cancer (a)
l>- Barium (a) 7.00E-02 (b) 1.00E-04 U-l00 U.l000 Increased blood pressure
H-I ferotoxl c Ity
Cadmium 5.00E-04 (b) NA High NA U-IO NA ProteInuria of the renel cortex
H-l throu~h Ingestion. (a)
1.00E-03 (b) High U-l0 Prote nurla of the renel cortex
H-1 through Ingestion. (e)
Chroml um (II II 1. OOE +00 (b) ND U-l00'
H-l0
Copper 3.70E-02 (a) NA (a) Local gasrolntestlnal Irritation
Only short-term effects
Cyanide 2.00E-02 la) NO la! u.soOla) NA la!
2.00E-02 sub-e) NO e U-SOO a) NA a
Hanganese 1. DOE -01 (b) 4.00E-04 (b) Hedlum U.l U-900 Central nervous system affects
Nickel 2.00E-02 (b) ND (a) Hedlum (b) U=100t) NA (a) for both oral and Inhalatlon.(e)
Reduced body size end organ
2.00E-02 (sub-e) ND (e) H.,3(b weight; Cancer (a)
U.300 a) NA (a) Reduced body size end organ
Zinc 3.00E-Ol (b) NO U=:\ NA weight; Cancer (a)
Anemia; NA
lal Source: EPA. Health Effects Assessment Summary Tebles (HEAST)
b Source: EPA. Integrated Risk Information Syst~ (IRIS)
c Under review by EPA work group
d Value hes been withdrawn. but Is under review by EPA.
I Use the long-term value. as data Is Inadequate to determine 10-day value
sub: Indicates the subchronlc RfO and associated uncertainties and effects
NA ~ Not avelleble NO. No Data
U - Uncertelnty factor
-------
7.1.3
Exoosure Assessment
.- ..- -.-.
The exposure assessment identified potential pathways for'
contaminants of concern to reach the exposed pop~1ation.
Exposure assumptions were based primarily on EPA regional and
national guidance, including EPA Superfund Standard Default
Exposure Factors, except where tailored to meet specific site
conditions. Current site use is industrial. Exposure to workers
through ingestion of surface water was evaluated in the Baseline
Risk Assessment. Future Site uses evaluated in the risk '
assessment included industrial and residential use. Pathways of
exposure to potential future residents include ingestion of
surface or ground water, inhalation of volatiles released during
domestic use of ground water, incidental ingestion of soil,
dermal contact with soil, and consumption of home-grown produce.
Standard Default Factors describe contact rate and exposure
frequency and duration for an exposed individual under the
Reasonable Maximum Exposure (RME) scenario. These factors
describe patterns of exposure that are higher than average, and
were selected with the intention that risk assessment results
would be protective of individuals in the exposed population who
had higher contact rates or longer exposure frequency and
duration. For example, the RME described a resident who spends
most of his or her time at home and lives at the same location
for thirty years. An individual with a more typical exposure
pattern for groundwater or soil would have less exposure. (Table
12) .
Exposure point concentrations for the QCF site risk
assessment were derived in a manner consistent with the EPA
guidance to evaluate Reasonable Maximum Exposures (RMEs). Since
toxicity from chemical exposures may be dependent on exposure
durations, the exposure models and exposure point concentrations
were consistent with the exposure periods incorporated in various
toxicity measures. For subchronic and chronic toxicity risks, ,
and for carcinogenic risks, where long duration exposures are of
concern (e.g., years or lifetime), RMEs are based on exposures to
average concentrations over the exposure period. Estimating the
average concentration based on a relatively small number of
samples results in statistical sampling errors and thus,
uncertainty. This uncertainty is addressed by calculating the
upper 95 percent confidence interval on the arithmetic average
concentration and using that value.
7.1.4
Risk Characterization
For carcinogens, risks are estimated as the incremental
probability of an individual developing cancer over a lifetime as
a result of exposure to the carcinogen. Excess lifetime cancer
risk is calculated by multiplying the SF (see toxicity assessment
above) by the "chronic daily intake" developed using the exposure
assumptions. These risks are probabilities generally expressed
-------
TABLE 12
Reasonable Maximum Exposure (RME) and Average Exposure Factors
RME AVERAGE
Exposure Factors (a) Exposure Factors (b)
Residential Scenarios
Water Ingestion
Intake Rate 2 Vday 1.4 Vday
Exposure Frequency 350 day/year 275 day/year
Exposure Duration 30 year 9 year
Body Weight 70 kg . 70 kg
Soil & Dust Ingestion
Intake Rate 200 mg/day (child) 100 mg/day
100 mg/day (adult)
Exposure Frequency 350 day/year 275 day/year
Exposure Duration 6 year (child) 9 year
24 year (adult)
Body Weight 15 kg (child) 70 kg
70 kg (adult)
(a) RME exposure factors from Standard Default Exposure Factors,
OSWER Directive No. 9285.6-03.
(b) Average exposure factors from EPA Region 10 Supplemental
Guidance for Superfund Risk Assessment. August. 1991.
-------
in scientific notation (e.g., 1 x 10-6). An excess lifetime
cancer of 1 x 10-6 indicates that an individual has a 1 in
1,000,000 chance of developing cancer as a result of site-related
--. exposure" to a carcinogen under the specific exposure conditions
assumed.
.- - -_...
The potential for non-carcinogenic effects is evaluated by
comparing an exposure level over a specified time period (e.g.
lifetime) with a reference dose (see toxicity assessment above)
derived for a similar exposure period. The ratio of exposure to
toxicity is called a hazard quotient. Hazard quotients are
calculated by dividing the chronic daily intake (CDI) by the
specific RfD. By adding the hazard quotients for all
contaminants of concern that affect the same target organ (e.g.,
liver), the hazard index (HI) can be generated.
The RME provides a conservative but realistic exposure in
considering remedial action at a Superfund site. Based on the
RME, when the excess lifetime cancer risk estimates are below 1 x
10-6, or when the noncancer HI is less than 1, EPA generally
considers the potential human health risks to be below levels of
concern. Remedial action is generally warranted when excess
cancer risks exceed 1 x 10-4 (one in ten thousand). Between 10-6
and 10-4, cleanup mayor may not be selected, depending on
individual site conditions including human health and ecological
concerns.
Tables 13 and 14 and the following discussion present
summarized non-cancer and cancer risk characterization results
for the QCF Site separately.
Non-cancer Risks:
The lifetime, adult and child non-cancer HIs for ingestion
of surface water and soil are well below 1. The non-cancer HIs
for ingestion and inhalation of, and dermal contact with, Aquifer
2 ground water is also below 1.
The HI for dermal contact with contaminated soil, based on a
future residential scenario, is above one, with the chemical
bis{2-ethylhexyl)phthalate being the major contributor to risk.
The HI for dermal contact with contaminated soil, based on a
future occupational scenario, is above 1.
The calculated HIs for all pathways
and dermal contact) for Aquifer 1 ground
1. The primary contaminant contributing
risk is 1,2,-DCE.
{ingestion, inhalation
water are greater than
to Aquifer 1 non-cancer
A future use scenario, which included the use of soil at the
site for planting food crops, yielded an HI of 2.0, the primary
contaminant of concern being cadmium.
-------
TABLE 13
TOTAL NON-CANCER RISKS AT QCF SITE
Pathway/Scenario
Chronic
HI
Primary contaminants
-- ---
-----------------------------------------------------------------
Surface Water Ingestion
Current occupational
Future Residential
0.17
0,24
Surface Water VOCs Inhalation
Future Residential
Not Calculated
Surface Soil Ingestion
Future Residential
Future occupational
0.039
0.0052
Surface plus Subsurface Soil Ingestion
Future Residential 0.30
Future occupational 0.040
Surface Soil/Dermal Exposure
Future Residential
2.0
Bis(2-ethylhexyl)
phthalate; Endosulfan
Future occupational
0.5
Surface plus Subsurface Soil/Dermal Exposure
Future Residential 2.2
Bis (2ethylhexyl)
phthalate
Future Occupational
0.54
Gr9und Water Ingestion (Aquifer 1)
Future Residential 14.0
Future occupational 5.1
Ground Water Ingestion (Aquifer 2)
Future Residential 0.46
Future occupational 0.16
DCE
DCE
Ground Water VOCs Inhalation (Aquifer 1)
Future Residential 5.2
DCE
Ground Water VOCs Inhalation (Aquifer 2)
Future Residential 0.32
GroundWater Dermal Contact (Aquifer 1)
Future Residential 1.5
DCE, naphthalene
Ground Water Dermal Contact (Aquifer 2)
, Future Residential 0.0052
Food Crops
Future Residential
2.0
Cadmium
-------
. - _. - _.-
TABLE 14
TOTAL CANCER RISKS AT QCF SITE
pathway/Scenario
Risk
Primary contaminants
-----------------------------------------------------------------
Surface Water Ingestion
Current occupational
Future Residential
2 x 10-5
3 x 10-5
vinyl chloride
vinyl chloride
Surface Water VOCs Inhalation
Future Residential
4 X 10-7
vinyl chloride
Surface Soil Ingestion
Future Residential
Future occupational
6 x 10-5
7 X 10-6
PCP, PCBs, PAH
PCP, PCBs, PAH
Surface plus Subsurface Soil Ingestion
Future Residential 1 X 10-4
Future occupational 1 x 10-5
PCP, PCBs, PAH
PCP, PCBs, PAH
Surface Soil/Dermal Exposure
Future Residential
1 X 10-3
PCBs, bis(2-
ethylhexyl) phthalate
PCBs, bis(2-
ethylhexyl) phthalate
Future occupational
2 X 10-4
Surface plus Subsurface Soil/Dermal Exposure
Future Residential 6 x 10-4
Future occupational
1 X 10-4
PCBs, bis(2-
ethylhexyl) phthalate
PCBs, bis(2-
ethylhexyl) phthalate
Ground Water Ingestion (Aquifer 1)
Future Residential 2 x 10-1
Future occupational 5 x 10-2
PCBs
PCBs
Ground Water Ingestion (Aquifer 2)
Future Residential 2 x 10-5
Future occupational 5 x 10-6
TCE
TCE
Ground Water VOCs Inhalation (Aquifer 1)
Future Residential 3 X 10-3
TCE, vinyl chloride
Ground Water VOCs Inhalation (Aquifer 2)
Future Residential 1 x 10-4
TCE
Ground Water Dermal Contact (Aquifer 1)
Future Residential 9 x 10-3
PCBs
Ground Water Dermal Contact (Aquifer 2)
Future Residential 3 X 10-6
TCE
Food Crops
Future Residential
3 X 10-3
PCBs
-------
Cancer Risks:
Cancer risks associated with surface water and soil
ingestion were within EPA' s acceptable risk range of 10-4 to 10-6.
Cancer risks associated with dermal contact with soil were above
EPA's acceptable risk range. PCBs and bis(2-ethylhexyl)phthalate
were the major contaminants of concern contributing to the
unacceptable cancer risk in soil.
Cancer risks for exposure scenarios associated with Aquifer
1 (ingestion, inhalation and dermal contact) are significantly
above EPA's acceptable risk range. The major contaminants of
concern in Aquifer 1 which contribute to risk are PCBs, 1,2-DCE,
naphthalene, TCE and vinyl chloride.
Future on-site residential and occupational cancer risks
associated with ingestion of Aquifer 2 ground water were within
EPA's acceptable risk range; however, future on-site residential
risks associated with inhalation of volatiles from domestic use
of Aquifer 2 ground water are precisely at the 1 x 10-4 risk
level for the RME case. (An estimate of risk for the average
case, assuming use of ground water with the same exposure point
concentration of contaminants for an individual with average
contact rate and exposure duration as shown in Table 12, would be
2 x 10-5). The primary contaminant of concern contributing to
Aquifer 2 risk levels is TCE. Future off-site residential use of
Aquifer 2 ground water was not evaluated in the risk-assessment,
but is of potential concern.
The future use scenario of planting food crops yielded a
c~ncer risk level of 3 x 10-3, the primary contaminant of concern
being PCBs.
7.2
Environmental Assessment
To assess the environmental effects of the contaminants
present at the QCF site, an evaluation of potentially affected
terrestrial species was conducted. No endangered or threatened
species were identified in the geographical area of the site. No
aquatic receptors other than plants were identified since none of
the on-site water bodies (Queen city Lake, Main Gravel pit Lake,
and the springs) can maintain aquatic animal populations.
After potential receptor population&:were identified,
potential ecological exposure pathways were identified. On-site
surface water bodies were analyzed and contaminants of concern
(TCE and DCE) associated with the site were only detected at low
levels in the intermittent springs along the gravel pit face.
The TCE and DCE apparently are" lost to volatilization a few feet
from the face. Therefore, use of on-site surface water as a
source of drinking water by wildlife does not appear to present a
risk. .
-------
Based on qualitative analysis, the highest potential for
wildlife contact with contaminants on-site is contact with ..
contaminated soil. contaminants of highest ecological concern in
the soil are PCBs, PABs,.-the pesticides (DDT, endosulfan,
dieldrin), and the pesticide breakdown products (DDD, DDE, and
heptachlor epoxide). . Quantitative estimation of the potential
extent of risk to wildlife due to the presence of this
contaminated soil was not possible due to lack of toxicological
data.
7.3
Uncertaintv in the Risk Assessment
The accuracy of the risk characterization depends in large
part on the accuracy and representativeness of the sampling,
exposure, and toxicological data. Most assumptions are
intentionally conservative so the risk assessment will be more
likely to overestimate risk than to underestimate it.
One source of uncertainty is the exposure scenario used for
Aquifer 1 ground water. Aquifer 1 ground water will most likely
not be used as a potable water source~ Aquifer 1 is limited in
areal extent to the northern portion of the QCF Site. There
would not be enough water in Aquifer 1 to support a potable well.
Therefore the residential inhalation, ingestion and dermal
contact exposure scenarios for Aquifer 1 which are presented in
the ris~ assessment are highly unlikely to occur.
Calculations of risk for potential future users of on-site
ground water in Aquifer 2 assumed that concentrations of TCE
measured during the RI will remain constant in the future. An
assumption of future on-site residential use of ground water
probably results in an over-estimate of risk due to the small
likelihood of this land use on the site. For off-site
residential use, future exposures and risks are probably less
than those calculated for on-site use. At locations of current
ground water use, no contaminants were detected at concentrations
that would result in risks exceeding 10-6. uncertainty is
introduced in estimating future concentrations at off-site
locations because it is not known whether ground-water conditions
in Aquifer 2 are stable or whether conditions will remain stable
in the future. Recharge to the aquifers, and fate of
contaminants in ground water, could be affected as surface use of
the site changes or as use of local ground water increases with
continued suburbanizati6n.
Calculations of risk for exposure to soil are likely to be
overestimations. soil samples were collected at "hot spot"
locations of suspected contamination. Exposure and risk
calculations assume long-term contact with the contaminant in
soil through incidental soil ingestion, dermal exposure, or
ingestion of garden produce. It is unlikely that this
combination of prolonged exposure at the areas of high
-------
concentration will occur because the areas of soil contamination
outside the IRM area are small.
Uncertainty in the toxicity evaluation may over-estimate - - .. -_._- - - --
risks by relying on slope factors that describe the upper
confidence limit on cancer risk for carcinogens. Some under-
estimation of risk may occur due to lack of quantitative toxicity
information for some contaminants detected at the QCF site.
Qualitative uncertainty exists in evaluating carcinogenicity of
chemicals that exhibit no carcinogenicity to humans. Evidence
for carcinogenicity of TCE is based on animal studies, and the
weight of the evidence for TCE is under review by EPA to
determine status as either B2, probable human carcinogen, or C,
possible human carcinogen.
..
7.4
Conclusions
Dermal exposure to soils at the site could result in excess
lifetime cancer risks of 1 in 1,000. Exposure to Aquifer 1
ground water could result in unacceptable lifetime cancer and
non-cancer risks. On-site risk estimates of exposure to Aquifer
2 ground water via the inhalation route are at the upper boundary
of EPA's acceptable risk range and would result in a lifetime
excess cancer risk of 1 in 10,000.
Based on the results of the RIfFS, concentrations of
contaminants of concern in Aquifer 1 and Aquifer 2 grDund water
exceed chemical-specific health-based standards such as the
Maximum Contaminant Levels (MCLs) set under the Safe Drinking
Water Act. Aquifer 2 serves as a potential drinking water
source. Aquifer 1 serves as a source of recharge and potential
contaminati~n to Aquifer 2.
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and s~bstantial
endangerment to pUblic health, welfare, or the environment.
Based on the results of the risk assessment, and on the
finding of the RIfFS that hazardous substances in soils from the
IRM area and BDA, and contaminants in LNAPL serve as a continuous
source to ground water contamination, the following remedial
action goals have been established for the QCF Site:
.<'
For soils: -
. Prevention of exposure to contaminated surface and
subsurface soils.
Prevention of migration of contaminants in subsurface
IRM and BOA soils to ground water.
Reduction of contaminant concentrations in subsurface
IRM and BOA soils.
.
.
For ground water:
. Prevention of exposure to contaminated ground water.
-------
_.."- ---
.
.
Prevention of migration of the contaminant plume.
Restoration of ground water for future use.
-------
8.0
DESCRIPTION OF ALTERNATIVES
-The QCF site was divided into three-areas in order to
facilitate evaluation of remedial alternatives. These three
areas are; (1) The rRM and associated areas, (2) the BDA, and
(3) the 4-Tek Industries facility. Various remedial alternatives
were analyzed in detail for each area of the Site.
Estimated costs for each of the alternatives are accurate
within the range of +50 percent to -30 percent. Estimated
present worth costs are based on a 30-year life of the remedial
alternative using a discount rate of 5 percent.
All of the evaluated alternatives, excluding the excavation
and incineration alternative (IRM Alternative 7), would result in
contaminants remaining on-site above health-based levels.
Therefore, CERCLA requires that site conditions be reviewed at
intervals of at least every five years. If warranted by the
review, remedial actions would be initiated at that time to
remove, contain or treat the remaining waste.
8.1
IRM and Associated Areas
A tota:J. of seven remedial alternatives, including "no
action", were considered for cleanup of contaminated soils,
LNAPL, and ground water associated with the IRM area. Elements
of the alternatives, excluding the "no action" alternative, are
summarized in Table 15.
IRM Alternative 1 - No Action
The NCP requires that a "no action" alternative be
analyzed as a potential remedial alternative for each
Superfund site. For this alternative, no further action
would be taken on the Site beyond that already implemented
for the IRM area. The IRM cap would be protected and
maintained as provided by existing institutional controls.
The existing deed restriction is intended to notify any
potential purchaser of the property that the land has been
used to manage hazardous waste and its use is restricted. A
security fence currently exists around the IRM area cap.
These existing instituti~nal controls would be maintained to
restrict access to the IRM area.
IRM Alternative 2:
controls.
Ground-water monitoring, institutional
This alternative requires monitoring of existing
ground-water wells in Aquifers 1, 2 and 3 at least twice per
year. Construction and monitoring of additional wells may
be required. The IRM cap would remain in place. Existing
institutional controls which include a security fence around
-------
TABLE 15
ELEMENTS OF IRM AREA REMEDIAL ALTERNATIVES
ALTERNATIVES
CLEANUP ELEMENT 2 3 4 5 6 7
Ground-Water Monitoring X X X X X X
Institutional Controls X X X X X
vertical Barrier System X X X X
IRM Area Dewatering/Ground-Water Treatment X X X X X
LNAPL Recovery/Incineration X X X X X
Aquifer 1 contingent; Extraction & Treatment X X
0\
V1 Aquifer 2 Extraction & Treatment X X X
X
Venting of IRM Soils X
soil Vapor Extraction of IRM 50ils X
Excavation and Incineration of IRM 50ils X
capital Cost (K = $Thousands; M = .$Millions) JOK 13M 16.1M 16.7M 24.8M 288M
o & M Cost (K = $Thousands; M"= $Millions) 640K 102M 108M 109M 108M 200K
-------
- -, ---~_.
the IRK area, and land use restrictions, would be
strengthened. The deed to the Site would be amended to
restrict use of Aquifers 1 and 2 until the contamination in
these aquifers was naturally diluted below levels B~~ the
. federal Safe Drinking Water Act, 42 U.S.C. SS300f et seq.
(SDWA) and state ground water standards.
The present worth cost of this alternative for a 30-
year period is approximately $9,900,000. The estimated time
to implement this alternative is approximately 3 months.
Potential applicable or relevant and appropriate
requirements (ARARs) for this alternative include the SDWA
Maximum Contaminant Levels (MCLs) and non-zero Maximum
Contaminant Level Goals, 40 C.F.R. 141; and the Resource
Conservation and Recovery Act, 42 U.S.C. SS6901 et sea.
(RCRA), Releases from Solid Waste Management Units
regulations, 40 C.F.R. Part 264, Subpart F, and the
Washington State Model Toxics Control Act (MTCA) Cleanup
Standards, WAC 173-340. The SDWA Secondary MCLs, 40 C.F.R.
143, Proposed MCLs, and Health Advisories for Drinking Water
are to be considered (TBC) for IRK Alternatives 2 through 7.
IRK Alternative 3: vertical barrier, dewatering and
treatment of Aquifer 1 within the IRK, recovery and off-site
incineration of LNAPL, institutional controls, and ground-
water monitoring.
This alternative would include installation of a
vertical ground-water flow barrier system, such as a soil-
bentonite slurry wall, and an expansion of the IRM cap,
which. would minimize ground water and surface water contact
. with contaminants in the IRM area. If necessary, this
alternative would include an option for installation of
dewatering. wells to reduce piezometric heads outside of the
slurry wall. A preliminary barrier wall construction
concept is shown in Figure 16. If a slurry wall is used it
would be keyed into the Aquifer 1 aquitard system that
underlies the area. The approximate depth of the slurry
wall would range between 30 and 70 feet, with a cross-
sectional thickness of about 3 feet. The wall may require
construction in panels to accommodate the sloping terrain
within the IRM area. The existing IRM cap would be expanded
to include the area bounded by the slurry wall. The
. existing cap surface water drainage system would be extended
to convey precipitation and upgradient surface runoff away
from the cap expansion area. This uncontaminated runoff
would be directed to Queen City Lake, as is the runoff from
the existing cap.
Extraction of ground water from within the IRM area
barrier system would be implemented to prevent eventual
discharge of this contaminated water through the Aquifer I
aquitard system into Aquifer 2. Short-term dewatering would
-------
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-------
be implemented to remove and treat the qround water
contained within the barrier system upon completion of
construction. Extraction wells would remove water from
inside the barrier system at.an.estimated rate of 50 gallons
per minute (qpm). Based on known aquifer characteristics,
it is estimated .that between 1 and 5 million gallons of
qround water would be extracted during the initial
dewatering. Treatment of qround water from short-term
dewaterinq would be accomplished usinq a temporary on-site
qround-water treatment system. A likely treatment train
would consist of oil/water separation, filtration, air
stripping, and carbon adsorption and offgas treatment (if
necessary). Treated water would most likely be discharged
to a Publically Operated Treatment Works (POTW).
Long-term dewatering would be implemented to further
control the mobility of residual contaminants within the
barrier system through recovery of any leakage through the
system. The estimated ground-water leakage rate through a
competent slurry wall around the IRK area could reach 1.5
qpm. It is estimated that approximately 5 extraction wells
would be needed for long-term dewatering. Extraction pumps
would be automatically activated, based on ground-water
level monitors within the extraction wells. Extracted
ground water would be treated on site and most likely
discharged to a POTW. A permanent on-site ground-water
treatment system would be installed. A likely treatment
train would consist of oil/water separation, precipitation,
filtration, and carbon adsorption.
LNAPL immobilization and recovery measures would be
implemented to control LNAPL within the IRK area.
Additional site characterization and pilot testing would be
required to determine the amount of recoverable LNAPL,
recovery rates and the duration of recovery. passive
skimming would be the preferred LNAPL recovery process. If
feasible, LNAPL recovery wells would be installed through
the IRK cap. Recovered LNAPL would be transported off-
site to be incinerated at a permitted hazardous waste
incineration facility. .
Ground-water monitoring of Aquifers 1, 2, and 3 would
be undertaken to evaluate the effectiveness of the barrier
system and associated dewatering remedial actions. within
the IRK Area, LNAPL levels would also be monitored.
The present worth cost of this alternative for a 30-
year period is approximately $31,000,000. The estimated
time to construct this alternative is approximately 3 years.
ARARs for this alternative include the SDWA MCLs and
MCLGs, 40 C.F.R. Part 141; RCRA Land Disposal Restrictions,
40 C.F.R. Part 268; RCRA Releases from Solid Waste
Management Units, 40 C.F.R. Part 264, Subpart F; RCRA
68
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Closure/Postclosure Requirements, 40 C.F.R. Part 264,
Subpart G; the Toxic Substances control Act, 42 U.S.C. S2601
et sea. (TSCA), PCB Disposal Requirements, 40 C.F.R. Part
761.60; Clean Wate~Act, 42 U.S.C. 1251 et sea. (CWA),
NPDES Industrial and/or stormwater Discharge Permits
regulations, 40 C.F.R. 122; Ambient Water Quality criteria,
40 C.F.R. Part 131, publically Operated Treatment Works
(POTW) Discharge Requirements, 40 C.F.R. Part 143; Clean
Air Act, 15 U.S.'C. S7401 et sea. (CAA), National Prim~ry and
Secondary Ambient Air Quality Standards, 40 C.F.R. Part 50,
National Emissions Standards for Hazardous Air pollutants,
40 C.F.R. Part 60; the Model Toxics Control Act Cleanup
Standards, WAC 173-340; washington Clean Air Act, General
Regulations, WAC 173-400, Volatile Emissions Standards, WAC
173-460, Controls for New Sources, WAC 173-490, and puget
Sound Air Pollution Control Agency (PSAPCA) Regulation III;
the Washington State Water Pollution Control Act, Surface
Water Quality Standards, WAC 173-201, Waste Discharge
Program, WAC 173-216, National Pollution Discharge
Elimination System (NPDES) Permit Program, WAC 173-220, and
Construction of Wastewater Facilities, WAC 173-240.
IRK Alternative 4: vertical barrier, dewatering and
treatment of Aquifer 1 within the IRK, contingent extraction
and treatment of Aquifer 1 outside of the IRK, recovery and
off-site incineration of LNAPL, extraction and contingent
treatment of Aquifer 2 ground water, institutional controls,
and ground-water monitoring. '
This alternative includes all the elements of IRM
Alternative 3. In addition, an extraction well system would
be constructed which would be designed to contain the
Aquifer 2 TCE and DCE plumes. A point of compliance would
be established as close to the contaminant source as
possible as provided for in National contingency Plan and
the washington state Model Toxics control Act. The areal
extent of the plumes would be shrunk as close to the point
of compliance as technically feasible. Volatile organic
contamination would be removed by recirculating the Aquifer
2 water back through the Main Gravel pit Lake or an
equivalent on-site surface water body. Should the extracted
water contain volatile organic contamination which is above
drinking water standards, then the water would be treated
via air strippers to meet those standards.
Contaminant levels in Aquifer 1 outside of the IRM area
are expected to decrease to regulatory standards within 5
years after completion of the vertical barrier around the
IRM. However, if Aquifer 1 levels do not decrease, then
Aquifer 1 ground water would also be extracted and treated
to meet regulatory standards. Treated Aquifer 1 and Aquifer
2 water would be discharged to the Main Gravel Pit Lake.
The institutional controls and long term ground-water
-------
monitoring which are described in Alternative 2, are
included in this alternative.
- --.-- .- . -- The present worth costs of this alternative are
estimated to be $43,000,000. The estimated time to
construct this alternative is 3 years.
Potential ARARs for this alternative would include all
the ARARs identified in IRM Alternative 3 in addition to the
CWA Disposal of Dredged Material Guidelines, 40 C.F.R. Part
230.
IRK Alternative 5: vertical barrier, dewatering and
treatment of Aquifer 1 within the IRK, contingent extraction
and treatment of Aquifer 1 outside of the IRK, recovery and
off-site incineration of LNAPL, venting of IRK soils,
extraction and contingent treatment of Aquifer 2,
institutional controls and ground-water monitoring.
This alternative is the same as IRM Alternative 4,
except .that it would include removal of some of the mobile
contaminants via venting of the IRM soils. This alternative
was analyzed in order to evaluate the feasibility of
providing an additional measure of protection at a minimal
cost.
A series of vent wells may be installed in the IRM cap.
The vents would be designed and installed in a manner which
prevents rainfall from entering the IRM cap. These vents
will provide an oxygen source which should promote the
aerobic biodegradation of the PAHs and xylenes within the
soils. In addition, the vents should promote the removal of
volatile and semi-volatile contaminants in the unsaturated
soils. Heavy metals and PCB contaminants can not be
degraded or removed using this technology, and would still
remain in place. However, heavy metal and PCB contaminants
are generally not mobile, and should not migrate from soils
to ground water. The vents will be monitored for off-gases
which may enter the atmosphere as a result of the breakdown
and/or removal of contaminants within the soils. If
necessary, best available technology will be utilized to
treat the gases emitted from the vents prior to entering the
atmosphere.
- Prior to installing the vents, treatability studies
will be performed to determine if the IRM soils are suitable
for treatment utilizing this technology. The treatability
studies will determine the contaminant removal efficiency of
the vents, and will aid in determining the number of vents
which will be necessary to optimize contaminant removal.
The institutional controls and long term ground-water
monitoring which are described in Alternative 2, are
included in this alternative.
70
-------
For purposes of estimating costs, it was assumed that
10 vents would be installed. The present worth cost of this
alternative is estimated to be $44,525,000. The estimated
time to construct this alternative is.3 years.
Potential ARARs for this. alternative would be the same
as those identified for IRM Alternative 4.
IRK Alternative 6: Temporary vertical barrier, soil vapor
extraction, dewatering and treatment of Aquifer 1 within the
IRK, contingent extraction and treatment of Aquifer 1 ground
water outside of the IRK, recovery and off-site incineration
of LNAPL, extraction and contingent treatment of Aquifer 2
ground water, institutional controls, and ground-water
monitoring.
soil vapor extraction (SVE) is a remedial technology
which removes volatile organic compounds from the
unsaturated zone. SVE involves drilling a system of
extraction wells through the IRM cap and construction of a
vacuum system to remove the soil air and the mass of
volatile organics contained in the soil air. The removal of
the volatile organics from the soil air results in the mass
transfer of more volatile organics from the soil water and
from the LNAPL. In addition, PAHs may be removed from LNAPL
along with the volatile organics. The extracted soil air is
then treated to remove the volatile organics-and the PAHs.
SVE technology is not effective for removing metals and
PCBs, so these contaminants would remain in the IRM soils.
In order to optimize the effectiveness of SVE
technology for treatment of the IRM soils, a temporary
vertical barrier may need to be installed to prevent
infiltration of ground water into the IRM area. In
addition, the water level of the portion of Aquifer 1 that
lies within the IRM area would need to be lowered. This may
involve the construction of a ground-water extraction system
to remove and treat Aquifer 1 ground water both within and
outside the IRM area. Extraction of Aquifer i water outside
the IRM area is necessary to contain ground-water flow and
gradients within the IRM. The Aquifer 1 ground-water
treatment system would be the same as that described for IRM
Alternative 3. The treated water would most likely be
discharged to a POTW.
As in IRM Alternative 3, oil from the LNAPL would be
recovered and incinerated, and institutional controls and
ground-water monitoring would be implemented. In addition,
the Aquifer 2 contaminant plume would be contained and a
point of compliance established as described for IRM
Alternative 4. Extracted ground water would most likely be
discharged on site to the Main Gravel pit Lake.
-------
The institutional controls and long term ground-water
monitoring which are described in Alternative 2, are
included in this alternative.
The present worth costs of this alternative are
estimated to be ,$54,000,000. The estimated time to
construct this alternative is 3 years.
Potential ARARs for this alternative would be the same
as those identified for IRM Alternative 4.
IRK Alternative 7: Excavation of the IRK cap, recovery and
on-site incineration of LNAPL, dewatering and treatment of
Aquifer 1 within the IRK, excavation and on-site
incineration of IRK soils, extraction and treatment of
Aquifer 2 ground water, and ground-water monitoring.
with this alternative, the IRM cap would be removed.
Prior to removal of the cap, the LNAPL would be recovered
and incinerated on-site. The IRM would be dewatered and the
contaminated water treated and discharged to a POTW. The
contaminated soils within the IRM would be excavated.
Debris from the multi-layered cap would be sampled to
determine if they are contaminated and need to be
incinerated. A mobile incinerator would be placed on-site
to incinerate the contaminated soils, LNAPL and, if
necessary, cap debris.
Soil left in place would meet cleanup levels
established under the Model Toxics Control Act. The IRM
area would be backfilled with clean soil. Aquifer 2 water
would be extracted and, if necessary, treated to meet
regulatory levels. Extracted Aquifer 2 ground water would
be discharged on-site to the Main Gravel Pit Lake or to an
equivalent on-site surface water body. Ground-water
monitoring would be required to ensure that health-based
levels are maintained.
The present worth cost of this alternative is
approximately $293,000,000 to set up and treat an estimated
280,000 cubic yards of contaminated soils. The time
required for implementation of this alternative is estimated
to be 5 years, largely due to the complexity of excavating
the IRM cap, and pretreatment requirements prior to
incineration. However, operation and maintenance of the IRM
area would not be required.
Potential ARARs which have been identified for this
alternative include the RCRA Standards for Hazardous Waste
Incinerators, 40 C.F.R. 264, Subpart 0, the RCRA Land
Disposal Restrictions, 40 C.F.R. 260, Subpart D; the TSCA
PCB Disposal and Incineration Standards, 40 C.F.R. 761.60
and 761.70; the SDWA MCLs and MCLGs, 40 C.F.R. 171; the
Clean Air Act, National Air Ambient Quality Standards, 40
-------
. ~.-._.- .. ......._.~
C.F.R. Subpart 50; the Model Toxics Control Act Cleanup
standards, WAC 173-340; and washington state Air Pollution
Regulations, WAC 173-400 through 490. The TSCA PCB Spill
--- .--. - - . €leanup Policy. is considered a TBC. .. .....
8.2
Buried Drum Area
Four remedial alternatives, including "no action", were
considered for their effectiveness in cleanup of contaminated
soils and debris associated with the BOA.
BDA Alternative 1:
No Action
This alternative is the same as the "no action"
alternative described for IRK Alternative 1. Removat
activities have already taken place in the BDA, and under
this alternative, no further action would be taken.
BDA Alternative 2:
BDA capping
A multilayered cap would be constructed to cover the
BOA. The cap would have the same design as the existing IRK
cap, and could be united with the existing IRK cap.
Approximately 30,000 ft2 of cap would be necessary for
isolation of the BOA. The cap would prevent direct contact
with contaminants, control generation of dust, and prevent
surface water infiltration through the BDA. Prevention of
surface water infiltration would eliminate potential
leaching of contaminants to Aquifer 1. A surface water
drainage system would be constructed to divert rainfall from
the cap area to Queen City Lake.
The present worth cost of this alternative is estimated
to be $725,000. The estimated time to implement this
alternative is 1 year.
Potential action-specific ARARs which would be
triggered for this capping alternative are the TSCA Chemical
Waste Landfill requirements, 40 C.F.R. Part 761.75; and RCRA
Hazardous Waste Landfill Closure/Postclosure requirements,
40 C.F.R. Part 264. Washington state regulations which are
potential ARARs include, the Minimum Functional Standards
for Solid Waste Handling, WAC 173-304, and the Model Toxics
Control Act Cleanup Standards, WAC 173-340. The TSCA PCB
spill Cleanup Policy is a TBC regulation.
BDA Alternative 3: Excavation, off-site treatment of debris
and consolidation of soil with low levels of contamination
below an expansion of the existing XRH cap.
Approximately 10,000 cubic yards of soil and debris
would be excavated. About 100 cubic yards of this material
consists of buried drum debris and associated soils which
-------
--- ~------
are contaminated with metals and organics. This drum debris
and soil would be separated and transported off-site for
treatment and disposal at a permitted hazardous waste
facili ty. The debris may need to be treated to. me.et__-.. -- - - -
regulatory requirements prior to off-site disposal.
Approximately 4,:000 cubic yards of soil have low levels of
metal and organic contamination. This soil would be
consolidated on-site below an expansion of the existing IRM
cap. The remaining 6,000 cubic yards of clean soil would be
used as backfill material on Site.
The present worth cost of this alternative is estimated
to be $2,040,000. The estimated time to implement this
alternative is 2 years.
Potential ARARs which would be triggered by this
alternative include all the ARARs identified for BDA
Alternative 2, in addition to, RCRA Land Disposal
Restrictions, 40 C.F.R. Part 268, and the Washington State
Hazardous Waste Management Act, RCW 70.105.
BDA Alternative 4: Excavation, off-site treatment of
debris, on-site treatment of low level contaminated soil and
consolidation of the treated soil below an expansion of the
existing IRK cap.
This alternative is the same as BDA Alternative 3,
except that the 4,000 cubic yards of soil with low levels of
contamination would be treated on-site by thermal
desorption. Thermal desorption is a process by which
contaminated soils are heated in a kiln to temperatures
between 500 and 800 degrees Fahrenheit to remove the organic
contaminants from the soil. Process equipment for this
technology is readily available. Offgas treatment processes
may need to include carbon adsorption, wet scrubbing, and
after-burning. The treated soil may contain low
concentrations of metals, so if necessary, the soil would be
stabilized with Portland cement prior to placement below the
extension of the IRM cap.
The present worth cost of this alternative is estimated
to be $5,960,000. The estimated time to implement this
alternative is 3 years.
potential ARARs which would be triggered by this
alternative include all the ARARs identified for BDA
Alternatives 2 and 3, in addition to, Clean Air Act,
National Primary and Secondary Ambient Air Quality
Standards, 40 C.F.R. Part 50, National Emissions Standards
for Hazardous Air Pollutants, 40 C.F.R. Part 60; Washington
Clean Air Act, General Regulations, WAC 173-400, Volatile
Emissions Standards, WAC 173-460, Controls for New Sources,
WAC 173-490, and puget Sound Air Pollution Control Agency
(PSAPCA) Regulation III.
-------
8.3
4-Tek
Two remedial alternatives, including "no action", were
considered for the cleanup of the 4-Tek Industries -portion of. the..
site.
4-Tek Alternative 1:
No Action
This alternative is the same as the "no action"
alternative described for IRM Alternative 1. Removal
activities have already taken place at 4-Tek, and under
alternative, no further action would be taken.
this
4-Tek Alternative 2: Ground-water monitoring with
continqent extraction and treatment.
Removal of contaminated soil at the 4-Tek facility has
eliminated a source of contamination. However, a shallow
water table zone at the 4-Tek facility is contaminated with
volatile organics. This water table zone is not used for
potable water but it is considered a potential source of
contamination to Aquifer 2. Currently, no Aquifer 2
monitoring wells exist at the 4-Tek facility. with this
alternative ground water from Aquifer 2 would be monitored
at least twice per year for a period of five years. Post
removal monitoring will also consist of sampling and
characterization of possible additional sources and the
perched water table zone. If a contaminant plume is
detected in Aquifer 2, with contaminant levels above
MCLs,then the plume will be contained, and if necessary,
reduced via ground-water extraction and treatment.
Treatment would probably involve the placement of air
strippers on the extraction wells. The treated ground water
will be discharged on site to the Main Gravel Pit Lake or to
an equivalent on site surface water body. The costs listed
here include the costs for the monitoring and extraction
wells and the treatment system.
The present worth cost of this alternative is estimated
to be $3,500,000. This estimated cost includes a ground-
water extraction and treatment system, as well as long-term
monitoring costs. The estimated time to construct this
alternative is 3 months to install the ground-water
monitoring wells, and 1 year to install a ground-water
extraction and treatment system.
Potential ARARs which would be triggered by this
alternative include, the SDWA MCLs and non-zero MCLGs, 40
C.F.R. Part 141; the Clean Air Act National Primary and
Secondary Ambient Air Quality Standards, 40 C.F.R. Part 50,
National Emissions Standards for Hazardous Air Pollutants,
40 C.F.R. Part 60; the Model Toxics Control Act Cleanup
Standards, WAC 173-340; Washington Clean Air Act~ General
-------
Regulations, WAC 173-400, Volatile Emissions Standards, WAC
173-460, Controls for New Sources, WAC 173-490; and puget
Sound Air Pollution Control Agency (PSAPCA) Regulation III.
The SDWA Secondary MCLs, 40 C.F.R. -Part 143, Proposed MCLs
and Health Advisories for Drinking Water are TBC.
76
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9.0
COMPARATIVE ANALYSIS OF ALTERNATIVES
- ..----. The NCP requires that each remedial alternat-iveooanalyz.ed .in
detail in the Feasibility study be evaluated according to
specific criteria. The purpose of this evaluation is to promote
consistent identification of the relative advantages and
disadvantages of each alternative, thereby guiding selection of
remedies offering the most effective and efficient means of
achieving site cleanup goals. There are nine criteria by which
feasible remedial alternatives are evaluated. While all nine
criteria are important, they are weighed differently in the
decision-making process depending on whether they describe a
required level of performance (threshold criteria), provide for
consideration of technical or socioeconomic merits (primary
balancing criteria), or involve the evaluation of non-EPA
reviewers that may influence an EPA decision (modifying
criteria). The nine criteria are summarized in Table 16.
9.1
Threshold criteria
The remedial alternatives were first evaluated by comparison
with the threshold criteria: overall protection of human health
and the environment and compliance with ARARs. The threshold
criteria must be fully satisfied by candidate alt~rnatives before
the alternatives can be given further consideration in remedy
selection.
9.1.1 Overall Protection of Human Health and the
Environment
This criterion addresses whether the remedial actions
provide adequate protection, and describes the mechanism for
controlling risks for the different exposure pathways.
The treatment alternatives (IRM Alternatives 5 through
7, BDA Alternatives 3 and 4, and 4-Tek Alternative 2) are
all protective of human health and the environment. These
alternatives are more protective because they employ
treatment to reduce the principal threats associated with
volatile organic contamination in ground water; remove
volatile, semi-volatile, and hydrocarbon contaminants from
the IRM and BDA soils; and reduce the likelihood of ground-
water or surface water contamination migrating off-site into
drinking water wells or nearby streams. SVE (IRM
Alternative 6), incineration (IRM Alternative 7), and
thermal desorption (BDA Alternative 4), would be more
protective of human health and the environment, because
these alternatives would destroy or remove the principal
contaminants found at the site.
IRM Alternatives 3 through 7 are protective because
they include the removal of LNAPL. If left in place, the
-------
, Table 16
Glossary of Evaluation criteria
... '-EPA ranks -the alternatives considered against the following nine
evaluation criteria:
Threshold Criteria:
1. Overall protection of human health and the environment - How
well does the alternative protect human health and the
environment, both during and after construction?
2. compliance with applicable or relevant and appropriate
standards (ARARs) - Does the alternative meet all applicable or
relevant and appropriate state and federal laws?
Balancing criteria:
3. Long-term effectiveness and permanence - How well does the
alternative protect human health and the environment after
completion of cleanup? What, if any, risks will remain at the
site?
4. Reduction of toxicity, mobility and volume through treatment -
Does the alternative effectively treat the contamination to
significantly reduce the toxicity, mobility and volume of the
hazardous substance?
s. Short-term effectiveness - Are there potential adverse effects
to either human health or the environment during construction or
implementation of the alternative? How fast does the alternative
reach the cle?nup goals? . .
6. Implementability - Is the alternative both technically and
administratively feasible? Has the technology been used
successfully on other similar sites?
7. Cost - What are the estimated costs of the alternative? How
do costs of the alternative being evaluated compare with costs of
the other alternatives?
Modifying Criteria:
8. State acceptance - What are the state's comments or concerns
about the alternatives considered and about EPA's preferred
alternative? Does the state support or oppose the preferred
alternative?
9. Community acceptance - What are the community's comments or
concerns about the preferred alternative? Does the community
generally support or oppose the preferred alternative?
-------
LNAPL would slowly dissolve, supplying potentially
significant concentrations of contaminants to ground water
over very long time periods.
.-.-- ---------. ..
SVE (IRK Alternative 6), and venting of IRK soils (IRK
Alternative 5), ,would directly treat or remove the mobile
contaminants which contribute most to human health risks.
Ground-water extraction (IRK Alternatives 3 through 7,
,and 4-Tek Alternative 2) is a proven technology for
containment of ground-water contamination. Ground-water
extraction along with source reduction or removal (IRK
Alternatives 5 through 7) would be more protective of human
health and the environment.
The containment alternatives (IRK Alternatives 3 and 4,
and BDA Alternative 2), are not as protective, because
containment alone without treatment may make it possible for
contaminants to migrate below the IRM and BDA into the
underlying aquifers.
The "no-action" alternatives (IRM Alternative 1, BDA
Alternative 1, and 4-Tek Alternative 1), and the alterative
requiring only monitoring (IRM Alternative 2), are not
protective of human health and the environment, because the
main contaminant sources to ground water, su~face water, and
soil would still remain uncontrolled.
9.1.2
Comn1iance with ARARs
~he purpose of this analysis is to evaluate the
alternatives for compliance with the major ARARs. Grounds
for invoking waivers of ARARs are included in this analysis
where appropriate.
CERCLA requires that remedial actions satisfy all
identified ARARs. These laws may include among others, the
Safe Drinking Water Act, the Resource Conservation and
Recovery Act, the Toxic Substances control Act, and state
laws, such as the Model Toxics Control Act with promulgated
standards more stringent than the corresponding federal law.
An "applicable" requirement directly and fully
addresses the situation at the site. It would legally apply
to the response action if that action were undertaken
independently from any CERCLA authority. A "relevant and
appropriate" requirement is one that is designed to apply to
problems which are sufficiently similar to the problem being
addressed at the site, that it's use is well suited to the
particular site.
All of the combination source treatment/containment
alternatives (IRK Alternatives 4 through 6, and BDA
-------
Alternatives 3 and 4) can meet all identified ARARs.
Additional offgas treatment systems may be required for the
SVE and venting alternatives to ensure compliance with
federal and state air regulations. .
. - ----'-
Ground-water extraction and treatment alternatives (IRM
Alternatives 4 through 7, and 4-Tek Alternative 1) may
qualify for an ARAR waiver in the future if cleanup
standards are not achievable within the required time frame,
provided the following two conditions are met:
a) There is a demonstration that it is technically
impracticable to meet the cleanup standards from an
engineering perspective, and this demonstration is made
to the satisfaction of EPA. EPA will make its
determination as to whether aquifer restoration to
cleanup standards is technically impracticable based
upon EPA-approved data, supporting analysis, and site
characterization. .
b) EPA determines the alternative remedial action
objectives.
The source containment alternatives (IRM Alternative 3
and BOA Alternative 2) may not comply with chemical-specific
ARARs because these alternative rely on natural dilution of
ground water to achieve SOWA MCLs and Model Toxicp Control
Act Cleanup Standards once the containment barrier is in
place. It is not known how long natural dilution will take,
or if dilution will be effective, to reduce the ground-water
contamination to health-based levels.
The "no action" and monitoring only alternatives (IRM
Alternative 1 and 2, BOA Alternative 1, 4-Tek Alternative 1)
do not comply with chemical-specific ARARs because soil and
ground-water contamination would remain above state soil
cleanup standards and federal SOWA MCLs.
. The "no action" alternatives (IRM Alternative 1, BOA
Alternative 1 and 4-Tek Alternative 1) will not be
considered further, as they do not meet the threshold
criteria.
9.2
Primary Balancinq criteria
For those alternatives satisfying the threshold criteria,
'five primary balancing criteria are used to evaluate other
aspects of the potential remedies. No single alternative will
necessarily receive the highest evaluation for every balancing
criterion.' This phase of the comparative analysis is useful in
refining the relative merits of candidate alternatives for site
cleanup. The five primary balancing criteria are: long-term
effectiveness and permanence, reduction of toxicity, mobility, or
-------
volume through treatment, short-term effectiveness,
implementability, and cost.
..-.-....-- ~.2.1
Lonq-Term .Effectiveness .and Permanence
This criterion evaluates the ability of a remedial
alternative to maintain reliable protection of human health
and the environment over time, once cleanup goals have been
achieved.
LNAPL recovery, venting, SVE, incineration (IRM
Alternatives 4 through 7), and off-site disposal and thermal
desorption (BOA Alternatives 3 and 4), are all effective
over the long term because they would destroy or remove
contaminants, thereby eliminating the potential for exposure
to contaminated soils and ground water.
A vertical barrier wall and cap around the IRM and BOA,
without source treatment (IRM Alternative 3 and BOA
Alternative 2), would reduce the mobility of contaminants,
but high concentrations of contaminants would still persist
on-site. The potential for future migration of contaminants
due to failure of the barrier wall, or long-term
fluctuations of the water levels within Aquifer 1, would
still remain.
Institutional controls and monitoring, as described in
IRM Alternative 2, are not permanent, because they do
nothing to reduce the levels of contaminants remaining on
site. It is not known how long it would take natural
attenuation to reduce ground-water contamination to health-
based cleanup levels.
9.2.2
Treatment
Reduction of Toxicitv. Mobilitv and Volume Throuqh
This criterion evaluates the anticipated performance of
the various treatment technologies and addresses the .
statutory preference for selecting remedial actions that.
employ treatment technologies which permanently and
significantly reduce toxicity, mobility, or volume of the
hazardous substances. This preference is satisfied when
treatment is used to reduce the principal threats at a site
through destruction of toxic contaminants, irreversible
reductions in contaminant mobility, or reductions in the
total volume of contaminated media.
IRM Alternatives 5 (venting) and 6 (SVE), and BOA
Alternative 4 (thermal desorption) employ a combination of
treatment and containment of contaminated soils and ground
water to significantly reduce contaminant toxicity,
mobility, and volume. SVE and venting would reduce the
contaminant volume of the more mobile contaminants within
the IRM soils. On-site incineration (IRM Alternative 7)
-------
would permanently reduce the toxicity and volume of al~ of
the contaminants in the IRM soils.
LNAPL removal and incineration (IRM Alternatives 3
through 7) would permanently reduce the toxicity and volume
of contaminants .within Aquifer 1 ground water.
Ground-water extraction and treatment (IRM Alternatives
4 through 7, and 4-Tek Alternative 2) would reduce the
volume and mobility of contaminants in ground water.
Off-site disposal (BDA Alternative 3), containment (BDA
Alternative 2), and monitoring (IRM Alternative 2), do not
employ treatment as a principal component of the remedy.
With each of these alternatives, toxicity, mobility, and
volume of the contaminants remain unchanged.
9.2.3
Short-Term Effectiveness
The short-term effectiveness criterion focuses on the
period of time needed to achieve protection of human health
and the environment, and adverse impacts which may occur
during remedial construction and remedial action, until
cleanup goals are achieved.
All of the IRM and BDA alternatives, with the exception
of IRM Alternative 2 (monitoring and institutional
controls), and the "no action" alternatives, would create
some level of short-term risk during construction of the
vertical barrier system and cap expansion. The estimated
time of construction for the vertical barrier system and cap
expansion is 3 years. The short-term risks are primarily
those associated with dust and air emissions resulting from
excavated soil, debris handling, and off-site disposal.
Short term risks, such as those from dust emissions, will be
mitigated to the maximum extent practicable, using best
available technology.
IRM Alternative 7 (excavation of IRM cap and
incineration of IRM soils) would have the greatest short-
term risks associated with volatilization and particulate
emissions during the excavation of highly contaminated soils
from the IRM. Installation of SVE (IRM Alternative 6)
extraction wells, vents, and ground-water extraction and
treatment systems, would have some short-term risks from air
emissions during construction and testing of the extraction,
treatment and disposal systems. These risks could be
minimized by controlling air emissions during construction
and operation of the treatment systems.
9.2.4
ImDlementabilitv
This evaluation addresses the technical and
administrative feasibility of implementing the alternatives,
-------
including the availability of materials and services
required ,to construct the remedy.
-.-.....--.
All of the alternatives can be implemented with varying
degrees of. difficulty. Excavation, incineration, and off-
site disposal would require extensive materials handling.
On-site incineration is an established technology; however,
there may not be an incinerator readily available to handle
the waste. Therefore, delays may be encountered due to
problems in scheduling a mobile incinerator. In addition,
metal and construction debris in the IRM soils may present
difficulties in controlling the quality of the feed to the
unit, resulting in a potential for excessive slagging,
volatile metals emissions, and variable destruction and
removal efficiencies. Trial burns would be necessary to
establish operating parameters and optimize the process
equipment.
venting and soil vapor extraction of IRM contaminants
would require treatability testing prior to implementation.
Equipment and services are readily available. In-field
modifications of equipment and/or operational procedures are
likely to be required prior to start-up in order to design a
system to maximize the amount of contaminants which can be
removed from the IRM soils.
Ground-water extraction, treatment, and-monitoring
systems are readily implementable. Ground-water extraction
is a proven technology and process services and equipment
are readily available. Ground-water discharge to a POTW
will require permitting prior to implementation.
Treatabil~ty studies may need to be performed on extracted
ground water prior to discharge to an on-site surface water
body, such as the Main Gravel Pit Lake.
LNAPL recovery would require pilot testing to determine
the amount of oil which can be removed from the IRM area.
It may be difficult to recover LNAPL from extraction wells
if much adsorption to subsurface soil particles has occurred
within the unsaturated zone.
Construction of the vertical barrier wall would be
complex, and take approximately two years to complete. The
vertical barrier wall would completely enclose the IRM area.
Difficulties might be encountered when attempting to key the
slurry wall into the Aquifer 1 aquitard which may not be
continuous around the IRM. ,In addition, the sloping terrain
of the IRM area requires that the depth of the slurry wall
vary between 30 and 70 feet. This variability in depth may
present difficulties during cutting and filling of the
slurry wall materials.
Long-term dewatering of Aquifer 1, as required by IRM
Alternatives 3 through 6, may be difficult to accomplish
-------
because of the large amount"of infiltration into the Aquifer
during the wet seasons. Piezometric heads within Aquifer 1
will need to be carefully monitored in order in ensure that
excess i ve pressure does not-cause a"- breakdown of t:;he IRM..
slurry wall.
9.2.5
Pro;ected Costs
Present worth costs are used to evaluate and compare
the estimated monetary value of each remedial alternative.
Present worth costs are determined by summing the estimated
capital costs and estimates of the discounted operation and
maintenance (O&M) costs over the projected lifetime of the
remedial alternative. Estimated present worth costs are
based on a 30-year life of the remedial alternative using a
discount rate of 5 percent. Table 17 gives a summary of
costs for each of the evaluated alternatives.
The estimated capital costs for the IRM alternatives
range from $30,000 (monitoring only) to $288,000,000
(excavation and incineration). The capital cost
differential for the combination containment/treatment
alternatives (IRM Alternatives 4 through 6) is only
$780,000.
The estimated capital costs for the BDA alternatives
range .from $610,000 to $5,960,000. The containment
alternative has the lowest capital costs, and the treatment
alternatives have the highest capital costs.
The estimated capital cost for the treatment
alternative at the 4-Tek facility is $1,300,000.
Alternatives that completely treat and/or destroy
contaminants have the lowest O&M costs (IRM Alternative 7
and BDA Alternative 4). Alternatives that include ground-
water monitoring and maintenance of containment features
have the highest O&M costs.
9.3
Modifvinq criteria
The modifying criteria are used in the final analysis of
remedial alternatives and are generally considered in altering an
otherwise viable alternative rather than deciding between very
different alternatives. The two modifying criteria are state and
community acceptance.
9.3.1
state Acceptance
Ecoiogy has been involved with the development and
review of the Remedial Investigation, Feasibility study and
Proposed Plan for the site. Ecology's comments have
resulted in substantive changes to these documents.
Ecology has also been integrally involved in determining
-------
TABLE 17
ESTIMATED COSTS FOR EVALUATED ALTERNATIVES
----IRM---*REA ALTERNATIVES
IRM Alternative 2
. .capital cost
operation and Maintenance (0 & M)
Present Worth
IRM Alternative 3
capital Cost
o & M
Present Worth
IRM Alternative 4
capital Cost
o & M
Present Worth
IRM Alternative 5
Capital Cost
o & M
Present Worth
IRM Alternative 6
Capital Cost
o & M
Present Worth
IRM Alternative 7
capital Cost
o & M
Present Worth
BDA ALTERNATIVES
BDA Alternative 2
capital Cost
o & M
Present Worth
BDA Alternative 3
capital Cost
o & M
Present Worth
BDA Alternative 4
Capital Cost
o & M
Present Worth
.4-TEK ALTERNATIVE 2
Capital Cost
o & M
Present Worth
$30,000
$640,000
$9,900,000
$13,000,000
$1,200,000
$31,000,000
$16,120,000
$1,800,000
$43,000,000
$16,700,000
$1,850,000
$44,525,000
$24,800,000
$1,760,000
$54,230,000
$288,000,000
$200,000
$293,000,000
$610,000
$4,000
$725,000
$2,040,000
o
$2,040,000
$5,960,000
o
$5,960,000
$1,300,000
$180,000
$3,446,000
-------
which cleanup standards will apply to contaminated soils and
ground water under the Model Toxics control Act. The state
has commented that the Proposed Plan is acceptable given
that the pump and treat element-for Aquifer- 2 remediation is
contingent upon documentation that levels of contaminants
decline once source control measures are in place. Ecology
has also stated that treatability studies should be
conducted on IRM soils to determine the effectiveness of
vent wells.
9.3.2
communitv AcceDtance
EPA has carefully considered all comments submitted
during the public comment period, and has taken them into
account during the selection of the remedy for the QCF site.
Members of the community are concerned about their
ground-water quality, and the threat of Site-related
contamination migrating into drinking water supplies.
community members are also concerned about the effect dust
emissions, which may be created during remedial action
construction activities, might have on the health and safety
of the surrounding community.
EPA responses to comments received during the public
comment period are included in the attached Responsiveness
Summary.
-------
- . -- . .. ~ ..
10.0
SELECTED REMEDY
.----" -Based on CERCLA, the NCP, the administrative record, and the
comparative analysis of alternatives, EPA has selected a
comprehensive site-wide remedy which combines the elements of IRM
Alternative 5, BDA Alternative 3, and 4-Tek Alternative 2. The
selected remedy includes the following:
For the IRM Area and Associated Ground-Water Contamination:
.
Isolation of contaminated soils by construction of a
vertical barrier system/slurry wall around the IRM.
.
Dewatering, treatment and off-site discharge of the
water within the IRM.
.
contingent extraction of
the IRM. Treatment, and
ground water to the Main
surface water body.
Aquifer 1 ground water outside
on-site discharge of treated
Gravel pit Lake or equivalent
.
Removal and off-site incineration of LNAPL from within,
and adjacent to, the IRM.
.
Contingent venting of IRM soils. The effectiveness of
venting will be determined by treatabirity studies to
be conducted during remedial design..
.
contingent extraction of contaminated Aquifer 2 ground
water in order to remove volatile organic
contami~ation. Volatiles would most likely be removed
by recirculation through the Main Gravel pit Lake, or
equivalent surface water body. Should the extracted
volatile organic contamination exceed action levels,
then the ground water may be treated via air stripping,
or best available technology, prior to discharge to the
Main Gravel Pit Lake or equivalent surfac~ water body.
For the BDA:
.
Excavation of approximately 10,000 cubic yards of soil
and debris from the BDA. Off-site treatment and
disposal of the soils with high levels of contamination
at a permitted hazardous waste landfill. On-site or
off-site treatment of debris prior to recycling, or
disposal of debris at an off-site solid waste &r
hazardous waste landfill. Placement of soil with low
levels of contamination below an extension of the
existing IRM cap. Backfilling of the uncontaminated
soil.
.
Construction of a surface water diversion system, to
prevent infiltration of water "into the IRM/BDA cap.
-------
For 4-Tek Industries:
.
Sampling and analysis of the shallow ground-water zone, .
and Aquifer 2, at-~he--4-'l'ek facility twice per year for
5 years. Should contamination be found above cleanup
levels, then the ground water may be. extracted and
treated on site. Treated ground water would be
discharged to the Main Gravel Pit Lake or equivalent
on-site surface water body.
site-Wide Actions:
.
Deed restrictions and institutional controls on land
and ground-water use.
.
Long-term ground-water and surface water monitoring.
Off-site Areas
.
Long-term monitoring of private drinking water wells,
with a contingency for providing an alternative water
supply, should site-related contaminants exceed action
levels.
.
Continued long-term monitoring of surface water and
ground-water in the southern portion of the Cedar Hills
Landfill.
10.1 IRK AREA AND ASSOCIATED GROUND-WATER CONTAMINATION
10.1.1
VERTICAL BARRIER SYSTEM
A vertical barrier-system, such as a slurry wall, will be
installed on a circumferential alignment that will enclose the
IRM area. The primary objective of the barrier wall shall be to
contain the contaminated soils within the IRM for a minimum of
thirty years. The following performance standards shall apply to
the qesign and construction of the barrier wall:
.
The barrier wall will be designed and constructed to
have a. maximum permeability of 1 x 10-7 cm/sec.
.
The barrier wall shall be stable and resistant to
degradation from hydraulic permeation of the wall and
from adjacent ground-water movement. The barrier wall
should remain effective in preventing ground-water flow
- from accumulating within the barrier for a minimum of
30 years.
.
The barrier wall shall maintain integrity and be
physically stable under environmental loading
conditions, such as settlement during seismic loading,
and/or dewatering of the interior formation.
-------
.
The barrier wall shall retain long-te~ physical
integrity during possible chemical alteration ..resulting
from the quality of permeating ground water, and
chemical constituents in the soil, .and ground water
which is incorporated into the backfill material.
10.1.2
DEWATERING OF IRK
Extraction of ground water from within the IRM area barrier
system will be implemented upon completion of construction of the
slurry/bentonite wall. The objective of the dewatering will be
to prevent the eventual discharge of the IRM ground water through
the Aquifer 1 aquitard system into Aquifer 2.
Short-term dewatering via extraction wells will be
implemented immediately upon completion of construction of the
barrier wall to remove and treat the ground water contained
within the barrier system. The most efficient pumping rates for
the extraction wells shall be determined based on an evaluation
of aquifer response to actual pumping conditions. Treatment of
ground water from short-term dewatering shall be accomplished
using an on-site ground-water treatment system which may consist
of oil/water separation, filtration, air stripping, and carbon
adsorption. Offgas treatment of treatment residuals will be
conducted, if necessary.
Long-term dewatering shall be implemented via extraction
wells to further control the mobility of residual contaminants
within the barrier system through .recovery of any leakage into
the system. Extracted water will be treated on-site and probably
discharged to a POTW, or treated to meet washington State water
quality discharge standards prior to being discharged to surface
water. Ground water treatment will be accomplished using a
permanent on-site ground-water treatment system which may consist
of oil/water separation, precipitation, filtration, and carbon
adsorption.
Performance standards for the ground-water treatment systems
will be established during remedial design in coordination with
the POTW and will comply with current pretreatment standards and
requirements. Air stripper offgas will be treated, if necessary,
to meet federal and state ambient air discharge requirements.
10.1.3
CONTINGENT EXTRACTION AND TREATMENT OF AOUIFER 1
GROUND WATER OUTSIDE BARRIER SYSTEM
Established cleanup levels for Aquifer 1 are shown in Table
18. Aquifer 1 samples taken from outside the IRM area, have
revealed only volatile organic contamination (VOC) above these
established cleanup levels. While the RME cancer and non-cancer
risks for the future residential scenario are above EPA's
acceptable risk range for inhalation of volatile organics from
Aquifer 1, it is not expected that Aquifer 1 will ever be used as
a potable water source, due to it's limited volume and areal
-------
TABLE 18
CLEANUP LEVELS FOR AQUIFER 1 GROUND WATER
The following cleanup levels have been established for
Aquifer 1 ground water outside the IRK vertical barrier system.
Aquifer 1 is not a drinking water source, however these
established concentrations will be protective of Aquifer 2.
These cleanup levels will also apply to the shallow ground-water
zone at the 4-Tek facility.
HAZARDOUS SUBSTANCE
CONCENTRATION (uq/l)
RISK LEVEL
chromium (total) 80 HI = 1. (non-cancer)
PCBs (total) .018 1 X 10-6 (cancer)
carcinogenic PARs .018 1 X 10-6
Tetrachloroethylene 1 1 X 10-6 (cancer)
(PCE, PERC)
1,1-Trichloroethene 5 1 X 10-6 ( cancer)
(TCE)
1,2-Dichloroethene (cis) 70 HI = 0.2 (non-cancer)
(DCE)
1,2-Dichloroethene (trans) 100 HI = 0.1 (non-cancer)
(DCE)
vinyl chloride .028 1 X 10-6 (cancer)
For all other hazardous substances detected in Aquifer 1 and in
the 4-Tek shallow ground-water zone, the cumulative cancer risks
must not exceed 1 X 10-5, and the non-cancer risks must not
exceed a HI = 1.0.
NOTE: Aquifer 1 will be dewatered inside the vertical barrier
system.
~/l = micrograms per liter
HI = Hazard Index
a = These levels may be below the Practical Quantitation Limit.
The decision to terminate remediation of Aquifer 1 will be made
by EPA in consultation with Ecology and will depend on (1)
expert knowledge of the ground water system at the QCF Site; (2)
an understanding of how the method of treatment affects ground
water flows and contamination levels at the site; and (3)
statistical results from monitoring wells from which levels of
contamination can be extapolated.
-------
extent. However, Aquifer 1 recharges Aquifer 2, which is used
off-site as a potable water source.
..- -..-- . .. .
. -----(}nce the. barrier wall- is constructed , it is expected that.
the source of contamination to. Aquifer 1 will be isolated. Based
on the conceptual hydrogeologic model of the QCF site, the
Aquifer 1 ground water, which is outside of the barrier wall, is
expected to discharge to springs along the gravel pit face in the
central portion of the site, or to Aquifer 2. Due to isolation
of the contaminant source, and volatilization of contaminants
through springs, it is expected that VOC contaminant levels in
Aquifer 1 will decrease to below cleanup levels within 5 years
after completion of the IRM vertical barrier system.
Aquifer 1 contaminant levels will be monitored on a
quarterly basis. Three years after completion of the IRM barrier
wall system, a statistical trend analysis will be performed on
the quarterly monitoring data. If this analysis reveals that the
trend in contaminant concentrations within Aquifer 1 will not
achieve the risk-based goal within 5 years after construction of
the IRM vertical barrier system, then extraction and treatment of
Aquifer 1 ground water may be implemented. The remedial action
risk-based goal for Aquifer 1 is a total risk not to exceed 1 x
10-5 for carcinogens, and a hazard index not to exceed 1.0 for
non-carcinogens. This risk-based goal for Aquifer 1 is the same
as the risk-based goal for Aquifer 2, and therefore, it will be
protective of Aquifer 2.
Extraction, if needed, will occur at the locations and rates
which will be appropriate to achieve the remedial action goal.
Extracted ground water will be treated on-site using air
stripping or the best availab~e technology. Air stripper offgas
treatment such as thermal oxidation will be implemented, if
necessary, to meet federal and state ambient air discharge
requirements. Treated ground water will be discharged on-site to
the Main Gravel pit Lake, or to an equivalent on-site surface
water body that directly recharges Aquifer 2.
10.1.4LNAPL RECOVERY/REMOVAL
LNAPL currently serves as a source of contamination to soils
and ground water ~t the QCF site. The remedial action goal of
this element of the remedy is the immobilization of the LNAPL
source.
LNAPL removal measures will begin prior to construction of
the barrier system. Selection of the appropriate options and
implementation program for LNAPL removal will be made during
remedial design. Additional site characterization and pilot
testing during remedial design will determine the estimate of
recoverable LNAPL, recovery rates, and duration of recovery.
LNAPL removal measures will continue until LNAPL within the
barrier system is sufficiently controlled to limit or p~event
-------
downward contaminant migration through the Aquifer 1 aquitard
system, once ground water is withdrawn from within the barrier
system.
. ..... no''''
...- ._- -- - ...
.
10.1.5
VENTING OF IRK.SOILS
The remedial action objective of this element of the remedy
is volume reduction of the mobile contaminants within the IRM
soils. This element of the selected remedy, if implemented,
should provide an additional measure of protection at a minimal
cost. Upon completion of the barrier system, on-site
treatability tests will be performed to determine if the
soils are suitable for contaminant removal via venting.
feasible, vent wells will be drilled through the IRM cap
unsaturated soils. The wells will be designed"such that
precipitation will be prevented from entering the vents. The
vents will be monitored for offgas, and if necessary, the offgas
will be treated to meet federal and state ambient air quality
requirements. If venting of IRM soils is not feasible, the
additional IRM source control, source removal, and treatment
measures outlined in the selected remedy should be adequately
protective.
IRM
If
to the
10.1.6
AQUIFER 2 EXTRACTION AND TREATMENT
The primary remedial action objective of this element of the
remedy is the on-site containment of the Aquifer 2 TCE and DCE
plume. The short-term remedial action objective for this element
is a reduction in the size of the Aquifer 2 plume. A long-term
goal of the remedial action is restoration of Aquifer 2 to its
beneficial use.
The boundary of the Aquifer 2 TCE and DCE contaminant plume
reaches as close as 200 feet from the site boundary to the south,
and may extend across the northern site boundary on to the Cedar
Hills Landfill. Aquifer 2 serves as a drinking water source for
residences south and southwest of the QCF site. Future on-site
residential and occupational cancer risks associated with
ingestion of Aquifer 2 ground water were within EPA's acceptable
risk range; however, future on-site residential risks associated
with inhalation of Aquifer 2 ground-water are at the 1 x 10-4
risk level for the RME case. The Washington state Model Toxics
Control Act defines the maximum acceptable excess cancer risk
under state law as a total risk of 1 x 10-5.
The Washington state Model Toxics Control Act, WAC 173-340,
allows establishment of a "point of compliance" where established
ground-water cleanup levels must be attained, WAC 173-340-720.
Established cleanup levels for Aquifer 2 are shown in Table 19.
The ground-water cleanup levels must be attained in all ground
waters from the point of compliance to the outer boundary of the
plume. Where hazardous substances remain on-site as part of the
clean-up action, a "conditional point of compliance" can be
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TABLE 19
CLEANUP LEVELS FOR AQUIFER 2 GROUND WATER
The following long-term cleanup levels have been established for
Aquifer 2 ground water throughout the QCF Site. These cleanup
levels have been established in order to achieve the cleanup goal
of restoration of Aquifer 2 for future use. They are either the
more stringent of levels established under the MTCA Method B or
the MCLs and non-zero MCLGs.
HAZARDOUS SUBSTANCE
CONCENTRATION
pg/l
1,2-Dichloroethene (cis)
70
BASIS RISK LEVEL
MTCA 1 X 10-6
MCL 2 X 10-6
MCLG HI = 0.2
MCLG HI = 0.1
MTCA 1 X 10-6
Tetrachloroethene (PCE, PERC)
1.0
Trichloroethene (TCE)
5.0
~,2-Dichloroethene (trans)
100
Vinyl chloride
0.028
~/l = micrograms per liter
HI = Hazard Index
a = These levels may be below the Practical Quantitation Limit.
The decision to terminate remediation of Aquifer 1 will be made
by EPA in consultation with Ecology and will depend on (1)
expert knowledge of the ground water system at the QCF Site; (2)
an understanding of how the method of treatment affects ground
water flows and contamination levels at the Site; and (3)
statistical results from monitoring wells from which levels of
contamination can be extapolated.
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established which must be as close as practicable to the source
of the contamination. For Aquifer 2 ground-water at the QCF
site the conditional point of compliance will be no greater than
the circumference defined by the boundaries of the IRM vertical
barrier system (Figure 17). Cleanup levels from the conditional
point of compliance to the outer boundary of the plume shall be
5.0 ~/l for TCE and 70 ~/l for cis-1,2-DCE. These cleanup
levels are the Maximum contaminant Levels (MCLs) established
under the Safe Drinking Water Act, 40 C.F.R. 141, and are
acceptable cleanup levels under the Model Toxics Control Act
Method B, WAC 173-340-720.
In order to achieve the cleanup objectives established for
Aquifer 2 ground water, the following contingent remedial action
will be implemented: .
Three years after construction of the IRM vertical
barrier system, an historical and statistical analysis of .
Aquifer 2 contaminant concentrations will be conducted. If
this analysis indicates that contaminant concentrations in
Aquifer 2 are not likely to decline to cleanup levels within
10 years after construction of the vertical barrier system,
ground-water extraction shall be implemented. The
determination as to whether Aquifer 2 cleanup levels are
achievable within the required time frame will be made by
EPA, in consultation with Ecology.
If at any time in the future plume expansion is
detected, ground water extraction will be implemented
immediately to reduce the size of the plume. The
determination of plume expansion will be made by EPA, in
consultation with Ecology, and will depend on, (1) expert
knowledge of the ground water system at the QCF Site, and
(2) statistical results from monitoring wells from which
levels of contamination can be measured.
To reduce the time needed to install a ground-water
extraction system, the needed technical data and,
information shall be gathered, and the design plan drafted,
during the general site remedial design phase.
Ground-water extraction, if necessary, will occur for an
estimated period of 10 years, during which time the
extraction system's performance will be carefully monitored
on a regular basis and adjusted as warranted by the
performance data collected during' operation. Modifications
to the ground-water extraction system may include any or all
of the following: .
a) at individual wells where cleanup goals have been
attained, pumping may be discontinued;
b) alternating pumping at wells to eliminate
stagnation points,
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FIeURE 17
CONDITIONAL POINT OF COMPLJANCE FOR AQUIFER 2
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c) pulse pumping to allow aquifer equilibration and to
allow adsorbed. contaminants to partition into ground
water; and,
d) installation of additional extraction wells to
facilitate;or accelerate cleanup of the contaminant
plume.
To ensure maintenance of cleanup levels, Aquifer 2 will be
monitored yearly, for a minimum period of 30 years, at those
wells where pumping has ceased.
Treatability studies will be conducted. to determine if the
extracted ground-water is suitable for treatment via air
stripping or using best available technoloqy. If the ground
water is suitable for treatment, then treatment via air stripping
or best available technoloqy will be implemented. Extracted and
treated Aquifer 2 ground water will be discharged on-site to the
Main Gravel pit Lake, or to an equivalent surface water body.
contaminant levels in ground water which will be discharged shall
not exceed cleanup levels. The requirement for treatability
studies prior to implementation will be consistent with the Model
Toxics Control Act requirement to provide "all known available
and reasonable methods of treatment" (AKART) prior to discharge
to state waters.
~ BURIED DRtJH AREA
BDA EXCAVATION/OFFSITE TREATMENT/DISPOSAL/ONSITE
CONSOLIDATION
10.2.1
The remedial action objectives of this element of the remedy
are to permanently remove and treat the BDA debris, and
permanently control the mobility of any residual contaminants
remaining after excavation and removal of the primary debris
source.
The Remedial Investigation has identified a discrete layer
of drum debris and directly associated soil materials which may
have contaminant levels above the state of Washington Dangerous
Waste Designation levels, WAC 173-303-70 et. sea., set under the
washinqton state Hazardous Waste Management Act, RCW 70.105.
This layer is variable in thickness and is located within 10-12
ft of the existing surface grade. This material, estimated to be
about 100 yd3, will be removed and segregated for subsequent off-
site treatment. An estimated 6,000 yd3 of clean soil located
above the drum debris, will be excavated and stockpiled on site.
Approximately 4,000 yd3 of soil associated with, and directly
below the drum debris layer, .may have contaminant concentrations
below state Dangerous Waste designation levels, but above cleanup
levels established under the washington state Model Toxics
Control Act Method B, WAC 173-340-740 (Table 20). This soil will
96
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TABLE 20
CLEANUP-LEVELS FOR BDA SOIL LEFT IN PLACE
Hazardous substances .in BDA soils which are left in place must be
below the following concentrations levels. These concentrations
are based upon the MTCA Human Health Risk Based Formula Values,
October 7, 1992:
HAZARDOUS SUBSTANCE
CONCENTRATION (mg/kg)
Arsenic
Cadmium
Chromium
Lead
PCBs (total)
PAHs (carcinogenic)
20a1
40
400
250aZ
1. Oa3
1. Oa3
a = Taken from Method A cleanup levels as described in "Model
Toxics Contol Act Cleanup Regulation, Chapter 173-340-WAC".
1 = background
2 = no Method B value available
3 = practical quantitation limit
-------
be consolidated on-site beneath an integral IRM area cap and
incorporated within the boundary of the barrier wall. priorto
backfilling, confirmatory soil samples will be taken. The 6,000
yd3 of excavated clean soil~~~l be placed into the excavation as
backfill, and additional clean soil/fill added as needed, to
match the surrounding topography.
Fugitive dust or volatile emissions during excavation
activities are not anticipated to be above health-based levels,
because of the limited volatility of the contaminants in the BOA,
and the anticipated moist nature of the soil. Worker protection
requirements will be developed during remedial design.
The drum debris and directly associated contaminated soil
will be treated prior to disposal. After treatment, the
contaminated soil and drum debris will be disposed at an off-site
solid waste or hazardous waste landfill. If feasible, the drum
debris may be recycled.
A test burn may be necessary to verify acceptability of the
excavated material for the incineration facility. This
requirement will be identified during remedial design.
10.2.2
IRM/BDA SURFACE WATER DRAINAGE SYSTEM
The existing surface water drainage system will be extended
to convey direct precipitation and upgradient surfac~ runoff from
the IRM/BDA cap expansion area. This runoff will be directed to
Queen City Lake, as is the runoff from the existing cap.
10.3 4-TEK INDUSTRIES
A previous removal action has removed the suspected source
of VOC contamination at the 4-Tek facility. However, residual
VOC contamination above cleanup levels has been detected in
shallow ground water. The goal of this element of the remedial
action is to confirm that residual contamination from 4-Tek has
not migrated and contaminated Aquifer 2; and to ensure that if
any 4-Tek-related contamination has reached Aquifer 2, it is
remediated to cleanup levels.
The shallow ground-water zone, in addition to Aquifer 2 at
the 4-Tek facility will be monitored at least twice per year for
a minimum of 5 years. If VOC contamination is detected above
-cleanup levels, and if EPA, in consultation with Ecology,
determines that the number of detections are statistically
. significant, an extraction and treatment remedy may be
implemented to contain and, if necessary, reduce the VOC plume.
The cleanup levels for this element of the remedy are shown in
Table 18.
Ground-water monitoring will commence during remedial
design. The ground-water extraction system will be designed as
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expeditiously as possible, once it is determined that extraction
and treatment are necessary.
10.4 SITE-WID~ ACTIONS
10.4.1
DEED RESTRICTIONS AND INSTITUTIONAL CONTROLS
The existing deed restriction required by an EPA Consent
Order (Docket No. 1085-10-12-106), will be maintained. This deed
restriction is intended to notify any potential purchaser of the
IRM area property that the land has been used to manage hazardous
waste and that its use is restricted.
The deed restrictions will be expanded to require ground-
water use restrictions, and maintenance and protection of the
ground-water monitoring facilities. Use of on-site untreated
ground water from Aquifers 1 and 2 will be restricted until
cleanup goals for the QCF site are achieved.
The deed restricting site use will be amended further to
restrict land use in the remainder of the IRM area which would
include the portion of this area outside of the existing fence
line. The security fence currently surrounding the IRM cap area
will be extended to included the expanded IRM area and the BDA.
Surface water springs, whose water source is Aquifer 1, will be
fenced where feasible. The fenced areas will be posted with
warning signs. The fence and signs will be maintained during the
life of the remedy. .
10.4.2
LONG-TERM MONITORING
Long-term on-site surface water .and ground~water monitoring
shall be implemented to provide an ongoing assessment of water
quality. A surface water and ground-water monitoring plan
shall be submitted for EPA and Ecology approval during remedial
design. At a minimum, the monitoring program shall include,
semi-annual sampling of Aquifer 1, Aquifer 2, and Aquifer 3
wells, surface water springs whose source is Aquifer 1, and all
on-site surface water lakes and streams which flow off site.
The monitoring program shall be conducted for a minimum of
30 years after cleanup goals are achieved.
10.4.3
CERCLA FIVE YEAR REVIEW
CERCLA mandates a 5-Year Review for remedial actions that
leave contaminants at the site. This review is required at least
once every five years to ensure protection of human health and
the environment. The five~year review is necessary for all of
the above elements. of the selected remedy.
10.5 OFF-SITE AREAS
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10.5.1
MONITORING OF OFF-SITE DRINKING WATER WELLS
Off-site drinking water wells will be monitored at least
annually, for a minimum of--LS years.. The off-site drinking water
well monitoring program will be a voluntary program for community
residents adjacent to the QCF Site. The goal of this element of
the remedy is to ensure that site-related contaminants are not
migrating into drinking water supplies.
If Site-related contamination above cleanup levels is
detected in off-site drinking water wells, an alternate source of
water supply may need to be provided for those affected community
residents. EPA in cooperation with Ecology and SKCDPH will
determine whether an alternate water supply is warranted based
upon an analysis of historical on-site and off-site sampling
data.
10.5.2
MONITORING OF CEDAR HILLS LANDFILL
A CERCLA section 106, 42 U.S.C. S9606, consent Order (EPA
Docket No. 1088-01-0S-106-A) agreed upon by EPA and King County,
requires continual long-term surface water and ground-water
monitoring of the southern portion of Cedar Hills Landfill. The
goal of this monitoring program is to ensure that surface water
and ground-water quality and flows from the Cedar Hills Landfill
do not impact the remedial action at the QCF site. In addition,
ground-water quality is being monitored at the Cedar Hills
Landfill to ensure that site-related contaminants are not
migrating to the landfill.
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11.0
REMEDIAL ACTION OBJECTrvES
Risks due to the QCF site will be managed or mitigated
through a number of source control-i .removal.,-,and -treatment - .
methods. In addition, long-term monitoring an~ institutional
controls will be implemented to prevent exposure to on-site
contaminated media.
The remedial action goals for the QCF site are:
For soils:
. Prevention of exposure to contaminated surface and
subsurface soils.
Prevention of migration of contaminants in subsurface
IRM and Buried Drum Area soils to ground water.
Reduction of contaminant concentrations in subsurface
IRM and Buried Drum Area soils.
.
.
For ground water:
. Prevention of exposure to contaminated ground water.
. Prevention of migration of the contaminant plume.
. Restoration of ground water for future use.
The following source control actions should achieve the
remedial action goals for soils and ground water:
. Construction of a vertical barrier system around the IRM
should prevent migration of contaminants in subsurface soil to
ground water. In addition, the vertical barrier system should
aid in the restoration of Aquifer 1 outside the slurry wall by
minimizing migration of contamination from within the IRM.
. Placement of BDA soils with low-levels of contamination
below an expansion of the existing IRM cap should prevent
exposure to contaminated surface and subsurface soils. Cleanup
levels for BDA soils remaining in-place are shown in Table 18.
These cleanup. levels are based on the MTCA Method B and are
protective of ground water.
The following removal and treatment methods will achieve the
established remedial action goals for soils and ground water:
For the IRM area:
. Removal of LNAPL will mitigate a source of ground water
contamination and therefore help prevent migration of
contaminants to Aquifer 2.
. Dewatering and treatment of Aquifer 1 within the IRM
will minimize an additional source of contamination to
Aquifer 2. Cleanup levels for Aquifer 1 outside the
vertical barrier system are shown in Table 18. These
cleanup levels are protective of Aquifer 2.
-------
. Venting of IRK soils, if implemented, will remove
mobile contaminants and reduce the concentrations of
contaminants remaining in the IRK soils.
4
For the BDA:
. Removal and off-site treatment of soil and debris will
prevent on-site exposure to contaminated soils, and reduce
the levels of soil contaminants remaining on-site.
For Aquifer 1 and the shallow ground-water zone at 4-Tek:
. contaminants within Aquifer 1 outside the IRM vertical
barrier system are expected to decrease, once the source
control measures are in place. contingent extraction and
treatment will ensure reduction of the levels of
contaminants in the shallower ground water, and therefore
prevent migration of contaminants to Aquifer 2. The cleanup
levels shown in Table ls"pertain to shallow ground water
throughout the Site, which is not used for drinking water.
These cleanup levels will be protective of Aquifer 2.
For Aquifer 2:
. Contaminants within Aquifer 2 are also expected to
decrease, once the source control measures are in place.
contingent extraction and treatment will ensure containment
of potential future migration of contaminants, and aid in
the restoration of Aquifer 2 for future use. Cleanup levels
for Aquifer 2 are shown in Table 19. Aquifer 2 is used off-
site as a source of drinking water. The cleanup levels are
protective of drinking water.
Institutional controls and long-term monitoring of surface
water, shallow ground water, and Aquifers 1, 2, and 3 will ensure
prevention of future exposure to contaminated media remaining on-
site.
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12.0
STATUTORY DETERMINATIONS
. ...- -----.-.- .- Under CERCLA, EPA's primary responsibility is to ensure
remedial actions are undertaken which protect human health,
welfare, and the environment. In addition, section 121 of
CERCLA, 42 U.S.C. S9621, establishes cleanup standards which
require that the selected remedial action complies with all ARARs
established under federal and state environmental law, unless
such requirements are waived by EPA in accordance with
established criteria. The selected remedy must also be cost-
effective and must utilize permanent solutions, alternative
treatment technologies, or resource recovery technologies to the
maximum extent practicable. Finally, CERCLA regulations include
a preference for remedies that employ treatment that permanently
and significantly reduces the volume, toxicity, or mobility of
hazardous waste. The following sections discuss how the selected
remedy for the QCF site meets these CERCLA requirements.
12.1 Protection of Human Health and the Environment
The selected remedy combines a number of containment,
treatment and monitoring measures which are designed to be
protective of human health and the environment.
containment of primary source areas will be accomplished
through isolation of the IRM and BDA areas. This-measure will
minimize or eliminate migration of contaminants to Aquifer 1, as
well as migration from Aquifer 1 to surface water, and to Aquifer
2. Much of the primary contaminant source was previously removed
during construction of the IRM in 1985 and 1986.
Principal sources of contamination such as "LNAPL,
contaminated ground water within the IRM area, and contaminated
IRM and BDA soil and debris will be reduced or eliminated through
a number of remedial actions. LNAPL will be recovered and
incinerated off-site. The IRM area will be dewatered, and the
extracted water treated and disposed off-site. BDA debris and
highly contaminated soil will be removed and treated off-site.
Some mobile contaminants in IRM soils may be removed via venting
of the soils. .
Prevention of migration of contaminants, and restoration of
ground water will be accomplished via the source containment and
treatment measures described above. In addition there may be
short-term and long-term ground-water extraction and treatment,
if necessary. .
Institutional controls will further the measures described
above by protecting the IRK cap, vertical barrier system, ground-
water extraction and treatment systems, and controlling land and
ground-water uses.
-------
Additional protection will be provided by the long-term
surface water and ground-water monitoring programs for the Cedar
Hills Landfill and for off-site drinking water wells.
'--..
...--. .
Implementation of the selected remedy will involve extensive
excavation of soils, and may result in some potential for air
emissions and additional short-term risks. Short-term risks will
be minimized to the maximum extent practicable. It is expected
that dust emissions from excavation activities can be controlled
to acceptable levels through the use of dust suppressants. No
adverse cross-media impacts are anticipated.
12.2 Com'Dliance with A'D'Dlicable or Relevant and A'D'Dro'Driate
Requirements CARARs)
The selected remedy will comply with all ARARs that have
been identified. No waiver of any ARAR is being sought or
invoked for any component of the selected remedy. The ARARs
identified for the QCF Site include, but are not limited to, the
following:
Chemical-specific ARARs
Chemical-specific requirements are usually health- or risk-
based numerical values or methodologies that establish the
acceptable amount or concentration of a chemical in the ambient
environment. Following are the chemical-specific requirements
for the QCF site:
1.
Washington state Model Toxics Control Ac~, RCW 70.105D,
(MTCA) Method B Soil Cleanup Standards, WAC 173-340-740.
These regulations are applicable for soils which will remain
in the BDA.
2.
SDWA MCLs and MCLGs, 40 C.F.R. Part 141; SDWA Secondary
MCLs, 40 C.F.R. Part 143.
Applicable for off-property drinking water supplies, if
these wells are community wells that serve more than two
residences. Relevant and appropriate for remedial action
goals for Aquifer 2 extraction and treatment, and for all
other off-site drinking water wells.
3.
MTCA Method B Ground Water Cleanup Standards, WAC 173-340-
720.
Applicable for remedial action goals for on-site shallow
ground water, Aquifer 1 and Aquifer 2.
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Location-specific ARARs
Location-specific requirements are restrictions based on the
concentration of hazardous substances .gr. the conduct of
activities in specific locations. These may restrict or preclude
certain remedial actions or may apply only to certain portions of
the site.
.---.- .
1.
Executive Order 11988, statement of Procedures on Floodplain
Management and Wetlands Protection, Appendix A to 40 C.F.R.
Part 6.
The selected remedy is not expected to have an impact on
wetlands at the site. However, this requirement is relevant
and appropriate to remedial actions which may affect on-site
surface water such as Queen city Lake.
Action-specific ARARs
Action-specific ARARs are technology- or activity based
controls or restrictions on activities related to management of
hazardous wastes. These requirements are triggered by the
particular remedial activities selected to cleanup the Site.
1.
TSCA PCB Disposal regulations, 40 C.F.R. S 701.60; TSCA
Chemical Waste Landfill regulations, 40 C.F.R. S 761.75.
These regulations are applicable for PCB-contaminated
materials that are disposed off-site. Relevant and
appropriate for PCB contaminated soils and LNAPL from the
IRM area and BDA which will be treated and disposed of in a
manner consistent with these requirements.
2.
RCRA Land Disposal Treatment Standards, 40 C.F.R. Part 268,
Subpart Dj RCRA Transportation regulations, 40 C.F.R. Part
263.
The LNAPL recovered from
treated soils and debris
determine whether or not
characteristics. If the
hazardous waste then the
the IRM area, and the excavated and
from the BDA, will be analyzed to
they exhibit RCRA hazardous waste
LNAPL, soils or debris are RCRA
above ARARs may be applicable.
3.
Washington state Hazardous Waste Management Act, RCW 70.105
and WAC 173-303.
These regulations are relevant and appropriate for the
management of hazardous wastes associated with the IRM, BDA
and 4-Tek facility.
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4.
Washington state Minimum Functional standards (MFS) for
Solid Waste Handling, RCW 70.95 and WAC 173-304.
This is the state statute..gcw~ning solid waste management.
This regulation is relevant and appropriate for capping,
surface water cqntrols and ground-water monitoring actions
which will be consistent with substantive MFS requirements.
5.
CWA Ambient Water Quality criteria, 40 C.F.R. Part 131; POTW
Discharge Requirements 40 C.F.R. Part 403.
WPCA Surface Water Quality Standards,
Waste Discharge Program, WAC 173-216;
Program, WAC 173-220; Construction of
WAC 173-240.
WAC 173-201; WPCA
WPCA NPDES Permit
Wastewater Facilities,
These regulations are applicable for Aquifer 1 and Aquifer 2
ground-water treatment systems which will be designed to
meet these requirements. Treated ground-water will be
discharged in a manner which complies with the substantive
requirements of the above-mentioned ARARs.
6.
CAA National Primary and Secondary Ambient Air Quality
Standards, 40 C.F.R. Part 50; CAA National Emissions
Standards for Hazardous Air pollutants, 40 C.F.R. 60; CAA
New Source Performance Standards, 40 C.F.R. 61.
WCAA Volatile Emissions Standards, WAC 173-460; WCAA
Controls for New Sources, WAC 173-490; puget Sound Air
Pollution Control Agency (PSAPCA) Regulation III.
These regulations are applicable for on-site air emissions
from ground-water and soils treatment systems. PSAPCA is a
regional agency which was created by the Washington Clean
Air Act. Regulation III controls and regulates new sources
of air emissions. Coordination with PSAPCA will ensure
compliance with above ARARs.
7.
occupational Safety and Health Act (OSHA), 29 U.S.C. 651;
the implementing regulations under OSHA, 20 C.F.R. Parts
1910 and 1926; and the Washington Industrial Safety and
Health Act, RCW 49.17.
These regulations are applicable for all construction
activities related to the selected remedy.
.
Policy. Guidance and Requlations TO-Be-considered.
Additional policies, guidance and other laws and regulations
to be considered for source control and remedial actions
-------
include, but are not necessarily limited to the TSCA PCB
Spill Cleanup Policy, 40 C.F.R. 761.120; the Guidance on
Selecting Remedies at Superfund sites with PCB
contamination; the Washington State Water Well Construction
Minimum Standards for Construction, RCW 18.104 and WAC 173-
160; and, EPA'sOff-site Disposal Policy.
The PCB Spill Cleanup Policy provides guidance on
recommended cleanup levels under certain access scenarios.
The Superfund PCB Guidance recommends cap designs which are
consistent with RCRA guidance, as well as specifying long-
term management controls.
The Washington State Water Well Construction regulations
specify minimal requirements for the design and construction
of ground-water wells.
EPA's Off-site Disposal Policy describes procedures that
should be implemented when a response action under CERCLA
involves off-site storage, treatment or disposal of
hazardous substances.
12.3 Cost Effectiveness
EPA believes that the combination of remedial actions
identified as the selected remedy will reduce or eliminate the
risks to human health and the environment in a cost-effective
manner. A potentially costly element of the selected remedy is
extraction and treatment of Aquifer 2 ground water. However,
this element won't be required unless less aggressive measures
are not effective. The level of protectiveness afforded by this
element of the selected remedy justifies any potential increase
in cost. Performance of this element of the selected remedy will
be monitored, and costs can be controlled by the measures
outlined in section 10.1.6 of the ROD.
By tailoring the remedy so that removal and any necessary
treatment are applied to major source areas and ground water, and
containment is used for large volumes of contaminated soils, the
selected remedy provides an appropriate level of protection for
each area of the Site, and for potential off-site receptors.
12.4 utilization of Permanent Solutions and Alternative Treatment
Technoloqies to the Maximum Extent practicable
The selected remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent
practicable. Among the alternatives which are protective of
human health and comply with ARARs, the selected remedy provides
the best balance of long-term effectiveness and permanence;
reduction of toxicity, mobility, volume and persistence; short-
term effectiveness; implementabilitYi and cost. The selected
-------
remedy considers the statutory preference for treatment as a
principal element, and considers state and community acceptance.
Excavation and incineration of IRK soils would be. fully
protective and comply with ARARSi however, the short-term risks,
difficulties with implementation, and the cost associated with
excavation of the highly contaminated soils and LNAPL do not
justify selection of this alternative. Soil vapor extraction
(SVE) is an innovative technology which may not be an appropriate
technology for the soil types at the QCF site. SVE would be
difficult to implement because of the nature of the contaminated
soil~ and ground water associated with the IRM.
All of the evaluated alternatives, with the exception of IRM
monitoring and institutional controls, would create some level of
short-term risk during the period in which construction occurs.
The short-term risks are primarily those associated with dust and
air emissions resulting from excavated soil, debris handling and
off-site disposal. Ground-water extraction and treatment would
have minimal short-term risks from air emissions during
construction and testing of the extraction, treatment and
disposal systems. These risks will be minimized by control of air
emissions during construction and operation of the treatment
systems.
Institutional controls and monitoring alone are not
permanent remedies, because they do nothing to reduce-the levels
of contaminants remaining on the site. It is not known how long
it would take natural dilution to reduce ground-water
contamination to cleanup levels.
A vertical barrier wall and cap around the IRM and BOA,
without treatment, would reduce the mobility of contaminants, but
high concentrations of contaminants would still persist. The
potential for future migration of contaminants due to failure of
the barrier wall, or long-term fluctuations of the water levels
would still remain.
All of the alternatives can be implemented with varying
degrees of difficulty. Excavation, incineration and off-site
disposal would require extensive materials handling.
Treatability testing would be necessary before a venting or soil
vapor extraction system could be designed which would effectively
remove contaminants from the IRM soils. Before LNAPL removal
could be implemented, pilot testing would be necessary to
determine the most cost effective method to remove the oily
layer. Construction of the. vertical barrier wall would be
complex, because it requires extensive coordination of
construction activities.
The selected remedy employs a combination of treatment and
containment of soils and ground water in a cost-effective manner
to reduce contaminant volume, mobility, and toxicity.
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12.5 Preference for Treatment as a Principal Element
Treatment of LNAPL, BDA soils, and Aquifer 1 and contingent
treatment of Aquifer 2 water will satisfy the CERCLA preference
for treatment of principal threats.. The selected remedy
incorporates a number of treatment elements which are designed to
reduce or eliminate the major sources of ground-water
contamination at the QCF Site.
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13.0
DOCUMENTATION OF SIGNIFICANT DIFFERENCES
Subsequent to issuing the Proposed Plan, EPA reviewed public
comments. In response, EPA clarified the remedial action
(cleanup) goals for .soils; clarified the proposed venting of IRM.
soils; re-evaluated the ground-water extraction and treatment
remedial element for Aquifer 2; and, provided more detail for the
remedial actions to be conducted at the 4-Tek facility. In
addition, EPA provided more detail on the on-site ground water
discharge option, and added a contingency for providing an
alternate off-site private drinking water supply.
Some of the changes are significant changes. However, all
these changes are logical outgrowths of the information available
to the public in the Proposed Plan and the RIfFS reports.
Additional public notice or public comment period was determined
not to be necessary.
The following sections discuss in more detail the changes
that have been incorporated into the selected remedy.
13.1
CleanuD Goals for Soils at the OCF site
The Proposed Plan described one of the three cleanup goals
for soils at the site as "prevention of exposure to contaminated
surface soils". The selected remedy incorporates source control,
in addition to LNAPL and soil removal measures which are also
designed to prevent exposure to contaminated subsurface soils.
Construction of a vertical barrier system, and removal of highly
contaminated soils with expansion of the IRM cap to incorporate
the BDA, should prevent exposure to subsurface contamination in
the IRM and BDA. Therefore, the cleanup goals for soils at the'
QCF Site are as follows:
.
Prevention of exposure to contaminated surface and
subsurface soils.
Prevention of migration of contaminants in subsurface IRM
and BDA soils to ground water. ..
Reduction of contaminant concentrations in subsurface IRM
and BDA soils.
.
.
13.2
ventina of IRK Soils
The Proposed Plan included bioventing of IRM soils as a
component of the preferred alternative. Bioventing is a
technology which is employed to enhance the biodegradation of
contaminants by injection of an oxygen source and/or a supply of
microorganisms into the subsurface soils through vent wells. .
This technology has been proven to be effective at some sites
with characteristics similar to the QCF site. However, there is
some uncertainty as to whether bioventing would be effective at
the QCF site because of the complex nature of the site geology,
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and the presence of contaminants which are not degradable, such
as metals.
In addition to metals.and' PCBs, the IRK soils are
contaminated with volatile and semi-volatile compounds. These
compounds are mobile in the environment, and may lend themselves
to passive techniques such as venting. The vent wells would be
installed to promote movement of volatile and semi-volatile
compounds to the surface. Venting would be a cost-effective
technique which, if effective, would require minimal operation
and maintenance. The complex geology of the site may limit the
removal efficiency of vent wells, therefore, treatability studies
will be conducted on the IRK soils prior to making the decision
to install the wells.
13.3
Aauifer2 Extraction and Treatment'
The Proposed Plan included an element for extraction of
Aquifer 2 ground water and removal of. volatile organic
contamination by treatment or recirculation through the Main
Gravel pit Lake. The selected remedy adds conditions before
implementation of this element of the cleanup would occur.
Either one of these conditions may trigger extraction of ground
water. These conditions are as follows:
1. Three years after construction of the IRM vertical
barrier system, an historical and statistical analysis of
Aquifer 2 contaminant concentrations will be conducted. If
this analysis indicates that contaminant concentrations in
. Aquifer 2 are not likely to decline to cleanup levels within
. 10 years after construction of the vertical barrier system,
ground-water extraction shall be implemented. The
determination as to whether Aquifer 2 cleanup levels are
achievable within the required time frame will be made by
EPA, in consultation with Ecology.
2. If, at any time in the future plume expansion is
detected, ground water extraction will be implemented
immediately to reduce the size of the plume.
The IRK source control, LNAPL removal, and IRK dewatering
measures outlined in the selected remedy should remove and
contain the contaminants in the IRM, and in Aquifer 1, which
currently serve as a source of contamination to Aquifer 2. The
Aquifer 2 contaminant plume should not expand once these measures
are implemented. contamination above cleanup levels has not
reached beyond the QCF site boundary. Perimeter wells will be
installed along the Site boundary to monitor for plume expansion.
If the contaminant plume expands to the perimeter wells, ground-
water extraction will be implemented immediately to contain the
plume.
Restoration of ground water for future use is a cleanup goal
for the QCF site. In order to help achieve this cleanup goal
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within a reasonable time frame, ground-water extraction may be
implemented to reduce the size and concentrations of the
contaminant plume.
. 13.4
4-Tek Industries
The Proposed Plan called for monitoring of Aquifer 2, and
provided a contingency for ground-water extraction and treatment
should contamination be detected. The selected remedy includes
characterization of the contamination within the shallow ground-
water zone, in addition t9 monitoring of Aquifer 2. The previous
soil removal action removed a source of potential contamination
to ground water. However, the contamination which has been
detected in the shallow ground-water zone could potentially serve
as a source of contamination to deeper ground water.
The remedial action, selected for the 4-Tek facility, in
addition to the other elements of the selected remedy, will
ensure that a comprehensive cleanup remedy is provided for the
entire site. .
13.5
on-site Surface Water Discharqe of Extracted Ground Water
Discharge of extracted ground water from Aquifer 1 outside
the IRM, and Aquifer 2, if necessary, would be to the Main Gravel
Pit Lake. The Main Gravel Pit Lake directly recharges to Aquifer
2. The discharged ground water would be below cleanup levels and
would serve as an additional source of clean water to Aquifer 2.
However, should physical conditions change at the site, which
would preclude discharge to the Main Gravel pit Lake, an
equivalent on-site surface water body would be used. In order to
help maintain steady-state surface water and ground-water flow
- conditions at the site, this equivalent surface water body must
directly recharge Aquifer 2.
13.6
Off-site Drinkinq Water Wells
The Proposed Plan included a provision for the continued
monitoring of off-site drinking water wells. The selected remedy
includes a contingency for the provision of an alternate source
of water supply should site-related contamination above cleanup
levels be detected in the off-site wells.
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