MCCORMICK AND BAXTER SUPERFUND SITE
CASE STUDY: STOCKTON, CALIFORNIA
U.S. Environmental Protection Agency
Office of Solid Waste and Emergency Response
Technology Innovation Office
Washington, D.C. 20460
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Notice
This material has been funded wholly by the United States Environmental Protection Agency
under Contract Number 68-W-02-034. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
Comments or questions about this report may be directed to the United States Environmental
Protection Agency, Technology Innovation Office (5102G), 401 M Street, SW, Washington, D.C.
20460; telephone (703)603-9910.
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FOREWORD
Cost-effective cleanup (remediation) of hazardous waste sites cannot occur unless the type,
quantities, and locations of chemical contaminants present at the site are adequately determined
by a process called characterization. Sampling and chemical analysis of environmental media
(water, soil, sediment, etc.) is vital to designing a remediation regimen that will accomplish the
desired goal of reducing risk to human health and the environment. Unfortunately, site
characterization has historically been very costly and time consuming because the technological
options have been few and sometimes inefficient.
Recent technological advances promise better site characterization at less cost and in a shorter
time frame, yet adoption of new technologies into mainstream engineering practice is very slow.
Three widely acknowledged barriers to the adoption and use of innovative site characterization
technologies at hazardous waste sites are:
• Potential users lack personal awareness and/or experience with the technology.
• Potential users lack the established performance criteria needed to assess the applicability of
the technology for a prospective project, and
• Potential users lack the cost and performance information needed to efficiently plan the
project and allocate resources.
The collection and dissemination of cost and performance information is essential to overcoming
these barriers. While technology developers and vendors can be valuable sources of this
information, their claims often carry less weight than evaluations from colleagues who have used
the technology themselves. Case studies are a means by which technology users and impartial
observers may disseminate information about successful applications of innovative technologies
and add to the pool of knowledge that helps move a technology past the "innovative" stage, thus
significantly shortening the time required for widespread benefits to be realized. Case studies can
also be a rich source of feedback to researchers and developers seeking to improve or refine
technology performance under various site conditions.
Individual case studies may focus on a particular technology or on a characterization approach or
process. Case studies focused on process can provide education about how efficient
characterization strategies can be implemented on a site-specific basis, and thus can be valuable
adjuncts in training courses, For many reasons, case studies are valuable tools for the
environmental remediation community.
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Table of Contents
NOTICE ii
FOREWORD iii
CASE STUDY ABSTRACT 1
EXECUTIVE SUMMARY 3
1.0 SITE BACKGROUND AND HISTORY 4
1.1 PRELIMINARY CONCEPTUAL SITE MODEL 6
1.1.1 Sources of Contamination 7
1.1.2 Description of the Contaminated Physical System 7
1.1.3 Description of Soil Contamination 8
1.1.4 Description of Groundwater Contamination 10
1.1.5 Description of Sediment Contamination 10
1.1.6 Contaminant Fate and Transport 12
2.0 APPROACH TO CHARACTERIZING SITE CONDITIONS AND DEVELOPING
THE REFINED CONCEPTUAL SITE MODEL 13
2.1 FIELD BASED ANALYTICAL METHODS 14
2.1.1 Site Characterization and Penetrometer System (SCAPS) 14
2.1.2 Cone Penetrometer (CPT) Sensors 15
2.1.3 Laser Induced Fluorescence (LIF) Sensors 15
2.2 MOBILE LABORATORY METHODS 16
2.3 EPA REGION IV AND COMMERCIAL LABORATORIES 17
3.0 1999 NAPL FIELD INVESTIGATION 19
4.0 2000 NAPL FIELD INVESTIGATION 22
5.0 INTERPRETATION OF DATA AND DEVELOPMENT OF THE FINAL
CONCEPTUAL SITE MODEL 27
5.1 EVALuation of SCAPS Soil Sampling and LIF Results 27
5.2 Site Geology 28
5.3 Site Hydrogeology 29
5.4 Site Contamination 30
6.0 CONCEPTUAL DESIGN DESICISIONS BASED ON 1999 AND 2000 NAPL FIELD
INVESTIGATIONS 32
TABLES
1 -1 MOBILE FIELD LABORATORY METHOD SUMMARY—SOIL
1 -2 MOBILE FIELD LABORATORY METHOD SUMMARY—GROUNDWATER
1 -3 FIXED LABORATORY METHOD SUMMARY—SOIL
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Table of Contents (Continued)
FIGURES
1 -1 SITE LOCATION AND WELLS
1 -2 PROCESS/SOURCE AREAS IDENTIFIED IN THE RI
5-1 SIMPLIFIED CONCEPTUAL GEOLOGY 0 TO -5 FEET ELEVATION
5-2 SIMPLIFIED CONCEPTUAL GEOLOGY -5 TO -10 FEET ELEVATION
5-3 SIMPLIFIED CONCEPTUAL GEOLOGY -10 TO -15 FEET ELEVATION
5-4 SIMPLIFIED CONCEPTUAL GEOLOGY -15 TO -20 FEET ELEVATION
5-5 SIMPLIFIED CONCEPTUAL GEOLOGY -20 TO -25 FEET ELEVATION
5-6 SIMPLIFIED CONCEPTUAL GEOLOGY -25 TO -30 FEET ELEVATION
5-7 SIMPLIFIED CONCEPTUAL GEOLOGY -30 TO -35 FEET ELEVATION
5-8 SIMPLIFIED CONCEPTUAL GEOLOGY -35 TO -40 FEET ELEVATION
5-9 SIMPLIFIED CONCEPTUAL GEOLOGY -40 TO -45 FEET ELEVATION
5-10 SIMPLIFIED CONCEPTUAL GEOLOGY -45 TO -50 FEET ELEVATION
5-11 SIMPLIFIED CONCEPTUAL GEOLOGY -50 TO -55 FEET ELEVATION
5-12 SIMPLIFIED CONCEPTUAL GEOLOGY -55 TO -60 FEET ELEVATION
5-13 SIMPLIFIED CONCEPTUAL GEOLOGY -60 TO -65 FEET ELEVATION
5-14 SIMPLIFIED CONCEPTUAL GEOLOGY -65 TO -70 FEET ELEVATION
5-15 SIMPLIFIED CONCEPTUAL GEOLOGY -70 TO -75 FEET ELEVATION
5-16 SIMPLIFIED CONCEPTUAL GEOLOGY -75 TO -80 FEET ELEVATION
5-17 SIMPLIFIED CONCEPTUAL GEOLOGY -80 TO -85 FEET ELEVATION
5-18 SIMPLIFIED CONCEPTUAL GEOLOGY -85 TO -90 FEET ELEVATION
5-19 SIMPLIFIED CONCEPTUAL GEOLOGY -90 TO -95 FEET ELEVATION
5-20 SIMPLIFIED CONCEPTUAL GEOLOGY -95 TO -100 FEET ELEVATION
5-21 SIMPLIFIED CONCEPTUAL GEOLOGY -100 TO -105 FEET ELEVATION
5-22 SIMPLIFIED CONCEPTUAL GEOLOGY -105 TO -110 FEET ELEVATION
5-23 SIMPLIFIED CONCEPTUAL GEOLOGY -110 TO -115 FEET ELEVATION
5-24 SIMPLIFIED CONCEPTUAL GEOLOGY -115 TO -120 FEET ELEVATION
5-25 SIMPLIFIED CONCEPTUAL GEOLOGY -120 TO -125 FEET ELEVATION
5-26 SIMPLIFIED CONCEPTUAL GEOLOGY -125 TO -130 FEET ELEVATION
5-27 SIMPLIFIED CONCEPTUAL GEOLOGY -130 TO -135 FEET ELEVATION
5-28 SIMPLIFIED CONCEPTUAL GEOLOGY -135 TO -140 FEET ELEVATION
5-29 SIMPLIFIED CONCEPTUAL GEOLOGY -140 TO -145 FEET ELEVATION
5-30 SIMPLIFIED CONCEPTUAL GEOLOGY -145 TO -150 FEET ELEVATION
5-31 SIMPLIFIED CONCEPTUAL GEOLOGY -150 TO -155 FEET ELEVATION
5-32 SIMPLIFIED CONCEPTUAL GEOLOGY -155 TO -160 FEET ELEVATION
5-33 SIMPLIFIED CONCEPTUAL GEOLOGY -160 TO -165 FEET ELEVATION
5-34 SIMPLIFIED CONCEPTUAL GEOLOGY -165 TO -170 FEET ELEVATION
5-35 SIMPLIFIED CONCEPTUAL GEOLOGY -170 TO -175 FEET ELEVATION
5-36 SIMPLIFIED CONCEPTUAL GEOLOGY -175 TO -180 FEET ELEVATION
5-37 SIMPLIFIED CONCEPTUAL GEOLOGY -180 TO -185 FEET ELEVATION
5-38 SIMPLIFIED CONCEPTUAL GEOLOGY -185 TO -190 FEET ELEVATION
5-39 SIMPLIFIED CONCEPTUAL GEOLOGY -190 TO -195 FEET ELEVATION
5-40 SIMPLIFIED CONCEPTUAL GEOLOGY -195 TO -200 FEET ELEVATION
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CASE STUDY ABSTRACT
McCormick and Baxter Creosoting Company
Stockton, San Joaquin County, California
Site Name and Location:
McCormick and Baxter Creosoting
Company, California
Sampling & Analytical Technologies:
Sampling Technologies
1. Site characterization and penetrometer system (SCAPS)
2. Rotosonic Drilling
3. Low-flow groundwater sampling
4. Conventional "3 volume purge" groundwater sampling
Field Based Analytical Technologies
5. Laser induced fluorescence (LIF) sensor
6. Cone penetrometer tip (CPT)
7. Total recoverable petroleum hydrocarbons (TRPH). SCAPS SOP.
8. TPH analysis with diesel range extended (TPH-Dx). EPA Region 9 SOP modified.
Fixed Laboratory
11. TPH-Dx. EPA Region 9 SOP.
12. PAHs and PCP. EPA Region 9 SOP modified.
13. Dioxin and Furans. SW-846 method 1613B.
14. Polychlorinated Biphenyls (PCBs). CLP-SOW modified.
15. Metals (As, Cu, Cr, Zn). CLP SOW.
16. Total Organic Carbon (TOC). Walkley-Black method.
17. Grain size. ASTM method D422.
18. Density. ASTM method D2937.
19. Porosity. API method RP40.
20. Permeability. Kerr laboratory SOP.
21. NAPL Saturation (Oil and Grease). PTS SOP.
22. Cation Exchange Capacity. SW-846 method 9081.
Period of Operation:
1942 to 1991. Creosoting facility.
Current Site Activities:
Site is currently closed.
Point of Contact:
Kira Lynch, US Army Core of
Engineers, Seattle District
4735 East Marginal Way South
EC-TB-ET
Seattle WA 98134
Phone: 206-764-6918
Fax: 206-764-3706
Media and Contaminants:
Groundwater, soils, and sediments at the
McCormick and Baxter facility in
Stockton, California are contaminated
with chlorinated and aromatic solvents,
metals, and petroleum compounds.
Technology Demonstrator:
None
Number of Samples Analyzed during the 1999 and 2000 NAPL Investigations:
• 181 SCAPS LIF/CPT pushes
• 161 TPH Confirmation Samples
Cost Savings:
The cost savings using this approach are estimated at 40-50% of traditional methods
Lessons Learned:
• It is often technically impossible to characterize complex NAPL sites using traditional sampling and analytical technologies
because of the density of data points required to characterize the source material distribution, the time associated with
collecting samples by conventional drilling techniques and analyzing at an analytical laboratory, the enormous costs
associated with a traditional investigation, and the inherent difficulties in locating NAPL in complex matrices.
• Data from field-based and fixed laboratory methods must be used collaboratively to characterize the NAPL and evaluate the
feasibility of proposed treatment options in a time and cost efficient manner.
• The use of performance based measurement standards (PBMS) is crucial in order to determine the applicability of methods
for the site-specific matrices, modify field and laboratory analytical methods to provide the data necessary for making
project decisions, and ultimately save the project time and money.
Results:
• Finished sampling 30 days ahead of schedule.
• Field crew and project manager were able to review data as it was produced at the site and then use that knowledge to
determine appropriate future sampling locations
• 31 Borings and a number of SCAPS sampling locations eliminated once it was determined that NAPL was not migrating
north of the Old Mormon Slough or found closer to the site.
• 19 Borings were added to increase data points in areas where the extent of contamination exceeded original estimates.
• 9 SCAPS LIF/CPT pushes were added to determine the source of TPH in a previously overlooked area.
• Although 11 microwells were planned, 16 were installed due to rapid installation times.
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WHO SHOULD READ THIS CASE STUDY
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Remedial Project Managers (RPMs) and technical teams developing conceptual site models
at large complex sites.
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RPMs and technical teams using dynamic field activities during the RI/FS and RD/RA
stages of the Superfund process.
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Technical personnel using site characterization and penetrometer systems (SCAPS) to
obtain site specific data.
V
Technical personnel using laser induced fluorescence (LIF) sensors to obtain site-specific
petroleum hydrocarbon data.
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Technical personnel using cone penetrometer (CPT) sensors to obtain site-specific
stratiographic and subsurface geological information.
WHAT YOU WILL LEARN FROM THIS CASE STUDY
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Why conventional sampling and analytical technologies may be inadequate or cost
prohibitive for use at large complex NAPL sites.
Information necessary to compile a comprehensive conceptual site model for subsurface
soil and groundwater contamination at a NAPL site.
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Example data quality objectives (DQOs) for field based measurement technologies,
modified mobile laboratory methods, and commercial analytical laboratories.
V
How field based measurement results for SCAPS LIF and CPT data are used
collaboratively with mobile and fixed lab methods to meet project objectives.
V
DQOs for development of field investigation programs to provide the necessary
information to make site decisions in the Superfund process.
V
How performance based measurement systems (PBMS) are used to determine method
applicability for the site matrices, make method modifications as necessary, and ultimately
save the project time and money.
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MCCORMICK AND BAXTER
EXECUTIVE SUMMARY
A case study of the McCormick and Baxter Superfund site located in Stockton, California is
provided in this attachment to highlight the processes involved in characterizing a Superfund site
and developing a conceptual site model (CSM) for remedial investigations and feasibility studies
(RI/FS) as well as remedial design and remedial action (RD/RA) activities. The McCormick and
Baxter site is relatively large, and given the various types, location, and volume of contamination,
it presents the project manager and other decision makers with a series of complex challenges that
must be met in order to characterize the site and ultimately determine a clean-up strategy.
For the purpose of this case study, we will focus on the non-aqueous phase liquids (NAPL)
contamination found in the subsurface soils and groundwater at the site and the dynamic field
activities used to characterize the contamination and develop a detailed CSM. Although this case
study provides some testimonial as to the effectiveness of the innovative site characterization
sampling and analytical techniques used, the main focus of the study is to provide insight into
how a dynamic approach to planning and field activities can provide large quantities of
appropriate quality data while saving the project time and money.
Due to the application of systematic planning and dynamic field activities used during the 1999
and 2000 NAPL field investigations, the volume of data points was significantly increased while
the number of mobilizations and the time needed to complete field activities decreased when
compared to the expectations of the original management plan. A conventional "static" workplan
that dictates the location and number of samples collected often does not allow for the real-time
data review and field decision-making utilized at the McCormick and Baxter site during these
investigations. When compared to the techniques used during the 1999 and 2000 NAPL
investigations it is clear that use of a conventional workplan would have resulted in an increased
number of field mobilizations leading to increased costs and a decreased number of usable data
points.
The most obvious advantage of using the dynamic work plan was the ability of the field crew and
project manager to review data as it was produced at the site and then use that knowledge to
determine appropriate future sampling locations. Analytical methods used at the on-site mobile
laboratory and the off-site fixed analytical laboratory were modified to increase turn around time
on the data and still provide the information necessary to make project decisions. Additionally,
the flexibility offered from this approach allowed for the completion of approximately 5
additional microwells and 60 more soil borings than expected, and field activities were completed
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30 days prior to the scheduled completion dates. The field crew also had the ability to sample
previously unidentified surface contamination found during the investigations and gather an
abundance of geotechnical and subsurface geologic data.
The large quantity of data collected was ultimately used to develop and refine a detailed CSM, a
necessary component used to aid in making informed project decisions. Crucial information
gathered included: determining the vertical and horizontal distribution of NAPL, physical and
chemical characteristics of the NAPL; type, thickness, and heterogeneity of the subsurface
geologic material and the presence of any manmade subsurface physical barriers. This
information was ultimately used to evaluate the fate and transport characteristics of the various
types of contamination found at the site and determine the technical and economic feasibility of
in-situ remedial options such as steam injection/stripping and electrical heating.
1.0 SITE BACKGROUND AND HISTORY
The McCormick and Baxter Company located in Stockton, California operated as a wood
treatment facility from 1942 to 1991. The site address is 1214 Washington Street in Stockton,
California 95203, and the EPA identification number is CAD009106527. The site occupies
approximately 32 acres in an industrial area near the Port of Stockton at the junction of Interstate
5 and State Highway 4 (Figure 1-1). The site is bound by the Old Mormon Slough to the north,
which connects the facility to the Stockton Deepwater Channel on the San Joaquin River,
Washington Street to the south, Interstate 5 to the east, and an industrial facility located at the
Port of Stockton Turning Basin to the west (Figure 1-1). In addition, an 8 acre parcel located in
the southeast portion of the McCormick and Baxter site is owned by the Union Pacific Railroad.
Entry to the site is controlled by a perimeter fence and 24-hour security.
A variety of wood preservation processes were conducted during the operational history of the
facility to provide treated wood products to the power and utility industry, railroads, and
construction companies. Preservatives used included: creosote, pentachlorophenol (PCP),
arsenic, chromium, copper, and zinc. In addition to the chemicals used to preserve wood
products, a number of other chemicals were used as carriers or solvents to aid in the preservation
process. These chemicals were mainly petroleum-based fuels and included kerosene, diesel,
butane, and ether. For most of the processes used at the site, wood products were impregnated
with the resulting solutions using a pressurized retort. The wood was then removed from the
pressurized retorts and allowed to dry at various storage locations throughout the site.
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Waste oils generated from the wood treatment processes were disposed of in unlined ponds and
concrete tanks on-site. In 1977, the California Department of Fish and Game investigated a fish
kill in the Old Mormon Slough and the Port of Stockton and concluded that the fish kill resulted
from PCB-contaminated water runoff from the McCormick and Baxter site. A cleanup abatement
order was issued to McCormick and Baxter by the California Regional Water Quality Control
Board (RWQCB) in January 1978 and water runoff from the site, which was previously
discharged into the Old Mormon Slough, began to be collected it in two storm water collection
ponds on site.
In 1981, McCormick and Baxter filed for bankruptcy protection under Chapter 11 of the
bankruptcy code. Then in early November 1990, the United States Bankruptcy court for the
District of Oregon entered a first amendment plan of reorganization, which included an
agreement for environmental remediation at the Stockton facility. The plan required McCormick
and Baxter to undertake environmental response actions at the site, however in October 1991 due
to actions taken by the lender for McCormick and Baxter the state was advised that they would
cease operating and discontinue environmental response actions. EPA added the site to the
national priorities list (NPL) in October 1992 and later conducted a number of investigations at
the site.
Early investigations at the site focused on upland soils and groundwater as well as surface water
and sediment contamination at the site. Preliminary site investigations included soil,
groundwater, and sediment sampling; well installation; aquifer testing; a NAPL study; tidal
influence study; vadose zone modeling; and performance of a human health and ecological risk
assessment.
The primary past sources of contamination in the upland area of the site were found to include:
• Old oily waste pond area
• Concrete oily waste tank
• Paved pole washing area
• Track pit
• Underground and aboveground storage tanks (USTs and ASTs)
• Oil/water separators
• Condensate storage tanks
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• Stormwater collection sumps
(Several of these source areas are identified in Figure 1-2)
Primary sources of contamination to the Old Mormon Slough were process spills, direct
discharges of industrial waste and storm water to the slough, and subsurface migration of
contaminants from the upland area.
Field activities conducted during the site characterization phase at McCormick and Baxter
revealed that soil and groundwater at the site were contaminated primarily with creosote, PCP,
dioxin/furans, and metals that were used as wood preservatives. Free phase product, found as
NAPL was determined to exist in the subsurface and additional contamination was found
dissolved in groundwater and adsorbed to subsurface geologic materials.
A record of decision (ROD) was signed on March 31,1999 to address basic, neutral, and acid-
extractable semivolatile organic compounds (SVOCs), dioxins and dibenzofurans, metals, and
polycyclic aromatic hydrocarbons (PAHs) in contaminated groundwater, sediments and soils.
The ROD presents final remedies for vadose zone soils and sediments, and an interim remedy for
groundwater. The selected remedies include excavation of some soils, consolidation and capping
of some soils, in-situ capping for some sediments and groundwater extraction and treatment with
systematic removal of dense non-aqeous phase liquids (DNAPL). The groundwater treatment
interim remedy was selected in order to contain the groundwater contamination, prevent
migration of contaminants in the downgradient direction, and prevent further degradation of the
aquifer beneath the site. Additional feasibility studies were conducted in 2000 and 2001 at the
McCormick and Baxter site to evaluate potential NAPL source material remedial actions and to
develop a final remedial strategy for contaminated groundwater.
1.1 PRELIMINARY CONCEPTUAL SITE MODEL
This section provides a conceptual model of the fate and transport of contaminants based on
sources of contamination, type and extent of contamination, and mechanisms impacting
contaminant migration. The preliminary conceptual site model (CSM) was developed from
information collected during the early site characterization activities at the McCormick and
Baxter site.
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1.1.1
Sources of Contamination
Areas identified as the probable sources of contamination found at the site include the main
(central) processing area (operational from 1942 through 1990), the oily waste pond area
(operational from 1942 through 1980), and the treated wood storage areas (operational from 1942
through 1990). In the main processing area, the primary sources of contamination were the
retorts and associated sumps and piping, track pit, pole washing area, USTs and ASTs, oil/water
separator (O/WS) systems, and condensate storage tanks.
All wood treatment process units and storage tanks at the site have been emptied of the chemicals
they contained, cleaned, and removed from the site. The remaining contaminant source areas at
the site developed from the past release of wood-treating chemicals to surface soils, deeper soils
and groundwater through past processing operations, spills, chemical handling practices, and
drippage from treated wood. The sediments of Old Mormon Slough were also found to be
contaminated as a result of chemical process spills, surface runoff, direct discharge of stormwater
through outfalls, and/or subsurface migration from other operable units (i.e., seepages from the
former oily waste pond area).
A removal action to control seeps in 1996 resulted in the development of a repository unit
adjacent to the main processing area and the filling of cement-lined basements in the main
processing area. The repository was used for 15,000 cubic yards of contaminated soil from the
oily waste pond area, and the basements were filled with tank bottom sludge, investigation-
derived waste, and other debris. The main processing area, which is the most heavily
contaminated area of the site, has been covered with an asphalt cap, but remains as a potential
contaminant source to the subsurface.
1.1.2 Description of the Contaminated Physical System
The wood-preserving process at this site used the preservatives creosote, PCP, copper, chromium,
and arsenic. Creosote is a blend of various coal tar distillates that may contain up to 90 percent
PAHs mixed with other hydrocarbons. Technical-grade PCP contains 85 to 95 percent PCP; the
remainder is a mix of other polychlorinated phenols and about 0.1 percent dioxins and furans.
Both creosote and PCP were mixed with an aromatic carrier oil such as No. 2 fuel oil prior to use
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for wood preservation. In addition, creosote was also mixed with butane and ether as carrier
fluids to create Cellon. Metals were typically mixed with ammonium.
Chemicals detected in LNAPL and DNAPL are consistent with the products historically used on
site (i.e., creosote, PCP, and aromatic carrier oils). These two liquid phases generally contain
varying concentrations of PAHs, poly chlorinated phenols, and various other semivolatile and
volatile organic compounds (SVOCs and VOCs). Detected chemical concentrations in LNAPL
and DNAPL are similar, except that PCP is more prevalent in LNAPL because LNAPL has a lot
of di-isopropyl ether which was used with PCP in the cellon process. The process and
contaminant source areas are shown on Figure 1-2.
The primary chemicals of concern (COC) for the site are creosote and PAH components of
creosote mixtures (including carcinogenic PAHs, non-carcinogenic PAHs (acenaphthene,
anthracene, fluorene, naphthalene, and pyrene), PCP, arsenic, and dioxins/furans. Dioxins/furans
are believed to have originated as manufacturing impurities contained in the PCP solutions.
Although relatively nontoxic, naphthalene is included as a COC because it is widely distributed
throughout soil and groundwater at the site in relatively high concentrations and it serves
as an indicator for the presence of noncarcinogenic PAHs.
1.1.3 Description of Soil Contamination
In general, elevated chemical concentrations in site soils appear to be present primarily in the
western portion of the site, mainly the former main process area, the Cellon process area, the oily
waste pond area, and the track pit. Only shallow soils are contaminated in the eastern portion of
the site, with the exception of a few isolated hot spots. Areas containing lower levels of
contaminants in the western portion of the facility are the former pole wash, tank farm, and butt
tank areas. Concentrations of COCs in soils generally decrease with increasing depth.
Two sources of NAPL have been identified at the site, creosote and non-creosote NAPL.
Creosote NAPL was identified using multiple lines of evidence, including:
• Visual observation of NAPL in soil cores
• Presence of Sheens in soil cores
• SCAPS LIF Data
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NAPL saturation observed in soil cores ranged from oozing or dripping product to brown stains
or a sheen.
Geologic cross-sections depicting the distribution of NAPL contamination were prepared by
reviewing soil logs for visible evidence of NAPL. It was determined from a review of available
data and logs the chemical compositions of the LNAPL and DNAPL were similar. The DNAPL
contains relatively more PAHs and less PCP than the LNAPL. The greater percentage of PAHs
in the DNAPLs (20 to 24 percent) relative to LNAPL (6 percent) may be an indication that the
mass of PAHs in the oil affects the products' density and may be a controlling factor in
determining whether the product sinks or floats. All NAPL samples contained a substantial
portion of miscellaneous hydrocarbons that were not identified. These likely derive from the
various fuel oils and petroleum products used as carriers in the original PCP and creosote
solutions.
Field observations, soil data, and SCAPS LIF data suggest that there are four primary NAPL
source areas at the McCormick and Baxter site: the oily waste pond area, the central processing
area, the main processing area, and the south main processing area known as the PCP mixing
shed. The data also suggests that NAPL has migrated and continues to migrate away from these
areas extending vertically downward as well as outward to the north south, east, and west.
DNAPL has migrated from the water table to a maximum observed depth of 212 feet below
ground surface (bgs) and existing DNAPL data has been interpreted as having migrated in the
saturated zone by moving vertically through permeable sand units, spreading laterally in sands
and above sloping low-permeability silts, pooling above low-permeability silts, and migrating
vertically through silts.
NAPL data compiled from previous investigations including the 1999 and 2000 events were used
to map the product distribution and estimate NAPL volumes sitewide. Although some NAPL has
migrated off-site, the amount of NAPL offsite is presumed to be small and plume volume
estimates have been truncated by the property boundaries. The minimum volume of subsurface
NAPL contamination is estimated at the site is 975,000 gallons, while the maximum estimates put
the volume of NAPL in the subsurface at 1.9 million gallons.
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1.1.4
Description of Groundwater Contamination
Groundwater contamination at the site was found to be limited to SVOCs and, to a lesser degree,
dioxins. The SVOCs naphthalene, benzo (a) pyrene, and PCP serve as indicators of site-related
contamination because they are compounds known to have been used in former processes and
they occur at greater concentrations than other SVOCs. Groundwater contamination above the
maximum contaminant level (MCL) was found not to extend beyond the site fenceline. However,
naphthalene, for which there is no MCL, was detected beyond the fenceline at levels exceeding
the Region 9 preliminary remediation goal (PRG) of 6.2 (xg/L. This indicates that the leading
edge of the plume may be moving off site because naphthalene is the most mobile PAH
compound. The extent of PCP and dioxin and furan contamination at levels above their
respective MCLs was found to be limited to the central portion of the site.
As in the soil contamination, two sources of NAPL have been identified at the site, creosote and
non-creosote NAPL. Creosote NAPL was identified using multiple lines of evidence, including:
• Visual observation of NAPL in soil cores
• Presence of Sheens in water
• SCAPS LIF Data
The extent of the dissolved phase plume from the McCormick and Baxter Site has been evaluated
by observing detections of naphthalene and PCP in down-gradient wells. Naphthalene and PCP
are two of the more soluble COCs at the site. In general, naphthalene and PCP contamination
outside of the NAPL source areas is limited. Dissolved PCP and some dioxin and furan
contamination was identified, mainly in the upper portions of the aquifer and are less of a concern
for deeper zones. Arsenic sampling was discontinued after the completion of the RI in 1998. It
was concluded that arsenic concentrations, which typically ranged up to 50 (xg/L, were
representative of background.
1.1.5 Description of Sediment Contamination
Sediment contamination at the site appears to be limited to Old Mormon Slough, which is directly
north of the facility. The sediments are variably contaminated with NAPL and the primary COCs
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identified in the sediments were PAHs and dioxin. PCP contamination is limited to the eastern
half of the slough sediments. The following contamination patterns were also identified:
PAHs
• Concentrations are generally greater at depth in Old Mormon Slough except at
the oily waste ponds. At the pond, contamination is worse near top due to run-
out.
• Concentrations are highest in sediments 2 to 8 feet below the mud line in the
main processing area, exceeding 1,500 mg/kg.
• The highest concentration is 1,811 mg/kg at 6 to 8 feet below the mud line in a
composite sample collected at the main processing area.
• Sediments deeper than 8 feet below the mud line at the oily waste ponds, main
processing area, and the eastern end are visibly contaminated with petroleum
hydrocarbons.
• The maximum depths sampled at two stations at the main processing area (29.2
feet below the mud line and 18 feet below the mud line) had PAH concentrations
of 87.1 and 1,573 mg/kg, respectively, so contamination may extend beneath
those depths.
PCDD/PCDF
• The dioxin toxicity equivalent concentration (TEQ) is often above 1 ppb.
• TEQs exceeded the Stockton Channel reference concentration (87.7 parts per
trillion) at the following locations and depths:
0 to 4 feet below the mud line at the east end
0 to 6 feet below the mud line at the main processing area
0 to 2 feet below the mud line at the oily waste ponds
PCP
• PCP is not widely distributed in Old Mormon Slough; it degrades over time.
• Concentrations are restricted to upper 4 feet bml in the END and upper 8 feet
below the mud line at the main processing area.
• The main processing area was most contaminated, up to 5.6 mg/kg in a 6- to
8-foot below the mud line composite sample.
• Shallow sediment concentrations correlated with concentrations of PCDD/PCDF.
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A soil cap remedy has been selected to limit interaction between contaminated sediments and the
slough. This remedy is expected prevent further communications between the sediments and
groundwater north of site, limiting source material for groundwater contamination.
1.1.6 Contaminant Fate and Transport
Based on the data obtained, some general conclusions concerning the fate and transport of COCs
have been made. Transport of contaminants is largely due to the movement of NAPL in the
subsurface. PAHs as a component of pure creosote NAPL are DNAPLs, however they can also
be found as LNAPLs if the creosote was mixed with as petroleum. PCP solutions are mainly
LNAPLs and PCP does not generally penetrate below the upper zone of the aquifer.
LNAPL and DNAPL were considered to be the principal sources of groundwater contamination
at the site. Both were present at the site in unsaturated soil and below the water table. Wood-
preserving chemicals that are only slightly soluble in water may travel greater distances when
dissolved in a carrier solvent such as LNAPL or DNAPL. Contaminants in the vadose zone move
as a mobile NAPL phase, adsorb onto soil, volatilize into soil gas, and dissolve into pore water.
Except for the volatilization pathway, similar partitioning occurs below the water table.
Compared with many other contaminants, the PAHs exhibit very low aqueous solubilities and are
strongly adsorbed to particulate surfaces. Volatilization is a dominant release mechanism for the
lower-molecular-weight PAHs with higher vapor pressure. Site conditions are not ideal and the
compounds are present in mixtures. These conditions must be considered in using the data to
evaluate contaminant movement.
Mobile NAPL migrates downward through the vadose zone until it reaches the water table.
NAPL phase separation occurs when the NAPL encounters the water table; LNAPL accumulates
at the water-table surface and continues to migrate laterally. DNAPL continues migrating
downward until it encounters an underlying less permeable stratum. The DNAPL then builds up
above this layer until it stabilizes, migrates laterally, or continues further downward migration
through pore spaces and fractures in the low-permeability layer.
The NAPL also undergoes dissolution as it encounters water in the pore spaces and in the
aquifers, resulting in dissolved contaminants in the groundwater. The contaminants are then
transported with the groundwater laterally and vertically downward, when gradients allow, into
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underlying groundwater through pore spaces and fractures in the low-permeability layer. The
mobility of contaminants in groundwater is affected by adsorption/desorption processes.
The movement of NAPL through the subsurface is complex highly non-uniform. NAPL released
to the subsurface migrates downward through the vadose zone under gravitation force and may
continue to move into the saturated zone. Once in the saturated zone, the NAPL begins
dissolving components into the flowing groundwater, creating a dissolved contaminant plume.
The NAPL continues to migrate through preferential pathways leaving a trail of residual liquid
trapped in pore spaces. At the McCormick and Baxter site the NAPL appears to migrate
regardless of soil type, such that aquitards in a hydrogeologic sense, do not prevent further
migration. Due to the complex migration of NAPL at the site it becomes very difficult to
characterize and limits the remediation options available to the project.
2.0 APPROACH TO CHARACTERIZING SITE CONDITIONS AND DEVELOPING
THE REFINED CONCEPTUAL SITE MODEL
Much of the information gathered in early investigations was used to begin developing a CSM in
order to understand the types and extent of contamination at the site. As the McCormick and
Baxter site progressed through the RI/FS stage and leads into RD/RA, increasingly specific
information concerning the location of contaminants and a thorough understanding of the
subsurface geology is required to develop and design remedial alternatives.
Two field efforts, one in 1999 and another in 2000 were conducted to sufficiently characterize the
NAPL contamination at the McCormick and Baxter site and help refine the CSM and begin to
develop remedial strategies for the NAPL source areas. A brief description of the field
investigations, how the Triad Approach was used, and how the resulting data were interpreted can
be found in Sections 3,4, and 5 of this case study. The following Sections provide information on
the types of equipment and analytical techniques used to conduct the 1999 and 2000 NAPL field
investigations.
The Triad Approach focuses on limiting the number of mobilizations necessary to conduct a site
investigation, however in the case of the NAPL investigations at the McCormick and Baxter site
it was necessary to conduct the field activities in two phases. The investigation was conducted in
two phases over the summers of 1999 and 2000 for several reasons. First, the costs associated
with the investigation could be split over two fiscal years. Second, the legal requirements
necessary to gain offsite access for the 2000 investigation took 6 months to finalize. Finally, the
drilling under the Old Mormon Slough was expensive because the drill rig had to be deployed
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from a floating barge and project planners did not want to sample the slough unless data collected
in 1999 indicated potential contamination issues. The extra time gained by conducting the NAPL
investigation over 2 years allowed project planners to refine the approach for sampling in the Old
Mormon Slough and minimize the time and costs associated with this sampling.
2.1 FIELD BASED ANALYTICAL METHODS
The "Triad Approach" incorporates real-time data, often supplied by field based analytical
methods (FAMs), in the context of thorough systematic planning and dynamic workplans to
achieve project objectives faster, cheaper and with less uncertainty. Several FAMS were used
during the field activities conducted during the 1999 and 2000 NAPL field investigations
including: a site characterization and penetrometer system (SCAPS), mounted with laser induced
fluorescence (LIF) and cone penetrometer (CPT) sensors.
Methods and equipment for the 1999 and 2000 NAPL field investigations were selected to give
rapid assessments of site conditions and therefore have a higher degree of uncertainty when
compared to more rigorous methods conducted in an analytical laboratory. The uncertainty
associated with these methods is acceptable because the greater number of measurements
collected allow for more representative sampling throughout the site despite the inherent
variability in the measurement methods and contaminant distribution heterogeneity.
2.1.1 Site Characterization and Penetrometer System (SCAPS)
The SCAPS uses direct push technology to hydraulically advance samplers and analytical
instrumentation such as the LIF and CPT sensors into the subsurface using a string of drill rods.
The very nature of the rig allows it to be used in hard to reach areas such as outside locations with
little overhead clearance. In addition, the direct push technology generates little waste because
drill cuttings are not produced from the hydraulic advancement of the drill rods but they are
limited to use in unconsolidated soils and generally cannot advance much more that 150 feet
below ground surface (bgs) even in ideal conditions. A more complete discussion of the
capabilities of direct push technologies can be found in Section 4.6.1 of the handbook.
The SCAPS is well suited for applications in the "Triad Approach" because the on-site analytical
tools and mounted sensors can be used to streamline sampling, analysis and data management
necessary to meet project objectives. The direct push technology incorporated by the SCAPS is
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ideal for large complex sites where accelerated sampling is needed to collect high volumes of
sample points and obtain access in difficult areas.
2.1.2 Cone Penetrometer (CPT) Sensors
The SCAPS CPT consists of a steel cone at the end of the hydraulic push rods that is advanced
into the subsurface. CPT sensors located on the end of the cone provide continuous
measurements of cone tip pressure and friction in accordance with ASTM standard D3441.
Software is then used to translate the electromechanical responses of the strain gauges into a soil
classification number. The cone tip pressure and friction sleeve respond independently to soil
stresses, however the combined ratio, which leads to the soil classification number and is given
by the software is actually determined using a ratio of cone pressure to sleeve friction. The soil
classification numbers and associated material descriptions produced by the SCAPS CPT are as
follows:
0
Peats
0-1
Clays
1-2
Silt mixtures
2-3
Sand mixtures
3-4
Sands
4-5
Sands and gravel
2.1.3 Laser Induced Fluorescence (LIF) Sensors
The SCAPS LIF sensor uses a nitrogen laser as the ultraviolet (UV) light source to bombard the
subsurface sample with UV causing petroleum hydrocarbons in the sample to fluoresce. The
fluorescence is actually the result of polycyclic aromatic hydrocarbons (PAH) components of the
petroleum products that become excited after receiving energy from the UV light and then give
off that energy in the form of fluorescence in order to return to their "natural" or ground state.
The resulting fluorescence is measured using an electronic detector and the reading is then
converted into a contaminant concentration.
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A fiber optic umbilical cord attached to the LIF sensor can actually provide "real time" in-situ
detection of subsurface petroleum hydrocarbons containing PAHs. This in-situ detection
provides a continuous reading of petroleum hydrocarbons in subsurface as the SCAPS advances
the LIF sensor. The result is a significant decrease in the time required to delineate the vertical
and lateral extent of a petroleum hydrocarbon plume. Multiple profiles across a site can also be
used to generate a 3 dimensional view of the plume for site characterization.
It is important to note that fuels with lower proportions of PAH compounds can have significantly
higher detection limits for the LIF and that a number of man-made and naturally occurring
compounds can produce fluorescence in the presence of UV light. Naturally occurring minerals
such as calcite or naturally occurring organic matter containing PAHs and other man-made non-
hydrocarbon materials such as deicers, antifreeze, and many detergents can also fluoresce.
Experienced operators may be able to determine the differences between petroleum products and
other interfering compounds, however confirmation samples are recommended. The 1999 and
2000 NAPL investigations included confirmation samples analyzed by LIF ex-situ and total
recoverable petroleum hydrocarbons (TRPH) in the SCAPS laboratory as well as total petroleum
hydrocarbons diesel extended (TPH-Dx) analyses conducted by the EPA Region IX laboratory.
2.2 MOBILE LABORATORY METHODS
In addition to the FAMs used to collect data during the 1999 and 2000 NAPL field investigations
a number of analyses were conducted on soil and groundwater samples in the SCAPS mobile
laboratory and the EPA Region 9 Field Analytical Support Program (FASP) mobile laboratory.
Soil samples were analyzed for TRPH by the SCAPS laboratory to provide estimated
concentrations of petroleum hydrocarbons and results were also used to correlate SCAPS LIF
responses. Results were generally available within an hour of sampling and were used to better
interpret SCAPS LIF responses.
Although the TRPH results do not identify specific fuel types or composition and can be subject
to interferences from natural organic materials, they provided valuable confirmation results and
assisted in interpreting LIF signatures.
The mobile laboratory conducted more comprehensive analyses of soil and groundwater samples
using a modified version of the Region 9 TPH-Dx method. The method was modified to allow
for a quicker less vigorous extraction and expanded recovery windows for QC parameters. This
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allowed for quick data generation assisting in on-site decision making. In addition to providing
estimated concentrations of TPH, the method provided gas chromatograph/mass spectroscopy
(GC/MS) analysis. The chromatograms provided by the TPH-Dx analysis were evaluated
qualitatively by an experienced analyst, and fuel types present (TPH fingerprinting) was
compared to a spectral library or other laboratory analyzed fuel standards to profile different fuel
types.
The TPH fingerprinting data was used as collaborative information to provide a chemical
signature for NAPL products found within various locations of the McCormick and Baxter site.
Known fuel patterns and other chemical data could then be reviewed against LIF signatures from
corresponding samples to link chemical data with specific LIF signatures. As LIF sampling
locations were extended out from source areas, changes in LIF signatures indicated the need to
collect additional soil samples for chemical analysis and TPH fingerprinting. This resulted in
better LIF interpretation and limited the need to collect costly analytical samples, by requiring
chemical analysis only in areas where the LIF signature changed from adjacent push locations.
Uncertainties in concentration and compound identification associated with the TPH-Dx analysis
are considered acceptable for the NAPL investigations because it still allows for the identification
of the presence or absence of TPH at the site. The on-site rapid analysis of samples allows for a
greater number of measurements resulting in a more representative sampling approach site-wide.
Additionally, results were immediately available to assist the sampling team in making informed
decisions as to subsequent sampling locations, and assure that the extent of different fuel types
present were identified. Tables 1-1 and 1-2 provide summaries of the methods used by the
SCAPS and FASP laboratories.
2.3 EPA REGION IV AND COMMERCIAL LABORATORIES
Off-site fixed analytical laboratories were also sent samples from the 1999 and 2000 NAPL field
investigations to analyze for a number of parameters. The TPH-Dx analysis was used
for confirmation of on-site laboratory TPH-Dx results and to assist with the interpretation of
SCAPS LIF data.
Additional analyses were also performed for target analytes that could not be analyzed in the field
or for analytes that provide secondary information crucial to the design of remedial alternatives.
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SVOC analyses for PAHs and PCP were based on SW-846 methods, although as in the case of
the TPH data the extraction was modified to include a quicker less vigorous procedure using
sonication and expanded recovery windows. The data was used to provide qualitative
information on the types of PAHs present in a sample and evaluating the exact concentration was
not as important. In general high concentrations of PAHs were found where the NAPL was
believed to be present and were not found in other areas.
A number of geotechical analyses and a NAPL saturation analysis were also performed to aid in
the interpretation of CPT results and design the remediation systems. The samples were collected
to provide information for different stratographic areas identified by CPT logs and provide
valuable information for the placement of extraction and injection wells for the remedial design.
Table 2-1 lists the analyses performed at all laboratories for the 1999 and 2000 NAPL field
investigations.
Analytical methods for the off-site laboratories were selected to provide additional data and
support project objectives. In some cases these methods were modified to allow rapid data
generation so that data would be available for on-site decision making. The modifications
generally included a shorter less vigorous extraction procedure and expanded recovery windows
for surrogate compounds. The shorter extraction time and expanded recovery windows allowed
for quick generation of data, generally within 48 hours of sampling.
The analytical methods, calibration procedures, and QC measurements and criteria were based on
analytical protocols from the following:
• EPA Contract Laboratory Program (CLP) scope of work
• EPA SW-846 Test Methods for Evaluation of Solid Waste (U.S. EPA 1994)
• American Society for Testing and Materials (ASTM annual updates)
• Methods for the Chemical Analysis of Water and Wastes (U.S. EPA 1979)
• Laboratory-specific SOPs
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Laboratory method summaries, including reference and preservation, extraction, cleanup and
instrumentation, are included in Tables 1-1 through 1-4. Laboratory-specific SOPs and project-
specific modifications to documented methods are not included with this case study.
3.0 1999 NAPL FIELD INVESTIGATION
During the period of July through September 1999, an investigation of the nature and extent of
the subsurface non-aqueous phase liquid (NAPL) contamination at the site was conducted to
better define the type and extent of NAPL contamination and further refine the conceptual site
model (CSM).
A number of activities were conducted during the 1999 NAPL field investigation including; a site
survey, geophysical investigation, groundwater sampling, NAPL sampling, site characterization
and penetrometer system (SCAPS) investigation using a laser induced fluorescence (LIF) sensor
and cone penetrometer (CPT) measurements, and rotosonic drilling with associated soil sampling
and monitoring well installations. A brief description of the tools and methods used for these
activities and the information provided is given below.
Site Survey - Conventional surveying equipment was used to establish horizontal and
vertical controls using state plane coordinates. Monuments were placed and
surveyed at the site and all pertinent site features were surveyed. Features
surveyed included: existing aboveground structure, the lined repository pit, the
sheetpile wall, perimeter fences, two stormwater holding ponds, corners of the
asphalt cap, buildings, paved areas, and the well pumphouse.
Geophysical Investigation - Electromagnetic line locating was used to locate near
surface metal objects such as: utilities, railroad spurs, and buried metallic debris.
Electromagnetic devices with terrain conductivity and in-phase component
sensors was used to determine shallow (10-15 feet below ground surface)
conductivity. Variations in conductivity are indicative of buried debris or
changes in subsurface materials. Additionally, total field magnetrometry
was used to locate buried ferrous objects.
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Groundwater and NAPL Sampling - Groundwater samples were collected from 15
existing wells using low-flow and conventional sampling techniques.
Additionally samples were collected at 18 wells where either dense NAPL
(DNAPL) or light NAPL (LNAPL) had been detected during earlier sampling
events or previous data indicated that dissolved phase contaminants were near
their respective solubility limits.
SCAPS LIF and CPT - SCAPS sampling was conducted using LIF sensors to evaluate
the presence or absence of TPH and estimate petroleum hydrocarbon
concentrations (specifically those containing polycyclic aromatic hydrocarbons
(PAH)). CPT data was used to provide continuous geotechnical and stratigraphic
information. The initial 10 SCAPS sampling locations were pre-selected based
on known or suspected areas of high contamination or where previous data gaps
were identified. A total of 106 SCAPS penetrations were made and they ranged
from 11.5 feet to 155.8 feet below ground surface (bgs).
SCAPS Soil Sampling - SCAPS LIF data was used to determine where additional
SCAPS soil samples should be collected. Soil samples were collected at a
variety of depths at new borings within 1 to 2 feet of 20 existing SCAPS
LIF/CPT push locations. Soil samples were collected and analyzed for TPH to
obtain SCAPS LIF calibration and verification samples representative of
different soil type, emission spectra, and emission intensities. SCAPS soil
sampling was used in areas where high concentrations or multiple types of
petroleum products were found, areas where petroleum concentrations exceeded
the LIF sensor threshold, areas where free product and dissolved concentrations
were found, to fill in previously determined data gaps, and aid in the refinement
of the CSM. Analytical results from samples collected from the SCAPS platform
also helped to verify anomalous LIF sensor responses and assist in LIF data
interpretation.
Physical analysis samples were also collected for permeability, density, porosity,
grain size, cation exchange capacity (CEC), and total organic carbon (TOC) to
provide crucial information used in the design of thermal treatment systems for
remediation. The CPT data was further evaluated by comparing the results with
visual core logging conducted by on-site geologists.
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Locations for SCAPS soil sampling was chosen in the field based on: push
locations where contamination was suspected but not found in order to confirm
low LIF responses, in areas where different LIF wavelength signatures were
found in order to determine the type of contamination, areas where NAPL may
be present above LIF response threshold values, and to verify the presence or
absence of contamination at locations where non-target fluorescence was
suspected.
Rotosonic Drilling, Soil Sampling, and Monitoring Well Installation - A total of 18
borings were completed using rotosonic drilling techniques to evaluate the extent
and type of contamination as well as the geology at depths beyond maximum
SCAPS penetrations and determine the potential for downward migration of
groundwater and NAPL. The borings were located adjacent to SCAPS borings
where the maximum depth of NAPL contamination had not been reached and the
SCAPS platform was unable to achieve deeper penetrations. Samples collected
were analyzed for TPH, PAH, PCP, heavy metals, and physical parameters. All
but two of the rotosonic borings were collocated with SCAPS penetration borings
and the analytical data was used to confirm LIF signature data and collect soil
samples and provide stratographic information at intervals deeper than the
SCAPS was able to penetrate. Finally, two additional groundwater monitoring
wells were installed at the site as part of the rotosonic drilling program.
Due to the application of dynamic field activities during the 1999 NAPL field investigation, a
number of changes to the original management plan were completed in order to obtain more
accurate and useful data and limit the number of field mobilizations necessary to achieve the
investigation objectives. The most obvious application of the dynamic work plan was the ability
of the field crew and project manager to review data as it was produced at the site and then use
that knowledge to determine appropriate future sampling locations. Additionally, the flexibility
offered from this approach allowed:
• The use of conventional groundwater sampling techniques at wells where the
presence of free product did not allow for low flow sampling.
• The completion of 104 SCAPS borings instead of 40. 40 SCAPS pushes were
used as the base estimate of the original management plan.
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• Surface sampling of crystals (later determined to be PCP) discovered during the
field investigation.
• Rotosonic drilling was used to provide additional samples and stratigraphic data
at depths greater than SCAPS penetration. Although the objective was to push to
a depth of 200 feet bgs with the SCAPS, the maximum depth achieved was 155.8
feet bgs. The definition of the bottom of the NAPL contamination was seen as a
critical data need and the rotosonic drilling was used to obtain this information.
4.0 2000 NAPL FIELD INVESTIGATION
The 2000 NAPL investigation was conducted as a second mobilization for the NAPL
characterization effort to spread the costs of the project over 2 fiscal years, allow time to gain
access agreements from off-site property owners and allow time for the refined of the costly
sampling approach for the Old Mormon Slough. The investigation was conducted from June to
August 2000 where the primary objectives were to determine the lateral and vertical extent of the
NAPL contamination, determine whether NAPL had migrated off-site, and aid in the selection of
a final groundwater remedy including an evaluation of the in situ thermal treatment technologies
being considered for remediation. Secondary objectives included further refinement of the CSM,
determining if natural attenuation was limiting the mobility of the NAPL contaminants in the
subsurface, determining the extent of surface and subsurface PCP contamination found during the
1999 investigation, determining if a light NAPL (LNAPL) is responsible for transporting PCP
into shallow groundwater, and determining the nature and extent of the subsurface anomaly
which prevented penetration of the SCAPS beyond 16 feet bgs in one area.
The Triad Approach was implemented to use systematic planning, dynamic field activities, and
field based measurement technologies to take into account the evolution of the CSM as data was
collected at the site. Several sampling locations were identified prior to the field activities,
however the majority of locations were determined based on "real time" results of chemical and
physical analysis performed on the site materials.
Data collected during this and the 1999 NAPL investigation were collected to aid in the
feasibility study (FS) portion of the Superfund process by providing information on the vertical
and horizontal distribution of NAPL; the physical and chemical characteristics of the NAPL; the
type, thickness, and heterogeneity of the subsurface geologic material; and the presence of any
manmade subsurface physical barriers. Information gathered during this investigation was used
to determine the technical and economic feasibility of in-situ remedial options such as steam
injection/stripping and electrical heating.
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The field activities conducted during the 2000 NAPL investigation were implemented in 4 stages.
The first phase was conducted to evaluate NAPL migration north of or in the Old Mormon
Slough, while the second phase was conducted to definitively determine the Eastern and
Southeastern limits of NAPL contamination. The third phase was conducted to evaluate the PCP
contamination in the Cellon process area and A-zone groundwater, while the fourth and last phase
was conducted to characterize the subsurface anomaly identified during the 1999 NAPL field
investigation, which resulted in refusal of the SCAPS penetration at 16 feet bgs.
Consistent with the tools and techniques used during the 1999 NAPL field investigation, the 2000
investigation involved surveying of new sampling locations and new well locations, collecting
groundwater samples for PCP and VOCs, SCAPS LIF and CPT measurements, SCAPS soil
sampling, rotosonic drilling with associated soil sampling and monitoring well installations, and
SCAPS microwell installations. A brief description of the tools and methods used for these
activities and the information provided is given below.
Surveying New Sampling and Monitoring Well Locations- SCAPS exploration
locations were surveyed during field activities using a hand-held global
positioning system (GPS). Elevation levels were also surveyed using a hand
level relative to existing site control monuments. Prior to exploration work in the
Old Mormon Slough, a survey team surveyed the elevation on a point on the east
end of the sheetpile wall. The surveyed locations was subsequently used by the
SCAPS team to survey elevations of sampling locations in the Old Mormon
Slough. Finally, after completion of all the field activities, the survey team
returned to survey the horizontal and vertical positions of the SCAPS exploration
locations, rotosonic soil borings, monitoring wells, and microwells.
PCP and VOC Groundwater Sampling- Preliminary groundwater samples were
collected at four existing wells screened in the A-zone (ft—ft) and analyzed for
volatile organic compounds (VOCs) and semi-volatile organic compounds
(SVOCs). The objective of the groundwater sampling was to determine if
isopropyl ether was present and migrating in the A-zone groundwater where PCP
was detected and evaluate groundwater quality in wells where PCP had been
detected previously. The sampling was also used to focus phase III of the field
investigation, which was to evaluate PCP contamination in the A-zone
groundwater. All groundwater samples except one were collected using low-
flow sampling techniques.
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SCAPS LIF and CPT- A total of 75 SCAPS pushes were completed at the site during
the 2000 NAPL field investigation. A part of the phase I objectives a number of
SCAPS locations were advanced around the Old Mormon Slough to determine
the extent of NAPL contamination beneath the slough and determine if the NAPL
contamination had migrated north of the slough. As part of the phase II
objectives of evaluating the extent of the NAPL contamination in the southern
and eastern portions, a number of SCAPS pushes were advanced in soils outside
the southeast corner of the McCormick and Baxter property in the Union Pacific
Railroad property. Finally, in accordance with phase III objectives, SCAPS
pushes were advanced around the PCP mixing shed to evaluate the extent of TPH
contamination in the area. Continuous measurements from the LIF and CPT
sensors were recorded for all the SCAPS push locations to provide stratiographic
information and an indication of the relative concentrations of TPH
contamination. Maximum depth of the 75 SCAPS pushes ranged from 13.6 to
144.2 feet bgs with an average push depth of 65.9 feet bgs. Initial SCAPS push
locations were determined based on data gaps identified from the 1999 NAPL
field investigation while the remaining locations were determined in the field
based on the following:
• SCAPS LIF borings were spaced to provide area-wide information on NAPL
occurrence and stratigraphy and further define the area of interest for potential in-
situ thermal treatment technologies.
• Areas of the highest TPH contamination and multiple fuel types were further
defined to evaluate if more than one type of contaminant might require treatment.
• The depth of TPH contamination above the LIF sensor threshold was defined.
• Data was also collected to fill in data gaps identified after the 1999 NAPL field
investigation to further refine the CSM.
• SCAPS pushes were also used to optimize the rotosonic soil boring locations and
the installation locations of monitoring wells and microwells.
SCAPS Soil Sampling - Similar to the 1999 SCAPS soil sampling, SCAPS soil
samples were collected to provide LIF sensor calibration and verification for
different soil types, emission spectra, and emission intensities within the SCAPS
depth limitations. These soil samples were also collected to verify anomalous
LIF responses and confirm the true depth of TPH, PAHs, and PCP, as well as to
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determine SVOC and trace metal contamination in dredge spoils located on the
Dutra Group property north of the facility. Other objectives of the SCAPS soil
sampling included: determining the LNAPL and PCP contamination in the A-
zone areas not contaminated with creosote NAPL, identifying PCP and LNAPL
contamination in subsurface soils around the PCP mixing shed, determining if a
subsurface confining structure is present, and finding the extent of PCP
contamination in the vadose zone around the Cellon Process area (Figure 1-2).
Again, consistent with the 1999 investigation, SCAPS soil sampling pushes were
offset from the original SCAPS LIF/CPT push locations by 1 to 2 feet to obtain
representative samples. The SCAPS 1.5 inch diameter sampling rods with a
hollow core were advanced to the desired sampling depth where a 2-foot core of
sample was collected. The core was then placed on a table in the field where a
visual soil classification was conducted and samples were collected for PCP/PAH
and VOC analyses.
Rotosonic Drilling, Soil Sampling, and Monitoring Well Installation- A total of 6
borings were logged and sampled using the rotosonic drilling rig and an
additional two groundwater monitoring wells were constructed during these field
activities. The two objectives of the rotosonic drilling program were to determine
the nature and extent of the contamination and evaluate geology in the E-zone
north of the Old Mormon Slough at depths beyond the SCAPS capabilities, as
well as in the E-zone southeast of the property on the Union Pacific Railroad
property at depths beyond the SCAPS capabilities. Four of the six rotosonic
drilling locations were adjacent to SCAPS sampling locations and the
information provided was used to confirm the SCAPS LIF data and provide data
for depths deeper than the SCAPS could penetrate. The other two locations were
used for monitoring well installations where the screen depths were located in the
E-zone groundwater.
SCAPS Micro well installations- A total of 15 micro wells were installed as part of the
2000 NAPL field investigations. The microwells were 1-inch diameter wells
with hydrophobic screens and were screened in the water table (approximately 16
feet bgs). The wells were collocated with a SCAPS LIF/CPT push locations and
were installed on the Union Pacific Railroad property east and southeast of
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suspected source areas, near the PCP mixing shed, south of the main processing
area, and south of the oily waste ponds to provide additional groundwater
monitoring in the A-zone.
Due to the application of dynamic field activities during the 2000 NAPL field investigation, a
number of changes to the original management plan were completed in order to obtain more
accurate and useful data and limit the number of field mobilizations necessary to achieve the
investigation objectives. The most obvious application of the dynamic work plan was the ability
of the field crew and project manager to review data as it was produced at the site and then use
that knowledge to determine appropriate future sampling locations. Additionally, the flexibility
offered from this approach allowed the following to be accomplished:
• The field activities were completed 30 days prior to the scheduled completion
date.
• A maximum of 45 SCAPS LIF/CPT and 18 SCAPS soil sampling locations were
planned on the Dutra Group and Stockton Cold Storage properties in the event
that NAPL was detected in the initial SCAPS or rotosonic boring locations.
Since it was determined that NAPL was not migrating north of the Old Mormon
Slough only 14 SCAPS LIF/CPT pushes were conducted and 13 SCAPS samples
were collected.
• A total of 18 SCAPS locations were planned in the Old Mormon Slough and a
total of 24 were investigated.
• A total of 20 SCAPS locations were planned on the Union Pacific Railroad
property and a total of 24 were completed.
• No SCAPS pushes were originally planned in the vicinity of the PCP mixing
shed, however discussion with former McCormick and Baxter personnel revealed
the use of medium weight petroleum hydrocarbons in this area. Based on this
information, 9 SCAPS LIF pushes were completed in the area to focus the
SCAPS soil sampling locations and determine if the PCP mixing shed was the
source of nearby TPH.
• A number of other SCAPS soil sampling locations originally planned were not
necessary because NAPL contamination was not found closer to the site.
• Although 11 microwells were planned, 16 were actually installed due to
decreased installation times.
26
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5.0 INTERPRETATION OF DATA AND DEVELOPMENT OF THE FINAL
CONCEPTUAL SITE MODEL
Based on the information collected during the 1999 and 2000 NAPL field investigations a number
of changes were made to the geologic and hydrogeologic CSM as well as to the NAPL
distribution CSM. Interpretation of data from these investigations is provided in the following
sections
5.1 EVALUATION OF SCAPS SOIL SAMPLING AND LIF RESULTS
The determination of the presence or absence of NAPL at the McCormick and Baxter site was
evaluated using the following criteria:
• LIF counts greater than 500 were considered indicative of the presence of NAPL
• LIF counts less than 300 were considered indicative of the absence of NAPL
• LIF counts between 300 and 500 were considered questionable but were evaluated and
may have been considered an indication of the presence of NAPL when used in
conjunction with other lines of evidence (i.e. mobile product or a visable sheen found
during the core inspection, or significant positive results from the TPH-Dx analysis)
Spectral profiles associated with creosote NAPL, the most abundant NAPL present and the main
risk driver at the McCormick and Baxter site due to the presence of PAH and pentachlorophenol
(PCP) components, were evaluated to define areas where NAPL was believed to be present. The
profiles generally showed the following:
• Site-wide, soil samples where confirmed visual observation of creosote NAPL was found
had corresponding LIF results associated with peak wavelengths of between 467 and 476
nanometers
• In the main processing area, soil samples where confirmed visual observation of creosote
NAPL was found had corresponding LIF results associated with peak wavelengths of
between 480 and 499 nanometers
Soil samples collected using the SCAPS were used to visually inspect cores and the presence of
creosote and other NAPLs at the McCormick and Baxter site were evaluated using the following
criteria:
• NAPL presence was reported as odor (sample had a strong creosote or diesel smell)
• NAPL presence was reported as visible (sample had a visible NAPL sheen)
27
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• NAPL presence was reported as mobile (mobile NAPL could be poured off of the
sample)
Finally, soil sample visual inspections, LIF data, and CPT results from nearby SCAPS pushes
were used in conjunction to evaluate down gradient locations where creosote NAPL may have
been present due to up gradient sources and preferential pathways for mobile NAPL.
5.2 SITE GEOLOGY
Given the density of CPT data collected during the 1999 and 2000 investigations, the relative
horizontal and vertical continuity of sand units beneath the site to approximately 110 feet bgs
were evaluated. For intervals deeper than 110 feet bgs the lithologic data available are relatively
sparse. The distribution of sand and silt within 5 foot thick slices are available in Figures 5-1
through 5-40, where Figures 5-1 through 5-20 represent the compilation of CPT data from
SCAPS push locations and Figures 5-21 through 5-40 were prepared the same however data from
rotosonic borings and monitoring well installations were used to supplement data below 110 feet
bgs.
A detailed geologic CSM has been developed by evaluating subsurface geology data collected at
depths ranging from the ground surface to approximately 200 feet bgs. The refinement of the
geologic CSM has been achieved through the compilation of data from numerous SCAPS CPT
pushes and rotosonic borings. The data have been compiled and visual representations of the
subsurface geology at the McCormick and Baxter site are available through numerous cross
sectional maps. Plate 1 provides a representation of the locations and orientation of 10 cross
sections spanning the site. Six of the cross sections (Plates 3 through 8) are orientated as
east/west cross sections extending from the north site boundary to the south site boundary. Four
additional cross sections (Plates 9 through 12) are orientated as north/south cross sections
extending from eastern to western portions of the McCormick and Baxter site. Each plate
represents a slice through the property either in the north to south or the east to west direction and
provides information on soil types, fill materials, areas where NAPL is believed to be present,
monitoring wells screen locations, soil cores exhibiting a sheen or the presence of NAPL, and
areas where the detailed lithology is somewhat uncertain. The cross sections also provide
approximate depths to water from previous water monitoring events. This information can be
used to further refine the hydrogeologic CSM discussed in Section 5.2.
28
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5.3 SITE HYDROGEOLOGY
The upper 200 feet of sediments beneath the site are now collectively referred to as the shallow
aquifer with groundwater occurring primarily in laterally continuous layers of fine to course
grained sand. Sediments from 200 feet bgs to at least 1,000 feet bgs have been termed the deep
aquifer. Previous investigations at the McCormick and Baxter site had divided the subsurface
into 5 hydrogeological sand zones designated A, B, C, D, and E with thick clay sequences
separating the zones. The problem with this strategy was that the well screens within a particular
zone were not always consistent across the site resulting in different A, B, C, D and E zones in
various locations at the site. Further refinement of the hydrogeologic CSM determined that
aquifer zone designations applied only to local areas where the silts are laterally continuous and
not intersected by vertical sand channels. As a result of these findings the A through E flow
zones are now believed to behave as a single contiguous aquifer system with substantial
communication between adjacent zones.
The groundwater flow at the site is southeastward in the A-zone and turns east/northeast in the
successfully deeper zones (B-E). The east/northeast E-zone flow is consistent with historical
regional groundwater flow data that show a large cone of depression from groundwater pumping
centered beneath the town of Stockton located north east of the site. Calculated vertical
groundwater velocities are 3 to 4 orders of magnitude less than the calculated horizontal
groundwater velocities, resulting in the majority of groundwater flow and contaminant transport
taking place horizontally within sand zones.
The Old Mormon Slough appears to have very poor communication with the upper aquifer due to
four lines of evidence. First, groundwater elevations in the previously designated A-zone have
historically fluctuated by more than 10 feet, however little difference can be seen between A-zone
wells next to the Old Mormon Slough and A-wells much further away from the slough.
Secondly, while tidal influences of 4 feet have been measured in the slough, little corresponding
fluctuations in A-zone wells next to the slough have been measured. Third, the A-zone
groundwater gradient does not deflect or alter near the Old Mormon Slough. Finally, the bottom
of the slough is blanketed with fine grain sediments having very low permeability and these
sediments are generally in contact with low permeability clayey silt rather than the higher
permeability sands. Given this information it is believed that the Old Mormon Slough has little
or no influence on the A-zone of the shallow aquifer.
29
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5.4 SITE CONTAMINATION
Identification and locations of the various types of TPH contamination found at the McCormick
and Baxter site were identified as factors that would have to be considered for the conceptual
design of an in-situ thermal treatment system. In order to determine the types of TPH at the site,
chromatograms from TPH-Dx analyses from the EPA FASP and Region 9 laboratory were
reviewed and compared to two different analytical standards. The first was the Florida TRPH
standard, which consisted of a mixture of even numbered alkanes from C6 to C40, and the second
was the XHc diesel fuel number 2 composite standard. By pattern matching or "fingerprinting"
the chromatographs of TPH results from field samples to the standards run in the laboratories, the
field team was able to identify 5 distinct fuel types (A through E) during the 1999 investigation
and 1 additional fuel type (F) from the 2000 investigation. A discussion of the 5 fuel types is
provided below.
Product Type A- This fuel pattern was only detected at one location during the 1999
investigation and one location during the 2000 investigation but was observed in all
samples collected from these locations with positive TPH-Dx results. The fuel pattern
did not match that of diesel or creosote and could not be identified. In addition, PAHs
and PCP were not detected in these samples.
Product Type B- This fuel pattern was detected at one location sampled in 1999 and two
locations sampled in 2000. The fuel pattern did not match that of diesel or creosote and
could not be identified. PCP, low concentrations of PAHs (relative to the detected TPH),
and low concentrations of diisoprpyl ether were also detected in samples from these
locations. Based on a review of PCP and PAH results it is thought that this product might
be a carrier for PCP.
Product Type C and D- These fuel patterns were observed in numerous samples
collected at the site during the 1999 and 2000 events and were almost identical except for
a single peak found near C-10 in the type D chromatogram not found in the type C
fingerprint. Both fuel types contain numerous PAH compounds, including naphthalene,
and closely resemble the creosote standard analyzed with the 1999 soil samples. PCP
and diisopropyl ether were also detected in a number of these samples, however not
necessarily in the same samples.
30
-------
Product Type E- This fuel pattern was only detected at one location from the 1999 event
and was not detected during the 2000 event. The fuel pattern did not match that of diesel
or creosote and could not be identified. In addition, PAHs and PCP were not detected at
this location.
Product Type F- This pattern was only detected in the top two samples from one location
during the 2000 event. The pattern did not resemble a petroleum product and associated
samples contained extremely high concentrations of PCP and diisopropyl ether.
The CSM for site contamination involving NAPL has been further refined using SCAPS LIF data
as well as analytical data from the EPA FASP and Region 9 laboratories. Plate 2 provides a
visual representation of all sampling locations from the 2000 NAPL investigation and specifies
locations and depths where VOCs and PCP were detected. The plate includes data collected from
groundwater monitoring well sampling points as well as SCAPS LIF pushes, SCAPS soil
sampling locations, and rotosonic borings.
The CSM for site contamination also provides a visual representation of the site-wide distribution
of NAPL by using 5-foot thick slices of the McCormick and Baxter site subsurface. This
representation can be seen in Figures 5-1 through 5-40, where Figures 5-1 through 5-20
represent the compilation of LIF data from SCAPS push locations and Figures 5-21 through 5-40
were prepared the same however data from rotosonic borings and monitoring well installations
were used to supplement data below 110 feet bgs.
Similar to the discussion of site geology in Section 5.1, Plate 1 and Plates 3 through 12 provide
cross sectional representations of the site and indicate locations where NAPL contamination has
been observed or is likely, given the available data. The CSM for site contamination was refined
through the compilation of data from numerous SCAPS LIF pushes, monitoring well data, and
rotosonic borings. A review of Plates 6, 7, 10, and 11 provide a good picture of where much of
the NAPL contamination at the site is located. These 4 plates and the remaining 6 plates also
provide detailed information on the subsurface geology and can be used to begin developing
contaminant fate and transport models as well as site remedial strategies.
Based on the scope of the 1999 NAPL investigation 9 data gaps were identified that needed to be
addressed during the 2000 NAPL investigation in order to sufficiently characterize the site for
31
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determination of a final groundwater remedy. The data gaps included: determining if NAPL
contamination had migrated south, north, and east of the McCormick and Baxter site boundary,
further evaluating near surface contamination sources and a subsurface obstruction identified
during the 1999 event, further investigating PCP contamination in the Cellon process area, and
evaluating the extent of PCP and dioxin contamination in the A-zone aquifer.
6.0 CONCEPTUAL DESIGN DESICISIONS BASED ON 1999 AND 2000 NAPL
FIELD INVESTIGATIONS
Following the completion of the 2000 investigation no new data gaps were identified and the pre-
design characterization data collected during the 1999 and 2000 NAPL field investigations was
considered sufficient to complete the evaluation of the in-situ thermal treatment technologies.
The final conceptual design for the thermal treatment technology was submitted to EPA in
November of 2001 (USACE 2001). The document provides a 10 percent conceptual design for in
situ thermal remediation of NAPL at the site including fundamental engineering design and cost
issues associated with the installation, operation, maintenance, and post-operational stages of a
combined steam injection and electrical heating remediation strategy.
These technologies are aggressively used to remediate both the heavier creosote DNAPL
components and the lighter LNAPLs such as diesel, and the approach is considered a viable
option for the treatment of both NAPLs present in the subsurface at the site. The combined steam
injection and electrical heating approach focuses on the remediation of the creosote DNAPL
because it is found at greater depths and is more widespread than LNAPLs at the site. Although
the depth and location of creosote DNAPL will dictate the engineering of the remedial design, it
is assumed that additional NAPLs within the treatment areas will be remediated using this
approach.
EPA separated the remedial action objectives (RAOs) for the treatment of the creosote
contamination into two distinct actions as the site; the remediation of creosote existing as NAPL
and the remediation of dissolved phase groundwater contamination. RAOs addressed in the
thermal treatment conceptual design (USACE 2001) are meant to address the contaminants on
site that exist as NAPL. Relevant RAOs for the treatment of contamination existing as NAPL
include:
32
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1) Remove NAPL to the maximum extent technically feasible to protect the
E-zone water aquifer (drinking water aquifer)
2) Reduce the need for long term pump and treat by remediation of the
source materials responsible for the dissolved phase contaminants in
groundwater
Three scenarios for well field design are included in the conceptual design with the coverage and
number of injection and extraction wells increasing from scenario 1 to scenario 3. The life cycle
cost of scenario 1 (likely the least costly option) for thermal treatment has been estimated at $83.2
million. Given the enormous costs associated with the remediation of the McCormick and Baxter
site several phased approaches have also been provided as alternatives.
Due to the enormous costs associated with these remedial strategies, five criteria were selected to
prioritize areas of the McCormick and Baxter site for thermal treatment. The criteria were
developed with input from the USEPA, USACE, California EPA and DTSC, and the California
Regional Water Quality Control Board (RWQCB), as well as a number of technical advisors from
various agencies and include:
• Relative amount of NAPL present
• Proximity of NAPL to drinking water risk receptors (i.e., the E-zone aquifer)
• Certainty of the data indicating the presence of mobile NAPL
• Potential for future changes in the land use and/or subsurface conditions that might
facilitate the mobilization of currently immobile NAPL (e.g., increased pumping of
drinking water in the E-zone downgradient of the site)
• Ease of access for follow-up remediation activities
To evaluate each of these five criteria a compilation of the data obtained during the 1999 and
2000 NAPL investigations was used. The relative amount of NAPL present at various depths and
locations around the site was evaluated using a combination of the LIF data, visual inspection of
cores from the SCAPS, and results from adjacent SCAPS pushes. LIF counts and wavelengths
data were crucial in determining the presence or absence of creosote NAPL but could not be used
alone. Instead, the LIF count and wavelength data was compared with visual inspection of
SCAPS cores. For example, if a sample had an LIF count greater than 500 (indicating the
presence of NAPL) but the wavelength was outside the observed windows of 467 to 476
nanometers and 480 to 499 nanometers (indicating a non creosote NAPL) the results were further
evaluated. Visual inspections of the associated core were used to evaluate the presence of a non-
33
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creosote NAPL (and LNAPL such as diesel) or a potential naturally occurring interference such
as calcite. Additionally, results from nearby SCAPS soil samples, LIF pushes, and CPT pushes,
were used to evaluate the likelihood of finding creosote NAPL contamination. For example, if up
gradient results indicated creosote NAPL present at a specific depth, but down gradient LIF data
indicated the absence of creosote NAPL at and below that depth the results were scrutinized for
false negatives and visually inspected cores were reviewed to confirm the absence of creosote
NAPL.
To evaluate the proximity of NAPL to drinking water risk receptors LIF data, CPT results and
visual core inspections were again used. The presence of NAPL was evaluated using the
approach described in the previous paragraph. The proximity of this contamination to the E-zone
(drinking water) aquifer was determined using visual core inspections and CPT results to evaluate
preferential pathways for NAPL migration and sample depth information to estimate proximity to
the E-zone aquifer at approximately 200 feet bgs.
To determine the certainty of the data indicating the presence of mobile NAPL the visual core
inspections and LIF data were again used. The visual core inspections were the most significant
piece of data to evaluate the presence of mobile NAPL because samples were considered to
contain mobile NAPL if product could be poured off of the sample once it was retrieved at the
surface. LIF counts and wavelength data were also used to help confirm the approximate quantity
and type of NAPL the sample contained. Areas with confirmed mobile NAPL included the
central portions of the Cellon and the main processing areas. These areas are considered the
highest priority for thermal treatment due to the relative quantities and depths of mobile NAPL.
Potential for future changes in the land use and/or subsurface conditions that might facilitate the
mobilization of currently immobile NAPL were also used to prioritize areas of treatment for the 3
treatment scenarios provided in the final conceptual design. Increased pumping in the E-zone
aquifer down gradient of the McCormick and Baxter site has the potential to mobilize currently
immobile NAPL components. Therefore, southern portions of the Cellon and the main
processing areas are considered the second highest priority in the treatment scenarios. Although
these areas have relatively less contamination identified as mobile NAPL they have been
identified as areas of the site that would be impacted by down gradient pumping in the E-zone
aquifer.
34
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Finally, ease of access for follow-up remediation activities was considered when prioritizing
areas of NAPL contamination for treatment. The groundwater at the site generally flows in a
southeastern direction and sources of recharge exist to the north of the site (The Old Mormon
Slough and the Stockton deepwater channel) and to the west of the site (San Joaquin River). For
this reason, southern portions of the Cellon and the main processing areas were again considered
the second highest priority in the treatment scenarios because NAPL contamination traveling
southeast in these areas of the site would be increasing difficult to address as the contamination
moved further off site. NAPL contamination found in the oily waste pond area in the western
portion of the site and east main processing area were considered the lowest priority for thermal
treatment since the relative amount of NAPL contamination was lower and the direction of
preferential pathways for mobile NAPL did lead directly offsite.
7.0 CONCLUSIONS
The McCormick and Baxter site provides a good example of why it is difficult to adequately
characterize complex NAPL sites using traditional sampling and analytical technologies and how
the Triad Approach offers a faster and less expensive pathway to making project decisions. The
large number of data points required for adequate characterization of the NAPL at the site and
ultimately design an economically viable remediation system required the use of a non-traditional
approach. Time and costs associated with a traditional approach and the inherent difficulty in
locating NAPL in complex matrices required that a new approach be used for this site.
The McCormick and Baxter site is also a good example of how data from field based analytical
technologies can be used in conjunction with modified mobile laboratory and fixed laboratory
methods to make project decisions in near real time. Data generated with mobile laboratory and
off-site laboratory methods provided better interpretation of field based results and provided the
confirmation necessary to have confidence in the LIF and CPT interpretations. The field based
analytical methods provided the density of data points necessary to make informed decisions at
the site.
The modified methods used for the investigation also provide insight into the performance based
measurement system (PBMS) that allows methods to be tailored to meet the specific needs of a
project. Traditional analytical methods were modified to allow for quick turn around and
subsequent use of real time data to make project decisions in the field. The data generated from
35
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the modified methods still provided the quality control and quality assurance measures necessary
to use the data for it's intended purpose but also allowed for the rapid data generation necessary
to keep the investigation moving. The PBMS approach also promotes determining the
applicability of methods for the unique matrices present in real time so that the usability of data is
evaluated as the project is progressing and not after the field mobilization has been completed.
The ultimate goal of developing a detailed CSM is to provide the decision makers with
information necessary to make informed project decisions. In the case of the McCormick and
Baxter site, development of a clean-up strategy has been difficult given our understanding of the
site contaminant distribution, contaminant fate and transport, and the subsurface geology. The
sheer size of the contaminant plumes, the number of contaminants of concern, the media
involved, and the enormous costs associated with remedial strategies present project managers
with difficult decisions. Fortunately, information obtained from 1999 and 2000 NAPL
investigations in conjunction with data from numerous other investigations will provide project
staff with the technical details necessary to understanding the sites unique challenges. Continued
refinement of the geologic, hydrogeologic, and contamination CSMs for the McCormick and
Baxter site will provide the basis for future project decisions.
The time and money saved using a dynamic approach to the field activities conducted in 1999 and
2000 has resulted in project cost savings and accelerated completion of the RI/FS component for
DNAPL contamination at the site. In addition, much of the data collected during the dynamic
field activities has provided crucial information for RD/RA activities including developing costs
and engineering specifications for the proposed thermal treatment designs.
36
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TABLE 1-1
MOBILE FIELD LABORATORY METHOD SUMMARY—SOIL
Aii;iI\U'
Method
UcTc.tcir'c.'
I'ri'MTMiliim
Mi-IIiimI
r.\lr;iiiiim
Method
( k';mu|)
Method
1 list rn incut
IK'U'lMor
Tl'l 1 In 1 ¦'luoiVM.vikv
AS IM D Ms"
(SCAPS SOP)
Y\
Y\
Y\
I' Iiioivm-vikv ik'tocliir
(photodiode array with
optical multichannel
analyzer)
TRPH
SCAPS SOP
Refrigeration
Sonication in Freon
Silica gel
Buck 404 Infrared
Sp ectrophotometer
TPH-Dx
Region 9 SOP -
Modified
Refrigeration
Vortex in hexane
NA
GC/FID
TABLE 1-2
MOBILE FIELD LABORATORY METHOD SUMMARY—GROUNDWATER
McIIkmI
I'lTMTMllioil
l''.\lr;iclioii
( k';iiui|)
I IIS( I'll ItlCIII
AiisiMc
KiTi'micc
Method
Method
Method
Detector
TPH-Dx
Region 9 SOP -
Refrigeration
Vortex in hexane
NA
GC/FID
Modified
37
-------
TABLE 1-3
FIXED LABORATORY METHOD SUMMARY—SOIL
Mi'lliixl
I'ri'MTMiliim
I'All'ilClioil
( k'niiiip
I IISl I'll IHCIll
Aii;iI\U'
U c It-mice
Method
Method
Method
Deteetor
TPlI-Dx
Region 9 SUP
4_: c
1'1'L
NA
GC.1TD
PAHs and PCP (rapid and
Region 9 SOP -
4 + 2 °C
PFE
GPC
GC/MS
standard TAT)
Modified
Dioxin/Furans
SW-846 1613B
4 + 2 °C
Soxhlet
See analytical request
form (Appendix D)
High-resolution GC/MS
PCBs
CLP SOW -
Modified
4 + 2 °C
PFE
Sulfuric acid/
permanganate, florisil
GC/ECD
Metals (As, Cu, Cr, Zn)
CLP RAS
None
Acid digestion
None
ICP/GFAA
Metals Speciation
Kerr Lab SOP
None
NA
NA
NA
TOC
Walkley-Black
4 + 2 °C
Dean-Stark
None
Titration with Fe SO4
Grain Size
ASTM D 422
None
NA
NA
NA
Density
ASTM D2937
None
NA
NA
NA
Porosity
API RP40
None
Toluene
None
NA
Permeability (Hydraulic
Conductivity)
Kerr Lab SOP
None
NA
NA
Constant-temperature
incubator with diaphragm
metering pump, fraction
collector, and Omega PX800
pressure transducers
NAPL Saturation (Oil and Grease)
PTS SOP
4 + 2 °C
PTS SOP
NA
Analytical balance
Cation Exchange Capacity
SW-846 9081
None
Sodium acetate
NA
Atomic absorption
Notes:
GFAA - graphite furnace atomic absorption
ICP - inductively coupled plasma - atomic emission spectroscopy
NA - not applicable
PFE - pressurized fluid extraction
TAT - turn-around time
38
-------
TABLE 1-4
FIXED LABORATORY METHOD SUMMARY—NAPL
Mi'lliixl
l'reser\;i(ion
I'Alrnclitm
( k'niiiip
I IISl I'll IHCIll
Aii;iI\U'
KiTi'mid'
Method
Method
Method
Deteetor
Tl'll-Dx
S\\-s40 suif
Modified
Refrigeration
NA
NA
GL.l-'lD
SVOC TAL with TICs
SW-846 8270C
Refrigeration
NA
NA
GC/MS
Viscosity
Kerr Lab SOP
(ASTM D1296)
Refrigeration
NA
NA
Brookfield Rotational
Voscometer Model DV-1
Density
Kerr Lab SOP
Refrigeration
NA
NA
Balance
Solubility
Kerr Lab SOP
Refrigeration
Methylene chloride
NA
GC/MS
Wettability
Kerr Lab SOP
Refrigeration
NA
NA
Visual inspection
Boiling point
distribution/distillation
Kerr Lab SOP
Refrigeration
NA
NA
Thermometer
(ASTM D86)
Oil-Water Interfacial Tension
Kerr Lab SOP
(ASTM D971)
Refrigeration
NA
NA
Fisher Surface Tensiometer
Model 20
Notes:
GC/FID - gas chromatograph/flame ionization detector
GC/MS - gas chromatograph/mass spectrophotometer
GPC - gel permeation chromatography
NA - not applicable
35
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TABLE 2-1
PROJECT LABORATORIES
Methods
M;ilri\
Address And (
S( AI'S Te;im
TRIM 1 In 1'Iiioivn.vmi.v
Soil
IM5 S. inisi 1 . Aw.
TRPH by 418.1
Soil
Tulsa, OK 74128
Geotech/Stratigraphy
Soil
Contact: Eddie Mattioda
Phone: (918)669-7445
EPA Region 9 FASP
TPH-Dx
Soil, GW
Contact: Jeff Mays (Lockheed Martin); Liza Finley (EPA)
EPA Region 9
TPH-Dx
Soil
1337 S. 46th Street, Building 201
Laboratory
SVOCs
Soil, GW
Richmond, CA 94804-4698
PCBs
Soil
Contact: Nancy Wilson
Metals
Soil
Phone: (510)412-2377
Total and Dissolved Manganese
GW
Backup Contact: Rich Bauer
Sulfate
GW
Phone: (510)412-2312
Chloride
GW
Reception: (510) 412-2300
Nitrate
GW
Nitrite
GW
TOC
GW
Pacific Analytical
Dioxin/Furans
Soil, GW
6349 Paseo del Lago
Laboratories
Carlsbad, CA 92009
Contact: Steven Parsons
Phone: (760)931-1766
Fax: (760)931-9479
EPA Robert S. Ken-
Density
NAPL, GW
919 Kerr Research Drive
Environmental
Viscosity
NAPL
Ada, OK 74820
Research Laboratory
Solubility
NAPL
Contact: Eva Davis
(Kerr Lab)
Oil-water Interfacial Tension
NAPL
Phone: (580)436-8548
Wettability
TPH-Dx
NAPL
SVOCs
NAPL
Permeability
NAPL
Metals Speciation
Soil
Treatability Testing
Soil
Soil
36
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TABLE 2-1 (Continued)
PROJECT LABORATORIES
Mi-Hinds
M:i( riv
Address And (
Columbia Analytical
TPH-Dx
NAPL
1317 S. 13th Ave., P.O. Box 479
Services
SVOCs
NAPL
Kelso, WA 98626
Contact: Diane Wiegle
Phone: (360)577-7222
Fax: (360)636-1068
PTS Laboratories, Inc.
Boiling Point Distribution
NAPL
8100 Secura Way
Grain Size
Soil
Santa Fe Springs, CA 90670
Porosity
Soil
Contact: Richard Young
Cation Exchange Capacity
Soil
Phone: (562)907-3607
Density
Soil
Fax: (562) 907-3610
NAPL Saturation
Soil
TOC
Soil
37
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TABLE 2-2
FIXED LABORATORY METHOD SUMMARY—SOIL
McMi.mI
I'ri'M'i'Miliim
I'Almi'liim
( k';mu|)
liislriimi'iil:
Aii;iI\U'
K c It' r c net-
Mi-IIiimI
Method
McIIiimI
Di'lt'i'lnr
TPH-Dx
Region 9 SOP
4 + 2 °C
PFE
NA
GC/FID
PAHs and PCP (rapid and
Region 9 SOP -
4 + 2 °C
PFE
GPC
GC/MS
standard TAT)
Modified
Dioxin/Furans
SW-846 1613B
4 + 2 °C
Soxhlet
See analytical request
form (Appendix D)
High-resolution GC/MS
PCBs
CLP SOW -
Modified
4 + 2 °C
PFE
Sulfuric acid/
permanganate, florisil
GC/ECD
Metals (As, Cu, Cr, Zn)
CLP RAS
None
Acid digestion
None
ICP/GFAA
Metals Speciation
Kerr Lab SOP
None
NA
NA
NA
TOC
Walkley-Black
4 + 2 °C
Dean-Stark
None
Titration with Fe SO4
Grain Size
ASTM D 422
None
NA
NA
NA
Density
ASTM D2937
None
NA
NA
NA
Porosity
API RP40
None
Toluene
None
NA
Permeability (Hydraulic
Conductivity)
Kerr Lab SOP
None
NA
NA
Constant-temperature
incubator with diaphragm
metering pump, fraction
collector, and Omega PX800
pressure transducers
NAPL Saturation (Oil and Grease)
PTS SOP
4 + 2 °C
PTS SOP
NA
Analytical balance
Cation Exchange Capacity
SW-846 9081
None
Sodium acetate
NA
Atomic absorption
Notes:
GFAA - graphite furnace atomic absorption
ICP - inductively coupled plasma - atomic emission spectroscopy
NA - not applicable
PFE - pressurized fluid extraction
TAT - turn-around time
38
-------
TABLE 2.3
FIXED LABORATORY METHOD SUMMARY—NAPL
\k-llllMl
I'ri'M'i'Miliim
I'Almcliim
( k'niiup
liislriimi'iil:
Aii;iI\U'
U C It-mice
Method
Mi-IIiimI
Mi-IIiimI
IK'K'iMor
TPH-Dx
SW-846 8015
Modified
Refrigeration
NA
NA
GC/FID
SVOC TAL with TICs
SW-846 8270C
Refrigeration
NA
NA
GC/MS
Viscosity
Kerr Lab SOP
(ASTM D1296)
Refrigeration
NA
NA
Brookfield Rotational
Voscometer Model DV-1
Density
Kerr Lab SOP
Refrigeration
NA
NA
Balance
Solubility
Kerr Lab SOP
Refrigeration
Methylene chloride
NA
GC/MS
Wettability
Kerr Lab SOP
Refrigeration
NA
NA
Visual inspection
Boiling point
distribution/distillation
Kerr Lab SOP
Refrigeration
NA
NA
Thermometer
(ASTM D86)
Oil-Water Interfacial Tension
Kerr Lab SOP
(ASTM D971)
Refrigeration
NA
NA
Fisher Surface Tensiometer
Model 20
Notes:
GC/FID - gas chromatograph/flame ionization detector
GC/MS - gas chromatograph/mass spectrophotometer
GPC - gel permeation chromatography
NA - not applicable
39
-------
TABLE 2.4
FIXED LABORATORY METHOD SUMMARY—GROUNDWATER
Aii;iI\U'
Mi'lliixl
U c It-mice
I'ri'MTMiliim
Method
I'All'ilClioil
Method
( k'niiiip
Method
I IISl I'll IHCIll
Deteetor
I'AI Is mill l'( 1' ij;ipiJ TAT;
SW -S4f' s2"U(
4_: (
( oniinuous liquid liquid
(IP(
(i( MS
SVOC TAL (standard TAT)
SW-846 8270C
4 + 2 °C
Continuous liquid/liquid
GPC
GC/MS
Dioxin/Furans
SW-846 1613B
4 + 2 °C
Sep funnel
See analytical request
form (Appendix D)
High Resolution GC/MS
TOC
EPA 415.1
4 + 2 °C
NA
NA
Dohrman Total Organic
Carbon Analyzer DC-190
Density
Kerr Lab SOP
4 + 2 °C
NA
NA
Balance
Total and Dissolved Manganese
EPA 200.7
Nitric acid to
< pH2, 4 ± 2 °C
Acid digestion
None
ICP-AES
Sulfate, Chloride, Nitrate, Nitrite
EPA 300 series
4 + 2 °C
None
None
Dionex Ion Chromatograph/
DX120
Notes:
GC/FID - gas chromatograph/flame ionization detector
GC/MS - gas chromatograph/mass spectrophotometer
GPC - gel permeation chromatography
ICP-AES - inductively coupled plasma - atomic emission spectrometry
NA - not applicable
TAT - turn-around time
40
-------
-------
-------
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes:
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
0 to -5 Feet Elevation
STOCKTON
Figure 5-1
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-10 to -15 Feet Elevation
STOCKTON
Figure 5-3
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-15 to -20 Feet Elevation
STOCKTON
Figure 5-4
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-30 to -35 Feet Elevation
STOCKTON
Figure 5-7
CALIFORNIA
-------
2,170,000
2,169,800
2,169,600
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-35 to -40 Feet Elevation
STOCKTON
Figure 5-8
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-40 to -45 Feet Elevation
STOCKTON
Figure 5-9
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-45 to -50 Feet Elevation
STOCKTON
Figure 5-10
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-50 to -55 Feet Elevation
STOCKTON
Figure 5-11
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-55 to -60 Feet Elevation
STOCKTON
Figure 5-12
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-60 to -65 Feet Elevation
STOCKTON
Figure 5-13
CALIFORNIA
-------
2,170,000
2,169,800
2,169,600
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-70 to -75 Feet Elevation
STOCKTON
Figure 5-15
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-95 to -100 Feet Elevation
STOCKTON
Figure 5-20
CALIFORNIA
-------
2,170,000
2,169,800
2,169,600
2,169,400
2,169,200-\ \
00
00
< 2,169,000
CD
,
-------
2,170,000
2,169,800
oo
00
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-105 to -110 Feet Elevation
STOCKTON
Figure 5-22
CALIFORNIA
-------
2,170,000
2,169,800
oo
00
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,600
CO
CO
< 2,169,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-115 to -120 Feet Elevation
STOCKTON
Figure 5-24
CALIFORNIA
-------
2,170,000
2,169,800
oo
00
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-120 to -125 Feet Elevation
STOCKTON
Figure 5-25
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-125 to -130 Feet Elevation
STOCKTON
Figure 5-26
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,600
2,169,400
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-150 to -155 Feet Elevation
STOCKTON
Figure 5-31
CALIFORNIA
-------
2,170,000
2,169,800
2,169,600
2,169,400
2,169,200
CO
CO
< 2,169,000
2,168,400
2,168,200
2,168,000
2,167,800
6,327,000 6,327,400
6,327,800
6,328,200
6,328,600
6,329,000
6,329,400
6,329,800
6,330,200
O
LEGEND
Sand and gravel
Clay and silt
NAPL potentially present
Monitoring well wholly or partially
screened in this elevation interval
Data points used in this analysis
Limits of confidence in stratigraphic
interpolation
Easting (feet NAD88)
Notes: a v '
1. A simplifying assumption was made that, for each 5 foot horizontal slice, a total of one foot of
sand represented a potentially significant pathway. Thus, areas on the map identified as sand
and gravel have a minimum of one foot of sand or gravel in that 5 foot horizontal slice.
2. Contouring accomplished using the minimum curvature method in Surfer v. 7.
3. Cross-hatched regions are horizontal slices through a volume of space bounded by the top
of NAPL and base of NAPL surfaces. NAPL is known to exist somewhere, but not necessarily
everywhere, within the cross-hatched region, because NAPL is known to be present above and
below this region.
4. Data from 0 to -100 feet are limited to quantitative SCAPS results. Due to limited data below
-100 feet, all available boring logs, SCAPS data, and geophysical logs were used. The limits of
the bounding area reflect variations in quantity and quality of data.
U.S. ARMY CORPS OF ENGINEERS
SEATTLE DISTRICT
McCormick and Baxter
Superfund Site
FYOO NAPL Investigation
Simplified Conceptual Geology
5 Foot Thick Horizontal Slice
-155 to -160 Feet Elevation
STOCKTON
Figure 5-32
CALIFORNIA
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
2,170,000
2,169,800
2,169,200
CO
CO
< 2,169,000
CD
,
-------
-------
LEGEND
o
©
u
nd
PCP
VOCs
1,1,2,2-TCA
XYLENES
-------
-------
-------
-------
-------
-------
-------
«as
mm
i •. . .guns.*
.MB*
mm*
eza mm&~
-------
-------
-------
-------
HEVI5IW5
OMCMIWM
PRODUCT TYPE A
PRODUCT TYPE 0
ffl
PRODUCT TYPE E
PRODUCT TYPE C
ll J
fi 3 » «:
;»?*» n »» »1 sin
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PROOUCT TYPE F
~
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~
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4«»
LEGEND
PRODUCT TYPE A
PROOUCT TYPE B
PROOUCT TYPE C
PROOUCT TYPE D
PROOUCT TYPE E
PROOUCT TYPE F
NOT DETECTED
.V
r
m. S
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a
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E3
s
J
E3
m--
t. •». »-
B El
r
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0
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m
I" > IOV -----
U.S. ARMY ENGINEER DISTRICT, SEATTLE
CORPS OF ENGINEERS
SCATHE. WASMNGTOM
MC CORMICX 4 BAXTER SUPERFUWD SITE
SITE MAP WITH PRODUCT TYPES
OATt A«l JiME *tOTTES>i K-UM-30dt iBllS
OfS(C.n rat. u»ae»i{|niMMt!i»c«ctv»MeC0<-m!e> * 0o-»<»^«mct>ji«mct'«c«Of.i3
------- |