EPA/540/R-05/007
July 2004
Field Evaluation of TerraTherm
In Situ Thermal Destruction (ISTD)
Treatment of
Hexachlorocyclopentadiene
Innovative Technology Evaluation Report
National Risk Management Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
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NOTICE
The information in this document has been funded by the U.S. Environmental Protection Agency (EPA)
under Contract No. 68-C-00-181 to Tetra Tech EM Inc. It has been subjected to the Agency's peer and
administrative reviews and has been approved for publication as an EPA document. Mention of trade names
or commercial products does not constitute an endorsement or recommendation for use.
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FOREWORD
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's land,
air, and water resources. Under a mandate of national environmental laws, the Agency strives to formulate
and implement actions leading to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, EPA's research program is providing data and
technical support for solving environmental problemstoday and building a science knowledge base necessary
to manage our ecological resources wisely, understand how pollutants affect our health, and prevent or
reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for investigation of
technological and management approaches for preventing and reducing risks from pollution that threaten
human health and the environment. The focus of the Laboratory's research program is on methods and their
cost-effectiveness for prevention and control of pollution to air, land, water, and subsurface resources;
protection of water quality in public water systems; remediation of contaminated sites, sediments and ground
water; prevention and control of indoor air pollution; and restoration of ecosystems. NRMRL collaborates
with both public and private sector partners to foster technologies that reduce the cost of compliance and to
anticipate emerging problems. NRMRL's research provides solutions to environmental problems by:
developing and promoting technologies that protect and improve the environment; advancing scientific and
engineering information to support regulatory and policy decisions; and providing the technical support and
information transfer to ensure implementation of environmental regulations and strategies at the national,
state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term research plan. It is
published and made available by EPA's Office of Research and Developmentto assist the user community
and to link researchers with their clients.
Sally Guitterez, Acting Director
National Risk Management Research Laboratory
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ABSTRACT
This report summarizes the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology
Evaluation (SITE) Program evaluation of the In Situ Thermal Destruction (ISTD) technology developed by
others and refined by TerraTherm, Inc. The demonstration was designed to evaluate the technology's ability
to treat soil-and-waste material contaminated with hexachlorocyclopentadiene (hex) and chlorinated
pesticides at a former disposal pit (the Hex Pit) located at the Rocky Mountain Arsenal in Commerce City,
Colorado. Operation of the system was terminated soon after initial startup and before the SITE
demonstration could be completed, due to the destruction of system components from highly corrosive vapors
and liquids.
ISTD is a soil remediation process that applies heat and vacuum simultaneously to contaminated soils, either
with surface heater blankets or with an array of vertical heater and vacuum extraction wells. The ISTD
system at the Hex Pit used an array of vertical heater and combination heater and vacuum extraction wells.
According to the developer, as the soil is heated, volatile contaminants are vaporized or destroyed by a
number of mechanisms, including the following: (1) evaporation into the vapor stream, (2) steam distillation
into the vapor stream, (3) boiling, (4) oxidation, and (5) pyrolysis (Stegemeier and Vinegar 2001). Most of
the contaminants are expected to be destroyed in the soil before the vapor stream is removed by vacuum
extraction. Contaminants that have not been destroyed in situ and remain in the vapor stream are destroyed
by an off-gas treatment system.
Evaluation of the ISTD technology as part of this SITE demonstration included extensive sampling to
characterize soil-and-waste material in the Hex Pit before construction and startup of the ISTD system. In
general, the Hex Pit contains layers or bands of virtually pure, tar-like waste material interlayered with soil
that was used to cover the waste. Due to the early termination of the treatment process, SITE's project
objectives and post-treatment sampling were modified from the original plan. For post-treatment sampling,
the revised demonstration objective was to evaluate potential contaminant destruction or removal resulting
from short-term operation of the system in the near vicinity of combination heater and vacuum extraction
wells. Sampling results were inconclusive regarding evidence of contaminant destruction or removal from
short-term operation of the system.
ISTD treatment at the Hex Pit was terminated 12 days after initial startup of the system due to the destruction
of system components, likely from higher-than-anticipated production of hydrogen chloride (HC1). In
addition, vapor-phase HC1 condensed to the more corrosive liquid form in the system piping. Corrosion
occurred in both aboveground and subsurface piping components constructed of 304 stainless steel.
Destruction of the system components appeared to result from a combination of circumstances, including (1)
the occurrence of layers of virtually pure, tar-like waste material that were not destroyed in situ; (2) the
generation of HC1 that was not adequately neutralized by in situ materials; (3) the choice of 304 stainless steel
for system components, which was insufficiently resistant to corrosion; and (4) the inability of the system to
maintain extracted vapors in the vapor phase for transport to the off-gas treatment system.
IV
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TABLE OF CONTENTS
Section Page
NOTICE ii
FOREWORD iii
ABSTRACT iv
ACRONYMS, ABBREVIATIONS, AND SYMBOLS viii
CONVERSION FACTORS x
ACKNOWLEDGMENTS xi
1.0 INTRODUCTION 1
1.1 DESCRIPTION OF THE SITE PROGRAM AND REPORTS 1
1.2 PURPOSE AND ORGANIZATION OF THE FINAL REPORT 2
1.3 DEMONSTRATION BACKGROUND 2
1.3.1 Site History 2
1.3.2 Technology Selection 4
1.4 GENERAL TECHNOLOGY DESCRIPTION 4
1.5 KEY CONTACTS 5
2.0 TECHNOLOGY APPLICATION ANALYSIS 6
2.1 PREVIOUS APPLICATIONS OF IN SITU THERMAL DESTRUCTION 6
2.2 HEX PIT SITE CHARACTERISTICS 6
2.2.1 Geologic and Hydrogeologic Settings 6
2.2.2 Previous Investigations 7
2.2.3 Summary of Hex Pit Characteristics 9
2.3 IN SITU THERMAL DESTRUCTION SYSTEM DESIGN AT THE HEX PIT 12
3.0 TREATMENT EFFECTIVENESS 18
3.1 DEMONSTRATION METHODOLOGY 18
3.1.1 SITE Demonstration Objectives 18
3.1.2 SITE Pre-treatment Sampling 19
3.1.3 SITE Post-Treatment Sampling 19
3.1.4 SITE Data Quality 24
3.2 DEMONSTRATION RESULTS 29
3.2.1 Preconstruction Evaluations 29
3.2.2 Chronology of System Operation at the Hex Pit 31
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CONTENTS (Continued)
Section Page
3.2.3 SITE Pre-treatment Sampling Results 32
3.2.4 SITE Post-Treatment Sampling Results 32
3.2.5 Comparison of SITE Pre- and Post-Treatment Sampling Results 33
4.0 TECHNOLOGY STATUS 48
4.1 DESTRUCTION OF SYSTEM COMPONENTS 48
4.1.1 Aboveground Piping Network and Insertion Heaters 48
4.1.2 Heater Cans and Well Screens 48
4.1.3 Off-Gas Treatment System 49
4.2 FAILURE ASSESSMENT 49
5.0 REFERENCES 51
Appendix
A TERRATHERM, INC. VENDOR REPORT: IN-SITU THERMAL DESTRUCTION (ISTD) AT
ROCKY MOUNTAIN ARSENAL HEX PIT
B HEX PIT REMEDIATION PROJECT: IN-SITU THERMAL DESORPTION (ISTD)
REMEDY FAILURE ASSESSMENT REPORT 2002
C DATA VALIDATION SUMMARY REPORTS
D SITE SOIL BOREHOLE LOGS
VI
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FIGURES
1-1 LOCATION OF THE HEX PIT AT ROCKY MOUNTAIN ARSENAL 3
2-1 HEX PIT BOUNDARY AND HISTORICAL SAMPLING LOCATIONS 10
2-2 HEX PIT GENERALIZED STRATIGRAPFflC COLUMN 11
2-3 IN SITU THERMAL DESTRUCTION SYSTEM WELL-FIELD LAYOUT 15
2-4 PROCESS FLOW DIAGRAM IN SITU THERMAL DESTRUCTION SYSTEM
TREATMENT SYSTEM 16
3-1 SITE PRE-TREATMENT SOIL-AND-WASTE MATERIAL SAMPLING LOCATIONS ... 22
3-2 SITE PRE-TREATMENT CONTIGUOUS SOIL SAMPLING LOCATIONS 23
3-3 SITE POST-TREATMENT LOCATIONS 26
3-4 POST-TREATMENT SAMPLING BOREHOLE-DRILLING PLAN 27
3-5 DATA COMPARISON FOR HEXACHLOROCYCLOPENTADIENE 36
3-6 DATA COMPARISON FORALDRIN 37
3-7 DATA COMPARISON FORDIELDRIN 38
3-8 DATA COMPARISON FOR TETRACHLOROETHENE 40
3-9 DATA COMPARISON FOR DIOXINS AND FURANS AS TOXICITY EQUIVALENTS . . 42
TABLES
Table Page
1-1 SUMMARY OF HEX PIT CLEAN-UP CRITERIA 4
2-1 SELECTED ANALYTICAL RESULTS FOR HEX PIT SOIL-AND-WASTE MATERIAL
SAMPLES 14
3-1 SITE PRE-TREATMENT HEX PIT SAMPLING SUMMARY 20
3-2 SITE POST-TREATMENT HEX PIT SAMPLING SUMMARY 25
3-3 SITE FIELD REPLICATE COMPARISON 30
3-4 SUMMARY OF SITE PRE- AND POST-TREATMENT ANALYTICAL RESULTS 34
3-5 SUMMARY STATISTICS FOR PRE- AND POST-TREATMENT DATA 43
3-6 WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA FOR HEXACHLOROCYCLOPENTADIENE 44
3-7 WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA FOR TETRACHLOROETHENE (PCE) 45
3-8 WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA FOR DIOXINS AND FURANS AS TEQs 46
VII
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ACRONYMS, ABBREVIATIONS, AND SYMBOLS
ฐF
%RSD
1,1-DCE
bgs
CDPHE
CMS
COC
cy
DRA
ORE
EMTEC
ENSR
EPA
FTO
FWENC
HC1
Hex
HHE
HV well
ISTD
LCS
mg/kg
M-g/kg
MK
MS/MSD
NRMRL
ORD
PARCC
PCB
PCE
Pg/kg
ppb
PRO
Degrees Fahrenheit
Percent relative standard deviation
1,1 -Dichloroethene
Below ground surface
Colorado Department of Public Health and Environment
Colorado Metallurgical Services
Contaminant of concern
Cubic yards
Dispute Resolution Agreement
Destruction and removal efficiency
Rocky Mountain Engineering and Materials Technology, Inc.
ENSR Corporation
U.S. Environmental Protection Agency
Flameless thermal oxidizer
Foster Wheeler Environmental Corporation
Hydrogen chloride (gas) or hydrochloric acid (water)
Hexachlorocyclopentadiene
Human health exceedance
Heater and vacuum extraction well
In Situ Thermal Destruction
Laboratory control sample
Milligrams per kilogram
Micrograms per kilogram
Morrison Knudson Environmental Services
Matrix spike/matrix spike duplicate
National Risk Management Research Laboratory
Office of Research and Development
Precision, accuracy, representativeness, completeness, and comparability
Polychlorinated biphenyl
Tetrachloroethene
Picograms per kilograms
Parts per billion
Preliminary remediation goal
VIM
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ACRONYMS, ABBREVIATIONS, AND SYMBOLS (Continued)
QAPP Quality Assurance Project Plan
QC Quality control
RMA Rocky Mountain Arsenal
ROD Record of Decision
RPD Relative percent difference
RVO Remediation Venture Office
SAP Sampling and analysis plan
SITE Superfund Innovative Technology Evaluation
South Plants South Plants Manufacturing Complex
SVOC Semivolatile organic compound
TCE Trichloroethene
TEQ Toxicity equivalent
TerraTherm TerraTherm, Inc.
Tetra Tech Tetra Tech EM Inc.
VOC Volatile organic compound
IX
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CONVERSION FACTORS
To Convert From
To
Multiply By
Length:
Area:
Volume:
inch
foot
mile
square foot
acre
gallon
cubic foot
centimeter
meter
kilometer
square meter
square meter
liter
cubic meter
2.54
0.305
1.61
0.0929
4,047
3.78
0.0283
Mass:
pound
kilogram
0.454
Energy:
kilowatt-hour megajoule
3.60
Power:
kilowatt horsepower
1.34
Temperature: (ฐFahrenheit -32) ฐCelsius
0.556
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ACKNOWLEDGMENTS
This report was prepared for the U.S. Environmental Protection Agency (EPA) Superfund Innovative
Technology Evaluation (SITE) program by Tetra Tech EM Inc. (Tetra Tech) under the direction and
coordination of Marta Richards at the National Risk Management Research Laboratory (NRMRL) in
Cincinnati, Ohio.
The In Situ Thermal Destruction (ISTD) technology evaluation was a cooperative effort that involved the
following personnel from EPA, the Rocky Mountain Arsenal (RMA), and TerraTherm, Inc. (TerraTherm):
Marta Richards EPA SITE Technical Project Manager
Lorri Harper RVO Project Manager
Kerry Guy EPA Region 8
Ralph Baker TerraTherm Project Manager
XI
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SECTION 1
INTRODUCTION
This section provides background information about the U.S.
Environmental Protection Agency (EPA) Superfund Innovative
Technology Evaluation (SITE) Program, and discusses the
purpose and organization of this Final Report. The technology
evaluated in this report is the In Situ Thermal Destruction
(ISTD) system developed by TerraTherm, Inc. (TerraTherm).
The evaluation site is a former hexachlorocyclopentadiene
disposal pit (the Hex Pit), located at the Rocky Mountain
Arsenal (RMA) in Commerce C ity, Colorado. This technology
evaluation has been conducted by the EPA SITE Program in
cooperation with EPA Region 8, the Colorado Department of
Public Health and Environment, and RMA's Remediation
Venture Office (RVO) (U.S. Army, Shell Oil Company, and
U.S. Fish and Wildlife Service). Key contacts for additional
information about the SITE Program, this technology, and the
demonstration site are listed at the end of this section.
1.1 DESCRIPTION OF THE SITE
PROGRAM AND REPORTS
The Superfund Amendments and Reauthorization Act of 1986
mandates that EPA select, to the maximum extent practicable,
remedial actions at Superfund sites that create permanent
solutions(as opposed to land-based disposal) for contamination
that affects human health and the environment. In response to
this mandate, the SITE Program was established by EPA's
Office of Solid Waste and Emergency Response and Office of
Research and Development (ORD). The SITE Program
promotes the development, demonstration, and use of new or
innovative technologies to clean up Superfund and other
contaminated sites across the country.
The SITE Program's primary purpose is to maximize the use
of alternatives in cleaning up hazardous waste sites by
encouraging the development and demonstration of innovative
treatment and monitoring technologies. It consists of the
Demonstration Program, the Emerging Technology Program,
the Monitoring and Measurement Technologies Program, and
the Technology Transfer Program. This evaluation of
TerraTherm's ISTD technology was completed under SITE'S
Demonstration Program.
The objective of the SITE Demonstration Program is to
develop reliable performance and cost data on innovative
treatment technologies so that potential users may assess
specific technologies. Technologies evaluated either are
currently, or will soon be, available for remediation of
Superfund sites. SITE demonstrations are conducted at
hazardous waste sites under conditions that closely simulate
full-scale remediation, thus assuring the usefulness and
reliability of information collected. Data collected are used to
assess the performance of the technology, the potential need for
pre- and post-treatment processing of wastes, potential
operating problems, and approximate costs. The
demonstrations also allow evaluation of long-term risks and
operating and maintenance costs. For this evaluation of the
ISTD technology, however, no cost information was
developed, because the ISTD system did not complete the
demonstration.
Technologiesare selected forthe SITE Demonstration Program
through annual requests for proposals. ORD staff review the
proposals, including any unsolicited proposals that may be
submitted throughoutthe year, to determine which technologies
show the most promise for use at Superfund sites.
Technologies chosen must be at the pilot- or full-scale stages
of development, must be innovative, and must have some
advantage over existing technologies. Once EPA has accepted
a proposal, cooperative agreements between EPA and the
technology developer establish responsibilities for conducting
the demonstration and evaluating the technology. The
technology developer is responsible for demonstrating the
technology at the selected site and is expected to pay any costs
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for transportation, operation, and removal of equipment. EPA
is responsible for project planning, site preparation, sampling
and analysis, quality assurance and quality control, and
preparing reports and disseminating information.
1.2 PURPOSE AND ORGANIZATION OF
THE FINAL REPORT
The Final Report (Report) provides information on
TerraTherm's ISTD technology and includes a description of
the demonstration and its results. EPA provides information
regarding the applicability of each technology to specific sites
and wastes; therefore, the Report includes information on
site-specific characteristics. Each SITE demonstration
evaluates the performance of a technology in treating a specific
waste. The waste characteristics at other sites may differ from
the characteristics of the treated waste; therefore, successful
field demonstration of a technology at one site does not
necessarily ensure that it will be applicable at other sites. Data
from the field demonstration may require extrapolation for
estimating the operating ranges in which the technology will
perform satisfactorily. Only limited conclusions can be drawn
from a single field demonstration.
TerraTherm's ISTD system did not complete the demonstration
at the Hex Pit at RMA. Operation of the ISTD system was
terminated soon after initial startup due to the destruction of
system components from highly corrosive vapors and liquids.
Consequently, this Report focuses primarily on site
characteristics unique to the Hex Pit and the ISTD system
design (Section 2.0); a description of the demonstration
methodology and results, including a chronology of activities
and events that occurred during operation of the ISTD system
(Section 3.0); and a description of the component destruction
and conditions that may have lead to the system's destruction
(Section4.0). Section 5.0 lists the references used in preparing
this Report. This report does not include cost information for
the ISTD technology, because the demonstration was stopped
during initial operation of the system.
1.3
DEMONSTRATION BACKGROUND
This section describes the history of the Hex Pit at RMA and
the selection of the ISTD technology for remediating
contamination at the Hex Pit and for evaluation under the SITE
Program.
1.3.1 Site History
RMA is located in Commerce City, Colorado, 10 miles
northeast of downtown Denver. The U.S. Army originally
developed the 27-square-mile facility in 1942, primarily for
manufacturing chemical weapons. After World War II, parts
of the facility were leased to private industry for pesticide
manufacturing.
The Hex Pit is an unlined, earthen-disposal pit located near the
northern edge of the South Plants Manufacturing Complex
(South Plants) at RMA (Figure 1-1). The pit was used to
dispose of distillation bottoms and other residues from the
production of hexachlorocyclopentadiene (referred to as "hex"
throughout this report), a manufacturing intermediary used in
the production of pesticides. Hex was produced in South
Plants by Julius Hyman and Company from 1947 to 1951, and
by Shell Chemical Company from 1951 to 1955. The black,
tar-like distillation bottoms and residues, in drums and in bulk,
were buried in the pit from mid-1951 to mid-1952. The waste
material was periodically covered with soil backfill. Although
the exact quantity of waste material disposed of in the Hex Pit
was not recorded, it has been estimated that 833 cubic yards
(cy) of waste was disposed of and that the pit contains a total
of 2,005 cy of waste materials interlayered with soil backfill
(TerraTherm 2001). By the end of 1952, the Hex Pit was
completely covered with a soil cap. By 1954, it appeared as an
unvegetated rectangular ground scar on aerial photographs. In
1976, waste materials from the Hex Pit were uncovered during
construction of the foundation for Building 571B. Building
571B was constructed over the southern end of the pit.
Building 571B was later demolished, and most of the
foundation was removed (Tetra Tech EM Inc. [Tetra Tech]
2001).
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NOTE: BASE MAP PROVIDED BY
DP ASSOCIATES, INC.
SCALE: 1" = 1 MILE
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 1-1
LOCATION OF THE HEX PIT
AT ROCKY MOUNTAIN ARSENAL
Tetra Tech EM Inc.
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1.3.2 Technology Selection
Innovative thermal treatment was specified for remediation of
the Hex Pit in the Record of Decision (ROD) (Foster Wheeler
Environmental Corporation [FWENC] 1996). Through the
process identified in the ROD Dispute Resolution Agreement
(DRA) (Program Manager Rocky Mountain Arsenal 1996) for
this area at RMA., regulatory agencies overseeing
environmental activities at RMA selected ISTD as the specific
innovative thermal treatment to be used at the Hex Pit. RMA
Remediation Goal 1
outlined in the ROD and DRA involves the destruction of
contaminants to levels that met human health exceedance
(HHE) criteria for the six site contaminants of concern (COCs).
The six site COCs consisted of hex and the pesticides aldrin,
dieldrin, endrin, isodrin, and chlordane. RMA Remediation
Goal 2 involved the destruction of the six COCs to levels that
met preliminary remediation goals (PRG). Table 1-1
summarizes the HHE criteria and PRGs for the six COCs.
TABLE 1-1
SUMMARY OF HEX PIT CLEAN-UP CRITERIA
coc
Hex
Aldrin
Dieldrin
Endrin
Isodrin
Chlordane
HHE Clean-up Criteria
(in parts per million [ppm])
1,100
71
41
230
52
55
PRGs (in ppm)
1,100
0.72
0.41
230
52
3.7
Source: Foster Wheeler Environmental Corporation (FWENC) 1996
The standard that ISTD was to achieve, as expected by RMA,
was 90 percent destruction and removal efficiency (DRE) for
hex, dieldrin, and chlordane. Endrin, isodrin, and aldrin were
reportedly below detection limits in pre-characterization
sampling results, and therefore, RMA did not include them in
the post-treatment DRE standard (TerraTherm 2001).
The primary objective of the SITE demonstration of
TerraTherm'sISTD technology was to determine the ability of
the technology to meet the HHE criteria for the six COCs.
Additional discussion of the SITE Program's originally-
planned primary and secondary objectives for this evaluation
is included in Section 3.1.1
1.4
GENERAL TECHNOLOGY DESCRIPTION
ISTD is a soil remediation process that applies heat and
vacuum simultaneously to contaminated soils, either with
surface heater blankets or with an array of vertical heater and
vacuum extraction wells. Surface heater blankets are used for
the removal of surficial contamination down to about 2 feet,
while vertical well arrays are used to treat deeper contamination
in subsurface soils. Heaters are operated at 1,450 to 1,650
degrees Fahrenheit (ฐF). According to the developer, as the soil
is heated, volatile contaminants are vaporized or destroyed by
a number of mechanisms, including the following: (1)
evaporation into the vapor stream, (2) steam distillation into the
vapor stream, (3) boiling, (4) oxidation, and (5) pyrolysis
(Stegemeier and Vinegar 2001). The vaporized water,
contaminants, and natural organic compounds are drawn in a
direction counter-current to the heat flow to the vacuum source
in the blankets or wells.
Because the soil in the proximity of the heater-vacuum wells is
heated to high temperatures (above 900 ฐF) for many days, the
technology developer claimed that contaminants in the heated
soil can be almost completely removed (Stegemeier and
Vinegar 2001). Most of the contaminants are expected to be
destroyed in the soil before the vapor stream is removed by
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vacuum extraction. For the Hex Pit site, the technology
developer claims that this expectation was borne out in the
results of the Hex Pit Treatability Study, in which the DREs for
the site COCs within the treatability study samples exceeded
99 percent (ENSR Corporation [ENSR] 2000, see also Section
3.2.1). Contaminants that have not been destroyed in situ that
remain in the vapor stream are destroyed by the off-gas
treatment system. The technology developer claims that both
thermal blankets and thermal wells have been highly effective
in removing a variety of contaminants, including
polychlorinated biphenyls (PCB), pesticides, chlorinated
solvents, and heavy and light hydrocarbons (Stegemeier and
Vinegar 2001).
1.5 KEY CONTACTS
Additional information on the SITE Program, TerraTherm's
ISTD technology, and the demonstration site can be obtained
from the following sources:
The SITE Program
Marta K. Richards and Scott Jacobs
U.S. Environmental Protection Agency
Office of Research and Development
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Telephone: (513) 569-7692 and (513) 569-7635
Fax: (513) 569-7676 and (513) 569-7585
Email: richards.marta(a),epa. gov
Email: Jacobs.scott(@,epa.gov
TerraTherm's ISTD Technology
Ralph Baker
TerraTherm, Inc.
356 Broad Street
Fitchburg, Massachusetts 01420
Telephone: (978) 343-0300
Fax: (978)343-2727
Email: rbaker(@,terratherm.com
RMA's Hex Pit Site
Lorri Harper
Remediation Venture Office
U.S. Fish and Wildlife
Rocky Mountain Arsenal
Building 111
Commerce City, Colorado 80022-1748
Telephone: (303)289-0411
Fax: (303)289-0485
Email: Lorri Harper(@FWS.gov
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SECTION 2
TECHNOLOGY APPLICATION ANALYSIS
This section describes the general applicability of
TerraTherm's ISTD technology to contaminated waste sites.
Previous ISTD applications are described; and, since the
technology treatmentwas not completed at this site,this section
focuses primarily on descriptions of the Hex Pit site
characteristics and the ISTD system specifically designed for
the site.
2.1 PREVIOUS APPLICATIONS OF IN SITU
THERMAL DESTRUCTION
The technology developer currently describes case studies of
six completed thermal treatment projects using the ISTD
technology on its internet website (www.terratherm.com).
These case studies include four sites contaminated with PCB s,
one chlorinated solvent site, and one petroleum hydrocarbon
site. Of the four PCB sites, three included vertical wells
installed to depths of 12 to 15 feet below ground surface (bgs),
similar to the thermal treatment approach at the Hex Pit. Two
of the sites used thermal blankets, in addition to the thermal
wells, to treat near-surface contamination or stockpiled soil,
one used only thermal wells, and one site used thermal blankets
in a batch-treatment process on stockpiled soil. PCB
concentrations ranged up to highs of 20,000 milligrams per
kilogram (mg/kg) in soil treated in situ using vertical wells and
were greater than 10,000 mg/kg in stockpiled soil treated using
thermal blankets. One site was also contaminated with dioxins
and furans up to a toxicity equivalent (TEQ) concentration of
3.2 parts per billion (ppb). TerraTherm reports that treatment
at all four PCB sites achieved cleanup goals ranging from less
than 1 mg/kg to 10 mg/kg PCBs. Dioxin and furan
contamination at the one site was reduced to the TEQ cleanup
goal of less than 1 ppb.
The technology developer claims that soil contaminated with
chlorinated solvents, including trichloroethene (TCE),
tetrachloroethene (PCE), and 1,1-dichloroethene, were
reportedly successfully remediated at one site using the ISTD
technology. The site included two vertical well fields; one
consisting of 15 wells installed to a depth of 12 feet bgs and the
other consisting of 130 wells installed to depths of up to 19 feet
bgs. For PCE, the pre-treatment concentrations were as high
as 3,500 mg/kg, while those for TCE were as high as 79 mg/kg.
For PCE, the post-treatment concentrations in all samples were
less than 0.5 mg/kg, while concentrations of TCE were less
than 0.02 mg/kg. ISTD technology was applied at one site
contaminated with petroleum hydrocarbons, including gasoline,
diesel-rangeorganics, and benzene. Reportedly, approximately
200,000 pounds of hydrocarbons, including immiscible
product, were successfully removed and treated during the 120-
day heating cycle.
The TerraTherm web site also includes the description of a
thermal treatment project at a former wood treatment site that
is apparently ongoing. Soil at the site is described as
contaminated with polyaromatic hydrocarbons,
pentachlorophenol, and dioxins and furans. Thermal treatment
will be conducted using vertical wells.
2.2 HEX PIT SITE CHARACTERISTICS
This section describes the geologic and hydrogeologic setting
and previous investigations completed at the Hex Pit site.
Information describing the characteristics of the pit's contents
is then summarized. Previous investigations at the site include
those completed by Morrison Knudson (MK) (MK 1989),
ENSR (ENSR 1999), and EPA (Tetra Tech 2001).
Descriptions of the characteristics of the waste material
contained in the pit are summarized from these previous
investigations, a bench-scale treatability study of the ISTD
technology (ENSR 2000), and from the pre-treatment sampling
and analysis completed as part of this technology
demonstration.
2.2.1 Geologic and Hydrogeologic Settings
The Hex Pit was excavated in alluvial material, predominantly
silty sand. This alluvial material is approximately 25 feet thick
in the immediately vicinity of the Hex Pit and appears to
thicken to the north. The alluvium is underlain by Denver
Formation bedrock. The Denver Formation consists of
weathered clayey sandstone and sandy shale. The top of the
Denver Formation in the area forms an apparent shallow
paleochannel that generally trends northward. The local
bedrock topography controls the northward thickening of the
alluvium and influences the pattern of groundwater flow (MK
1989).
Recently, the water-table surface has been about 13 to 14 feet
-------
bgs in the immediate vicinity of the Hex Pit (Tetra Tech 2001,
measured during pre-treatment sampling). The depth to the
water-table surface reportedly varies seasonally by about 3 feet
and is at its lowest during the winter and highest in late spring
(TerraTherm 2001). Regional groundwater flow is to
the north-northeast at a gradient of about 0.008 feet per foot, or
about 42 feet per mile (MK 1989).
2.2.2 Previous Investigations
Previous field investigations have been completed at the
location of the Hex Pit. In 1989, MK completed an
investigation to evaluate whether the Hex Pit was an active
primary source of groundwater contamination in the South
Plants area (MK 1989). In 1998, MK completed a preliminary
investigation to evaluate the boundaries of the Hex Pit and to
characterize its contents (MK 1998). In 1999, ENSR
completed a more extensive evaluation of the boundaries of the
Hex Pit and the characteristics of the contained waste material
(ENSR 1999). The 1999 ENSR investigation also involved
collection of samples of material disposed of in the Hex Pit that
were used for a bench-scale treatability study of the ISTD
technology (ENSR 2000). On behalf of EPA, Tetra Tech
completed a screening investigation in 2000 to further evaluate
the boundaries of the Hex Pit, focusing primarily on the south
end of the pit that was previously covered by the concrete
foundation slab of Building 571B (Tetra Tech 2001). The
screening investigation also involved collection of soil samples
from just outside the boundaries of the Hex Pit to evaluate the
potential migration of contaminants from the Hex Pit to native
soils, and installation of piezometers to measure the water table
elevation in the immediate vicinity of the Hex Pit. Finally,
samples were collected and analyzed as part of this technology
demonstration in 2001, further characterizing the contents of
the Hex Pit and contaminant concentrations in soil covering,
adjacent to, and immediately below the pit before the ISTD
system was constructed and operated (pre-treatment sampling
and analysis). This section describes the objectives of, and
activities completed as part of, these previous investigations
and the pre-treatment sampling and analysis. Section 2.2.3
summarizes the characteristics of the Hex Pit based on the
results of these previous investigations.
Groundwater Impact Study (MK 1989)
MK completed the following activities to evaluate whether the
Hex Pit was an active primary source of groundwater
contamination in the South Plants area (MK 1 989):
Aerial photographs from 1948 to 1978 and
a blueline sketch dated November 19, 1967
were examined to delineate the approximate
boundaries of the site.
Five new groundwater monitoring wells
were installed, one hydraulically upgradient
and four downgradient of the Hex Pit. The
nearest downgradient monitoring well was
located approximately 60 feet from the Hex
Pit.
Groundwater samples were collected and
analyzed from the five new monitoring wells
and three existing monitoring wells located
in the general area. Water-level elevation
measurements were also obtained.
The MK study concluded thattwo compounds associated with
waste material in the Hex Pit, hexachlorobenzene and
hexachlorobutadiene, may be migrating at relatively low
concentrations from the Hex Pit into the alluvial groundwater.
However, the study also concluded that the risk to human and
non-human biotic receptors from groundwater emanating from
the Hex Pit area was insignificant and that no long-term benefit
would be gained by conducting an interim response action at
the site. The study also established the direction of
groundwater flow in the area of the Hex Pit (north-northeast).
Preliminary Investigation (MK 1998)
The preliminary investigation of the boundaries of the Hex Pit
and characteristics of its contents included the following
activities (MK 1998):
Geophysical surveys of the area, including
an electromagnetic-conductivity survey to
evaluate the dimensions of the pit, a metal-
detector survey to evaluate the presence of
metal objects, and direct-current
measurements to evaluate the character of
the waste material.
Drilling three paired soil borings (six total
borings) to evaluate the boundaries of the
pit.
Drilling three soil borings to collect waste
samples from the pit for chemical, odor, and
physical analyses.
The results of the geophysical surveys and observations from
drilling the three paired borings provided a preliminary
indication of the dimensions of the Hex Pit. Metal objects,
presumably buried drums, were detected within the boundary
of the pit. The waste samples were found to contain 33 to 38
-------
percent volatile material, 5 to 27 percent carbon, and 14 to 23
percent chlorine. Concentrations of hex ranged from 1.3 to 16
percent. Although the odor from the Hex Pit was judged
offensive, it was determined to be unlikely to present any off-
post odor problems.
Characterization Study (ENSR 1999)
The objectives of the ENSR Hex Pit characterization study
were as follows (ENSR 1999):
Delineate the vertical and lateral extent of
the planned ISTD treatment zone.
Characterize the chemical and physical
nature of the material in the pit.
Collect samples of the material in the pit for
use in a bench-scale treatability study.
Collect samples outside and beneath the pit
to establish background levels of
contaminants and physical properties of soil.
Locate and examine buried utilities in the
vicinity of the pit.
Confirm the depth to groundwater at the pit.
In addition, several former site workers were interviewed as
part of the ENSR investigation regarding their recollection of
activities at the Hex Pit.
As part of the ENSR investigation, 51 soil borings were drilled
within and around the perimeter of the Hex Pit to visually
identify its lateral and vertical boundaries. Samples collected
to characterize the contents of the Hex Pit included three
composite samples obtained from the north, middle, and south
portions of the pit, and one sample collected from beneath the
concrete foundation that remained from Building 571B. Two
composite samples were also collected for a bench-scale
treatability study. The SITE Program witnessed the process of
opening the collected soil cores and compositing the sub-
samples into the Master and Waste Composite samples that
were tested during the bench-scale treatability study.
"Background" soil samples were collected from beneath the pit
and at four locations just outside the boundaries of the pit.
Treatability Study (ENSR 2000)
A bench-scale treatability study of the ISTD technology was
conducted on contaminated samples collected from the Hex Pit
as part of the characterization study (ENSR 1999). Two
composite samples were tested during the treatability study,
including the "Master Compo site," which was representative of
the entire contents of the pit, and the "Waste Composite, which
was representative of only visibly contaminated soil-and-waste
material. The purpose of the treatability study was to evaluate
whether the ISTD technology could achieve a 90 percentDRE
for each of the site COCs. Additional objectives of the study
included comparing post-treatment concentrations of the site
COCs to the site-specific clean-up goals established in the site
ROD, and evaluating the off-gas stream produced for use in
designing an emission control system. Results from analyses
of the Master-and Waste-Composite samples before treatment
are included in the summary of Hex Pit characteristics (Section
2.2.3). The results of the treatability study are summarized in
Section 3.2.1
Screening Investigation (Tetra Tech 2001)
EPA's screening investigation included drilling 57 soil borings
to evaluate the boundaries of the Hex Pit and to collect samples
of native soil surrounding the pit to evaluate the potential
lateral migration of contaminants. In addition, four
piezometers were installed near the sides of the pit to measure
the local water-table elevation. The screening investigation
was completed between September and October 2000,
immediately after most of the foundation of Building 57 IB was
demolished and removed. During demolition of the concrete
foundation slab of Building 571B, it was discovered that
foundation structures under the slab were more extensive than
had been previously estimated. These foundation structures
included concrete footers and columns that extended to depths
exceeding 16 feetbgs near the northwestern corner of the slab.
In addition, deteriorating drums and other waste material were
discovered beneath the northern half of the slab and extending
an unknown distance to the west. Because of these
observations, the screening investigation was modified from
the outset to focus primarily on evaluating the lateral
boundaries and vertical depth of waste material beneath the
foundation of Building 57 IB.
Technology Demonstration Pre-treatment Sampling and
Analysis
Samples were collected as part of this SITE demonstration to
establish conditions existing at the Hex Pit before construction
and operation of the ISTD treatment system. The "pre-
treatment" samples were collected and analyzed as described
in the SITE project quality assurance project plan (QAPP)
(EPA 2001) in July 2001. Pre-treatment samples included
composites of the materials disposed of in the Hex Pit (Hex Pit
soil-and-waste material); soil above, below, and laterally
contiguous to the disposal pit (contiguous soil); and
-------
ground-water from the four piezometers previously installed as
part of the screening investigation. The pre-treatment sampling
is further described in Section 3.1.2, and all pre-treatment
sampling results are included in Section 3.2.3
2.2.3 Summary of Hex Pit Characteristics
The characteristics of the Hex Pit can be summarized based on
the results of previous investigations and the pre-treatment
sampling and analysis completed as part of this technology
demonstration. Figure 2-1 shows the lateral boundaries of the
Hex Pit. The main part of the Hex Pit measures approximately
94 feet long, 45 feet wide, and varies from 8 to 10 feet deep.
A narrow trench extends west near the south end of the pit. A
ramp is also evident at the south end of the Hex Pit where,
presumably, a bulldozer or other heavy equipment entered the
pit when itwas originally excavated. The north end of the Hex
Pit is also sloping, while the east and west sides and the sides
of the trench extending west are nearly vertical. The total
volume of material in the Hex Pit is estimated to be 2,005
cubic yards (TerraTherm 2001)
Figure 2-2 shows a generalized stratigraphic column through
the Hex Pit. As shown in Figure 2-2, materials logged in
borings completed as part of the previous investigations can be
divided into the following general categories:
Cover material
Soil-and-waste material
Mixed fill-and-waste material from removal
of the foundation of Building 571B
Native soil
-------
01114
HB-02B2
HB-02B1
HB-13B1
ฎ
HXB05
HXB10
O O
HB-12B1
HB-12B18
.HXB02
HB-12B13
HBV25Q
HB-06B1
HB-07B1
ENSR-1
HB-17B1
01112
HB-12B17 HB-12B1
HB-12B8
/G8HB-09B3
/ HBV27
HB-12B7
HB-11B1
LEGEND
o
HEX PIT BOUNDARY
SOIL SAMPLING LOCATION (ENSR 2000)
O NORTH COMPOSITE
MIDDLE COMPOSITE
O SOUTH COMPOSITE
SOIL SAMPLING LOCATION (TETRA TECH 2001)
PIEZOMETER AND MONITORING WELL LOCATION
DIRT ROAD
10'
10'
01113
20'
SCALE: 1" = 20'
NOTE: BASE MAP PROVIDED BY DP ASSOCIATES, INC.
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 2-1
HEX PIT BOUNDARY AND
HISTORICAL SAMPLING LOCATIONS
Tetra Tech EM Inc.
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0
GROUND SURFACE
2 -
4 -
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CO
o
a:
o
o
6 -
8 -
10
12
Cover Material. Primarily mixed sand, gravel,
and silt that covers the area of the Hex Pit,
usually to a depth of several feet.
Mixed Fill and Waste Material. Mixed clean
imported fill material and soil and waste material
originally disposed of in the Hex Pit. Formed
during the removal of the foundation of Building
571B in September 2000 and restricted to the
south end of the Hex Pit. Generally consists of
silty sand with occasional gravel or concrete
rubble fragments; streaks or granules of black,
tarlike hex; and rusted metal fragments.
Soil and Waste Material. Material orginally
disposed of in the Hex Pit. Mostly silty sand,
often stained dark brown, rust orange, or black,
and mixed with granules or globules of hex.
Includes bands or layers of relatively pure, black,
tarlike hex, usually less than 1 foot thick, often
watersaturated, and frequently occurring near
the base of the unit. Other substances include
rusted metal fragments (probably drum remains);
black, orange, or white crystalline substances;
cloth rags; and wood fragments. Extends to
depths of about 8 to 10 feet.
Native Soil. Primarily sand, silty sand, and silt,
usually yellowbrown in color. Often stained rust
orange with occasional streaks of black hex
staining to depths of several feet below the soil
and waste material unit.
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 2-2
HEX PIT GENERALIZED
STRATIGRAPHIC COLUMN
Tetra Tech EM Inc.
-------
The Hex Pit cover material is primarily composed of mixed
sand, gravel, and silt that were placed as a cap over the entire
area. The soil-and-waste material is composed of the material
that was originally disposed of in the pit. It consists of soil
(primarily silty sand) that is often stained dark brown, rust
orange, or black, and may be mixed with granules or globules
of hex. Black, tar-like relatively pure hex residue occurs in
layers or bands usually less than 1 foot thick. Other substances
include rusted metal fragments (probably drum remains), black
to orange and occasionally white crystalline substances, layers
of light bluish-gray paste-like material that is probably lime,
and wood fragments. The layered nature of the soil-and-waste -
material unit reflects the historical disposal practices; that is,
hex disposed of in drums (that ruptured when dumped or later
corroded) or in bulk that was then covered with soil backfill.
It is also apparent that lime was occasionally dumped into the
pit.
The mixed fill-and-waste material from the removal of the
foundation of Building 571B is from the demolition and
removal of the building's concrete foundation in September
2000. Foundation structures, including concrete footers and
columns, were found to extend below the concrete slab, and
attempts were made to excavate and remove these structures.
Clean fill was used to cover the excavation at the end of each
day to control odors from the Hex Pit waste material. The next
morning, this fill material was dug out of the excavation so
demolition and removal of the foundation structures could
continue. Moving this material in and out of the excavation
each day resulted in a mix of clean fill-and-waste material. The
mixed fill and waste generally consists of silty sand with
occasional gravel or concrete rubble fragments; streaks of
granules of black, tar-like hex waste material; and trace
amounts of rusted metal fragments. This material is restricted
to the southern end of the Hex Pit beneath the location of the
former building foundation
Native soil beneath and adjacent to the pit consists of sand,
silty sand, and silt, usually yellow-brown in color. The native
soil may be stained rust orange to depths of several feet below
the Hex Pit waste material. Occasionally, streaks of black hex
staining also occur in native soil immediately beneath the pit.
Samples of Hex Pit soil-and-waste material were analyzed as
part of the characterization study (ENSR 1999) and the SITE
pre-treatment sampling effort. The characterization study
samples included three composite samples obtained from the
northern, middle, and southern portions of the pit and one
sample collected beneath the concrete foundation slab of
Building 571B. Two composite samples were collected for the
treatability study (ENSR 2000), including the "Master
Composite, which was representative of the entire content of
the pit, and the "Waste Composite, which was representative of
only visibly contaminated soil-and-waste material. These
samples were analyzed for volatile organic compounds
(VOCs), total chlorine, and the Hex Pit COCs. The Master
Composite sample was also analyzed for dioxins and furans.
The SITE pre-treatment sampling effort included the collection
of six composite samples analyzed for the site COCs,
semivolatile organic compounds (SVOCs), and dioxins and
furans. In addition, the SITE pre-treatment sampling included
the collection of eight grab samples that were analyzed for
VOCs. These samples were collected from depths of
approximately 5 feet bgs, without regard to whether the
material was primarily waste or soil backfill. Table 2-1
summarizes the concentrations of selected chemical
constituents detected in these samples of soil-and-waste
material disposed of in the Hex Pit.
Samples of native soil (referred to as "contiguous soil") were
collected from beneath and adjacent to the Hex Pit as part of
the characterization study (ENSR 1999), the screening
investigation (Tetra Tech 2001), and the pre-treatment
sampling effort. Many of the native soil samples collected
beneath or very near the sides of the Hex Pit were visibly
stained rust-orange or with streaks of black hex. Visibly
contaminated contiguous soil samples often contained
concentrations of the site's COCs similar to the soil-and-waste
material composite samples. Contamination did not appear to
migrate more than a few feet laterally into contiguous soil as
evidenced by the lack of hex detected in contiguous soil
samples collected approximately 8.5 feet from the sides of the
Hex Pit as part of the pre-treatment sampling effort (see also
Section 3.2.3).
Groundwater samples were analyzed as part of the screening
investigation (Tetra Tech 2001) and pre-treatment sampling
effort. Several VOCs, including chloroform, carbon
tetrachloride, benzene, TCE, and PCE, were detected in these
groundwater samples (Tetra Tech 2001), which are typical of
a regional groundwater contaminant plume in the area (MK
1989). However, hex was not detected in these groundwater
samples collected as near as approximately 13 feet
downgradient of the Hex Pit boundaries.
2.3 IN SITU THERMAL DESTRUCTION
SYSTEM DESIGN AT THE HEX PIT
TerraTherm'sISTD configuration at the Hex Pit was described
in the Hex Pit Remediation Final (100%) Design Package
(TerraTherm 2001). At this site, ISTD was designed to heat
the soil above the boiling points of the COCs using a network
of heater wells. The ISTD remediation design for the Hex Pit
12
-------
assumed that contamination extended 10 feet bgs. To attempt
to ensure adequate heating and treatment of the contaminated
soils within the delineated boundaries of the Hex Pit, the ISTD
remediation design included heating the soil 5 feet laterally and
2 feet vertically beyond the delineated boundaries of the Hex
Pit. This area encompassed a target treatment soil volume of
3,198 cy, extending from 0 to 12 feet bgs and 5 feet laterally
beyond the boundaries of the Hex Pit. The ISTD heating
duration was designed to be 85 days.
Approximately one-quarter of the heater wells were
configured as combined heater-and-vacuum extraction wells
(HV wells) to allow collection of the volatilized vapors. The
well-field layout consisted of a triangular grid of thermal wells
spaced on 6-foot centers with a 3.75:1 ratio of heater-only to
heater-vacuum wells. The grid resulted in a total of 266 wells,
of which 210 were heater-only wells and 56 were HV wells.
All well casings (and screens for the HV wells) were
constructed of Type 304 stainless steel. Figure 2-3 shows the
well-field layout for the ISTD system. According to the
developer's design, electrical heating elements placed in the
wells were designed to reach temperatures of 1,400 to 1,600
ฐF, resulting in an extremely hot zone surrounding each heater
well. The thermal well field was designed to achieve a
minimum temperature of 617 ฐF between wells within the
delineated boundary of the Hex Pit. A thermal heat front was
to advance radially outward from the heater wells through
thermal conduction.
As contaminants were drawn through the extremely hot zone
that surrounds the heater wells, the technology developer
expected the majority of the contaminant mass to be destroyed
by oxidation or pyrolysis. Thus, the majority of contaminant
mass destruction was expected to occur in situ. Steam
stripping of contaminants was also expected to occur as the soil
pore water was boiled off during the initial heating phase.
Soil along the boundaries of the treatment area were
maintained under negative pressure to attempt to ensure that
steam and volatilized contaminant vapors were captured and
directed to the off-gas treatment system. A small vacuum
(approximately 20 inches of water column) was expected to
provide adequate capture of the vapors released during heating.
Vapors extracted from the subsurface were treated
aboveground. The aboveground piping network designed to
transport vapors to the treatment system was constructed of
Type 304 stainless steel, except for high-temperature
reinforced flexible hose connecting vapor tees at the HV
wellheads to the piping network.
The off-gas treatment system was designed to treat the
incoming process vapor stream from the ISTD wellfield to
reduce concentrations of organic and inorganic contaminants,
including acid gases. The off-gas treatment system consisted
of a cyclone separator, flameless thermal oxidizer (FTO), heat
exchanger, knock-out pot, two acid gas dry scrubbers, two
carbon bed adsorbers, and two main process blowers. The
main process blowers were induced draft fans. The fans were
designed to supply the motive force (vacuum) needed to draw
the vapors from the well field and through the off-gas treatment
system. Figure 2-4 is a process flow diagram of the ISTD
system.
The cyclone separator was designed to remove particulates
from the incoming vapor stream to prevent damage to, or
clogging of, downstream off-gas treatment system equipment.
The technology developer expected the quantity of particulates
to be low at all times, but to increase with time as the soil dried
out
The FTO was designed to convert organic constituents in the
process stream to carbon dioxide and water vapor. Because a
significant quantity of chlorinated organics was expected in the
waste stream, hydrogen chloride (HC1) was expected to be
produced during the oxidation process. Generation of the acid
gas required a separate neutralization step before discharge to
the atmosphere. The FTO was expected to operate at
temperatures in the range of 1,500 to 1,900 ฐF.
13
-------
TABLE 2-1
SELECTED ANALYTICAL RESULTS FOR HEX PIT
SOIL-AND-WASTE-MATERIAL SAMPLES
Sample
Hexachlorocyclopentadiene
(mg/kg)
Dieldrin
(mg/kg)
Carbon Tetrachloride
(mg/kg)
Chloroform
(mg/kg)
Tetrachloroethene
(mg/kg)
Dioxin/furan TEQ
(PPb)
Composite Samples from ENSR 2000 Investigation
STorth Composite a'd
Middle Composite a
South Composite a-tl
Master Composite a'd
Waste Composite a
HBV25"
3,350
5,700
7,950
8,100
21,000
6,100
130 U
2,200
130 U
5,600
1,800
130 U
17
21
20
8.3
34
14
8.3U
8.3 U
8.3 U
1.9
31
10
17
22
18
13
51
25
NA
NA
NA
123
NA
NA
Composite Samples from SITE Pre-Treatment Sampling
PRE-W-P
PRE-W-y-"
PRE-W-30
PRE-W-4C
PRE-W-50
PRE-W-6C
5,500
9,100
7,800
6,000
11,000
9,500
1,300
1,367
360
280
1,500
23
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
581
287
596
147
178
430
Grab Samples from SITE Pre-Treatment Sampling
PRE-W-1 (VOC)
PRE-W-6 (VOC)
PRE-W-14 (VOC)
PRE-W-1 5 (VOC)
PRE-W-16 (VOC)
PRE-W-23 (VOC)
PRE-W-31 (VOC)
PRE-W-33 (VOC)
PRE-W-36 (VOC)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
8.6
0.01
0.035
0.49
3.8
0.58
13
4.6
5.6
22
0.17
0.15
2.3
2.4
1.1
4.6
0.58
0.47
4.8
0.084
0.2
1.2
6.7
0.48
3.7
0.35
4.3
NA
NA
NA
NA
NA
NA
NA
NA
NA
Notes:
Composite samples from northern, middle, and southern portions of the pit were produced by mixing
core samples from three boreholes each (nine borings total). The Master Composite was generated by
mixing portions of core from all nine borings. The Waste Composite was generated by mixing visibly
contaminated material from all nine borings.
Sample HBV25 was obtained from the 4- to 6-foot depth interval from beneath the concrete slab
remaining from Building 571B.
Pre-treatment composite samples were produced by mixing core samples from three borings each (18
borings total).
Average concentration calculated from original and field replicate sample analytical results.
mg/kg Milligrams per kilogram
NA Not analyzed
pb Parts per billion
T EQ Toxicity equivalent
U Not detected above detection limit shown
Sample results reported on a dry-weight basis
14
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LEGEND
- - HEX PIT BOUNDARY
TREATMENT AREA BOUNDARY
NOTE: BASE MAP PROVIDED BY DP ASSOCIATES, INC.
O
N
HEATER-ONLY WELLS
HEATER-VACUUM WELLS
DIRT ROAD
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 2-3
IN SITU THERMAL DESTRUCTION SYSTEM
WELLFIELD LAYOUT
Tetra Tech EM Inc.
-------
R:\EPA\RMA\G1093\46UO\ processflow.dwg 05/07/2003 karmen.griffith DN
LOW-PERMEABILITY
COVER
GROUND SURFACE
VAPOR
SAMPLING
PORT
L
WELL FIELD
HEATER AND COMBINATION HEATER
AND VACUUM EXTRACTION WELLS
(2) SCRUBBER
/ BEDS
VAPOR
SAMPLING
PORT
VAPOR
FROM
WELL
FIELD
STACK
KNOCK
OUT
POT
(2) CARBON
ABSORBERS
CYCLONE
SEPARATOR
FLAMELESS
THERMAL
OXIDIZOR
HEAT
EXCHANGER
CONDENSATE
STORAGE
TANK
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 2-4
PROCESS FLOW DIAGRAM
IN SITU THERMAL DESTRUCTION
TREATMENT SYSTEM
Tetra Tech EM Inc.
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A heat exchanger was incorporated to decrease the temperature
of the hot process gases that exited the FTO before it entered
the scrubber and carbon adsorbers. The high-efficiency air-to-
air heat exchanger was designed to cool the hot process stream
from 1,600 to 200 ฐF with a residence time of less than 0.3
second.
Following the heat exchanger, the knock-out pot was used to
separate the liquid from the vapor. The vapor passed into a dry
scrubber used to neutralize acid gases in the vapor stream. The
vapor stream flowed through two packed beds of granular
scrubbing media, which were expected to neutralize
hydrochloric acid vapor.
Two vapor-phase carbon adsorbers were installed downstream
of the scrubber beds as a final polishing step to remove any
remaining organic contaminants from the vapor stream.
Contaminant mass loading on the adsorber was expected to be
low because the technology developer expected that most of
the contamination would be destroyed upstream of the carbon
adsorbers. As a precaution, an emergency generator was
provided and connected so that in the event of a loss of grid
power, an automatic transfer switch would cause the generator
to start within 30 seconds and continue to power the blowers
and air quality control equipment throughout such an outage.
17
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SECTION 3
TREATMENT EFFECTIVENESS
The following sections describe the methods by which the
ISTD treatment technology was evaluated and the results of the
evaluations.
3.1 DEMONSTRATION METHODOLOGY
and carbon bed).
S4 Compare contaminants remaining in the site soil after
treatment to the contaminants present before
treatment.
The following sections describe the SITE demonstration
objectives, including the original demonstration objectives and
how the objectives were modified after failure of the ISTD
system, the SITE pre- and post-treatment sampling that was
completed, and the data quality assessment of the analytical
results.
3.1.1 SITE Demonstration Objectives
Similar to other SITE demonstration projects, the ISTD
demonstration at the Hex Pit included primary and secondary
objectives designed to evaluate the ability of the technology to
achieve specific clean-up criteria and to assess the cost and
overall effectiveness of the treatment system. The primary
objective planned for the demonstration, as described in the
SITE project QAPP (EPA 2001), was as follows:
PI To determine the ability of the TerraTherm ISTD
remediation technology to meet RMA HHE cleanup
criteria for COCs in soil-and-waste material within
the Hex Pit boundaries. The COCs are
hexachlorocyclopentadiene (hex), aldrin, dieldrin,
endrin, isodrin, and chlordane.
The HHE clean-up criteria are included in Table 1 -1 in Section
1.3.2. Secondary objectives planned for the ISTD
demonstration were the following:
SI Determine thecostoftreatmentforcontaminated soil-
and-waste material in the RMA Hex Pit.
S2 Evaluate the effluent gas-phase emissions from the
TerraTherm treatment process.
S3 Evaluate the DREs of the Hex Pit COCs and dioxins
and furans by in situ thermal treatment and the off-gas
treatment system (FTO, heat exchanger, dry scrubber,
S5 Evaluate changes in concentrations of hex in soil and
groundwater outside the boundary of the treatment
area.
S6 Determine the ability of TerraTherm's ISTD
technology to meet PRG clean-up criteria (shown in
Table 1-1 in Section 1.3.2).
These objectives formed the basis for the sampling design
described in the SITE project QAPP (EPA 2001) to evaluate
the ISTD treatment process. The SITE objectives were to be
achieved by collecting and analyzing soil-and-waste sample sin
the northern portion of the Hex Pit before and after the ISTD
demonstration. Pre-treatment sampling was completed as
described in the QAPP and is summarized in Section 3.1.2.
However, as described in Section4.0, the ISTD demonstration
was terminated prematurely due to unexpected material
failures. The average concentration of contaminants in post-
treatment samples was considered unlikely to be much different
from the average concentration of contaminants found in the
pre-treatment samples. Consequently, the sampling strategy to
achieve the demonstration objectives was no longer considered
viable and was re-evaluated in the SITE post-treatment
sampling and analysis plan (SAP) (EPA 2002).
Consistent with TerraTherm's Operations and Maintenance
Manual, the heater-only wells were energized in stages. On the
fifth day of heating, all heater-only wells in the southern third
of the well field were energized; however, the heater-only wells
in the northern two-thirds of the well field, which were
scheduled to be energized around the time of the failure of the
piping, were never turned on. Thus, heating within the
northern portion was limited to the HV wells
The SITE post-treatment SAP considered that all HV wells
were active for 12 days before system shutdown and may have
produced discernable changes in contaminant concentrations in
soil-and-waste material immediately adjacent to the wells.
18
-------
Thus, the objective of the post-treatment sampling was to
characterize contaminant concentrations in soil-and-waste
material inclose proximity to the HV wells (approximately 0.5
feet) for comparison to pre-treatment soil-and-waste material
contaminant concentrations. Section 3.1.3 summarizes the
post-treatment sampling.
3.1.2 SITE Pre-treatment Sampling
SITE pre-treatment sampling was completed as described in
the SITE project QAPP (EPA 2001) to establish baseline
conditions at the Hex Pit before construction and operation of
the ISTD system. Sampling was confined to the northern half
of the Hex Pit and was completed in July 2001. Sampling was
confined to the northern half of the Hex Pit because the
southern portion of the Hex Pit had been disturbed during the
demolition and removal of the foundation of Building 571B,
including the mixing of clean fill with material originally
disposed of in the Hex Pit. Sampled materials included the
soil-and-waste material originally disposed of in the pit;
contiguous soil above, below, and laterally adjacent to the pit;
and groundwater from piezometers flanking the pit. Table 3-1
summarizes the pre-treatment sampling, andFigures 3-1 and 3-
2 show the sampling locations. The pre-treatment sampling
results are summarized in Section 3.2.3.
The soil-and-waste material unit was the focus of the ISTD
treatment process. Six composite soil-and-waste material
samples were collected for analysis. Each composite sample
was created by mixing material from three soil cores collected
from2to lOfeetbgs. Boreholes were drilled using direct-push
techniques, and soil cores were obtained with dual-tube
sampling equipment. Samples were composited by mixing
core material in disposable aluminum pans with disposable
plastic scoops. Nine grab samples were also collected for
analysis of VOCs. These grab samples were collected from
soil cores from 5 feet bgs before the core material was
transferred to the aluminum pans for compositing. Figure 3-1
shows the cores that were combined to form the composite
samples, and the cores that were used to collect the grab
samples for VOC analysis.
Three separate areas of contiguous soil were sampled: cover
material above the Hex Pit soil-and-waste material unit (0 to 2
feet bgs); native soil below the soil-and-waste material unit
(from two different depth intervals, including 10 to 12 feet bgs
and 12 to 13 feet bgs); and native soil outside the perimeter of
the Hex Pit. Three composite samples each were collected
from the cover material and soil beneath the soil-and-waste
material unit (from the two different depth intervals). Each
composite sample was created by mixing material from six soil
cores collected from the specified depth intervals. Nine grab
samples were also collected for analysis of VOCs from a depth
of 1 foot bgs in the cover material. Twelve native soil samples
were collected outside the perimeter of the Hex Pit,
approximately 3.5 feet beyond the boundary of the treatment
area (8.5 feet beyond the edge of the Hex Pit). These soil
samples were created by homogenizing core material collected
from 2 to 10 feet bgs in boreholes drilled outside the Hex Pit.
Figure 3-2 shows the cores that were combined to form the
composite samples, the cores that were used to collect the grab
samples for VOC analyses, and the outside perimeter borehole
locations. Compositing and grab-sampling procedures for the
contiguous soil samples were the same as procedures described
for the soil-and-waste material samples.
Groundwater samples were collected from four piezometers
located about 28 feet from the edges of the Hex Pit in each
major compass direction (north, south, east, and west). Figures
3-1 and 3-2 show the piezometer locations.
3.1.3 SITE Post-Treatment Sampling
As described in Section 3.1.1, the ISTD demonstration was
terminated prematurely due to unforseen material failures.
Consequently, the post-treatment sampling strategy to achieve
the demonstration objectives originally described in the SITE
project QAPP (EPA 2001) was no longer considered viable.
19
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TABLE 3-1
SITE PRE-TREATMENT HEX PIT SAMPLING SUMMARY
Hex Pit Soil-and- Waste Material - Pre-Treatment (Figure 3-1)
Sample Identification
PRE-W-1
PRE-W-1 (VOC)
PRE-W-1 6 (VOC)
PRE-W-2'
PRE-W-6 (VOC)
PRE-W-3
PRE-W-14(VOC)
PRE-W-1 5 (VOC)
PRE-W-4
PRE-W-23 (VOC)
PRE-W-5
PRE-W-3 1 (VOC)
PRE-W-6
PRE-W-33 (VOC)
PRE-W-36 (VOC)
Depth
(feet bgs)
2-10
5
2-10
5
2-10
5
2-10
5
2-10
5
2-10
5
Composited Locations
1,5, 16
7,6,9
14, 15, 17
21,23,25
28,31,32
26, 33, 36
VOC Sampling Locations
(5 feet bgs)
1, 16
6
14, 15
23
31
33,36
Analyses
COCs, SVOCs, D&F
VOC
COCs, SVOCs, D&F
VOCs
COCs, SVOCs, D&F
VOCs
COCs, SVOCs, D&F
VOCs
COCs, SVOCs, D&F
VOCs
COCs, SVOCs, D&F
VOCs
Contiguous Soil, Inside Pit Boundaries - Pre-Treatment (Figure 3-2)
Sample
Identification
PRE-S-1 (0-2)
PRE-S-1 (10-12)
PRE-S-1 (12-13)
PRE-S-1 (VOC)
PRE-S-16 (VOC)
PRE-S-33 (VOC)
PRE-S-36 (VOC)
PRE-S-2 (0-2)
PRE-S-2(10-12)
PRE-S-2 (12-13)
PRE-S-6 (VOC)
PRE-S-14 (VOC)
PRE-S-1 5 (VOC)
PRE-S-3 (0-2)
PRE-S-3 (10-12)
PRE-S-3 (12-13)"
PRE-S-23 (VOC)
PRE-S-3 1 (VOC)
Depth Range
(feet bgs)
0-2
10- 12
12- 13
1
0-2
10- 12
12- 13
1
0-2
10- 12
12- 13
1
Composited Locations
1, 5, 16,26,33,36
6, 7, 9, 14, 15, 17
21,23,25,28,31,32
VOC Sampling Locations
(1 foot bgs)
1, 16,33, 36
6, 14, 15
23, 31
Analyses
COCs, SVOCs
D&F
Hex
VOCs
COCs, SVOCs
D&F
Hex
VOCs
COCs, SVOCs
D&F
Hex
VOCs
20
-------
TABLE 3-1 (Continued)
SITE PRE-TREATMENT HEX PIT SAMPLING SUMMARY
Contiguous Soil, Outside Pit Boundaries - Pre-Treatment (Figure 3-2)
Sample Identification
PRE-S-E1 through E12d
Depth Range (feet bgs)
2- 10
Analyses
Hex
Groundwater - Pre-Treatment
Sample Identification
PRE-GW-01111
PRE-GW-01112
PRE-GW-01113
PRE-GW-01114
Analyses
Hex
Hex
Hex
Hex
Notes:
bgs
COCs
D&F
Hex
Samples collected in triplicate for field replicate
Below ground surface
Contaminants of concern (hexachlorocyclopentadiene, aldrin, chlordane, dieldrin, endrin, and isodrin)
Dioxin and furan congeners
Hexachlorocyclopentadiene
SVOCs Semi volatile organic compounds
VOCs Volatile organic compounds
21
-------
o o
PRE-W-1
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PRE-W-4-
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PRE-W-5^i '
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01112
PRE-W-6
10' 0 10' 20'
I I I
SCALE: 1" = 20'
LEGEND
HEX PIT BOUNDARY
TREATMENT AREA BOUNDARY ^01113
A HEX PIT INTERIOR PRETREATMENT SAMPLING LOCATION
PRETREATMENT VOC SAMPLING LOCATION NOTE: BASE MAp PROV|DED BY Dp ASSOC|ATES, INC.
HEATER-ONLY WELLS
HEATER-VACUUM WELLS
PIEZOMETER WELL LOCATION
DIRT ROAD
2'-10' COMPOSITES
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 3-1
SITE PRETREATMENT SOIL AND WASTE
MATERIAL SAMPLING LOCATIONS
Tetra Tech EM Inc.
-------
E5Y"T~TEV (0-2, 10-12, AND 12-13)
o a.Q--o"~~o---Q..
' _ _ป ฃ- -_
(0-2, 10-12, AND 12-13)
E3
(0-2, 10-12, AND 12-13)
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-------
The SITE post-treatment sampling objectives and procedures
were re-evaluated in the SITE post-treatment SAP (EPA
2002). The post-treatment sampling consisted of collecting six
samples from the soil-and-waste material unit from close
proximity (approximately 0.5 foot) to six ISTD HV wells.
Table 3-2 summarizes the SITE post-treatment sampling, and
Figure 3-3 shows the sampling locations. The post-treatment
sampling results are summarized in Section 3.2.4.
Following the failure of the ISTD system, the site was buried
under approximately 3 feet of imported fill material. Since the
southern portion of the site was lost to physical disturbance
and was unavailable for sampling, the SITE post-treatment
sampling was completed by first marking the presumed
locations of buried H V wells in the northern half of the Hex
Pit. Handdigging thro ugh the fill material was then conducted
to find the tops of the H V wells. Once the tops were verified,
offsets were measured to locate where an angled borehole
would be started to collect cores from the soil-and-waste
material unit adjacent to the HV well casing. The boreholes
were angled to avoid steel plates welded to the well casings
and to position the borehole approximately 0.5 foot from the
HV well at depths of 2 to 10 feet below the original surface of
the Hex Pit cover material. Figure 3-4 diagrams this approach
to drilling the SITE post-treatment sampling boreholes.
Similar to the SITE pre-treatment sampling effort, the
boreholes were drilled by direct-push techniques, and core
samples were collected using dual-tube sampling equipment.
The samples were created by homogenizing core material
collected from 2 to 10 feet below the original top of the Hex
Pit cover material. Six grab samples were also collected for
analysis of VOCs from a depth of 5 feet below the top of the
soil-and-waste material unit.
3.1.4 SITE Data Quality
SITE pre- and post-treatment laboratory analytical data were
validated to confirm that the results were satisfactory for use
in addressing the project objectives. Appendix A includes the
validation reports for all SITE pre- and post-treatment
laboratory analytical data generated for this project. The
validation reports discuss the performance of the internal
quality control (QC) checks conducted by the laboratory
during the sample analyses, such as results for matrix
spike/matrix spike duplicate (MS/MSD) samples and surrogate
spikes. In addition to the internal QC checks, field replicate
samples were collected during the treatment demonstration as
external (field) QC samples. These co-located samples
included one triplicate sample of contiguous soil and another
of soil-and-waste material collected during the pre-treatment
sampling, and one duplicate soil-and-waste material sample
collected during the post-treatment sampling.
Overall, the findings of the QC checks and data validation
indicated that the sample analyses were acceptable as
qualified; no results were considered unusable. All validation
qualifiers are listed with the analytical results summarized in
the validation reports in Appendix A. As described in the
validation reports, the analyses rendered an expected level of
data quality, given the nature of the analytical methods and the
samples. The analytical methods were designed to identify and
quantitate low concentrations of organic compounds in
relatively uncontaminated soil matrices. However,many ofthe
samples contained relatively high concentrations of many
organic compounds. This complexity produced many failures
of QC measures, such as matrix interferences manifested in
irregular MS/MSD results, surrogate recoveries, and internal
standard results. In other instances, QC data were lost entirely
due to the high dilutions required for many samples prior to
analysis. Required dilutions produced very high quantitation
limits for many analytes and samples.
24
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TABLE 3-2
SITE POST-TREATMENT HEX PIT SAMPLING SUMMARY
Sample Identification
POST-W-HVH4a
POST-W-HVP4
POST-W-HVL4
POST-W-HVJ6
POST-W-HVH8
POST-W-HVP8
Depth
(feet bgs)
7.6- 15.6
12.6
4.8- 12.8
7.8
5.5- 13.5
8.5
5.7- 13.7
8.7
5.8- 13.8
8.8
6- 14
7.5
Analyses
COCs, SVOCs
D&F
VOCs
COCs, SVOCs
D&F
VOCs
COCs, SVOCs
D&F
VOCs
COCs, SVOCs
D&F
VOCs
COCs, SVOCs
D&F
VOCs
COCs, SVOCs
D&F
VOCs
Notes:
a Samples collected in duplicate for field replicate
bgs Below original ground surface
COCs Contaminants of concern (hexachlorocyclopentadiene, aldrin, chlordane, dieldrin, endrin, and isodrin)
D&F Dioxin and furan congeners
SVOCs Semivolatile organic compounds
VOCs Volatile organic compounds
25
-------
.01111
01114
HOI HI1 HK1 HM1 HOI
wV 9 9 ฐ!U~
eft) o ffl6
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5 H5
IUJ6 HW6 HL6
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H_B12 mmi2 HF12 ^g12 HJ12
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HBB21 HDD21 HFF21 HHH21 HJI21 HUL21 HNN21
o o o cT o o o
HB24 HD24 HF24 H-B24 HE4 ILL24
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.01112
LEGEND
HVB6
HVL20
POST-TREATMENT SAMPLING LOCATION
HEATER-VACUUM WELL LOCATION
HEATER-ONLY WELL LOCATION
PIEZOMETER WELL LOCATION
HEX PIT BOUNDARY
.01113
10' 0 10' 20'
I I I
SCALE: 1" = 20'
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 3-3
SITE POST-TREATMENT SAMPLING
LOCATIONS
Tetra Tech EM Inc.
-------
DISTANCE ~ 18 INCHES FROM
CENTER OF WELL
GROUND SURFACE
HEATER/VACUUM EXTRACTION
WELL
STEEL PLATES
TOP OF HEX PIT
2 FT. BELOW TOP OF PIT
<
CL
2
<
10 FT. BELOW TOP OF PIT _
BOREHOLE ANGLED
~ 10 DEGREES FROM
VERTICAL
DISTANCE ~ 6 INCHES FROM
WELL
DISTANCE
WELL
6 INCHES FROM
ISTD DEMONSTRATION
ROCKY MT. ARSENAL
FIGURE 3-4
POST-TREATMENT SAMPLING
BOREHOLE DRILLING PLAN
Tetra Tech EM Inc.
-------
In general, the high concentrations and complex sample
matrices increase the potential for false positives in the data
sets and give the quantitative results an "estimated" character.
Although the complex nature of the samples remained
consistent between the SITE pre- and post-treatment samples,
the comparability of the two data sets is limited by the different
sampling approaches applied for the pre- and post-treatment
events. The utility of the data sets for assessing the effects of
the ISTD treatment process is further limited by the inherent
heterogeneity of the soil-and-waste material in the treatment
zone. The comparability of the two sampling events is further
discussed in Section 3.2.5.
The SITE pre- and post-treatment analytical data were
compared to precision, accuracy, representativeness,
completeness, and comparability (PARCC) objectives outlined
in the project QAPP (EPA 2001). The following sections
summarize the evaluation of the PARCC objectives.
Precision
Precisionis a measure ofthe reproducibility of an experimental
value without regard to a true or referenced value. The primary
indicators of precision were the relative percent difference
(RPD) results for the MS/MSD analyses, the RPD between the
field duplicate pair collected during the post-treatment
sampling, and the percent relative standard deviation (%RSD)
between the three replicate field samples collected during the
pre-treatment sampling. The RPD and %RSD values for the
duplicate and replicate samples are shown in Table 3-3. The
inherentheterogeneity of soil samples often result in high RPD
and %RSD values in duplicate and replicate analyses. This
heterogeneity is apparent in some ofthe field replicate results
shown in Table 3-3, particularly in the high RPDs calculated
for the VOCs in the post-treatment duplicate. Due the high
concentration of analytes,the MS/MSD spiking amounts were
diluted out for many samples and could not be used to evaluate
the level of precision. Overall, however, acceptable precision
was found for the pre- and post-treatment analytical results for
the field, given the high analyte concentrations and complex
matrices in the samples analyzed.
Accuracy
Accuracy assesses the proximity of an experimental value to a
true or referenced value. The primary indicators of accuracy
are compound recoveries in surrogate, MS, and laboratory
control sample (LCS) analyses. Accuracy is expressed as
percent recovery. Due to the high concentration of analytes in
the samples, the MS spiking amount was often diluted out and
could not be used to evaluate accuracy. Having only partial
data to evaluate the overall accuracy, leads to an inconclusive
judgement. Though the surrogate and LCS recoveries were
adequate, the overall accuracy of these data could not be
determined.
Representativeness
Representativeness refers to the ability of data to reflect true
environmental conditions. Results were evaluated for
representativeness by examining items that were related to the
collection of the samples, such as the chain-of-custody
documentation, which included accurate sample labeling,
recording correct sample collection dates, and confirming the
condition of the samples when they were received at the
laboratory. Laboratory procedures were also examined,
including anomalies reported by the laboratory either when the
samples were received or during the analytical process,
including evaluating sample holding times, appropriate
calibration of laboratory instruments, adherence to analytical
methods, appropriate quantitation limits, and the completeness
of the data package documentation. Items not meeting the
criteria are documented in the validation reports. Overall,
acceptable representativeness was found for the pre- and post-
treatment analytical results.
Completeness
Completeness is defined as the percentage of measurements
that are considered valid. The validity ofthe analytical results
is assessed through the data validation process. All results that
are rejected and any missing values are considered incomplete.
Data that are qualified as estimated or nondetected are
considered valid. Completeness is measured by comparing the
total number of samples planned in the QAPP to the total
number of samples collected, and the total number valid results
compared to the total number of analytical results. Analytical
comp leteness is measured by dividing the total number o f valid
results by the total number of results and multiplying by 100.
Each analyte from each method is multiplied by the number of
samples analyzed to calculate the total number of results. As
no data were rejected and all data were collected and analyzed
as specified in the SITE project QAPP (EPA 2001) and post-
treatment SAP (EPA 2002), completeness for this investigation
was 100 percent.
Comparability
Comparability is a qualitative parameter that expresses the
confidence with which one data set may be compared to
another. Comparability of data is achieved by the use of
uniform sampling procedures, standard methods of analysis,
standard quantitation limits, and standardized data validation
procedures. The use of approved laboratories, specified and
well-documented analyses, and standard processes of data
28
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review and validation give the pre-and post-treatment data sets
a high degree of analytical comparability. However, as
discussed in Section 3.5.2, the need to modify the post-
treatment sample collection and preparation procedures relative
to those procedures used to obtain the pre-treatment samples
renders accurate comparability of the data sets somewhat
questionable.
3.2 DEMONSTRATION RESULTS
The following sections summarize evaluations of the ISTD
system at the RMA Hex Pit. Pre-construction evaluations are
summarized that were not completed by EPA's SITE Program,
but by the technology developer, to estimate the performance
of the system to assist in the design process. A brief
chronology of system operations at the Hex Pit is presented as
well as SITE'S pre- and post-treatment sampling results.
Finally, a comparison of the SITE pre- and post-treatment
sampling results is presented.
3.2.1
Pre-construction Evaluations
Pre-construction evaluations completed by the technology
developer included a treatability study of the effectiveness of
thermal treatment on representative contaminated soil-and-
waste samples from the Hex Pit, computer simulation
modeling to optimize the subsurface thermal and vapor flow
operating parameters, and field testing of the ISTD well design
at a separate test site. The results of these evaluations are
summarized below.
A bench-scale treatability study of the ISTD technology was
conducted on contaminated samples collected from the Hex Pit
(ENSR 2000). The treatability study samples were collected
during the characterization study (ENSR 1999) and included
the Master Composite and the Waste Composite. Table 2-1
includes a summary of contaminant concentrations detected in
the Master and Waste Composite samples before treatment.
The purpose of the treatability study was to evaluate whether
the ISTD technology could achieve a 90 percent DRE for each
of the site C DCs.
Additional objectives of the study included comparing post-
treatment concentrations of the site COCs to the site-specific
clean-up goals, and evaluating the off-gas stream produced for
use in designing an emission control system.
In the treatability study, the test samples were thermally treated
at a target temperature range of approximately 1,000 to 1,900
ฐF under controlled vapor flow conditions to simulate treatment
of the Hex Pit material by the ISTD process. After treatment,
the test samples were recovered and analyzed for residual
contaminant concentrations. The po st-treatment sampling
results indicated that DRE s of 99 percent were achieved for the
site COCs and that the site cleanup goals could be met. Dioxin
and furan concentrations were reduced by more than 90
percent, and test results indicated that dioxins and furans were
not created by the thermal treatment process. Evaluation of
off-gas emissions from the test indicated that a significant
quantity of HC1 vapor or chlorine gas was emitted during
thermal treatment. However, it was postulated by the
developer that actual field emission rates would be lower
because of the buffering capacity of the soils in the Hex Pit.
Treatability Study
29
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TABLE 3-3
SITE FIELD REPLICATE COMPARISON
Target Analyte
Pre-Treatment Contiguous Soil (one triplicate)
Hexachlorocyclopentadiene
Pre-Treatment Soil-and-Waste Material (one triplicate)
Hexachlorocyclopentadiene
Hexachlorobenzene
Hexachloro butadiene
Chlorinated pesticides3
Chlorinated dioxins/fiirans
Post-Treatment Soil-and-Waste Material (one duplicate)11
Carbon tetrachloride
Chloroform
Tetrachloroethene (PCE)
Hexachlorocyclopentadiene
Hexachlorobenzene
Chlorinated pesticides3
Chlorinated dioxins/furans
%RSD or RPD
%RSD
18.7
%RSD
6.9
16.5
12.8
14 -44
27.7
RPD
177
81
192
69
14
5-6
13
Notes:
%RSD
RPD
For multi-parameter analytes, the range of %RSDs is reported for the individual
compounds that were detected in all samples of the replicate.
The post-treatment duplicate results include data for selected VOC s of interest. No pre-
treatment replicates were collected for VOC analysis.
Percent relative standard deviation
Relative percent difference
30
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Simulation Modeling
The developer conducted simulation modeling as part of the
ISTD system design effort to evaluate optimal subsurface
thermal and vapor flow operating parameters. The simulation
modeling report was included as Appendix I to the Final 100
Percent Design Package (TerraTherm 2001). Simulations were
conducted using a three-dimensional, multiphase flow,
multicomponent, non-isothermal model to evaluate the
following:
The optimal placement of HV and heater-only wells
and the required electrical load per heater.
The expected time-course and duration of heating to
achieve the target temperature throughout the
treatment zone.
The extraction vacuum and flow rate required to
accommodate the predicted water vapor and
emissions generation rates.
The length of time required after heating for soil to
cool to ambient temperatures.
system operation at the Hex Pit (adapted from TerraTherm
2002 and FWENC 2002):
October 4, 2001 - The technology developer
(TerraTherm) mobilizes to the Hex Pit site.
October 9, 2001 through February 18, 2002 -
Construction of the ISTD system at the Hex Pit.
Activities include site preparation, installation of
wells, placement of the surface cover and above-
ground piping network, installation of the electrical
system, and assembly of the off-gas treatment system.
In addition, RVO installed three horizontal wells
under the Hex Pit as a contingency for dewatering
should the water table surface rise to a level that
would be detrimental to operation of the ISTD
system.
February 19 through March 2, 2002 - System
shakedown testing and checking, and preheating of
the piping network and FTO.
March 3, 2002 - Start of ISTD heating operation. All
56 HV wells were energized and vapors were drawn
from the wellfield.
The simulation results indicated that a ratio of 3 to 1 heater-
only to HV wells set at a 6-foot inter-well spacing was optimal
to achieve the site clean-up goals in a relatively short period of
time. An edge-well 3:1 triangular well placement pattern best
ensured the capture of volatilized contaminants. Simulation
results also indicated that soil temperatures in portions of the
treated area may remain in the range of 450 to 500 ฐF for up to
120 days after heating, and may remain as hot as 300 ฐF for up
to 180 days after heating ceases.
Field Testing
Field testing of ISTD wells at a location in Houston, Texas was
completed as part of the 95 percent design effort. The field
testing report was included as Appendix J to the Final 100
Percent Design Package (TerraTherm 2001). The purpose of
the field test was to evaluate a new generation of HV and
heater-only wells for use at the Hex Pit site. ISTD wells used
during previous applications were relatively complex in design
and expensive to construct. Field testing identified a new well
design that could result in substantial cost savings for the Hex
Pit project by using materials that were readily available and
that could be routinely fabricated. Problem-free performance
over the course of a 63-day field trial resulted in the new well
design being incorporated into the ISTD system at the Hex Pit.
3.2.2 Chronology of System Operation at the Hex
Pit
March 5, 2002 - 84 heater-only wells were energized
in the southern third of the wellfield
March 11, 2002 - Liquid observed collecting in
flexible hoses connecting the HV wells to the
aboveground piping network.
March 11, 2002 - Sagging noticed in aboveground
piping at the southern end of the well field and a faint
odor noticed from the wellfield.
March 14, 2002 - Two manifold pipe taps in the
aboveground piping network observed to be leaning,
closer inspection concluded that tap welds had
corroded. During investigation of the damage, a seal
on an HV well was damaged and steam leaked out at
the baseplate.
March 15, 2002 - Steam and strong odors emitted
fromanHV well. Loss of vacuum pressure noticedin
southern end of wellfield. Several heaters experience
electrical shorting, including an insertion heater in the
aboveground piping network and a down-hole heater
in an HV well. Power to the wellfield heaters was
shut down. The piping network insertion heaters and
off-gas treatment system continue to operate.
The following is a summary of the chronology for the ISTD
March 17, 2002 - All wellfield manifold valves were
31
-------
closed and the off-gas treatment system and insertion
heaters were shut down.
Soil temperatures were variable in the northern portion of the
Hex Pit (location of EPA SITE'S pre- and post-treatment
sampling efforts) during the 12-day heating period. By heating
day 5, thermocouples located 1 foot from HV well HVD16,
located in the row immediately north of the southern third of
the well field, reached temperatures of approximately 70 ฐF,
120 to 170 ฐF, and 250 ฐF at near the ground surface, the 4- to
7-foot-deep, and the 10-foot-deep locations, respectively. By
heating day 12, temperatures were 120 ฐF near the ground
surface, just over 200 ฐF at 4 to 7 feet, and 416 ฐF at 10 feet.
Farther north in the wellfield, temperatures within 1 foot of
HVP8 at heating day 5 were 200 to 220 ฐF, except at a depth
of 4 feet, where the temperature was approximately 125 ฐF. By
heating day 12, temperatures at that location reached a
maximum of 237, 237, 398, and 458 ฐF at depths of 1, 4, 7, and
10 feet, respectively. Soil temperatures measured by
thermocouples installed in the far northern end of the pit were
still below 100 ฐF after 12 days of heating. Following
shutdown of the wellfield heaters, soil temperatures in the
vicinity of the operating HV wells in the northern half of the pit
generally dropped 50 to 100 ฐF or more within 1 week of
shutdown.
3.2.3 SITE Pre-Treatment Sampling Results
As described in Section 3.1.2, SITE pre-treatment samples
were collected of soil-and-waste material originally disposed
of in the pit; contiguous soil above, below, and laterally
adjacent to the pit; and groundwater from piezometers flanking
the pit. Table 3-1 summarizes the SITE pre-treatment
sampling completed, and Figures 3-1 and 3-2 show the
sampling locations. All SITE pre-treatment sample analytical
results are included in the validation summary reports in
Appendix A. All results are included in the validation
summary reports, even though only analytical results from the
soil-and-waste material samples are necessary to address the
project objectives that were modified after failure ofthelSTD
system. For completeness, Appendix B includes all borehole
logs completed as part of the pre-treatment sampling event.
As expected from previous investigations, the soil-and-waste
material unit consisted primarily of soil (primarily silty sand)
layered with waste material. The soil was often stained dark
brown, rust orange, or black, and often contained granules of
probable hex. Tar-like, relatively pure hex waste material often
occurred as bands or layers, usually less than 1 foot thick.
Other substances observed in the soil-and-waste material unit
included rusted metal fragments (probably from corroded
drums), black to orange and occasionally white crystalline
substances, layers of a lightbluish-gray paste-like material that
was probably lime, and wood fragments. The SITE pre-
treatment soil-and-waste material samples were composited
from core samples collected from 2 to 10 feet bgs. In general,
most of the tar-like hex waste material occurred between depths
of 4 to 7 feet bgs. Soil from 7 to 10 feet bgs was often stained
with small amounts of contamination. In general, a distinct
contact between soil-and-waste material disposed of in the pit
and native so il was difficult to determine. Table2-l in Section
2.2.3 includes selected analytical results from SITE pre-
treatment sampling of the soil-and-waste-material unit.
Contiguous soil above the soil-and-waste material unit
generally consisted of a surficial cover, often about 1 foot
thick, consisting primarily of silty sand and gravel. SITE pre-
treatment samples were collected from 0 to 2 feet bgs and often
the lower half of this interval included the silty sand material
characteristic of the soil-and-waste material unit, often
containing minor amounts of probable hex granules.
Contiguous soil beneath the soil-and-waste material unit was
collected from two intervals: lOto 12 feet bgs and 12 to 13feet
bgs. Although the base of the Hex Pit was often difficult to
accurately determine, it appeared that soil below 10 feet bgs
was probably in-place native soil. Minor contaminant staining,
including streaks of black hex, was occasionally observed in
the native soil beneath the Hex Pit.
Contiguous soil was also sampled adjacent to the Hex Pit.
These soil samples all appeared as uncontaminated native soil.
Samples of the laterally contiguous soil were only analyzed for
hex concentrations, and no hex was detected in these samples.
3.2.4 SITE Post-Treatment Sampling Results
As described in Section 3.1.3, the SITE post-treatment
sampling boreholes were drilled through a soil cover that was
placed overthe site following failure ofthelSTD system. Core
samples were examined to determine when the borehole had
reached the surface of the soil-and-waste material unit. Once
into the soil-and-waste material unit, core samples were
collected and prepared for laboratory analysis. The SITE
post-treatment samples were created by homogenizing core
material from single boreholes drilled through the soil-and-
waste material unit. The SITE post-treatment sampling
procedure was different from the SITE pre-treatment sampling
procedure, which composited core material from three separate
boreholes for each soil-and-waste material sample.
In general, the post-treatment core samples from the soil-and-
waste material unit appeared similarto the pre-treatment cores.
That is, the unit did not appear to have undergone a significant
change in physical characteristics as a result of the relatively
32
-------
short-term operation of the HV wells. All SITE post-treatment
sample analytical results are included in the validation
summary reports in Appendix A. Appendix B includes all
borehole logs completed as part of the post-treatment sampling
event.
3.2.5 Comparison of SITE Pre-
Treatment Sampling Results
and Post-
The objective of collecting the SITE post-treatment samples
was to evaluate if contaminant concentrations in the soil-and-
waste material in close proximity to the HV wells were
appreciably different from concentrations detected in the SITE
pre-treatment samples. Table 3-4 lists the concentrations of
selected compounds detected in SITE pre- and post-treatment
samples collected from the soil-and-waste material unit. The
selected compounds shown in Table 3-4 were consistently
detected in historical and SITE pre-treatment samples and
include the site COCs hex, aldrin, and dieldrin; VOCs carbon
tetrachloride, chloroform, andPCE; and total TEQs calculated
for dioxins and furans. The comparison between contaminant
concentrations detected in the SITE pre- and post-treatment
samples is intended to evaluate whether any contaminant
destruction or removal took place during the brief operation of
the ISTD system. Two different evaluations are presented,
including a qualitative comparison and a statistical comparison
conducted according to procedures specified in the SITE post-
treatment SAP (EPA 2002).
Qualitative Comparison of SITE Pre- and Post-
Treatment Sampling Results
The following sections describe a qualitative comparison of
SITE pre- and post-treatment sampling data for the site COCs,
VOCs, and dioxin and furan TEQs. Various plots were
generated to evaluate the data including frequency plots,
normal probability plots, box-and-whisker plots, and scatter
plots (Figures 3-5 through 3-9). The frequency plots are similar
to histograms and showthenumberof observations (y-axis)per
concentration grouping (x-axis) for the pre-treatment and post-
treatment samples. The scatter plot simply shows the
concentration (y-axis) of the chemical in each sample (x-axis).
The box and whisker plots show the median concentration (50th
percentile) as the small square, the interquartile range (25th to
75th percentile) as the larger rectangular box, and the whiskers
extending out to the minimum and maximum concentrations.
The symmetry (or lack thereof) of the box and whiskers around
the median reflects the data distribution (that is, normal or
skewed). Finally, the normal probability plots show the
concentration of each chemical in each sample in a manner that
also shows how well the data set fits a normal distribution.
Specifically, a probability plot is a graph of values, ordered
from lowest to highest and plotted against a standard normal
distribution function. The horizontal axis is scaled in units of
concentration and the vertical axis is scaled in units of the
normal distribution function (normal quantile). The straight
line on the probability plots shows the normal distribution,
which is a theoretical probability distribution that is symmetric
and has other specific attributes (Gilbert 1987).
Site COCs
Evaluations for the selected site COCs assessed the range,
variability, and distribution of SITE pre- and post-treatment
sampling data, and compared results from the two sampling
events. A review of the box-and-whisker plot in Figure 3-5
suggests that hex concentrations may have decreased from the
SITE pre- to post-treatment sampling events. The same trend
is evident for aldrin and dieldrin (Figures 3-6 and 3-7),
although the evaluation is complicated by the number of non-
detected results in the SITE post-treatment data set.
33
-------
TABLE 3-4
SUMMARY OF SITE PRE- AND POST-TREATMENT
ANALYTICAL RESULTS
Sample
Hexachlorocyclopentadiene
(mg/kg)
Aldrin
(mg/kg)
Dieldrin (mg/kg)
Dioxin/furan
TEQ (ppb)
Composite Samples from Pre-Treatment Sampling
PRE-W-1
PRE-W-2
PRE-W-2018
PRE-W-202a
PRE-W-3
PRE-W-4
PRE-W-5
PRE-W-6
5,500
8,600
8,900
9,800
7,800
6,000
11,000
9,500
110
700
490
570
110
40
1,400
3.8
1,300
1,700
1,200
1,200
360
280
1,500
23
581
376
260
224
596
147
178
430
Composite Samples from Post-Treatment Sampling
POST-HVH4
POST-HVP4
POST-HVL4
POST-HVL401"
POST-HVJ6
POST-HVH8
POST-HVP8
4,700
5,000
190
93
1,500
4
7,300
21
14 U
14 U
14 U
16 U
68
14U
190
14 U
14 U
14 U
40
480
14 U
305
432
798
910
62
19
674
Notes:
Field replicate of sample PRE-W-2
" Field replicate of sample POST-HVL4
mg/kg Milligrams per kilogram
ppb Parts per billion
TEQ Toxicity equivalent
U Not detected abo ve detection limit shown
Sample results reported on a dry-weight basis
34
-------
TABLE 3-4 (Continued)
SUMMARY OF SITE PRE- AND POST-TREATMENT
ANALYTICAL RESULTS
Sample
Carbon Tetrachloride
(mg/kg)
Chloroform
(mg/kg)
Tetrachloroethene
(mg/kg)
Grab Samples from Pre-Treatment Sampling
PRE-W-1 (VOC)
PRE-W-6 (VOC)
PRE-W-14 (VOC)
PRE-W-1 5 (VOC)
PRE-W-16 (VOC)
PRE-W-23 (VOC)
PRE-W-31 (VOC)
PRE-W-33 (VOC)
PRE-W-36 (VOC)
8.6
0.01
0.035
0.49
3.8
0.58
13
4.6
5.6
22
0.17
0.15
2.3
2.4
1.1
4.6
0.58
0.47
4.8
0.084
0.2
1.2
6.7
0.48
3.7
0.35
4.3
Grab Samples from Post-Treatment Sampling
POST-HVH4
POST-HVP4
POST-HVL4
POST-HVL401"
POST-HVJ6
POST-HVH8
POST-HVP8
5.2
3.8
0.87
0.054
8.3
0.63
1
4.4
2.3
1.1
2.6
0.67
0.18
4.4
3.7
2.5
1.4
0.028
0.1
0.055
0.09
Notes:
Field replicate of sample PRE-W-2
" Field replicate of sample POST-HVL4
mg/kg Milligrams per kilogram
Sample results reported on a dry-weight basis
35
-------
Figure 3-5
Data Comparison for Hexachlorocyclopentadiene
Frequency Plots of Hexachlorocyclopentadiene
Pre-Treatment
100% Detects
Mean = 8,387,500 fig/kg
Std Dev = 1,
380,300 fig/kg
-T-
1
Post-Treatment
100% Detects
Mean = 2,683,900 fig/kg
-,
StdD
ev = 2,951,100 fig/kg
R
-2e6 0 2e6 4e6 6e6 8e6 Ie7 1.2e7 -2e6 0 2e6 4e6 6e6 8e6 Ie7 1.2e7
Micrograms per Kilogram Micrograms per Kilogram
Normal Probability Plots of Hexachlorocyclopentadiene
N
a o.o
@
I -"
Pre-Treatment
Q'
Q'
6
o/
-1.8 I
-2e6 0 2e6 4e6 6e6 8e6 Ie7 1.2e7
Micrograms per Kilogram
Post-Treatment p
O'
/o
O /
O /
0'
0 2e6 4e6 6e6 8e6 Ie7 1.2e7
Micrograms per Kilogram
Plot of Hexachlorocyclopentadiene Concentration (fig/kg) in Each Sample
Post-Treatment
Pre-Treatment
an
W-l W-3 W-5 W-201 HVH4 HVL4 HVJ6 HVP8
W-2 W-4 W-6 W-202 HVP4 HVL401a HVH8
Sample ID
Box and Whisker Plots of Hexachlorocyclopentadiene
.ง 7,,
S o
Pre-Treatment
Post-Treatment
-------
Figure 3-6
Data Comparison for Aldrin
Frequency Plot of Aldrin
Pre-Treatment
100% Detects
Mean = 428,000 fig/kg
Std Dev = 474,400 fig/kg
Post-Treatment
28.6% Detects
Mean = 17,900 fig/kg
Std Dev = 22,700 fig/kg
-2e5 2e5 6e5 Ie6 1.4e6 -2e5 2e5 6e5 Ie6 1.4e6
0 4e5 8e5 1.2e6 1.6e6 0 4e5 8e5 1.2e6 1.6e6
Concentration in ug/kg Concentration in ug/kg
Normal Probability Plots of Aldrin
Pre-Treatment
ฃ
o
"S -0-6
Post-Treatment
-2e5 2e5 6e5 Ie6 1.4e6 -2e5 2e5 6e5 Ie6 1.4e6
0 4e5 8e5 1.2e6 1.6e6 0 4e5 8e5 1.2e6 1.6e6
Plot of Aldrin Concentration (fig/kg) in Each Sample
1
n
i
brj
.g
ฃ
-g
1
n
^
1.4e6
Ie6
8e5
6e5
4e5
2e5
0
-2e5
n
n
n
n
Post-Treatment
D D Q
Sample ID
Box and Whisker Plots of Aldrin
1.6e6
1.4e6
1.2e6
Ie6
4e5
2e5
Micrograms per Kilogram
Micrograms per Kilogram
Pre-Treatment
Post-Treatment
-------
Figure 3-7
Data Comparison for Dieldrin
Frequency Plots of Dieldrin
Plot of Dieldrin Concentration (fig/kg) in Each Sample
Pre-Treatment
100% Detects
Mean = 945,400 fig/kg
Std Dev = 628,900 fig/kg
|
%
i
1
F1
Pre-Treatment
42.9% Detects
Mean = 105,400 fig/kg
Std Dev = 178,200 fig/kg
^
g 1.8e6
g^ 1.4e6
2
8. Ie6
I
1 6C5
n
o
"ง 2e5
2
8 -2e5
D
n
n
n n
Post-Treatment
n
Dฐ
n D n n n n
ggg|^vvv^SR^o2g|SS^35||
-2e5 2e5 6e5 Ie6 1.4e6 1.8e6 -2e5 2e5 6e5 Ie6 1.4e6 1.8e6
0 4e5 8e5 1.2e6 1.6e6 2e6 0 4e5 8e5 1.2e6 1.6e6 2e6
Micrograms per Kilogram Micrograms per Kilogram
Normal Probability Plots of Dieldrin
Sample ID
Box and Whisker Plots of Dieldrin
Pre-Treatment
Post-Treatment
-2e5 2e5 6e5 Ie6 1.4e6 1.8e6 2.2e6 -2e5 2e5 6e5 Ie6 1.4e6 1.8e6 2.2e6
Micrograms per Kilogram Micrograms per Kilogram
Pre-Treatment
Post-Treatment
-------
Comparison of the SITE pre- and post-treatment data sets,
however, must take into account differences in the way
samples were collected during the two events. As described in
Section 3.1.1, each pre-treatment sample was obtained by
compositing soil-and-waste material from three separate
boreholes. For the post-treatment samples, however, core
material was not composited from multiple boreholes; instead,
samples were collected from single boreholes (see Section
3.1.2). Post-treatment samples from several boreholes
contained relatively low concentrations of the site COCs,
including samples HVH8, HVJ6, and HVL4 (Table 3-4). A
review of the borehole logs (Appendix A) indicates that layers
or bands of relatively pure, tar-like hex were not observed in
these borings. Relatively thick layers of probable lime
material (approximately 3.5 feet thick) were observed through
the sampled intervals in borings HVH8 and HVJ6. The high
pH values (12) measured in these samples supports the
observation of probable lime material in the borehole logs (see
sample analytical results summarized in Appendix A). The
relatively low concentrations of COCs in samples from these
borings may or may not be representative of typical
concentrations remaining in the Hex Pit.
VOCs
Grab samples were collected for analysis of VOC
concentrations from predetermined depths during both the
SITE pre- and post-treatment sampling events. These samples
were collected without regard to sample matrix and may have
been obtained from relatively uncontaminated soil or highly
contaminated waste material. Figure 3-8 presents an
evaluation of analytical results for PCE, which is
representative of trends observed for VOCs frequently
detected in the pre- and post-treatment soil-and-waste material
samples. The box plot shown in Figure 3-8 illustrates the
relatively broad range of PCE concentrations detected in both
the pre- and post-treatment samples. The broad range of PCE
concentrations detected probably results from the different
sample matrices collected. The box-and-whisker plot shown
in Figure 3-8 suggests a slight decrease in PCE concentrations
from the pre- to post-treatment sampling events. However, the
wide scatter in both the pre- and post-treatment data sets
complicates any comparison. Presumably, VOCs should have
been quickly volatilized and removed had the ISTD system
reached the intended operating temperatures. As described in
Section 3.2.3, the chronology of system operation, soil
temperatures measured near HV wells in the northern part of
the Hex Pit did not reach the minimum treatment temperatures
designed for the system.
Dioxin and Furan TEQs
Figure 3-9 presents an evaluation of analytical results for total
TEQs calculated for dioxins and furans. A review of the box-
and-whisker plot in Figure 3-9 suggests that TEQ
concentrations may have increased slightly from the SITE pre-
to post-treatment sampling events. However, the wide scatter
of TEQ concentrations in the post-treatment data set suggests
that a meaningful comparison with the pre-treatment data set
may not be possible. In addition, soil temperatures measured
near HV wells did not reach minimum treatment temperatures
Statistical Comparison of SITE Pre- and Post-
Treatment Sampling Results
The SITE post-treatment SAP specified two types of statistical
tests to compare the SITE pre- and post-treatment sampling
results (EPA 2002). The following sections describe these
statistical tests, test assumptions (hence, applicability to the
data collected), and the results of the comparison of SITE pre -
and post-treatment sampling results. Three representative
compounds were selected for the statistical comparison,
including hex, PCE, and TEQs for dioxins and furans. Hex
was selected as a representative compound because in was the
site COC detected in greatest concentration in the SITE pre-
treatment samples. PCE, although not a site COC, was
selected to evaluate whether brief operation of the thermal
treatment system had any affect on a volatile compound.
Dioxin and furan TEQs were evaluated to assess potential
creation of these compounds from operation of the thermal
treatment process. Summary statistics for these selected
compounds are presented in Table 3-5.
39
-------
Figure 3-8
Data Comparison for Tetrachloroethene
Frequency Plots of Tetrachloroethene (PCE)
Pre-Treatment
100% Detects
Mean = 2,424 ug/kg
Std Dev = 2,477 ug/kg
Post-Treatment
100% Detects
Mean = 1,125 ug/kg
Std Dev = 1,476 ug/kg
-1000 1000 3000 5000
Micrograms per Kilogram
7000 -1000 1000 3000 5000 7000
Micrograms per Kilogram
Normal Probability Plots of Tetrachloroethene (PCE)
Pre-Treatment
Q'
o .'
o
q
.'o
.0
P Post-Treatment
O .'
-1000 1000 3000 5000 7000 -1000 1000 3000 5000 7000
Micrograms per Kilogram Micrograms per Kilogram
Plot of Tetrachloroethene (PCE) Concentraion (ug/kg) in Each Sample
Pre-Treatment -
D
Post-Treatment
W-l W-14 W-16 W-31 W-36 HVP4 HVL401a HVH8
W-6 W-15 W-23 W-33 HVH4 HVL4 HVJ6 HVP8
Sample ID
Box and Whisker Plots of Tetrachloroethene (PCE)
8000
7000
6000
5000
4000
3000
2000
1000
0
-1000
Pre-Treatment
Post-Treatment
-------
Method 1: Linearized Ratios
Method 1 evaluated the SITE pre- and post-treatment
means for contaminant concentrations using a linearized
ratio test and a null hypothesis of a 50 percent reduction
in contaminant concentrations; that is, the null hypothesis
stated that a 50 percent reduction in contaminant
concentrations occurred between the SITE pre- and post-
treatment sampling results. The test was to be applied to
data for the three representative compounds discussed in
the qualitative comparison (hex, PCE, and TEQs for
dioxins and furans); however, one of the fundamental
assumptions of this test - that data sets have
approximately equal variance - was violated. Another
test assumption - that data sets be normally or log-
normally distributed - could not be quantitatively
evaluated, but qualitative review of the data suggests that
this assumption was also violated in some cases. As a
result of these violations, the linearized ratio test was not
performed. The second statistical test described in the
work plan (Wilcoxon Signed Rank Test) is a non-
parametric test (that is, the test does not assume data are
normally or log-normally distributed). Results from this
non-parametric test (Method 2) are discussed in the
following paragraphs.
Method 2: Bootstrapping and the Wilcoxon
Signed Rank Test
A second statistical method to evaluate the data used the
"bootstrap" method to provide a better estimate of the
SITE pre-treatment mean concentrations for the three
representativecompounds. "Bootstrapping" is a tool that
uses random re-sampling of the original data sets, then
provides an estimate of the mean for (in this case) 1,000
samples instead of the eight or nine samples that
composed the original data sets. Bootstrapping or re-
sampling methods take the combined samples as a
representation of the population from which the data
came, and create 1,000 or more bootstrapped samples.
The bootstrapping process was applied 10 times (10
iterations) to produce 10 different estimates of the mean
for pre-treatment concentrations of the three
representative compounds (Tables 3-6 through 3-8).
The Wilcoxon Signed Rank test (a non-parametric
one-sample test) was used to compare the SITE
post-treatment data to each of the 10 bootstrapped
estimates of the SITE pre-treatment mean concentrations
of the representative compounds (hex, PCE, and TEQs
for dioxins and furans). The SITE post-treatment SAP
specified a null hypothesis stating that a 50 percent
reduction in contaminant concentrations wasnot achieved
(EPA 2002). That is, the null hypothesis stated that the
post-treatment concentration of a compound was greater
than the threshold value. The threshold value in this case,
was one-half of each of the 10 bootstrapped pre-treatment
mean concentrations.
To conduct the Wilcoxon Signed Rank test, the SITE
post-treatment data were compared with each iteration
value of the SITE pre-treatment bootstrapped mean, then
the absolute values of the difference between the
estimated mean and the post-treatment data were assigned
a rank based on their magnitude. After the results were
ranked, then the rank values were assigned the
appropriate sign (negative or positive value) and the
positive values of rank were summed. If the sum was
greater than the critical value (from a lookup table),
which is based on sample size and the specified
confidence (95 percent in this case), then the null
hypothesis was rejected. In all cases, there was a failure
to reject the null hypothesis; thereby indicating that the
post-treatment data could not be shown to indicate a 50
percent reduction in contaminant concentrations. In these
tests, however, failure to reject the null hypothesis was
due to extreme variability in sample concentrations and
too few samples to adequately characterize post-treatment
conditions. These two factors resulted in poor power of
the statistical test to reject the null hypothesis. Results of
the Wilcoxon Signed Rank test for the three
representative compounds are summarized in Tables 3-6
through 3-8.
41
-------
Figure 3-9
Data Comparison for Dioxins and Furans (as Toxicity Equivalents, TEQs)
Frequency Plots of Dioxins as Toxicity Equivalents
Plot of Dioxins as Toxicity Equivalents (pg/kg) in Each Sample
Expected Normal Z Values Number of Observations
ii i o ^- to '
Concentration in Picograms per Kilogram (pg/kg)
i > UJ L/l ^ ^D ^
5e5 7e5 9e5 I.le6 -Ie5 Ie5 3e5 5e5 7e5 9e5 I.le6 , <-
D
n
n
n D
n n
n
n
D n
n
D n
W-l W-3 W-5 W-201 HVH4 HVL4 HVJ6 HVP8
W-2 W-4 W-6 W-202 HVP4 HVL401a HVH8
Sample ID
Box and Whisker Plots of Dioxins as Toxicity Equivalents
1 Non-Outlier Max
Non-Outlier Min
| 1 75%
D Median
D
n
^~
'
Pre-Treatment
Post-Treatment
-------
TABLE 3-5
SUMMARY STATISTICS FOR PRE- AND POST-TREATMENT DATA
Event
Pre
Pre
Pre
Pre
Pre
Analyte
Aldrin
Dieldrin
Hex
PCE
TEQ
Post |Aldrin
Post
Post
Post
Post
Dieldrin
Hex
PCE
TEQ
N
8
8
8
9
8
7
7
7
7
7
Mean
428,000
945,000
8,390,000
2,420
349,000
17,900
105,000
2,680,000
1,120
457,000
SD
474,000
629,000
1,880,000
2,480
175,000
22,700
178,000
2,950,000
1,480
351,000
Variance
225,000,000,000
396,000,000,000
3,540,000,000,000
6,130,000
30,800,000,000
515,000,000
31,700,000,000
8,710,000,000,000
2,180,000
123,000,000,000
Units
ug/kg
ug/kg
ug/kg
ug/kg
Pg/kg
ug/kg
ug/kg
ug/kg
ug/kg
PS/kg
Notes:
Event
Hex
PCE
TEQ
N
Mean
SD
Variance
ug/kg
Pg/kg
Specifies SITE pre-treatment or post-treatment results
Hexachlorocyclopentadiene
Tetrachloro ethene
Toxicity equivalents reported for dioxins and furans
Number of samples
Arithmetic mean
Standard deviation
Square of the standard deviation
Micrograms per kilogram
Picograms per kilogram
43
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TABLE 3-6
WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA (ug/kg) FOR HEXACHLOROCYCLOPENTADIENE
Bootstrap N for
Pre-Treatment
Data Set
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
Pre-Treatment
Threshold (One-half
of estimated
bootstrapped mean)
4,115,625
4,203,125
4,146,875
4,115,625
4,146,875
4,046,875
4,084,375
4,043,750
4,006,250
4,031,250
N for Post-
treatment
Data Set
7
7
7
7
7
7
7
7
7
7
R = sum of
positive ranks
21
21
21
21
21
21
21
21
21
21
Value for
W0.9S
4
4
4
4
4
4
4
4
4
4
Calculated
Value
24
24
24
24
24
24
24
24
24
24
Does R >
Calculated
Value?
No
No
No
No
No
No
No
No
No
No
Reject Null
Hypothesis?
No
No
No
No
No
No
No
No
No
No
Notes:
Bootstrap N
Pre-Treatment
Threshold Value
Nfor
Post-Treatment
R
Critical Value
for w095
Number of times the pre-treatment data set (N = 8) wasresampled ("bootstrapped")
The threshold value, as specified in the SAP (EPA 2002), is one-half the value of the bootstrapped
mean for pre-treatment data
The actual number of samples collected and analyzed for post-treatment conditions
R is the sum of positive ranks, generated as part of the Wilcoxon Signed Rank test (EPA 2000)
Critical value obtained from a lookup table of critical values for w (EPA 2000, Table A-6)
Calculated Value = (n x (n + 1 )/2) - w
Where n = number of post-treatment samples and w is from the lookup table
IfR> [nx(n+ l)/2] - w , then rej ect Ho
Where Ho, the null hypothesis, states that the post-treatment mean exceeds the threshold value (EPA 2002)
ug/kg
Micrograms per kilogram
44
-------
TABLE 3-7
WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA (ug/kg) FOR TETRACHLOROETHENE (PCE)
Bootstrap N for
Pre-Treatment
Data Set
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
Pre-Treatment
Threshold (One-
half of estimated
bootstrapped mean)
1,390
1,291
1,341
1,356
1,259
1,359
1,270
1,408
1,321
1,481
N for Post-
Treatment
Data Set
7
7
7
7
7
7
7
7
7
7
R = sum of
positive ranks
6
13
10
10
10
10
14
16
10
16
Value for
Wo.95
4
4
4
4
4
4
4
4
4
4
Calculated
Value
24
24
24
24
24
24
24
24
24
24
Does R >
Calculated
Value?
No
No
No
No
No
No
No
No
No
No
Reject Null
Hypothesis?
No
No
No
No
No
No
No
No
No
No
Notes:
Bootstrap N
Number of times the pre-treatment data set (N = 8) was resampled ("bootstrapped")
Pre-Treatment
Threshold Value The threshold value, as specified in the SAP (EPA 2002), is one-half the value of the bootstrapped mean for
pre-treatment data
Nfor
Post-Treatment The actual number of samples collected and analyzed for post-treatment conditions
R
Critical Value
for Wn os
R is the sum of positive ranks, generated as part of the Wilcoxon Signed Rank test (EPA 2000)
Critical value obtained from a lookup table of critical values for w (EPA 2000, Table A-6)
Calculated Value = (n x (n + 1 )/2) - w
Where n = number of post-treatment samples and w is from the lookup table
If R > [n x (n + 1 )/2] - w , then reject Ho
Where Ho, the null hypothesis, states that the post-treatment mean exceeds the threshold value (EPA 2002)
ug/kg
Micrograms per kilogram
45
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TABLE 3-8
WILCOXON SIGNED RANK TEST PERFORMED USING BOOTSTRAP MEANS FOR
PRE-TREATMENT DATA (ug/kg) FOR DIOXINS AND FURANS AS TEQS
Bootstrap N for
Pre-Treatment
Data Set
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
1,000
Pre-Treatment
Threshold (One-half
of estimated
bootstrapped mean)
183,700
178,206
176,357
180,825
185,419
180,381
186,113
179,438
176,906
172,994
Nfor
Post-Treatment
Data Set
7
7
7
7
7
7
7
7
7
7
R = sum of
positive
ranks
5
4
4
4
5
4
5
4
4
4
Value for
W0.9S
4
4
4
4
4
4
4
4
4
4
Calculated
Value
24
24
24
24
24
24
24
24
24
24
Does R >
Calculated
Value?
No
No
No
No
No
No
No
No
No
No
Reject Null
Hypothesis?
No
No
No
No
No
No
No
No
No
No
Notes:
Bootstrap N
Number of times the pre-treatment data set (N = 8) was resampled ("bootstrapped")
Pre-treatment
Threshold Value The threshold value, as specified in the SAP (EPA 2002), is one-half the value of the bootstrapped mean for
pre-treatment data
Nfor
Post-Treatment The actual number of samples collected and analyzed for post-treatment conditions
R
R is the sum of positive ranks, generated as part of the Wilcoxon Signed Rank test (EPA 2000)
Critical Value
for w095 Critical value obtained from a lookup table of critical values for w (EPA 2000, Table A-6)
Calculated Value = (n x (n + 1 )/2) - w
Where n = number of post-treatment samples and w is from the lookup table
If R > [n x (n + 1 )/2] - w , then reject Ho
Where Ho, the null hypothesis, states that the post-treatment mean exceeds the threshold value (EPA 2002)
ug/kg
Micrograms per kilogram
46
-------
With regard to assumptions, the Wilcoxon Signed Rank test
assumes the data constitute a random sample from a symmetric
continuous population. The statistical plots (Figures 3-5
through 3-7) show that the data for hex and dioxins and furans
(as TEQ s) are roughly symmetrical; however the data for PCE
are not symmetrical, which violates this test assumption.
Nonetheless, the results from the Wilcoxon Signed Rank test
offer information to be evaluated in the context of other
evidence.
Summary of Statistical Test Results
A statistical hypothesis is a statement that may be supported or
rejected based on relevant data. In statistical hypothesis
testing, the "burden of proof rests on the alternative
hypothesis, which is the logical opposite of the null hypothesis.
When testing a statistical hypothesis, two types of errors may
occur; these are termed Type I error (false rejection of the null
hypothesis) and Type II error (false acceptance of the null
hypothesis). The Type I error is specified by the confidence
level; for example, a 95-percent confidence level means there
is a 5 percent probability of making a Type I error. The
probability of making a Type II error is related to the "power"
of the test. Power can simply be defined as "the probability of
rejecting the null hypothesis when it is indeed false." Poor
power means that the probability of correctly rejecting the null
hypothesis is low.
For the statistical test (Wilcoxon Signed Rank test) used on the
SITE pre- and post-treatment data, a confidence level of 95
percent was specified. The null hypothesis stated that the
contaminant concentrations were not reduced by 50 percent.
Results of the Wilcoxon Signed Rank Test indicate that, in
every case, there was a failure to reject the null hypothesis. In
other words, results of the statistical test do not indicate that
contaminant concentrations were reduced by 50 percent.
Results for the Wilcoxon Signed Rank Test may appear to
contradict what is visible in the data plots (see Figures 3-5
through 3-9), until one reviews the summary statistics. The
table of summary statistics (Table 3-5) shows extremely large
variability (quantified as the standard deviation and variance)
in contaminant concentrations. In six out of ten cases, the
standard deviation was larger than the mean. The consequence
of this variability is that any statistical test will have poor
power to reject the null hypothesis. The power of a statistical
test can be checked to determine if an adequate number of
samples were collected to achieve a specified level of
confidence (here, 95 percent). When the power of the tests is
examined, for all data sets, the power of the test to reject the
null hypothesis using data from the seven post-treatment
samples, was poor in all cases.
In the case of the data examined here, poor power to resolve
differences and reject the null hypothesis is a consequence of
examining populations with high variance for which there are
too few samples. Generally, the desired performance for a
statistical test is spelled out in project data quality objectives
and includes the selection of a minimum detectable difference,
which is the width of the gray region on a test performance
plot, the confidence level, and the power desired. The number
of samples required can then be estimated using existing
information on population variance. Because information on
population variance was not available for this SITE
demonstration, the number of samples collected was not based
on existing data. As a result, the extreme variance (standard
deviation approximately equal to or greater than the mean
value in many cases, see Table 3-5) translated into poor power
and poor performance for the statistical tests to reject the null
hypothesis.
Due to the extreme variance in contaminant concentrations,
there are insufficient data to statistically determine whether or
not contaminant concentrations were reduced by 50 percent or
more of their pre-treatment concentrations during this SITE
demonstration. In summary, the results of the statistical tests
are inconclusive.
47
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SECTION 4
TECHNOLOGY STATUS
The following sections describe the physical destruction of
ISTD system components, and summarize the results of
investigations conducted to determine the cause of the
component destruction.
4.1 DESTRUCTION OF SYSTEM
COMPONENTS
Thermal treatment at the Hex Pit was terminated 12 days after
startup of all the HV wells and 10 days after startup of heater-
only wells along the southern one-third of the well field.
Electrical power to the well-field heaters was shut down after
corrosion that resulted in structural and containment failure of
segments of the abo veground stainless steelpiping network was
observed and heaters began shorting, including an insertion
heater in the aboveground piping and a down-hole heater in
one of the HV wells. All insertion heaters and the off-gas
treatment system were shut down three days later. Evaluation
of damage to the ISTD system focused on several areas as
described below, including the aboveground piping network
and insertion heaters, the down-hole heater cans and well
screens in the HV wells, and the off-gas treatment system
components. This discussion is summarized from TerraTherm
(2002), except where referenced otherwise.
4.1.1 Aboveground Piping Network and Insertion
Heaters
Initial visual observations of disassembled portions of the
aboveground piping network indicated significant corrosion of
the pipe interior in the immediate vicinity (within 1 to 4 inches)
of corroded manifold pipe taps. (The manifold pipe taps were
short pieces of vertical piping that connected flexible hoses
from tee fittings at the HV wellheads to the aboveground
piping network. Observations of leaning pipe taps caused by
disintegration of the stainless steel were initial indications of
corrosion problems with the ISTD system.) Vendor-acquired
metallurgical evaluation of the corroded piping indicated that
several forms of corrosion had occurred, including stress
corrosion cracking and intergranular corrosion or end grain
attack (Colorado Metallurgical Services [CMS] 2002). No
other visual evidence of significant corrosion and only minor
heat discoloration or rust-colored staining in areas was noted
throughout the rest of the aboveground piping network.
However, metallurgical laboratory evaluation of selected
sections of piping reported that general corrosive attack was
evidenced by a reduction in wall thickness from the initial
0.125 inch to 0.108 inch, considered a high rate of metal loss
(CMS 2002).
The flexible, high-temperature rubber hoses that connected tee
fittings at the HV wellheads to the manifold pipe taps were also
disassembled and evaluated. During operation of the ISTD
system, these hoses trapped liquids that prevented the vacuum
from pulling vapors into the off-gas treatment system (Versaw
2003). TerraTherm operators attempted to drain the hoses
periodically during system operation to prevent the blockage.
A majority of the tee fittings and hose end connections were
observed to be encrusted with materials and in some cases were
completely blocked. The deposits ranged from crystalline or
fibrous to tarry, muddy, powdery, or cake-like material.
Chemical analysis of these precipitates indicated that they
included metallic salts and both amorphous and crystalline
organic materials containing high concentrations of hex. The
flexible hoses did not appear to be corroded.
One of the insertion heaters near the location of a failed
manifold pipe tap that experienced an electrical short was
removed and evaluated. The insertion heaters were contained
in sections of stainless steel pipe or "cans" designed to protect
the heater elements. The heater can reportedly showed some
heat discoloration and visible pitting in one area, and was
substantially unaffected in other areas. The insertion heater
can was pressure tested and appeared tight. The electrical
failure appeared to be from the melting of a thin-gauge wire
and was claimed not to be related to the corrosion observed at
the failed manifold pipe tap.
4.1.2 Heater Cans and Well Screens
Damage to heater cans and well screens in the HV wells was
evaluated by visual inspection following removal of the heater
cans, down-hole video camera inspection, and metallurgical
laboratory analysis. During removal of the heater cans, several
wells were corroded to the extent that the cans broke off below
ground surface. Heater cans remained stuck in several other
wells and at five locations, the entire units including the well
screen were pulled from the ground when attempting to remove
48
-------
the heater cans.
4.2 FAILURE ASSESSMENT
The well screens were observed to be severely corroded and
some sections of well screen were completely corroded away.
One well was completely corroded through the screen and into
the heater can, and hex material was observed to have
accumulated in the heater can to a depth of 6 to 7 feet bgs
(approximately 5 to 6 feet of hex had accumulated in the heater
can). Video camera inspection revealed thathex material could
be seen on, and coming through, the screen slots in several
wells. In some wells, "streamers" of hex material could be
seen running down the inside of the screen interval from highly
corroded areas.
In general, components of the ISTD system at the Hex Pit
failed due to severe and rapid corrosive attack. Conditions that
led to the corrosive attack appeared to include the following:
Higher than anticipated production of
chloride and HC1
Lower than anticipated buffering or
neutralization of HC1 by other materials
disposed of in the Hex Pit and in the
surrounding soil
Metallurgical laboratory evaluation of corroded screen
intervals indicated corrosion resulted from preferential
corrosive attack (Rocky Mountain Engineering and Materials
Technology, Inc. [EMTEC] 2002) or "molten salt corrosion"
(CMS 2002). An overall assessment of the pipe corrosion in
EMTEC's 2002 report was described as "classic
manifestations of chloride attack of austenitic stainless steels,
from stress corrosion cracking and knifeline attack to pitting
and preferential attack caused by chromium depletion."
4.1.3 Off-Gas Treatment System
Several components of the off-gas treatment system were
evaluated for potential corrosion problems folio wing shutdown
of the ISTD system. Visual inspection of the interior of the
cyclone separator and the base of the FTO did not reveal any
significant corrosion. The knockout pot storage tank was also
visually inspected. The tank had accumulated approximately
200 gallons of corrosive liquids (pH approximately 0) during
operation of the off-gas treatment system. The tank was
flushed and no visual evidence of corrosion was evident,
except corrosion on the tank sight glass holder from contact
with corrosive liquid that escaped through a small leak.
However, a transfer pump and discharge line used in an initial
attempt to drain liquids from the knockout pot tank were
corroded and damaged (Versaw 2003).
The off-gas treatment system was shut down under emergency
conditions because of an operational failure (Versaw 2003).
Some liquid appeared to escape the knockout pot to the acid
scrubbers and some discoloration of acid scrubber media in
Scrubber Bed No. 1 was observed. Samples of this discolored
acid scrubber media were analyzed for remaining neutralization
potential and analytical results indicated that 75 percent of the
neutralization potential remained in the discolored media.
However, in an attempt to dry out the scrubber bed, the heat
exchanger between the FTO and the scrubber bed was
bypassed. The resulting hot air caused the combustion of
carbon in the final carbon bed that precipitated the emergency
shutdown.
Higher than anticipated heat losses in the
aboveground piping network
As discussed in TerraTherm (2002), the high level of HC1
production could have resulted from the occurrence of layers
or lenses of highly concentrated hex residues disposed of in the
Hex Pit. The tar-like waste material was disposed of in bulk or
thin-walled drums, many of which probably broke when
dumped or later corroded in the highly acidic environment.
The waste material was periodically covered with soil or lime,
eventually resulting in a mix of relatively pure waste material
sandwiched between layers of soil and lime (see also
descriptions of the Hex Pit contents in Section 2.2.3 and the
soil borehole logs in Appendix B). With the start of thermal
treatment, the tar-like waste material may have lost viscosity
and flowed into the HV wells. The heat and vacuum pressure,
combined with the presence of steam, may have allowed the
waste material to rapidly produce HC1 as it flowed into and was
drawn up inside the HV wells. The waste material may have
undergone very little in situ treatment (thermal destruction) and
the HC1 produced may not have been significantly neutralized
by the soil and lime also disposed of in the pit.
It appears that vaporized or steam-stripped contaminants
cooled in the un-heated flexible hoses that connected the HV
wells to the aboveground piping network. Cooling may have
allowed precipitates to form at the tee fittings and in the hose
end connectors, which restricted or completely blocked the
vapor flow. The resulting loss of flow velocity in the vapor
stream may have allowed the formation of corrosive liquid
condensates. Conversely, cooling may have led directly to the
formation of liquid condensates, which restricted or completely
blocked the vapor flow. Precipitates may have formed
primarily after the cessation of heating. Regardless of the
mechanism of condensate formation, the resulting aqueousHCl
is much more corrosive than HC1 in the vapor phase, and its
contact with the sy stem components at temperatures around the
boiling point of water was likely to lead to the corrosion
observed.
In summary, destruction of the ISTD system at the Hex Pit
49
-------
appears to have been primarily due to the occurrence of layers components, which were exposed to chloride attack during
of virtually pure, tar-like waste material, which was not system operation; and the inability of the system to maintain
destroyed in situ; the generation of HC1, which was not the vaporized or stream-stripped contaminants in the vapor
adequately neutralized by in situ materials; the choice of 304 phase for transport to the off-gas treatment system.
stainless steel for both aboveground and subsurface
50
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SECTION 5
REFERENCES
Colorado Metallurgical Services (CMS). 2002. Report on Evaluation of Corrosion. Prepared for TerraTherm, Inc. April.
Department of the Army. 2002. Memorandum from B. M. Huenefeld, Rocky Mountain Arsenal Committee Coordinator, to
K. Guy, U.S. Environmental Protection Agency. Subject: Draft Hex Pits Material Failure Assessment Report. April
25.
Rocky Mountain Engineering and Materials Technology, Inc. (EMTEC). 2002. Hex Pit Soil Remediation Failure Evaluation.
Prepared for David Bradfield, Foster Wheeler Environmental Corporation. July 8.
ENSR Corporation (ENSR). 1999. Hex Pit Site Characterization Report, Rocky Mountain Arsenal, Commerce City,
Colorado. Document Number 2840-005-500. August.
ENSR. 2000. Hex Pit Treatability Study Report, Part A - Treatability Test Results, Part B - Conceptual Design and Cost
Estimate. February.
Foster Wheeler Environmental Corporation (FWENC). 1996. Record of Decision for the On-Post Operable Unit, Final. Ver.
3.1. June.
FWENC. 2002. Hex Pit Remediation Project Draft Construction Completion Report. December 10.
FWENC. 2003. Amendment to the Record of Decision for the On-Post Operable Unit, Rocky Mountain Arsenal Federal
Facility Site, Hex Pit Remediation. April 17.
Gilbert, R. O. 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand Reinhold. New York, New
York.
MK-Environmental Services (MK). 1989. Investigation of the Hex Pit as a Possible Source of Groundwater Contamination at
the RMA. August.
MK. 1998. Hex Pit Design Data Collection Sampling Report. February.
Program Manager for Rocky Mountain Arsenal. 1996. Rocky Mountain Arsenal On-Post Operable Unit Record of Decision
Dispute Resolution Agreement (DRA). June 10.
Stegemeier, G. L., and Vinegar, H J. 2001. Thermal Conduction Heating for In-Situ Thermal Desorption of Soils. Ch. 4.6-1
in: Chang H. Oh (ed.), Hazardous and Radioactive Waste Treatment Technologies Handbook, CRC Press, Boca
Raton, FL.
TerraTherm, Inc. (TerraTherm). 2001. Hex Pit Remediation Final (100%) Design Package. March.
TerraTherm. 2002. Hex Pit Remediation Material Failure Assessment Report. April.
Tetra Tech EM Inc. (Tetra Tech). 2001. Draft Screening Investigation Report for the Hex Pit Screening Investigation.
January.
U.S. Environmental Protection Agency (EPA^OOO. Guidance for Data Quality Assessment: Practical Methods for Data
Analysis. QA/G-9. July.
EPA2001. Quality Assurance Project Plan, In Situ Thermal Destruction Technology Evaluation at the Hex Pit, Rocky
Mountain Arsenal, Commerce City, Colorado. June.
51
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EPA. 2002. Draft Post-Demonstration Sampling and Analysis Plan, In Situ Thermal Destruction Technology Evaluation at
the Hex Pit, Rocky Mountain Arsenal, Commerce City, Colorado. October.
Versaw. 2003. Personal communication from Ron Versaw, Foster Wheeler Environmental Corporation, to Neil Bingert, Tetra
Tech EM Inc. April 14.
52
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APPENDIX A
TERRATHERM, INC. VENDOR REPORT: IN-SITU THERMAL DESTRUCTION (ISTD)
AT ROCKY MOUNTAIN ARSENAL HEX PIT
53
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TERRATHERM, INC. VENDOR REPORT:
IN-SITU THERMAL DESTRUCTION (ISTD)
AT ROCKY MOUNTAIN ARSENAL HEX PIT
Ralph S. Baker, James P. Galligan, and John M. Bierschenk
(TerraTherm, Inc., Fitchburg, Massachusetts 01450, USA)
EXECUTIVE SUMMARY
Rocky Mountain Arsenal (RMA) is a former U.S. Dept. of Defense facility
located in Commerce City, CO, just outside of Denver, that is in the process of
undergoing remediation and conversion to one of the nation's largest urban wildlife
refuges. A unit at RMA known as the Hex Pit contains buried organochlorine pesticide
wastes, tars and residues derived from a period of post-World War II conversion of
chemical weapons facilities to commercial pesticide manufacturing. Contaminants of
Concern (COCs) identified at the Hex Pit included hexachlorocyclopentadiene (Hex),
aldrin, dieldrin, endrin, isodrin and chlordane, compounds that all have high boiling
points and are highly chlorinated. Delineation efforts identified approximately 2,550
cubic yards of impacted soil that required treatment.
Comprehensive treatability study and remedial design efforts led to the selection
of TerraTherm's patented In-Situ Thermal Destruction (ISTD) technology, also known as
In-Situ Thermal Desorption, for remediation of the Hex Pit. TerraTherm's ISTD
technology utilizes simultaneous application of thermal conduction heating and vacuum
to treat contaminated soil without excavation. As demonstrated in completed projects,
the applied heat volatilizes both water and organic contaminants within the soil, enabling
them to be carried in the vapor stream toward vacuum extraction wells. Because of the
high inter-well temperatures possible (e.g., 300-600ฐC) and the fact that the vacuum
extraction wells are also heater wells (operating at temperatures of 700-800ฐC), extracted
vapors are exposed to high temperatures over a long residence time, and a significant
percentage of the contaminant mass present in the subsurface is destroyed in situ.
Contaminants not destroyed in situ are removed with the vapor stream and treated in an
aboveground Air Quality Control (AQC) system consisting of a flameless thermal
oxizider, dry scrubbers and granular activated carbon. Based on treatability and design
work, it was anticipated that >98% of the contaminant mass present would be destroyed
in the heated soil at the Hex Pit, and that the remainder would be destroyed in the AQC
system. In addition to oversight by federal, state and local regulatory agencies, the
United States Environmental Protection Agency (USEPA) Superfund Innovative
Technology Evaluation (SITE) program, as detailed in the accompanying report,
scrutinized full-scale implementation of ISTD at the Hex Pit.
Upon the completion of the Hex Pit Treatability Study in February 2000,
TerraTherm was selected to prepare the Remedial Design, which was prepared as four
deliverables (30%, 95%, 95% Design Addendum, and 100%), the last of which was
issued as the Final Design package in March 2001. TerraTherm was awarded the
-------
remedial implementation contract in August 2001, initiated ISTD construction in
September 2001, and completed construction and shakedown in February 2002.
On March 15, 2002, 12 days into the initial heating period, acidic corrosion of
segments of the aboveground piping began to be observed, and TerraTherm recognized it
as a potentially serious problem that, if allowed to continue, could have jeopardized the
ability to collect and treat gases that were being generated from the subsurface.
Therefore, TerraTherm shut down power to the thermal wells. Air sampling and analysis
confirmed that none of the stipulated hourly rolling average air quality standards for off-
gas emissions were exceeded. Site workers were protected from exposure to
contaminants through appropriate use of Personal Protective Equipment throughout the
subsequent assessment period.
With the concurrence of our client, Foster Wheeler Environmental Corporation
(FWENC), which serves as the Program Management Contractor (PMC) at RMA; their
client, the Remediation Venture Office (RVO) which represents the responsible parties at
RMA; and the various Regulatory Agencies, TerraTherm commenced a comprehensive
assessment of the damage to its piping system, the results of which were presented in a
document entitled "Hex Pit Material Failure Assessment Report" [Assessment Report]1,
and summarized herein.
TerraTherm found a total of three manifold stubs in the aboveground piping that
failed due to acidic corrosion during operation. It appears that those failures were due to
a combination of a higher than anticipated production of hydrochloric acid (HC1) coming
out of the heater-vacuum wells, and, when exposed to the abnormally cold, subzero wind
chill, in higher than anticipated heat losses from the short uninsulated piping legs located
between the hot thermal wells and the heated manifolds. This enabled the temperature of
the vapor stream (including steam, pesticides and HC1) at such portions of the piping to
drop below the condensation points of the constituents. The resulting liquid condensate
may then, at adjacent heated locations, have reboiled, possibly repeatedly, and become
more concentrated with respect to HC1, causing acidic corrosion and failure of the
manifold stubs. TerraTherm later found that acidic corrosion of the subsurface
components was widespread, with at least some corrosion evident in approximately half
of the 56 heater-vacuum wells, but believes that most of the subsurface corrosion may
have occurred following shutdown, rather than prior to it.
All piping components, including the wells, had been constructed of stainless
steel, except for high-temperature rubber steam hose between the wells and manifolds,
which exhibited no damage. TerraTherm selected materials based on past experience
with the ISTD technology and the concentrations of HC1 vapors that were expected, as
outlined in the Design Analysis2.
TerraTherm, Inc. 2002. Hex Pit Material Failure Assessment Report. Submitted to Foster Wheeler Environmental
Corporation - Program Management Contract, Rocky Mountain Arsenal, Commerce City, Colorado. April.
2 TerraTherm, Inc. 2001. Hex Pit Remediation Final (100%) Design Package. DocumentNo. 2001-FWENC-007.
Prepared for Foster Wheeler Environmental Corporation - Program Management Contract, Rocky Mountain Arsenal,
Commerce City, Colorado. March.
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Substantial amounts of solid deposits of corrosion products such as metallic salts
and of both amorphous and crystalline organic materials were found to have accumulated
within the subsurface and aboveground piping system. It is not known to what extent
such precipitates occurred during heating, versus after the thermal wells were shut off, at
which point the wells cooled faster than the adjacent soil.
The acidic corrosion damage that occurred is without precedent considering all
seven previous completed ISTD field projects3, five of which were performed at sites
with polychlorinated biphenyls (PCBs) being present in the soil at concentrations as high
as 2% by weight (20,000 mg/kg)4, and one at a chlorinated solvent site contaminated with
tetrachloroethene (PCE) and trichloroethene (TCE). The Hex Pit piping design was
similar to what had been proven successful at those past projects. By contrast with
concentrations of contaminants present at past ISTD projects, the highest concentration of
Hex reported during the various pre-remedial investigations at the Hex Pit was 1.8%
(18,000 mg/kg)5'6. Nevertheless, it is recognized that at some locations, concentrations of
chlorinated liquid waste within the Hex Pit were probably much higher. In several of the
soil borings, tarry non-aqueous phase liquid (NAPL) pesticide wastes had been visually
observed without any intervening soil (and therefore at local concentrations of
approaching 100%, although no samples of such materials were analyzed). TerraTherm
now believes that heating enabled the pesticide NAPL to hydrolyze to HC1 as it flowed
into the heater-vacuum wells, or after it flowed into them, but in either case before it
could undergo a significant amount of in-situ treatment within the soil as had been
expected based on past ISTD projects. Hot aqueous HC1 then corroded the piping, as
confirmed by subsequent metallurgical testing.
After reconsidering what happened, it is noteworthy that as confirmed through
interviews of site workers, thin-walled drums of liquid pesticide wastes had been dumped
directly into the Hex Pit when it was filled in the early 1950s, whereupon most broke and
some limited infiltration into the soil occurred. The liquid waste was then allowed to
cool and harden, after which it was covered with lime and soil. The resulting occurrence
of neat layers or lenses of highly chlorinated tar in between layers of soil is an unusual
condition whereby the tar bodies did not occupy a porous medium. As such, the heated
tar was apparently able to flow unimpeded into heater-vacuum wells. This effect was not
anticipated.
Another contributing factor was the horizontal drilling performed by another
subcontractor to FWENC, after construction of the ISTD well field but prior to the start
of ISTD heating. During the drilling of three horizontal wells beneath the Hex Pit in
February 2002, TerraTherm observed a number of "frac-out" incidents. The horizontal
Stegemeier, G.L., and Vinegar, HJ. 2001. "Thermal Conduction Heating for In-Situ Thermal Desorption of Soils."
Ch. 4.6-1 in: ChangH. Oh (ed.), Hazardous and Radioactive Waste Treatment Technologies Handbook, CRC Press,
Boca Raton, FL.
4 France-Isetts, P. 1998. "In Situ Thermal Blankets and Wells for PCB Removal in Tight Clay Soils," Tech Trends,
EPA Region 7. (February, 1998). Available at: http://clu-in.org/products/newsltrs/TTREND/tt0298.htm
ENSR Corporation. 1999. Hex Pit Site Characterization Report, Rocky Mountain Arsenal, Commerce City,
Colorado. Doc. No. 2840-005-500. August.
Tetra Tech EMI. 2001. Draft Screening Investigation Report, Rocky Mountain Arsenal, Commerce City, Colorado.
January.
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drilling method involved injection of drilling fluids (e.g., water and drilling mud) into
each borehole under high pressure for the purpose of advancing the borehole and clearing
the cuttings from it. Resistance at the cutting head can cause the drilling fluids to over-
pressurize. A frac-out occurs when the drilling fluids, rather than returning back out the
entry point of the borehole, instead suddenly fracture the subsurface formation and
emerge at the ground surface in a pool of fluid. TerraTherm observed such pools at
several locations of the exposed soils around the ISTD well field and underneath its
surface seal at several locations during the installation of the horizontal wells. The
locations of the known frac-outs appear to correlate with locations of 1he earliest as well
as the most severe cases of corrosion during ISTD operation. The first known frac-out
occurred during the drilling of the westernmost horizontal well, and emerged close to the
location where the first two manifold taps subsequently failed. In addition, a number of
frac-outs occurred while the easternmost horizontal well was being drilled. During the
Assessment, TerraTherm noticed that seven out of the nine most severely corroded
heater-vacuum wells, plus the third failed manifold tap and the sole instance of a
corroded heater-only well, all occurred directly above the path of that easternmost
horizontal well. This seems more than can be explained by chance. TerraTherm believes
that the frac-out incidents must have caused a displacement of the pit liquids, and in
doing so the over-pressurization may have forced chlorinated tarry liquids into a large
number of the thermal wells (the open annuli of which served as paths of least resistance
providing pressure relief). Injection of tarry liquids into some of the well screens would
have loaded them with corrosive materials, predisposing them to failure. Installation of
these horizontal wells was not anticipated in the 100% Design and was added to the
project after TerraTherm was awarded the implementation contract, without any technical
input or comment from TerraTherm. The frac-outs and their effects constitute a changed
condition relative to what was known about the Hex Pit prior to design and installation,
one that TerraTherm could not have anticipated.
Conclusions of the Assessment Report included the following:
(1) TerraTherm's materials and methods of construction were not defective, and were
consistent with generally accepted practices in the remediation field.
Furthermore, the material selections (e.g., 304 stainless steel) were reasonable
based on past experience with the ISTD technology at highly chlorinated sites and
with the concentrations of HC1 that were expected. The subsurface component
design did not, however, anticipate the potential for fluid tar and very
concentrated HC1 to flow into the wells screens with virtually no in-situ treatment
or neutralization. This led to much more harshly corrosive conditions than
anticipated within the aboveground piping system.
(2) The process design was appropriate, based on what was known about the site
conditions and past experience with the ISTD technology. Specifically, the
aboveground piping was designed to withstand the expected concentrations of
vaporous constituents emanating from the heater-vacuum wells. The system
operated properly for 12 days, and the soil heated up according to expectations.
Every one of the 266 wells was equipped with a heater. That, along with
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extensive use of heated manifold piping and short uninsulated piping segments
between the heated wells and the heated manifold piping was believed, based on
past project experience, to be adequate to maintain the off-gas in the vapor state.
(3) The combination of pre-existing subsurface conditions, changes in subsurface
conditions caused by others (i.e., the "frac-outs"), and excessive heat losses
within the aboveground piping due to abnormally cold weather led to
unanticipated levels of acidic corrosion that TerraTherm did not and could not
anticipate. Such results might have been evident had a pilot study been
performed, but this step was not taken for the project. The Hex Pit project itself
was somewhat experimental by nature, in that an in-situ remediation at such a
highly concentrated chlorinated waste pit had never before been attempted. It was
in large part for this reason that it was being conducted as a USEPA-SITE
Program demonstration. The destruction of portions of the stainless steel piping
within such a short duration of heating was unprecedented with respect to past
ISTD projects conducted at similarly high temperatures and on similarly highly
chlorinated compounds, and therefore unanticipated.
Had there been sufficient time and funding, TerraTherm believes that a suitable
pilot test could have been designed and performed to determine what metallurgy would
be necessary to prevent corrosion, and/or what modifications would need to be made to
the heater-vacuum wells to address the presence of neat waste liquids. Such a pilot test,
however, would have conflicted with major remedial actions scheduled for
implementation in adjacent and surrounding RMA soils, and was thus FWENC and RVO
indicated that it was not an option.
In May of 2002, FWENC terminated TerraTherm's contract for the convenience
of the government, i.e., without fault. Under FWENC's direction, TerraTherm
demobilized from the site, and FWENC subsequently covered the Hex Pit with an interim
soil cover pending a decision on its disposition. The post-treatment sampling described
in the accompanying SITE report was conducted following its placement.
INTRODUCTION
The Rocky Mountain Arsenal (RMA) is located in Commerce City, Colorado, 10
miles northeast of Denver. The U.S. Army originally developed the 27-square mile
facility in 1942, primarily for manufacturing chemical weapons. After World War II,
parts of the facility were leased to private industry for pesticide manufacturing. RMA is
one of the U.S. Department of Defense's most complex CERCLA sites and is
administered through the RMA Remediation Venture Office (RVO), consisting of U.S.
Army, Shell Oil Co., and U.S. Fish & Wildlife Service.
Hexachlorocyclopentadiene (Hex) is an intermediary used in the production of
pesticides and was manufactured at RMA's South Plants Manufacturing Complex (South
Plants) between 1947 and 1955 (see Figure 1). Between 1951 and 1952, distillation
bottoms from the production of Hex were dumped into an unlined earthen disposal pit
(the Hex Pit), located near the northern edge of the South Plants (see Figure 1). The
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black, tar-like substance was placed in the pit in drums and bulk form. It has been
estimated that the Hex Pit contains approximately 3,200 cubic yards (cy) of pesticide
contaminated soil and waste.7 Table 1 summarizes the physical/chemical properties of
constituents of concern (COCs) identified in the Hex Pit.
Figure 1 - 1999 View of RMA's South Plants Mannufacturing Complex. None of
the structures shown remained at the time of the 2002 Hex Pit remediation.
Table 1 - Physical/Chemical Properties of Hex Pit COCs
Hex Pit COC
Hex
Al drin
Isodrin
Dieldrin
Endrin
Chlordane
Formula
C5C16
CuHsC\6
QACls
QAClsO
dzHgClsO
C^HgClg
MW
272.7
364.9
364.9
380.9
380.9
409.8
BP
239 ฐC
Similar to Hex
Similar to Hex
Decomposes
before boiling
Decomposes
before boiling
Decomposes
before boiling
VP
~20mm@ 100 ฐC
Similar to Hex
Similar to Hex
<1 mm@ 100 ฐC
200 mm @ 340 ฐC
Similar to Dieldrin
Similar to Dieldrin
MW = Molecular Weight; BP = Boiling Point; VP = Vapor Pressure.
Following detailed treatability studies and design efforts, the Hex Pit Working
Group, comprised of USEPA Region 8, Colorado Dept. of Public Health and
Environment (CDPHE), Tri-County Public Health Dept. (TCPHD), and the RVO
selected the TerraTherm In-Situ Thermal Destruction (ISTD) technology for remediation
of the Hex Pit. As demonstrated in previous completed projects, TerraTherm's patented
ISTD technology utilizes simultaneous application of thermal conduction heating and
vacuum to treat contaminated soil without excavation. The applied heat volatilizes both
water and organic contaminants within the soil, enabling them to be carried in the vapor
stream toward vacuum extraction wells. Because of the high inter-well temperatures
possible (e.g., 300-600ฐC) and the fact that the vacuum extraction wells are also heater
wells (at temperatures of 700-800ฐC), a significant percentage of the contaminant mass
present in the subsurface is destroyed in situ. Contaminants not destroyed in situ are
removed with the vapor stream and treated in an aboveground vapor treatment system.
Based on treatability and design work, it was anticipated that >98% of the contaminant
mass present would be destroyed in the heated soil at the Hex Pit, and that the remainder
would be destroyed in the Air Quality Control (AQC) unit.
7 TerraTherm, Inc. 2001. Ibid.
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This report provides a description of pre-treatment conditions at the Hex Pit, a
summary of TerraTherm's ISTD design basis, including the remedial goals and the extent
of treatment predicted, and a summary of the failure that occurred following startup, with
TerraTherm's data and evaluation of the causes of the failure.
SITE CONDITIONS/GEOLOGY
At the time of TerraTherm's remedial design effort in 2000-2001, a total of 117
soil borings had been performed in Hex Pit pre-design studies to identify the geology,
delineate the boundaries of the pit (i.e., determine the horizontal and vertical limits of the
waste), and evaluate the potential for lateral migration of the contaminants.8'9 In addition,
8 piezometer/monitoring wells were installed around the pit to determine the local depth
to groundwater (see Figure 2). The main portion of the Hex Pit is approximately 94 feet
long (north-to-south) and 45 feet wide (east-to-west). There is also a narrow 10 foot wide
portion that runs approximately 55 feet to the west of the southern portion of the pit. For
design purposes, the vertical extent of the pit and the depth to groundwater were
approximately 10 and 14 feet, respectively.
* Monitoring Well/Piezometer
ฉ Master Composite Soil Boring
Soil Boring
Delineated Limits
of Hex Pit
Extent of ISTD
Treatment Zone
T
I
I
Heater-Only
Well
Heater-Vacuum
/ Well
Horizontal
Well
Figure 2 - Hex Pit Delineation and ISTD Heater/Heater-Vacuum Well Layout, a)
Locations of soil borings used to delineate limits of Hex Pit and to produce Master
Composite for Treatability Study; b) Positions of thermal wells within and outside
delineated limits of Hex Pit, and of horizontal wells installed beneath ISTD well
field.
The Hex Pit was excavated in alluvial material generally consisting of silty to
clayey sand. The alluvial material extends to a depth of approximately 25 feet.
' ENSR Corporation. 1999. Ibid.
' Tetra Tech EM. 2001. Ibid.
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Underlying the alluvial material is the Denver Formation bedrock, which consists of
weathered clayey sandstone and sandy shale. Material within the pit consists of cover
material (a mixture of sand, gravel, and silt) and native soil and/or imported fill mixed
with waste material.
FWENC contracted with ENSR in 1999 to perform a pre-design site
characterization and treatability study. The authors of this report were employed by
ENSR at the time. The lead author assembled and analyzed a Master Composite sample
for the purpose of developing an average concentration of chlorinated pesticides (i.e., the
COCs) within the Hex Pit. In the presence of SITE Program staff, the lead author
constructed the Master Composite by mixing the entire soil column (a mixture of soil and
waste material) collected from nine soil borings installed along three transects through
the Hex Pit (three borings per transect). Table 2 presents the average pretreatment
concentrations of COCs in the Master Composite. Although pretreatment concentrations
of Polychlorinated Dibenzo-Dioxin/Furan (PCDD/F) congeners in the Hex Pit were non-
calculable due to matrix interferences, the average PCDD/F concentration in soil
expressed in units of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) Toxicity Equivalence
(TEQ) was estimated to be at least 120 ng/g. Prior to this finding, the presence of
PCDD/Fs in Hex Pit wastes had not been known, nor were PCDD/Fs stipulated as COCs
during the ISTD design or implementation.
REMEDIAL GOALS
The target performance goal set by the RMA RVO and the Hex Pit Working
Group for application of TerraTherm's ISTD technology at the Hex Pit was to achieve a
90% destruction and removal efficiency (DRE) for each of the COCs (see Table 2). The
90% DRE goals were calculated based on the average COC concentration in the Master
Composite sample (see Table 2). An additional objective critical to determining the
success of ISTD at the Hex Pit was evaluation of whether the technology could achieve
the RMA human health evaluation (HHE) cleanup criteria for COCs in soil within the
treatment area (see Table 2).
Table 2 - COC Concentrations in Master Composite and ISTD Performance Goals
Hex Pit COC
Hex
Aldrin
Chlordane (total)
Dieldrin
Endrin
Isodrin
Master Composite
Average Concentrations '
(mg/kg)
7,600
<170
670
3,100
<280
<200
Human Health
Exceedance Criteria
(mg/kg)
1100
71
55
41
230
52
Target Performance Goal
90% DRE
(mg/kg)
760
N/A
67
335
N/A
N/A
Average of duplicate samples from Master Composite Pre-Treatment. Less-than sign indicates
concentrations were less than the stated detection limits.
TREATABILITY STUDY
A bench-scale treatability study designed by ENSR and performed by an
independent laboratory (Kiber, a division of Kemron) was intended to simulate the ISTD
process and enable analysis of key process parameters including temperature and off-gas
concentrations. Hex Pit composite samples were heated in an 8-in. wide x 2-in. high x
14-in. long test cell to temperatures of 300-500ฐC over a 30-hr period. DREs exceeded
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99.5% for the COCs (Table 3), with the mass balance indicating that >99% of the ORE
was attributable to in-situ destruction.10
Table 3 - Treatability Study: Comparison of Pre- and Post-Treatment Results
Hex Pit COC
Hex
Aldrin
Isodrin
Dieldrin
Endrin
Chlordane (total)
MC Pre -Treatment
Avg. Concentrations
(mg/kg)
7,600
<170
<200
3,100
<280
670
HHE
Criteria
(mg/kg)
1,100
71
52
41
230
55
TPG
Criteria
(mg/kg)
760
N/A
N/A
335
N/A
67
Treated
@400 ฐC
(mg/kg)
2.80
3.39
3.96
2.50
5.63
2.50
Treated
@300 ฐC
(mg/kg)
2.80
3.39
3.96
2.50
5.63
2.50
ORE
%
99.981
NC
NC
99.960
NC
99.610
MC - Master Composite
TPG- Target Performance Goal
NC - Not calculable
HHE - Human Health Evaluation
DRE - Destruction and Removal Efficiency
N/A - Not applicable
Additional findings of the treatability study included the following:
Permeability of the soil/waste in both the composite samples became much
greater (e.g., 10,000 to 100,000-fold increase) following treatment. This was
primarily due to a desiccation of the clay and removal of organic material, and is
an important benefit in low permeability soils as the increased permeability
allows efficient and effective vapor capture and treatment.
Analyses of post-treatment samples indicated that ISTD also has the potential to
destroy >90% of the PCCD/F isomers tentatively identified at the Hex Pit site.
Steam distillation and volatilization were not significant removal mechanisms of
the site COCs and detected PCDD/Fs. Instead, most of these compounds were
destroyed within the soil (i.e., in situ within the test cell).
ISTD combined with vapor treatment processes (flameless thermal oxidation;
carbon adsorption) having an accumulative efficiency of >99.99999 % can be
expected to produce a 2,3,7,8-TCDD TEQ emission rate of less than 0.002 ng/m3.
This emission rate is five orders of magnitude less than published discharge rates
from municipal solid waste incinerators and two orders of magnitude less than the
recently promulgated Maximum Achievable Control Technology (MACT)
standards for new hazardous waste incinerators.
These results are consistent with past ISTD field and laboratory results.
ISTD DESIGN FOR HEX PIT
Under contract to and oversight of FWENC, TerraTherm prepared the remedial
design of the Hex Pit ISTD system, beginning in 2000. The ISTD design for the Hex Pit
was developed based on the results of the treatability studies and consideration of the
following design criteria: 1) Target treatment temperatures, 2) Heating duration, 3)
Spacing between wells, 4) Power input, and 5) Above ground treatment.
ENSR. 2000. Hex Pit Treatability Study Report, Rocky Mountain Arsenal, Commerce City, CO. February.
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TerraTherm selected the target treatment temperature (325ฐC) based on
consideration of the boiling points of the COCs (Table 1) and how the vapor pressures
and reaction kinetics (e.g., pyrolysis and oxidation reaction rates) vary as a function of
temperature. The spacing between wells and the heating duration were designed to
optimize the cost of well installation and the cost of heating (a function of power
consumption and treatment and operational costs). Consideration was also given to the
capacity of the soil to accept heat when dry, as the upper limit of the amount of power or
heat that can be input at a well is a function of the soil's dry thermal conductivity and
diffusivity. TerraTherm also conducted a field trial of the thermal wells at a clean site as
a component of the Hex Pit remedial design program.
Numerical Modeling
TerraTherm commissioned a three-dimensional, multiphase, multicomponent,
non-isothermal numerical model to simulate the behavior of water and the COCs in the
subsurface as a function of temperature and to aid in the design of the Hex Pit ISTD
system.n The model also provided valuable predictions of COC loading during various
phases of the ISTD treatment process at the Hex Pit. These phases included: 1) Heat up
of the treatment area (increase in temperatures from ~20ฐC up to 100ฐC), 2) Boiling off of
the soil moisture within the treatment zone (initial steam production or steam drive,
temperatures at 100ฐC), 3) Superheat phase (temperatures from 100ฐC to >325ฐC), and 4)
Cool down.
Figure 3 presents an example of the model's prediction of soil temperature
immediately adjacent to a heater-vacuum (H-V) well and the steam and hex production
from one of the H-V wells during ISTD treatment at the Hex Pit. Figure 3 indicates that
the initial heating was predicted to be rapid and that steam production (corresponding to
temperatures of approximately 100ฐC) was expected to be significant during the first 10
days. The initial steam flood represents the boiling off of the soil moisture present within
the Hex Pit at locations adjacent to the H-V wells. Following removal of this water,
temperatures increase above 100ฐC. Some steam continues to be produced after the
initial steam flood, and represents water entering the H-V well from points farther from
the well, and eventually includes water entering the treatment zone from the underlying
aquifer. A small amount of hex was expected to be produced at the tail end of the initial
steam flood as a result of steam stripping. At the predicted end of the primary steam
flood (-day 11), temperatures at the H-V wells were expected to rapidly increase up to
peak operating temperatures (600-700ฐC) and continue through the ensuing superheat
phase of the ISTD process. After day 18 (corresponding to H-V temperatures of
approximately 1000ฐF or 540ฐC), most of the hex was expected to be destroyed in situ
and no longer produced in significant amounts. Dieldrin and the other similar COCs are
known to decompose at these temperatures and were expected to be destroyed in situ.
The superheating of the subsurface is responsible for the very high in situ destruction
removal efficiencies predicted for the Hex Pit ISTD system. These simulation results
agreed with the bench-scale treatability studies described earlier.
Kuhlman, M. 2000. Simulations of In Situ Thermal Desorption at Rocky Mountian Arsenal Hex Pit, Prepared for
TerraTherm, Inc., by MK Tech Solutions, Inc., Houston, TX.
10
-------
900
T3
C
3
o
0.
o
in
Q
HI
Q.
E
Days of Heating
Figure 3 - Simulated Performance of the Hex Pit ISTD System
The figure can be interpreted in the following manner: Water is predicted to boil at the heater-vacuum well for ten
days, during which the soil temperature immediately adjacent to the heater-vacuum well (red curve) is 199ฐF (water
boiling temperature at 20 inches vacuum at Denver's average atmospheric pressure). Around day 10, when enough
pore water has been produced as steam (blue curve), the temperature begins to rise, the near-heater soil volume dries
out, and hex production (dashed green curve) begins. The production rapidly rises as Hex is vaporized in the steam.
Hex's partial pressure in the steam at day 12 is about 0.01 ppm. About day 14, as the temperature of the soil adjacent
to the heater-vacuum well reaches 700ฐF, steam pyrolysis of Hex becomes important. Thus, while Hex desorption
(solid green curve) continues to increase for over 20 days, the concentration of Hex in the produced gases decreases
with the increasing temperature of the soil adjacent to the heater-vacuum well. Only traces of Hex are being produced
by the time the soil adjacent to the heater-vacuum well reaches 1,000ฐF (20 days). The temperature of the soil
adjacent to the heater-vacuum well continues to rise to 1300ฐF before the heaters are turned off. Approximately 99%
of the Hex that is desorbed is predicted to be destroyed in-situ or in the heater-vacuum well. Courtesy of MK Tech
Solutions, Houston, TX.
TerraTherm selected a design heating duration of 60 to 70 days at a thermal well
spacing of 6.0 ft, with a power input rate of 315 W/ft in the non-boosted segment of the
heaters (0.5 to 10.0 ft bgs), and 400 W/ft in the boosted segment (10.0 to 12.0 ft bgs). To
reduce and spread out the anticipated peak production of steam, TerraTherm planned to
start up the well field in two to three phases several days apart. Thus, the overall period
TerraTherm allotted for heating was 85 days.
Predicted Vapor Production and Acid Gas Neutralization
TerraTherm designed the Hex Pit AQC unit by considering the amount of vapor
produced, the peak COC loads, the total amount of COC expected, the degree of
treatment required (air discharge permit requirements), the need fcr acid gas treatment,
and the criteria that dioxins not be produced. As a rule of thumb, each kilowatt of power
delivered to the subsurface is capable of generating 1 cubic foot/minute (CFM) of steam.
The Hex Pit AQC unit also included an acid-gas scrubber because of the levels of HC1
(e.g., 100s of ppm) that TerraTherm expected to be produced by the ISTD system. The
production of HC1, and the need for acid-gas treatment was determined based on the
nature of the hydrocarbons being treated (i.e., ISTD of chlorinated compounds was
expected to produce HC1), their concentrations, and the degree of natural acid-buffering
11
-------
capacity of the soil (i.e., calcium [Ca+2] and iron [Fe+3] present in the soil). TerraTherm
calculated the soil's buffering capacity based on concentrations in the Master Composite
soil of 98,500 mg/kg for Ca+2 and 28,500 mg/kg for Fe+3. Even after assuming that only
20% of the buffering capacity would be accessible to HC1 vapors, it was estimated to be
capable of providing several times the required neutralizing capacity, when compared to
the total amount of chloride present within the Hex Pit.12 It was thus expected, based on
past experience, that the presence of these buffering agents would result in neutralization
in-situ of a very high percentage of the HC1 vapors generated in-situ.
Materials of Construction
TerraTherm's design utilized materials and associated methods of construction
consistent with generally accepted practices in the remediation field. Furthermore, the
material selections (e.g., 304 stainless steel well and manifold piping) were based on past
experience with the ISTD technology as successfully used at previous ISTD field
projects, five of which were performed at sites with poly chlorinated biphenyls (PCBs)
being present in the soil at concentrations as high as 2% by weight (20,000 mg/kg).13 In
contrast with concentrations of contaminants present at past ISTD projects, the highest
concentration of hex reported during the various pre-remedial design investigations was
1.8% (18,000 mg/kg).14'15 Material selections were also based on the concentrations of
hydrochloric acid vapors that were expected (e.g., 100s of ppm), as mentioned in the
previous paragraph. The adverse effects of installing horizontal wells beneath a
completed ISTD well field and the resulting frac-out events were not taken into
consideration, since these horizontal wells were not even contemplated during the Hex
Pit ISTD remediation design period. The subsurface component design did not
incorporate the possibility that neat tar and/or very concentrated liquid HC1 would flow
into the wells screens with virtually no in-situ treatment or neutralization. The actual
subsurface corrosion conditions encountered were thus much harsher than had been
anticipated.
Overall Design and Installation
TerraTherm's final design of the Hex Pit ISTD system16 consisted of 266 thermal
wells, including 210 heater-only and 56 heater-vacuum wells installed in a hexagonal
pattern at 6.0 foot spacing and to a depth of 12.5 feet bgs (see Figures 2 and 6). The
treatment zone was to be heated over an 85-day period to inter-well temperatures of at
least 325ฐC, under an applied vacuum of 20 inches of water. A surface seal consisting of
6 inches of mineral wool insulation board sandwiched between a vapor barrier and a rain
12 TerraTherm, Inc. 2001. Ibid.
13 France-Isetts, P. 1998. "In Situ Thermal Blankets and Wells for PCB Removal in Tight Clay Soils," Tech Trends,
EPA Region 7. (February, 1998). Available at: http://clu-in.org/products/newsltrs/TTREND/tt0298.htm
ENSR Corporation. 1999. Hex Pit Site Characterization Report, Rocky Mountain Arsenal, Commerce City,
Colorado. Doc. No. 2840-005-500. August.
Tetra Tech EMI. 2001. Draft Screening Investigation Report, Rocky Mountain Arsenal, Commerce City, Colorado.
January.
16 TerraTherm, Inc. 2001. Ibid.
12
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cover was designed to ensure that the boundaries of the treatment zone would be
maintained under a net negative pressure.
The off-gas was to be treated in an AQC unit consisting of the following major
components (Figure 4): cyclone separator; Thermatrix Flameless Thermal Oxidizer
with demonstrated capability of achieving 99.99% DRE; high-efficiency air-to-air heat
exchanger; dual acid-gas scrubber beds; and dual granular activated carbon (GAC) beds.
Redundant process blowers maintained the entire system under vacuum. A continuous
emissions monitoring system (CEMS) at the stack was used to monitor progress of ISTD
treatment and to ensure compliance with the air quality discharge limits. As a precaution,
TerraTherm provided an emergency generator connected so that in the event of a loss of
grid power, an automatic transfer switch would cause the generator to start within 30
seconds and continue to power the blowers and AQC equipment throughout
HEAT EXCHANGER
ACID SCRUBBER/CARBON BEJS
ILDVERS STACK
Figure 4 - Process Flow Diagram of AQC System
such an outage. This application of ISTD in conjunction with the vapor treatment
processes utilizing destructive and/or adsorption technologies was expected to achieve an
accumulative DRE of >99.99999 %.
Post-treatment sampling of soil and waste material was to have been performed
by FWENC and by the USEPA's SITE program. Soil samples were to be collected from
within and around the perimeter of the Hex Pit, analyzed for COCs, and compared with
pre-treatment samples to evaluate the performance of the ISTD treatment. Additional
sampling of groundwater and off-gas vapors were also intended to be conducted as part
of the USEPA's SITE program and compared with initial conditions and cleanup criteria.
As discussed within the accompanying USEPA SITE Report, it was decided during the
design of the SITE demonstration to focus the post-treatment soil sampling within the
northern half of the Hex Pit, as soils within the southern half had been disturbed by
removal of the deep foundations of former Building 571B. Pre- and post-treatment soil
concentrations within the northern half of the Hex Pit were believed to be more suitable
for comparison.17
17
TetraTech. 2001. Draft Quality Assurance Project Plan, In Situ Thermal Destruction Technology Evaluation at the
Hex Pit, Rocky Mountain Arsenal, Commerce City, CO.
13
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Figure 5 presents photographs of portions of the ISTD well field and associated
surface completions at the Hex Pit, while Figure 6 presents a schematic of a cross-section
passing east-to-west through the ISTD treatment zone.
Figure 5 - Photographs of Installation and Operation of Hex Pit ISTD Well Field.
Several inches of snow cover the surface seal. In the foreground of photo at left is a
row of heater-only wells (shorter wells with electrical junction boxes on top). In the
left foreground of photo at right is a heater-vacuum well (taller well with black
vapor extraction line leading into jacketed and insulated horizontal manifold
piping). The AQC system in the background of the photo at right includes thermal
oxidizer in rear center (behind light stand); blowers and stack are at right.
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Figure 6 - Typical Cross-Section through the Hex Pit ISTD Treatment Zone,
looking from south towards north. During installation of the horizontal wells by
others, a number of "frac-outs" occurred, several above the eastern-most horizontal
well. Subsequently, during the Failure Assessment, seven out of the nine most
seriously corroded heater-vacuum wells were found to be in column "P", located
almost directly above the eastern-most of the horizontal wells. It is believed that the
"frac-outs" forced movement of hex fluids into the heater-vacuum well annuli prior
to heating, compromising their operation.
14
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ISTD IMPLEMENTATION, CESSATION AND DAMAGE ASSESSMENT
Chronology Leading to Curtailment of Operation
TerraTherm's installation of the heater and heater-vacuum wells, above ground
electrical and piping systems, the surface seal, and the off-gas treatment system
components began in November 2001 and was completed by February 15, 2002. System
shakedown followed over the next two weeks. Startup of the ISTD treatment system
began on March 3, 2002. Treatment had been expected to occur for 85 days and to be
completed by the end of May 2002, but was curtailed after only 12 days of heating. The
events leading up to this cessation, and the reasons for it, are described below.
Frac-Out Events
Prior to the start of ISTD heating operation, in February 2002, a drilling
subcontractor to FWENC installed three horizontal wells beneath the completed ISTD
well field (refer to locations indicated in Figure 2b and Figure 5), during which "frac-out"
events occurred that resulted in emergence of drilling fluids around the ISTD well field
and beneath the ISTD surface seal at a number of known locations. The horizontal wells
were an afterthought on the part of FWENC, intended to enable the water table to be
depressed in the event that wet weather caused the groundwater table to rise to near the
bottom of the Hex pit during ISTD. TerraTherm agreed with this in concept, but did not
participate in the design or implementation of the drilling itself, nor was TerraTherm
consulted on the drilling methods and their possible impacts on the ISTD project. The
horizontal drilling method that FWENC selected involved injection of drilling fluids
(e.g., water and drilling mud) into each borehole under high pressure for the purpose of
advancing the borehole and clearing the cuttings from it. Resistance at the cutting head
can cause the drilling fluids to over-pressurize. A frac-out occurs when the drilling
fluids, rather than returning back out the entry point of the borehole, instead suddenly
fracture the subsurface formation above it and emerge at the ground surface in a pool of
fluid. TerraTherm observed such pools around the completed ISTD well field and at
several locations underneath its surface seal during the installation of the horizontal
wells. TerraTherm reported these events to FWENC on February 19, 2002 in a Notice of
Changed Conditions. FWENC's response was to downplay the significance of the firac-
outs.
The locations of the known frac-outs appear to correlate with locations of the
earliest as well as the most severe cases of corrosion during ISTD operation. The first
known frac-out occurred during the drilling of the westernmost horizontal well, and
emerged close to the location where the first two manifold taps subsequently failed. In
addition, a number of frac-outs occurred while the easternmost horizontal well was being
drilled. In the Assessment Report, TerraTherm reported that seven out of the nine most
severely corroded heater-vacuum wells, plus the third failed manifold tap and the sole
instance of a corroded heater-only well, all occurred directly above the path of that
easternmost horizontal well. Considering the relatively large number of heater-vacuum
wells (56) and heater-only wells (210), this linear co-location of frac-out events and wells
showing severe corrosion is, in TerraTherm's opinion, more than can be explained by
chance.
15
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TerraTherm believes that the over-pressurization that produced the frac-out
incidents must have caused a displacement of the pit liquids, and in doing so the injection
pressure may have forced tarry liquids into a large number of the thermal wells (the open
annuli of which would have served as paths of least resistance providing pressure relief).
Injection of tarry liquids into some of the well screens would have pre-loaded them with
hex and other chlorinated pesticides. Upon being heated, they quickly hydrolyzed within
the well annuli into boiling HC1. We believe that this, in large part, led to the premature
destruction of the piping system. Absent the frac-out events, hydrolysis of the pit
contents would have occurred outside the heater-vacuum wells, and the HC1 that would
have arrived there would have been in the vapor phase, which is what the materials of
construction were designed to withstand. 304SS is far more resistant to HC1 in the vapor
phase than as a liquid. There would also have been more in-situ neutralization of acid
gas by buffering within the soil than could occur with acidic liquids forming directly in
the wells. The frac-outs and their effects constitute a changed condition relative to what
was known about the Hex Pit prior to design and installation.
Weather Conditions
Ambient temperatures during the last week of shakedown/pre-heating and during
ISTD operation were abnormally cold. Minimum ambient temperatures for the period
March 3 through March 15, 2002 are presented in Figure 7. These cold ambient
temperatures, along with average winds of 10-15 mph, had the effect of reducing the
near-surface soil temperatures prior to the start of heating. However, more significantly,
these cold temperatures may have resulted in greater than anticipated heat losses in the
vapor tees, the short (approx. 2") exposed stubs of the manifold taps, and flexible hoses
connecting these points, based on the field observations described in subsequent sections.
This, we believe, contributed to the condensation of steam, pesticide vapors and HC1
vapors and resulting accumulation of acidic, corrosive liquids at such locations.
S15
Figure 7 - Minimum daily temperatures during the period of ISTD operation as
reported by the National Weather Bureau, Denver, CO. Startup began on March 3,
and ISTD operation continued until March 15, 2002.
16
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ISTD Startup and Discovery of Initial Corrosion
Prior to energizing the well field, TerraTherm pre-heated the oxidizer and
energized all of the manifold insertion heaters to pre-heat the well field piping manifold.
The off-gas treatment system was drawing only ambient air during this pre-heating
period. On March 3, 2002, after all 56 of the heater-vacuum wells were energized and
reached their operating temperature, the fresh air inlet valves on the manifold lines were
gradually closed to allow vapors to be drawn from the subsurface into the AQC system.
On March 5, TerraTherm also energized 84 heater-only wells in the southern third of the
well field (rows 17-24). Thermocouple data (reviewed below) indicated that the well
field was heating up as expected, and the AQC system was also functioning well.
On March 15, 12 days into the initial heating period, TerraTherm operators
reported that two l-Va" diameter manifold pipe taps (i.e., vertical "tees") on manifold leg
#9 (southwestern quadrant of the well field) had tipped. These 304SS taps were located
where the steam hose leading from two adjacent heater-vacuum wells connected down
into a horizontal piping manifold. Each of the piping manifolds was being heated to
>200ฐC (>390ฐF) with insertion heaters running the lengths of the manifolds, which were
in turn insulated with calcium silicate insulation and jacketed with stainless steel. The
lower ends of the manifold pipe taps, situated inside the manifold insulation, had been
eaten away by corrosion.
ISTD Shutdown and Actions Taken
TerraTherm recognized this corrosion as a potentially serious problem that, if
allowed to continue, might jeopardize the ability to collect and treat gases that were being
generated from the heated subsurface. Therefore, TerraTherm shut down power to the
thermal wells, but continued to operate the AQC system for the next two days. Air
sampling and analysis confirmed that none of the stipulated hourly rolling average air
quality standards for off-gas emissions had been or were ever exceeded. Ste workers
were protected from exposure to contaminants through appropriate use of Personal
Protective Equipment throughout the damage assessment that followed.
With the concurrence of FWENC, the RVO and the various Regulatory Agencies,
TerraTherm commenced a comprehensive assessment of the damage to its piping system,
the results of which TerraTherm presented in a document entitled "Hex Pit Material
Failure Assessment Report" [Assessment Report]18.
Evaluation of the Initial Corrosion
TerraTherm found a total of three manifold taps in the aboveground piping that
failed due to acidic corrosion during operation. It appeared that those failures were due
to a combination of a much higher-than-anticipated production of hydrochloric acid
(HC1) coming out of the heater-vacuum wells, and, in the abnormally cold, near-zero
weather, higher-than-anticipated heat losses from the uninsulated piping connections
18TerraTherm,Inc. 2002. Ibid.
17
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located between the hot thermal wells and the heated manifolds. More specifically, the
upper ends of the vertical well field heaters within each heater-vacuum well terminated at
least 12 inches beneath the surface seal, while the connection from the wellhead to the
heated horizontal manifold consisting of heat-resistant flexible rubber steam hose (visible
in Figure 5) ranged from approximately 4 to 8 ft in length. This arrangement, coupled
with the low ambient temperatures, enabled the temperature of the vapor stream
(including steam, pesticides and HC1) at such portions of the piping to drop below the
condensation points of the constituents.
For several days during heating, TerraTherm's operators had noted the presence
of liquid condensate in a number of the flexible steam hoses, which had to be manually
emptied each shift to relieve the liquid obstruction in the hoses. Accumulation of some
liquid condensate in abnormally cold weather is not unexpected during ISTD operation
and has been observed on past ISTD projects. Nevertheless, these flow restrictions, along
with the much higher-than-expected production of HC1 (at percent levels) from the
heater-vacuum wells, are believed to have led to the corrosion of the failed manifold taps.
Under normal operating conditions, the vapor stream velocity through the
manifold taps was designed to be fairly high, estimated to be on the order of 24 ft/sec.
This flow velocity, along with the imposed vacuum of 20 to 30" water column should
have been enough to sweep liquid droplets and corrosive vapors rapidly through the taps
and minimize formation of a liquid condensate film on the interior walls of the manifold
tap. It appears, however, that as the flow obstruction became more substantial, the vapor
flow through the affected taps was reduced and eventually may have ceased. Without the
sweeping effect of the high velocity vapor stream, corrosive liquids may have been able
to condense in the approximately 2" length of exposed, uninsulated manifold tap that
protruded above the manifold pipe insulation, where the temperature dropped below the
condensation points of steam and/or contaminants. Boiling aqueous HC1 is
approximately 1000 times more corrosive than HC1 in the vapor phase. A very
aggressively corrosive liquid film may have condensed on the interior wall of the
uninsulated tap segment where it streamed down along the hot, insulated segment of the
tap. As the liquid reached the hotter segment of the tap (or possibly entered the hot 4"
manifold pipe), it is believed that the water vapor flashed to steam and carried the
corrosive acid back up into the uninsulated segment of the tap where it subsequently re-
condensed on the interior walls and again streamed down. Such a reflux cycle, if
repeated, may have had the effect of concentrating the acid to its constant-boiling
azeotrope, containing approximately 20% HC1 by weight.19 Metallurgical analysis of the
failed taps indicated they had undergone general corrosive attack, evidenced by a
reduction in wall thickness from the initial 0.125" to 0.108" over a period of several days,
which is a very high rate of metal loss. Note that TerraTherm does not believe this could
have occurred had the levels of HC1 entering the heater-vacuum wells not been so
elevated to begin with. Thus the root cause is believed to be the changed subsurface
conditions, as discussed above.
McGraw-Hill, Inc. 1974. Chemical and Process Technology Encyclopedia, p. 588.
18
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AQC Shutdown
TerraTherm mobilized its Project Engineer to the site immediately upon the
decision to shut down the well field heaters. Upon his arrival on March 16, 2002, he
discovered the presence of approximately 200 gallons of highly acidic (pH 0) condensate
in the knockout pot located between the heat exchanger and the dry scrubber vessels, and
proceeded to transfer it to the condensate storage tank that was on-site for this purpose.
While pumping an additional 300 to 500 gallons of rinse water through the knockout pot
and into condensate storage tank, some liquid was accidentally drafted over into Scrubber
Bed #1 and accumulated at the bottom of the bed. The Project Engineer immediately
bypassed Scrubber Bed #1 due to the excessive pressure drop created by the liquid
accumulation.
On March 17, attempts were made to drain water out of Scrubber Bed #1, and
later to dry it out using hot air from the oxidizer, which resulted in excess heat
inadvertently arriving at Carbon Bed #1. A brief carbon monoxide excursion was noted,
and the elevated carbon bed temperature tripped the system interlock. The TerraTherm
Operator immediately isolated the carbon and scrubber beds, closed the well field
manifold valves, and shut down the blower. Upon investigation, TerraTherm concluded
that incomplete combustion (a carbon vessel fire quenched by lack of air) had briefly
occurred in Carbon Bed #1. Neither the ISTD well field nor the AQC system were
subsequently restarted during the Assessment phase that followed.
Well Field Temperatures
It is pertinent to review the data collected by the well field thermocouples
throughout the period leading up to and following cessation of the ISTD system.
Following is a summary of the well field temperature data trends:
One heater-vacuum well in the north end of the field (HVD4) had been outfitted
with thermocouples within the heater can, in the annulus between the heater can and the
well screen, and within the sand pack just outside the well screen. A heater-only well at
the southern end of the pit (HOO16), located just south of the zone where heater-only
wells were operating, was also outfitted with thermocouples just outside the well screen.
Within 24 hours in the instrumented heater-vacuum well at the northern end of the site
(HVD4), the temperature inside the heater can was over 900ฐF, while the temperature of
the annulus between the vacuum well screen and heater can was nearly 700ฐF, and the
temperature in the sand pack just outside the well screen was over 100ฐF. However, the
soil temperature just outside the instrumented heater-only well just north of the southern
end of the pit (HOO16) remained between 50 and 60ฐF for approximately 5 days.
Heating in the southern third of the pit (Heater Rows 17-24) where heater-only
and heater-vacuum wells were all operating was progressing normally, and appeared to
be slightly ahead of schedule relative to what had been simulated during the Remedial
Design. By Day 5 of heating, soil temperatures measured in the south end thermocouple
arrays located approximately 2 feet from the wells and 7-10' deep were at or above
19
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150ฐF, while the shallower (1 to 4' deep) thermocouples were approximately 100-120ฐF.
At this time, soil temperatures approximately 3 feet from the wells were 75-100ฐF. By
heating Day 10, temperatures measured in thermocouples located 2 feet from south-end
wells were at or above the boiling point of water at the 5280-ft elevation of RMA
(200ฐF), and temperatures 3 feet from the wells were very nearly 200ฐF, again with the
exception of the l'-deep zone which was lagging 20 to 30 degrees behind.
In the northern two-thirds of the pit (Heater Rows 1-16) where only heater-
vacuum wells were operating, the temperature distributions were somewhat more
irregular, as this area did not have the benefit of superposition of heating, as did the fully
operational southern end. By Heating Day 5, thermocouples located at the southern edge
of that portion of the pit, approximately 1 foot from heater vacuum well HVD16 (Figure
8a) were approximately 250ฐF at 10' depth, and ranged from 120 to 170ฐF at the 4 to 7
foot depth ranges, while the near-surface temperature was approximately 70ฐF. By the
end of the 12-day heating period, the lO'-deep thermocouple at this location had reached
a temperature of 416ฐF, and the mid-depth thermocouples were just over 200ฐF, while the
shallow thermocouple was lagging behind at approximately 120ฐF. Further north in the
field, temperatures within 1 foot of an energized heater-vacuum well in Row 8 (HVP8)
on Heating Day 5 were at or above 200ฐF (Figure 8b), with the exception of the mid-
depth 4' deep thermocouple reading, which was approximately 125ฐF. This may be
indicative of locally saturated conditions in the mid-depth region. In contrast, soil
temperatures measured by thermocouples installed in the far northern end of the pit had
typically increased only 20 to 30ฐF and were still below 100ฐF after 12 days of heating.
Those locations that increased by 30ฐF were nearer to the operating heater vacuum wells.
This rate of heating was normal and as expected.
1 ft Horizontally from HVD16
10 20 30
Days from Startup
40
1 ft Horizontally from HVP8
10 20 30
Days from Startup
40
Figure 8a,b - Representative temperature data from thermocouple arrays located
1.0 ft horizontally from each of two heater-vacuum wells. Maximum temperatures
were achieved on day 12, at which time heaters were turned off. Deeper locations
were generally hotter, attributable to the boosted wattage in the lower two feet of
the heaters. After shutdown, temperatures equilibrated and gradually declined.
Following shutdown of the well field heaters, the soil in the pit remained hot.
Thermocouple temperatures in the southern portion of the pit generally held steady or
20
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dropped only a few degrees for the first several days after the heaters were shut down. In
some cases, the temperatures actually increased as a result of equilibration from the
radially advancing heat front to adjacent, cooler soil. One week after shutdown of the
heaters, soil temperatures in the southern end of the well field were still within 2 to 10
degrees of where they had been prior to shutdown, ranging from 170 to 210ฐF, with a few
exceptions. In the northern end of the pit where only the more widely-spaced heater-
vacuum wells were operating, temperatures changed more dramatically. Although some
soil temperatures increased slightly as a result of equilibration, the temperature of the soil
in the vicinity of the operating heater-vacuum wells generally dropped 50 to 100ฐF or
more within 1 week of shutdown. As expected, thermocouples that were more distant
from an operating heater-vacuum well, where the soil temperature was only 20 to 40ฐF
above ambient soil temperatures did not exhibit as significant a drop in temperature.
Post-Shutdown Findings
As reported in the Assessment Report, TerraTherm made numerous observations
concerning the post-shutdown conditions within the ISTD well field. These included
most prominently blockages within the aboveground vapor tees, and blockages and
corrosion within subsurface portions of the heater-vacuum wells. The following
paragraphs summarize these findings.
Approximately 30 of the 56 vapor tees (located near the tops of each of the
heater-vacuum wells) were observed to have deposits and varying degrees of clogging,
with 11 being completely clogged. In addition, both ends of the steam hose connecting
the vapor tees to the manifold pipe taps had flanged end connections. The flanged ends
of approximately 40 of the 56 flexible hoses were observed to have accumulated deposits.
Of these, approximately 12 exhibited only minor accumulations of damp red or black
tarry material. Eighteen of the hose end connections were more than 50% clogged, while
4 segments were found to be completely clogged. In most cases when significant
clogging was observed in either the vapor tee or hose connection, it was observed in both
locations.
Deposits observed ranged from yellow/orange/brown needle-like crystalline or
fibrous material, to black tarry residue and red/black muddy residue, to tan/yellow/green
or white powdery or cake-like material, in no particular pattern of occurrence. Based on
visual observations, the yellowish fibrous material was initially believed to be dieldrin or
aldrin crystals; however, laboratory testing results discussed in the Assessment Report
appear to indicate that the material was comprised predominantly of Hex rather than of
dieldrin or aldrin. There did not appear to be a discernable pattern of clogging in the
heater-vacuum wells or flexible hoses. Significant clogging, (>50% obstruction in either
the vapor tee or hose connections), was observed in heater-vacuum wells in both the fully
energized southern end and the partially energized northern end of the Hex Pit.
It is not known whether these vapor tee and hose end deposits accumulated at the
same time as the highly acidic liquid condensate that is believed to have resulted in
failure of the manifold pipe taps described above, or whether they formed afterwards,
during the period when the well field was beginning to cool. As suggested by the
21
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thermocouple data, vapors may have continued to be produced from the still hot soils for
some time after shutdown. During this time, the AQC was shut down and the well field
piping manifold was isolated such that vapors could have risen into the vacuum wells and
accumulated in the pipe manifold. The simulation (Figure 3) furthermore indicates that
the shutdown occurred when the production of Hex was starting to peak, but prior to
when Hex destruction (and therefore reduced production of Hex) would have been
expected to become predominant. Thus, the presence of Hex and related deposits within
the heater-vacuum vapor tees and hose end fittings, although undoubtedly exacerbated by
the abnormally low temperatures, may be a transient artifact of the shutdown that would
have literally evaporated and been swept into the AQC system as the well field continued
to heat up, had highly acidic and corrosive liquids not compromised the piping system
first. The few locations completely blocked with crystalline deposits may have
experienced liquid blockage of the steam hoses first, as a precondition. Otherwise, the
velocity of the vapor extraction would have tended to keep the deposits in check. It is not
possible to say what fraction of the vapor tee and hose connection clogging occurred
during the heating operation and what fraction occurred after the heating was shut down.
Based on the loss-of-flow scenario described above, it is believed that some of the
clogging occurred during the heating operation. However, the majority of the clogging is
believed to have occurred after the well heaters were shut down.
TerraTherm also found that acidic corrosion of the subsurface components,
including chloride stress corrosion cracking was widespread, with at least some corrosion
evident in approximately half of the 56 heater-vacuum wells. Most of the subsurface
corrosion probably occurred following shutdown, rather than prior to it.20 This
conclusion is based on the self-protective characteristics of thermal wells. As mentioned
above, gaseous HC1 is approximately 1000-fold less corrosive than liquid HC1.
Whenever thermal wells are energized, their operational temperatures are so high (as
exemplified by the very high 1000-1100ฐF operating temperature measured within the
annulus of HVD4, and presumably representative of all the heater-vacuum wells) that
liquids in contact with them will instantly flash to steam or other gases unless there is a
significant source of recharge of liquid to the well. It is not believed that there was such
a source of recharge within the Hex Pit. Although small, localized pockets of perched
liquid were evident during the Hex Pit site investigation, most (>95%) of the volume of
soil and waste was observed to be far below saturation. However, once the thermal wells
were de-energized, they could no longer protect themselves. The soil and waste around
them remained near the boiling temperature of water for weeks, during which it is
believed that conditions remained highly corrosive. Thus the conditions following
shutdown probably produced most of the subsurface damage observed during the
Assessment.
SITE Program Findings
TerraTherm was given the opportunity to review the final draft of the
accompanying SITE Program Hex Pit Demonstration Report. It is noteworthy that the
mean concentration of hex reported in Table 2-1 of the SITE report for the various
20 TerraTherm, Inc. 2002. Ibid.
22
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"Composite Samples from SITE Pre-treatment Sampling" (8,150 mg/kg) corresponded
well to the concentration of hex observed in the Master Composite (8,100 mg/kg), which
was the basis for the Hex Pit treatability study and the remedial design described above.
In our comments on the final draft SITE Program Hex Pit Demonstration Report,
we pointed out that given the obvious data trends, it was surprising that the authors chose
not to perform a statistical evaluation of pre- versus post-treatment concentrations of
dieldrin, the second most important COC, and aldrin, while instead including an
evaluation of trichloroethylene, a compound that was not even included among the COCs
and not present at significant concentrations. An examination of the data trends in the
SITE Program data (Table 3-4, "Summary of SITE Pre- and Post-Treatment Analytical
Results") suggests that despite the short period of operation, a significant amount of in-
situ destruction occurred with respect to dieldrin (for which the mean pre- and post-
treatment concentrations were 805 and 122 mg/kg, respectively) and aldrin (mean pre-
and post-treatment concentrations of 375 and 20 mg/kg, respectively).
LESSONS LEARNED
TerraTherm learned the following lessons from this experience, and is applying
them in current ISTD projects:
> Horizontal drilling should never be conducted beneath an already completed
ISTD well field, especially if there is any possibility of over-pressurization
leading to frac-outs.
> Include the worst-case conditions encountered in treatability studies, design
calculations and simulations.
> When contemplating applications of ISTD to treat wastes that are qualitatively
different than those previously encountered (e.g., a waste lagoon like the Hex Pit
in which the wastes may reside as neat layers of tar, rather than as residual NAPL
within a porous medium), perform a pilot test first. Such a pilot test affords the
opportunity to examine the suitability of materials of construction; assumptions
regarding off-gas production and loading rates; the time periods required to treat
the waste at a given wattage and spacing of thermal wells; etc. Consider
performing such pilot tests in worst-case locations.
> If there is a possibility that abnormally cold weather may occur during startup,
insulate and/or heat as many sections of the above-ground ISTD piping as
possible, without producing overheating of sensitive components.
> Lateral connections from ISTD heater-vacuum well vapor tees to the piping
manifold have been re-designed to prevent sagging of the flexible connector and
eliminate low-points that may serve as liquid accumulation/flow obstruction
points.
> Do not assume 90% in-situ neutralization of acids, especially in the case of
mobile, highly chlorinated NAPL.
> Use of Magnehelic gauge taps and ball valves at the vapor tee of each heater-
vacuum well, while slightly more expensive, affords the ability to confirm flow
from each heater-vacuum well, and to rebalance such flows under changing
conditions during treatment.
23
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CLOSING
As mentioned in the Executive Summary, in May 2002, FWENC Terminated
TerraTherm's Subcontract for the Convenience of the Government, and subsequently
reached a settlement with TerraTherm that recognized no fault on the part of either party.
TerraTherm is releasing this report in an effort to promote a better understanding of the
conditions that led to and resulted in the cessation of this project, in hopes that future
applications of the ISTD technology will benefit from what was learned.
It must be emphasized that what occurred at the Hex Pit was unprecedented
relative to prior applications of the ISTD technology, five of which were performed at
sites with polychlorinated biphenyls (PCBs) being present in the soil at concentrations as
high as 2% by weight (20,000 mg/kg), and one at a chlorinated solvent (PCE/TCE) site.
The Hex Pit ISTD piping design was similar to what had been proven successful at those
past projects. By contrast with concentrations of contaminants present at past ISTD
projects, the highest concentration of hex reported during the various pre-remedial
investigations was 1.8% (18,000 mg/kg). Field project experience from the completed
ISTD projects and laboratory treatability studies, including the treatability test performed
on Hex Pit waste material, indicate that high subsurface temperatures maintained over a
period of days are capable of extremely high in situ destruction removal efficiencies of
even high boiling point contaminants such as PCBs, pesticides, PAHs and other heavy
hydrocarbons. Despite high pre-treatment concentrations, post-treatment soil
concentrations have typically been non-detect. ISTD thus offers a means to reliably
achieve stringent cleanup goals that have not been previously possible by other in situ
treatment technologies.21'22
ACKNOWLEDGEMENTS
The authors wish to acknowledge Keith Bowden of TerraTherm, Inc. for
supervising the ISTD construction, Glenn Anderson for supervising the Damage
Assessment and demobilization, Denis M. Conley of Haley and Aldrich, Inc., Houston,
TX for providing emissions-related technical support, Myron Kuhlman of MK Tech
Solutions, Inc., Houston, TX for providing numerical modeling simulations of the ISTD
processes, Steve Hall of Kemron Environmental Services Inc., Norcross, GA for
performing the treatability study, and John LaChance of TerraTherm for support.
Baker, R.S., J. M. Bierschenk. 2001. "In-Situ Thermal Destruction Makes Stringent Soil and Sediment Cleanup
Goals Attainable," Fourth Tri- Services Environmental Technology Symposium, San Diego, CA.
Stegemeier and Vinegar, 2001. Ibid.
24
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APPENDIX B
RVO REPORT: HEX PIT REMEDIATION PROJECT: IN-SITU THERMAL DESORPTION (ISTD)
REMEDY FAILURE ASSESSMENT REPORT 2002
54
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Hex Pit Remediation Project
In-Situ Thermal Desorption (ISTD) Remedy
Failure Assessment Report
2002
This Failure Assessment Report was prepared by the Remediation Venture Office (RVO). This
failure assessment summarizes information in documents in the Administrative Record, which present
the hex pit history, technology selection, remedial design, treatability study, field implementation, and
subsequent failure of the In-Situ Thermal Desorption (ISTD) remedy.
Record of Decision (ROD) Remedy Description
The ROD for Rocky Mountain Arsenal (RMA) identifies the remedy for the Hex Pit site as,
"Treatment of approximately 1,000 bank cubic yards (bey) of principal threat material using an
innovative thermal technology. The remaining 2,300 bey are excavated and disposed in the on-post
hazardous waste landfill. Remediation activities are conducted using vapor- and odor-suppression
measures as required. Treatability testing will be performed during remedial design to verify the
effectiveness of the innovative thermal process and establish operating parameters for the design of
the full-scale operation. The innovative thermal technology must meet the treatability study
technology evaluation criteria described in the dispute resolution agreement (PMRMA 1996).
Solidification/stabilization will become the selected remedy if all evaluation criteria for the
innovative thermal technology are not met. Treatability testing for solidification will be performed to
verify the effectiveness of the solidification process and determine appropriate
solidification/stabilization agents. Treatability testing and technology evaluation will be conducted in
accordance with EPA guidance (OSWER-EPA 1989a) and EPA's "Guide for Conducting Treatability
Studies under CERCLA" (1992)."
Technology Choice
The Innovative Thermal Technology Evaluation Report for the Hex Pit Site at RMA, prepared by the
Colorado Department of Public Health and the Environment (CDPHE), Tri-County Health
Department (TCHD), and the United States Environmental Protection Agency (EPA), was finalized
on September 10, 1998. (HPWG 1998) This report documented the comparative analyses and
evaluation process that lead to the final selection of ISTD as the most technically appropriate
technology for this site. Of the 12 innovative thermal technologies investigated, ISTD was chosen to
be the most technically appropriate using characteristics of effectiveness, implementability, and cost.
At the time of selection of this technology, no full-scale ISTD operations had been conducted on
sludge or buried drums. However, bench-scale tests indicated the operation was likely to be
successful for both. (ENSR 2000)
Site History
The Hex Pit site covers approximately 205 square yards and is located in Section 1 of the RMA near
the north boundary of the South Plants Central Processing Area (SPCPA). The Hex Pit was used
between 1950 and 1952 to dispose of residual materials (tar-like, chlorinated organic, resinous
material called Hex bottoms or Hex residue) resulting from the production of
hexachlorocyclopentadiene (Hex, also known as HCCPD and CL6CP). The material was buried in
drums and in bulk and the pit was covered with several feet of soil. During site investigation work, it
was clearly demonstrated that the site contained not only contaminated soil but also lenses of pure
waste. Concentrations of HCCPD obtained through sampling ranged up to 160,000 parts per million
(ppm). The primary contaminant of concern at the site is HCCPD. However, other organic pesticide
and dioxin contamination is present at the site as well. HCCPD characteristics include a relatively
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high boiling point and the tendency to corrode iron and other metals. It is a semi-volatile organic
compound with a strong tendency to adsorb onto organic matter. It has low water solubility and a
high organic partitioning coefficient, which indicates a relatively immobile contaminant. Immobility
of the waste pit material was demonstrated through synthetic precipitation leaching procedure (SPLP)
testing performed July 2002, after system failure. (RVO 2002)
ISTD Technology Description
ISTD is an in-situ remediation process involving the application of heat and a vacuum simultaneously
to subsurface contaminated soils. Heat and vacuum are applied to the subsurface through the use of
heater and heater vacuum wells. As heat is applied and soil temperatures rise, the vaporized
contaminated fluids are collected by the vacuum system and drawn into an off-gas treatment system.
Destruction of contamination is most effective once heater wells have reached higher temperatures
(>250 C). At the start of heating, higher amounts of water vapor, carbon dioxide, and hydrochloric
acid (HC1) are present. As configured for the Hex Pit remediation, the vacuum system delivers the
vapors to a mobile off gas treatment unit consisting of six major components: cyclone separator,
flameless thermal oxidizer (FTO), heat exchanger, two acid gas scrubber beds, two carbon adsorber
beds, and main process blower. The system also contained a knockout pot for collection of HC1. The
knockout pot was located between the heat exchanger and the acid gas scrubber beds.
Treatability Study Report (TSR), Feb 2000
A Treatability Study (TS) was performed in late 1999 with its report completed February 2000.
(ENSR 2000) Some of the conclusions reached by the TS were:
HC1 vapor and sulfur dioxide (SO2) gas were produced from the thermal oxidation and/or
pyrolysis of the site contaminants of concern (COCs), and may require treatment during full-scale
remediation.
PCDD/F cogeners (dioxins) were detected in the Master and Waste Composite samples and in the
post-treatment samples
Analytical PCDD/F results for the Waste Composite test sample could not be quantitated due to
their high concentration
Steam distillation and volatilization were not significant removal mechanisms of the site COCs
System Failure
Construction of the ISTD system started in October 2001, and field implementation of the process
began in March 2002. As the soil and waste became heated, the contaminants were being destroyed as
planned, releasing the chlorine present in the waste. When mixed with heated water from the
surrounding soil, HC1 vapor was formed.
The sequence of events leading to system shutdown are:
On the morning of Thursday 3/14/02, one of the 1.5-inch by 6-inch long flanged nipples that were
welded to the 4 inch manifold piping on the western most vacuum pipe spool appeared to be
leaning over. The manifold tap was connected to well HVGG18. Inspection determined the
welded joint between the 1.5 inch flanged tap and the 4 inch manifold pipe had failed. The
reason for the failure (faulty weld or corrosion) could not be readily determined with the
insulation in place. During the overnight shift on Thursday 3/14/02 PM - Friday 3/15/02 AM, a
second flanged nipple, this one connected to well HVKK18, was observed to be leaning over,
and, upon inspection, appeared to be in a similar condition.
During the overnight shift on Thursday 3/14/02 PM - Friday 3/15/02 AM, the RTV caulk
between the well and the steel plate was apparently pulled apart while the ISTD operator was
walking in the vicinity of well HVGG18. As a result, steam began escaping from the torn RTV
seal. It should be noted that due to the thermal expansion the ISTD thermal wells undergo upon
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heating, the RTV seals would need to be regularly checked and re-applied as necessary
throughout the project. The appearance of vapor was disconcerting and an indication of low
vacuum in the well field.
On the afternoon of Friday, 3/15/02, it was discovered there was no amperage to heater circuit
CB7 and that CB7 in DP2 was in the tripped position. Since there appeared to be a problem with
the heaters in one of the heater-vacuum well circuits, TerraTherm decided to shut down all of the
currently operating well heaters.
The electricians determined the location of the failed heater element in the heater vacuum well.
The NEMA housing was removed revealing that acidic material had collected in the housing.
Several unsuccessful attempts (in Level B) were made to remove the heater element and/or the
heater can (3 inch Stainless Steel pipe) housing the heater element. Apparently, when the heater
element shorted, it arced sufficiently to weld the heater can to the Stainless Steel vacuum well
casing that surrounds it. The determined cause for failure of the heater element was extensive
acid corrosion.
TerraTherm donned Level B personal protective equipment (PPE) and went into the well field
Saturday, 03/16/02. The flanged nipples were easily removed as only the RTV caulk was holding
them in place. It was clear failure occurred because of acidic corrosion from the HC1 produced
by the system. Approximately 2 inches of the pipe was completely corroded and the rest was
very thin or perforated. The apparent cause was rapid cooling and condensation of the hot HC1
vapors emerging from the heater vacuum wells after hitting the exposed metal flange and nipple.
Liquid HC1 is many times more corrosive than the hot vapor phase gas.
The in-line insertion heater in the same manifold pipe as the two failed nipples, shorted against
the thermocouple wire. The pipe housing the insertion heater was pressure tested and held
meaning it had not also been compromised to the point of failure yet by the acid in the manifold.
The failure of this heater and thermocouple precipitated the first of the two FTO shutdowns. The
FTO shut down twice over the weekend.
The knockout pot sight glass was discovered to be slowly leaking. Upon investigation,
approximately 200 gallons of nearly 0 pH HC1 were discovered in the tank.
In the process of removing the HC1 from the knockout pot and rinsing the tank, excessive water
was drawn by vacuum into the first acid gas scrubber bed. The acid gas scrubber bed was
flooded, effectively making it impermeable. When this occurred, there was such vacuum loss
through the tank that the flow out of the well field dramatically dropped and caused the second
FTO shutdown. As much weakly acidic liquid as possible was pumped from the acid gas
scrubber bed. The ambient airflow through the heat exchanger was dropped to raise the exhaust
temperature in hopes of drying the acid gas scrubber bed. In the meantime most of the airflow
was diverted through the carbon absorber beds. This resulted in a fire in the first carbon adsorber
bed. The entire system had to be shut down.
Upon further inspection of various wellfield components it was determined that most of the
system had some degree of damage due to corrosive HC1.
As part of the ISTD subcontractor assessment, 23 samples of liquid and solid residues were
collected from various locations throughout the wellfield and off-gas treatment system. The pH
of all samples was acidic and Hex was the most commonly detected and most concentrated
organochlorine pesticides in the solid samples. The maximum concentration detected was
148,000 ug/g (comparable to maximum level identified in previous studies). Chloride was the
most common anion detected with a maximum value of 237,000 ug/g in solids and a maximum of
284,000 mg/L in liquid samples.
The corrosion resulted in failure of some of the ISTD process equipment and forced a shutdown of
the entire system. The ISTD design anticipated that the HC1 formed would be largely neutralized by
the higher pH of the surrounding soil; however, this did not occur. Assessment of the system
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indicated that the corrosion rate of the HC1 for the system materials was greater than anticipated
resulting in the failure. Large volumes of highly concentrated HC1 vapor were drawn into the vacuum
wells, piping, and process equipment. This vapor, as it condensed, began to corrode the piping, wells
and other process equipment. The first corrosion failures detected were in uninsulated areas of the
well field.
The ISTD subcontractor identified extremely cold weather as a contributing factor to failure due to
greater than anticipated heat losses in uninsulated piping. These conditions should have been
foreseen, and the uninsulated piping design probably was a contributing factor to failure, since during
the design of the project, the remediation system was always scheduled to occur during the winter
months to avoid high groundwater and high summer electrical demand.
There was speculation if the majority of clogging in the vapor tees and hoses occurred prior to or after
the heaters were shut down. There were several documented occurrences when vacuum loss occurred
prior to heater shutdown. The increasingly difficult to achieve vacuum on the well field prior to
shutdown indicates that clogging was occurring during heating. Clogging may have been exacerbated
once heaters were shut down due to continued condensation caused by cooling.
There was also speculation if corrosion occurred primarily before or after shutdown of the heaters. It
would seem obvious that corrosion occurred before shutdown due to the fact that the heaters were
shut off after corrosion had already caused two different pieces of aboveground wellfield equipment
to fail. At that point, with further investigation, the corrosion was discovered to be widespread. No
definitive conclusion can be made as to whether most of the corrosion occurred pre- or post-
shutdown.
Another concern was if there were any potential impacts from horizontal well installation to the
heater well field. During well installation, drilling mud frac out (loss of drilling muds or fluids)
occurred twice within the Hex Pit boundary. The ISTD subcontractor suggested there was potential
that the frac out events may have caused hex to be forced into the heater wells, changing the
underground conditions. This seems unlikely given the volume of drilling mud calculated to have
been lost during the frac out events was minimal (800 gallons or less). The total estimated quantity of
soil moisture in the Hex Pit is greater than 170,000 gallons, so suggesting that the addition of up to
800 gallons of frac-out liquid could move Hex contamination around or could increase the rate or
quantity of HC1 formed during heating seems unlikely. It is also unlikely that the very low pressure
(8 psi) used to install the horizontal wells would have been sufficient to move a much higher density
and viscous (tar-like) material such as hex. It was noted during the follow-up remediation that upon
completion of the excavation to elevation 5250.0 (approximately. 8 feet above the horizontal wells)
there was no evidence of drilling mud frac out on the excavation surface.
The ISTD technology has changed hands throughout the process of technology selection, design, and
implementation. Although the company names have changed over this period of time, the same
initially identified experts have remained. Concerns as to HC1 generation during the treatment
process were expressed to the ISTD experts as early as the Draft sampling and analysis plan for the
technology selection in 1999. Per the experts' advice, samples were analyzed for chlorine,
chlorinated COCs, and total chlorine in the airstream from the technology selection. This information
was to be used by the ISTD subcontractor to design the system to account for HC1 generation during
treatment. The 100% design (Section 5.3, 5.4, Appendix A) included requirements for robustness of
materials to withstand extreme temperatures and a corrosive atmosphere of HC1. Of potential impact
to robustness was the decision by the ISTD designer to replace the previously used wells with Gen 2
Heater well designs. The original well design called for the use of expensive materials. The designer
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never metallurgically tested materials in order to select correct materials for the system in this
environment.
Again, Section 6.1.2 of the design states that highly chlorinated vapors will be present in the
subsurface during heating. (TerraTherm 2001) The design concluded that the corrosive environment
necessitated the use of heater cans to protect the heater elements. In the field, the heater cans proved
ineffective against the environment and in protecting the heater elements. Throughout the design, a
highly corrosive atmosphere is acknowledged by the ISTD designer, yet the material specified for the
equipment is consistently stainless steel (304L). This type of stainless steel is generally the least
expensive and the least acid corrosion resistant stainless steel available.
In RVO's evaluation, the primary causes of failure of this system were due to an underestimation of
volume of HC1 generation during remediation, an inappropriate equipment material choice for the site
conditions, and an overestimation of buffering capacity of surrounding soils. There were also
contributing factors to the failure such as uninsulated piping where cold temperatures caused
condensation of HC1 vapor, and shutdown of the off gas treatment system exacerbating condensation.
REFERENCES
ENSR (ENSR Corporation)
2000 (Feb.) Hex Pit Treatability Study Report (TSR), Part A - Treatability Test Results,
Part B - Conceptual Design and Cost Estimate.
HPWG (The Hex Pit Working Group)
1998 (Sept.) Innovative Technology Evaluation Report for the Hex Pit Site at Rocky
Mountain Arsenal.
RVO (Remediation Venture Office)
2002 (Aug.) Hex Pits Leachate Investigation Summary Report
TerraTherm (TerraTherm, Inc.)
2001 (Mar.) Hex Pit Remediation Final -100% Design Package
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APPENDIX C
DATA VALIDATION SUMMARY REPORTS
60
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MEMORANDUM
To: ISTD File
From: Harry Ellis
Date: July 1, 2002 (revised February 11, 2003 by Neil Bingert)
Subject: Data Validation for Pre-Demonstration Samples (VOC, SVOC, and Pesticide Analyses)
This memorandum documents a data validation of the analytical results from soil, waste, and groundwater
samples collected during predemonstration sampling for the In Situ Thermal Destruction (ISTD)
Technology Evaluation at the "Hex Pit" of the Rocky Mountain Arsenal, Adams County, Colorado. Tetra
Tech EM Inc. (Tetra Tech) supported the U.S. Environmental Protection Agency (EPA) with the
sampling effort as contracted under the Field Evaluation and Technical Support (FEATS) program.
Tetra Tech collected 30 soil samples (plus two field replicate samples), 15 waste samples (plus two field
replicates), and four groundwater samples from July 12 to 30, 2001. The samples were accumulated at
the site for 2 or more days, and sent by overnight courier to Accura Analytical Laboratory (AAL) of
Norcross, Georgia. AAL analyzed each day's shipment as a separate sample delivery group (SDG), Nos.
28376, 28404, 28443, 28451, 28467, 28502, and 28509. Some samples were analyzed by EPA Test
Methods for Evaluating Solid Wastes (SW-846) Method 8270C for hexachlorocyclopentadiene only.
Some samples were analyzed by EPA SW-846 Methods 8260B, 8270C, and 8081A for a full array of
volatile organic compounds (VOC), semivolatile organic compounds (SVOC), and organochlorine
pesticides, respectively. Most samples received only one or two analyses.
The data were evaluated in general accordance with the EPA Contract Laboratory Program National
Functional Guidelines (NFG) for organic data review, dated October 1999. The EPA test methods
provide guidance on procedures and method acceptance criteria that, in some cases, differ from those in
the NFG. When differences exist between the EPA test methods and the NFG, the data validation
followed the acceptance criteria given in the methods. In addition, if the data package presented
laboratory-specific acceptance criteria, these criteria were used to evaluate the data unless the criteria
were considered inadequate. In cases where the criteria in Section 6.0 of the quality assurance project
plan (QAPP) are different from the others, the QAPP criteria are used in the validation. The evaluation of
the data was based on the following parameters:
Data package completeness
Holding times
Gas chromatography/mass spectroscopy (GC/MS) instrument performance check
1
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TABLE 1 (Continued)
SUMMARY OF PREDEMONSTRATION SAMPLES
Initial and continuing calibrations
Blanks
Matrix spike/matrix spike duplicate (MS/MSD) analyses
Laboratory control samples (LCS)
Internal standards
Surrogate recoveries
Compound quantitation
Table 1 lists all samples, SDGs, and analyses performed.
TABLE 1
SUMMARY OF PREDEMONSTRATION SAMPLES
Sample
PRE-S-E1
PRE-S-E2
PRE-S-E3
PRE-S-E4
PRE-S-E5
PRE-S-E6
PRE-S-E7
PRE-S-E8
PRE-S-E9
PRE-S-E10
PRE-S-E11
PRE-S-E12
PRE-S-1 (VOC)
PRE-S-1 (0-2)
PRE-S-1 (10-12)
PRE-S-1 (12-13)
SDG
No.
28376
28376
28404
28404
28376
28376
28376
28404
28404
28404
28404
28404
28443
28443
28443
28443
Analyses Performed3
Hex
X
X
X
X
X
X
X
X
X
X
X
X
X
VOC
X
svoc
X
X
OCP
X
X
X
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TABLE 1 (Continued)
SUMMARY OF PREDEMONSTRATION SAMPLES
Sample
PRE-S-2 (0-2)
PRE-S-2 (10-12)
PRE-S-2 (12-13)
PRE-S-3 (0-2)
PRE-S-3 (10-12)
PRE-S-3 (12-13)
PRE-S-6 (VOC)
PRE-S-14 (VOC)
PRE-S-15 (VOC)
PRE-S-16 (VOC)
PRE-S-23 (VOC)
PRE-S-3 1 (VOC)
PRE-S-33 (VOC)
PRE-S-36 (VOC)
PRE-S-301 (12-13)b
PRE-S-302 (12-13)b
PRE-W-1 (VOC)
PRE-W-1
PRE-W-2
PRE-W-3
PRE-W-4
PRE-W-5
PRE-W-6
PRE-W-6 (VOC)
PRE-W-1 4 (VOC)
PRE-W-1 5 (VOC)
PRE-W-1 6 (VOC)
PRE-W-23 (VOC)
PRE-W-3 1 (VOC)
PRE-W-3 3 (VOC)
SDG
No.
28467
28467
28467
28451
28451
28451
28467
28467
28451
28443
28451
28443
28443
28443
28451
28451
28443
28443
28467
28467
28451
28451
28443
28467
28467
28451
28443
28451
28443
28443
Analyses Performed3
Hex
X
X
X
X
VOC
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
svoc
X
X
X
X
X
X
X
X
X
X
OCP
X
X
X
X
X
X
X
X
X
X
X
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TABLE 1 (Continued)
SUMMARY OF PREDEMONSTRATION SAMPLES
Sample
PRE-W-36 (VOC)
PRE-W-201C
PRE-W-202C
PRE-GW-01111
PRE-GW-01112
PRE-GW-01113
PRE-GW-01114
SDG
No.
28443
28467
28467
28502
28502
28509
28509
Hex
X
X
X
X
Analyses Performed3
VOC SVOC
X
X
X
OCP
X
X
Notes:
b
c
HEX = Hexachlorocyclopentadiene only
VOC = Full volatile organic compounds list
SVOC = Full semivolatile organic compounds list
OCP = Organochlorine pesticides
Field replicate of sample PRE-S-3 (12-13)
Field replicate of sample PRE-W-2
1.0 HEXACHLOROCYCLOPENTADIENE ANALYSES
This section discusses the SVOC analyses performed for hexachlorocyclopentadiene. Table 2 includes
validated results for that compound, including those that were derived during analyses for the full list of
SVOCs that are discussed in Section 3.0. No problems were noted with data package completeness,
GC/MS instrument performance check, initial and continuing calibrations, blanks, internal standards, or
compound quantitation.
Due to a login error, sample PRE-GW-01112 was extracted 8 days after collection, just beyond the 7-day
holding time. In addition, the LCS accompanying the initial full-list SVOC analyses was spiked only
with hexachlorocyclopentadiene. As a result, these samples were re-extracted with new quality control
(QC) samples as much as 2 weeks after the expiration of their holding times. However,
hexachlorocyclopentadiene is a relatively stable compound and no qualifications will be applied for these
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holding time exceedances.
The MS/MSD analysis with SDG Nos. 28502 and 28509 was performed on sample PRE-GW-01112.
Recoveries were 23 and 32 percent, respectively, and recovery from the accompanying LCS sample was
37 percent, versus QC requirements of 50 to 150 percent recovery for both MS and LCS analyses. The
MS/MSD analysis also yielded an excessive relative percent difference (RPD) between the two
recoveries. The results for hexachlorocyclopentadiene in the samples in that SDG are flagged "UJ" to
indicate that the reporting limits are estimated, biased low.
Several sample extracts were diluted so much that surrogate recovery could not be determined. No
qualifications are warranted for these data gaps.
Quantitative results were calculated correctly, with soil results corrected to dry weight. Most soil and
waste samples were extracted by the medium-level procedure. Extracts were diluted as necessary to bring
all positive results within calibration range, so no qualifications are required for quantitation problems.
TABLE 2
HEXACHLOROCYCLOPENTADIENE RESULTS
Sample
PRE-S-E1
PRE-S-E2
PRE-S-E3
PRE-S-E4
PRE-S-E5
PRE-S-E6
PRE-S-E7
PRE-S-E8
PRE-S-E9
PRE-S-E10
PRE-S-E11
PRE-S-E12
PRE-S-1 (0-2)
PRE-S-1 (10-12)
PRE-S-1 (12-13)
Concentration
360 U
370 U
370 U
370 U
370 U
360 U
370 U
370 U
370 U
370 U
360 U
370 U
11,000 U
5,800,000
1,100,000
Units
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
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Notes:
U
TABLE 2 (Continued)
HEXACHLOROCYCLOPENTADIENE RESULTS
Sample
PRE-S-2 (0-2)
PRE-S-2 (10-12)
PRE-S-2 (12-13)
PRE-S-3 (0-2)
PRE-S-3 (10-12)
PRE-S-3 (12-13)
PRE-S-301 (12-13)3
PRE-S-302 (12-13)3
PRE-W-1
PRE-W-2
PRE-W-3
PRE-W-4
PRE-W-5
PRE-W-6
PRE-W-201b
PRE-W-202b
PRE-GW-01111
PRE-GW-01112
PRE-GW-01113
PRE-GW-01114
Concentration
2,800 J
1,800,000
1,300,000
63,000
4,400,000
920,000
1,300,000
1,300,000
5,500,000
8,600,000
7,800,000
6,000,000
11,000,000
9,500,000
8,900,000
9,800,000
10 UJ
10 UJ
10 UJ
10 UJ
Units
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/L
Mg/L
Mg/L
Ug/L
UJ
Micrograms per kilogram
Micrograms per liter
Hexachlorocyclopentadiene was not detected. The reported numerical value is
the sample quantitation limit.
Hexachlorocyclopentadiene was detected, but the result is considered to be
estimated for quality control reasons.
Hexachlorocyclopentadiene was not detected. The sample quantitation limit is
considered to be estimated for quality control reasons.
Field replicate of sample PRE-S-3 (12-13)
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TABLE 2 (Continued)
HEXACHLOROCYCLOPENTADIENE RESULTS
Field replicate of sample PRE-W-2
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2.0 VOLATILE ORGANIC COMPOUND ANALYSES
This section discusses the results for VOC analyses. Table 3 contains validated results for all samples;
only the target compounds reported in at least one sample are listed. No problems were noted with data
package completeness, holding times, GC/MS instrument performance checks, LCS analyses, or internal
standards. No MS/MSD analyses were performed on samples collected for VOC analyses.
All initial calibration results on both instruments were within QC limits. In the first continuing
calibration on the instrument used for the low-level analyses, dichlorodifluoromethane and isobutyl
alcohol yielded percent differences (%D) above the QC limit of less than or equal to 25 percent. In the
second continuing calibration on that instrument, acetone and methylene chloride yielded %Ds over the
25 percent QC limit. In the only continuing calibration on the instrument used for the medium-level
analyses, dichlorodifluoromethane and pentachloroethane yielded excessive %Ds. Results for the named
compounds are flagged "J" or "UJ," as appropriate, in the associated samples to indicate that they are
estimates.
The laboratory blanks contained trace levels of 1,2-dichlorobenzene and chloromethane. Similar
concentrations of those compounds in some samples were flagged "U" to indicate that they may be
laboratory artifacts.
Samples PRE-W-1, PRE-W-16, and PRE-W-33 had recoveries of the third (of three) surrogates,
4-bromofluorobenzene, above the QC limits during low-level analyses. This exceedance was caused by a
matrix interference noted in the chromatograms that was confirmed by the absence of surrogate
irregularities in the medium level analyses. All positive results for those samples that were derived from
the low-level analyses are flagged "J" to indicate that they are estimates.
The VOCs in these samples displayed a wide range of concentrations, much wider than the calibration
range. Most samples were analyzed twice, with the second time at a dilution or by the medium-level
procedure, in an attempt to bring results within that calibration range. However, the available quantity of
sample limited the reanalyses, especially at the lower concentration end, which requires more sample
mass. Despite the laboratory's efforts, some results, such as carbon tetrachloride in sample PRE-S-1, are
below the calibration range and others, such as chloroform in that same sample, are above the calibration
-------
range. All such extrapolations are flagged "J" to indicate that they are estimates. The laboratory
calculated results correctly, including adjustment to dry weight for soil samples.
-------
TABLE 3
VALIDATED RESULTS OF VOLATILE ORGANIC COMPOUND ANALYSES (jig/kg)
Sample:
1,1,1 ,2-Tetrachloroethane
1,1,1 -Trichloroethane
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethene
1 ,2,3 -Trichloropropane
1 ,2-Dichlorobenzene
1 ,2-Dichloroethane
1 ,2-Dichloropropane
1 ,3 -Dichlorobenzene
1 ,4-Dichlorobenzene
2-Butanone
2-Hexanone
4-Methyl-2-pentanone
Acetone
Acrolein
Benzene
Bromomethane
Carbon disulfide
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
PRE-S-1
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
3.0 U
30 U
30 U
30 U
5.7 J
60 U
0.75 J
3.0 U
3.0 U
0.38 J
3.0 U
3.0 U
240 J
PRE-S-6
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
1.8 J
28 U
28 U
14 J
56 U
0.33 J
2.8 U
2.8 U
3.0
2.8 U
2.8 U
64
PRE-S-14
2.9 U
2.9 U
2.9 U
2.9 U
2.4
1.3 U
2.9 U
2.9 U
2.9 U
0.41 J
2.9 U
1.3 J
1.3 J
29 U
29 U
16 J
57 U
26
2.9 U
2.9 U
25
1.1 J
2.9 U
3,700
PRE-S-15
3.7 U
3.7 U
3.7 U
3.7 U
4.1
3.7 U
3.7 U
7.3
3.7 U
3.7 U
3.5 J
29
17 J
37 U
0.99 J
370 J
75 U
42
3.7 U
0.78 J
2.0 J
7.7
3.7 U
8.3
PRE-S-16
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
3.4 U
5.4 J
34 U
34 U
28 J
68 U
0.67 J
3.4 U
3.4 U
56
3.4 U
3.4 U
100
PRE-S-23
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
0.40 J
2.0 J
28 U
28 U
18 J
56 U
2.8 U
2.8 U
2.8 U
8.4
2.8 U
2.8 U
290
PRE-S-31
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
2.2 J
33 U
33 U
84 J
66 U
3.3 U
3.3 U
3.3 U
27
3.3 U
3.3 U
720 J
PRE-S-33
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
3.3 U
1.5 J
33 U
33 U
6.9 J
65 U
0.35 J
0.45 J
3.3 U
5.5
3.3 U
3.3 U
39
PRE-S-36
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
2.8 U
1.9 J
28 U
28 U
13 J
57 U
2.8 U
0.31 J
2.8 U
12
2.8 U
2.8 U
47
10
-------
TABLE 3 (Continued)
VALIDATED RESULTS OF VOLATILE ORGANIC COMPOUND ANALYSES (ug/kg)
Sample:
Chloromethane
Dichlorodifluoromethane
Ethylbenzene
Isobutyl alcohol
Methylene chloride
Pentachloroethane
Styrene
Tetrachloroethene
Toluene
trans- 1 ,2-Dichloroethene
Trichloroethene
rrichlorofluoromethane
Xylenes
PRE-S-1
3.0 U
1.6 J
3.0 U
0.62 J
6.0 UJ
3.0 U
3.0 U
13
1.8 J
3.0 U
1.3 J
3.0 U
1.3 J
PRE-S-6
2.8 U
1.0 J
2.8 U
28 UJ
5.6 UJ
2.8 U
2.8 U
21
1.7 J
2.8 U
1.9 J
2.8 U
1.2 J
PRE-S-14
22
1.1 J
0.73 J
29 UJ
6.2 J
2.9 U
2.9 U
330 J
1.0 J
0.70 J
58
2.9 U
2.5 J
PRE-S-15
37
2.1 J
14
37 UJ
50 J
3.7 U
3.7 U
500 J
4.1
3.7 U
10
3.7 U
48
PRE-S-16
3.4 U
7.1 J
3.4 U
34 UJ
1.5 J
3.4 U
3.4 U
67
8.5
3.4 U
1.8 J
0.50 J
0.69 J
PRE-S-23
2.8 U
1.5 J
2.8 U
28 UJ
5.6 UJ
2.8 U
2.8 U
18
1.7 J
2.8 U
1.0 J
2.8 U
0.32 J
PRE-S-31
3.3 U
1.8 J
3.3 U
33 UJ
0.51 J
3.3 U
3.3 U
60
2.4 J
3.3 U
2.9 J
3.3 U
0.61 J
PRE-S-33
3.3 U
2.1 J
0.33 J
33 UJ
6.5 UJ
3.3 U
3.3 U
20
1.4 J
3.3 U
0.48 J
0.34 J
1.6 J
PRE-S-36
2.8 U
1.6 J
2.8 U
0.34 J
5.7 UJ
2.8 U
2.8 U
38
0.77 J
2.8 U
1.0 J
2.8 U
0.64 J
Sample:
1,1,1 ,2-Tetrachloroethane
1,1,1 -Trichloroethane
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethene
1 ,2,3 -Trichloropropane
1 ,2-Dichlorobenzene
PRE-W-1
2.3 J
3.8 U
3.6 J
1.6 J
3.8 U
3.8 U
3.8 U
9.9 J
PRE-W-6
4.1 U
4.1 U
4.1 U
4.1 U
0.76 J
4.1 U
4.1 U
4.1 U
PRE-W-14
7.1 U
7.1 U
7.1 U
7.1 U
4.3 J
7.1 U
7.1 U
7.1 U
PRE-W-15
6.0 U
2.3 J
6.0 U
6.0 U
5.2 J
1.2 J
6.0 U
6.0 U
PRE-W-16
1.9 J
8.4 J
3.4 U
3.2 J
3.4 U
3.4 U
3.4 U
550
PRE-W-23
2.8 U
1.2 J
1.5 J
1.7 J
1.9 J
0.52 J
2.8 U
2.9 U
PRE-W-31
4,000 U
4,000 U
4,000 U
4,000 U
4,000 U
4,000 U
4,000 U
4,000 U
PRE-W-33
3.1 U
1.8 J
2.3 J
3.1 U
3.1 U
3.1 U
4.4 J
3.1 U
PRE-W-36
2.9 U
2.6 J
3.2
2.9 U
0.94 J
2.9 U
2.9 U
36 J
11
-------
TABLE 3 (Continued)
VALIDATED RESULTS OF VOLATILE ORGANIC COMPOUND ANALYSES (ug/kg)
Sample:
1 ,2-Dichloroethane
1 ,2-Dichloropropane
1 ,3 -Dichlorobenzene
1 ,4-Dichlorobenzene
2-Butanone
2-Hexanone
4-Methyl-2-pentanone
Acetone
Acrolein
Benzene
Bromomethane
Carbon disulfide
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Dichlorodifluoromethane
Ethylbenzene
Isobutyl alcohol
Methylene chloride
Pentachloroethane
Styrene
Tetrachloroethene
PRE-W-1
3.8 U
1.0 J
13 J
50 J
9.6 J
38 U
38 U
81 J
76 U
5.5 J
0.61 J
3.8 U
8,600
3.8 U
3.8 U
22,000
4.0 U
2.4 J
1.3 J
38 UJ
7.6 UJ
61 J
3.8 U
4,800
PRE-W-6
0.68 J
4.1 U
4.1 U
2.0 J
22 J
0.48 J
0.72 J
280 J
82 U
30
4.1 U
2.1 J
9.9
4.1 U
4.1 U
170
47
1.8 J
1.9 J
41 UJ
17 J
4.1 U
4.1 U
84
PRE-W-14
7.1 U
7.1 U
7.1 U
12
39 J
1.5 J
2.6 J
850 J
140 U
23
7.1 U
6.2 J
35
0.84 J
7.1 U
150
150
3.5 J
2.2 J
71 UJ
52 J
7.1 U
2.4 J
200
PRE-W-15
6.0 U
1.2 J
0.65 J
7.0
15 J
60 U
60 U
200 J
120 U
8.0
6.0 U
6.0 U
490 J
36
6.0 U
2,300 J
19
1.2 J
6.0 U
60 UJ
12 UJ
6.0 U
6.0 U
1,200 J
PRE-W-16
3.4 U
3.4 U
240 J
1,000
7.7 J
34 U
34 U
1,100 J
1.2 J
0.72 J
3.4 U
3.4 U
3,800
3.4 U
9.5 J
2,400
18 J
1.4 J
11 J
34 UJ
24 J
3.4 U
3.4 U
6,700
PRE-W-23
2.8 U
2.8 U
2.1 J
15
5.5 J
28 U
28 U
54 J
56 U
6.3
2.8 U
2.8 U
580 J
0.82 J
9.1
1,100 J
9.0
1.3 J
0.91 J
28 UJ
4.7 J
0.58 J
2.8 U
480 J
PRE-W-31
4,000 U
4,000 U
4,000 U
840 J
40,000 U
40,000 U
40,000 U
2,500 J
81,000 U
4,000 U
4,000 U
4,000 U
13,000
4,000 U
4,000 U
4,600
15,000
4,000 UJ
4,000 U
40,000 U
1,600 J
4,000 UJ
4,000 U
3,700 J
PRE-W-33
3.1 U
0.81 J
2.0 J
12 J
9.7 J
31 U
0.87 J
140 J
63 U
4.4 J
3.1 U
3.1 U
4,600
4.3 J
3.1 U
580 J
24 J
2.0 J
3.8 J
31 UJ
50 J
30 J
3.1 U
350 J
PRE-W-36
2.9 U
2.9 U
46 J
110 J
4.1 J
29 U
1.6 J
52 J
59 U
3.6 J
2.9 U
2.9 U
5,600
16 J
2.9 U
470 J
19 J
1.8 J
6.5 J
29 UJ
19 J
57 J
2.9 U
4,300
12
-------
TABLE 3 (Continued)
VALIDATED RESULTS OF VOLATILE ORGANIC COMPOUND ANALYSES (ug/kg)
Sample:
Toluene
trans-l,2-Dichloroethene
rrichloroethene
rrichlorofluoromethane
Xylenes
PRE-W-1
5.8 J
3.8 U
67 J
3.8 U
4.0 J
PRE-W-6
1.9 J
4.1 U
9.2
4.1 U
6.6
PRE-W-14
11
7.1 U
31
7.1 U
11
PRE-W-15
2.8 J
6.0 U
73
6.0 U
1.2 J
PRE-W-16
280 J
3.4 U
53 J
3.4 U
210 J
PRE-W-23
1.7 J
0.62 J
61
2.8 U
2.8
PRE-W-31
4,000 U
4,000 U
540 J
4,000 U
720 J
PRE-W-33
9.2 J
3.1 U
24 J
3.1 U
8.7 J
PRE-W-36
3.4 J
2.9 U
29 J
2.9 U
20 J
Notes:
(ig/kg = Micrograms per kilogram
U = The compound was not detected. The reported numerical value is the sample quantitation limit.
J = The compound was detected, but the result is considered to be estimated for quality control reasons.
UJ = The compound was not detected. The sample quantitation limit is considered to be estimated for quality control reasons.
13
-------
3.0 SEMIVOLATILE ORGANIC COMPOUND ANALYSES
This section discusses the results for the full-list SVOC analyses. Table 4 contains validated results for
all samples; only compounds reported in at least one sample are listed. No problems were noted with data
package completeness, GC/MS instrument performance checks, initial and continuing calibrations,
blanks, MS/MSD analyses, LCS analyses, or internal standards.
The LCS accompanying the initial analyses was spiked with hexachlorocyclopentadiene only, and the
analyses showed that the samples were generally complex mixtures with high concentration of SVOCs.
Several extracts could not be concentrated to 1.0 milliliter, and the analyst described these extracts as
"thick, dark, and nasty." The laboratory discarded these initial results and reextracted all samples 3 to 4
weeks after collection, beyond the holding time limit of 14 days. However, all of the detected compounds
are relatively stable and very persistent in the environment. Since the samples were kept well cooled
(below their original, in situ temperature) from collection until extraction, no qualifications are warranted
for these delays.
A few extracts exhibited low recoveries for one acidic surrogate, 2,4,6-tribromophenol. No qualifications
are warranted for such minor irregularities with only one surrogate. Many extracts were so diluted (up to
500-fold) that surrogate recoveries could not be determined. No qualifications are warranted for these
data gaps.
Calculations were performed correctly, with soil results adjusted to dry weight. Most sample extracts
were diluted (and some diluted more than once) to bring the more concentrated contaminants into
calibration range. However, some results were below the calibration range in the least diluted analytical
run. These extrapolations are flagged "J" to indicate that they are estimates.
14
-------
TABLE 4
VALIDATED RESULTS FOR SEMIVOLATILE ORGANIC COMPOUNDS (jig/kg)
Sample:
1 ,2,4-Trichlorobenzene
2-Chloronaphthalene
4-Chlorophenyl phenyl ether
Fluoranthene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Naphthalene
Phenanthrene
Pvrene
PRE-S-1 (0-2)
11,000 U
11,000 U
11,000 U
11,000 U
29,000
11,000 U
11,000 U
11,000 U
11,000 U
11,000 U
11.000 U
PRE-S-1 (10-12)
530,000 U
530,000 U
530,000 U
530,000 U
410,000 J
530,000 U
5,800,000
530,000 U
530,000 U
530,000 U
530.000 U
PRE-S-2 (0-2)
13,000 U
13,000 U
13,000 U
4,900 J
45,000
4,700 J
2,800 J
13,000 U
13,000 U
3,300 J
3.800 J
PRE-S-2 (10-12)
11,000 U
11,000 U
11,000 U
11,000 U
130,000
11,000 U
1,800,000
10,000 J
11,000 U
11,000 U
11.000 U
PRE-S-3 (0-2)
11,000 U
11,000 U
11,000 U
11,000 U
44,000
11,000 U
63,000
11,000 U
11,000 U
11,000 U
11.000 U
PRE-S-3 (10-12)
13,000 U
13,000 U
13,000 U
13,000 U
520,000
89,000
4,400,000
40,000
13,000 U
13,000 U
13.000 U
PRE-W-1
490,000 U
490,000 U
490,000 U
490,000 U
1,300,000
380,000 J
5,500,000
490,000 U
490,000 U
490,000 U
490.000 U
Sample:
1 ,2,4-Trichlorobenzene
2-Chloronaphthalene
4-Chlorophenyl phenyl ether
Fluoranthene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Naphthalene
Phenanthrene
Pvrene
PRE-W-2
570,000 U
570,000 U
570,000 U
570,000 U
4,100,000
240,000 J
8,600,000
570,000 U
570,000 U
570,000 U
500.000 U
PRE-W-3
630,000 U
630,000 U
630,000 U
630,000 U
3,600,000
200,000 J
7,800,000
630,000 U
630,000 U
630,000 U
630.000 U
PRE-W-4
5,200 J
10,000 J
11,000 J
14,000 U
2,100,000
180,000
6,000,000
92,000
13,000 J
14,000 U
14.000 U
PRE-W-5
600,000 U
600,000 U
600,000 U
600,000 U
3,000,000
290,000 J
11,000,000
130,000 J
600,000 U
600,000 U
600.000 U
PRE-W-6
580,000 U
580,000 U
580,000 U
580,000 U
2,600,000
250,000 J
9,500,000
120,000 J
580,000 U
580,000 U
580.000 U
PRE-W-201"
560,000 U
560,000 U
560,000 U
560,000 U
5,300,000
270,000 J
8,900,000
560,000 U
560,000 U
560,000 U
560.000 U
PRE-W-202"
600,000 U
600,000 U
600,000 U
600,000 U
5,700,000
310,000 J
9,800,000
600,000 U
600,000 U
600,000 U
600.000 U
Notes:
ug/kg = Micrograms per kilogram
U = The compound was not detected. The reported numerical value is the sample quantitation limit.
J = The compound was detected, but the result is considered to be estimated for quality control reasons.
a = Field replicate of sample PRE-W-2
15
-------
4.0 ORGANOCHLORINE PESTICIDE ANALYSES
This section discusses the results for organochlorine pesticide analyses. Table 5 contains validated results
for all samples; only compounds reported in at least one sample are listed. No problems were noted with
data package completeness, holding times, or initial calibrations. (GC/MS instrument performance check
and internal standards are not relevant to organochlorine pesticide analyses.)
During continuing calibrations, an occasional result in one column was outside QC limits. Since the other
column results were acceptable, no qualifications are warranted.
The laboratory blank contained low-level concentrations of aldrin, dieldrin, endrin, and endrin ketone.
The samples contained such high concentrations of pesticides (including these four) however, that no
qualifications are warranted.
MS/MSD analyses were performed on sample PRE-W-1, but results were not usable because the parent
sample contained much higher concentrations of pesticides than the spikes. No qualifications are
warranted for this data gap.
The LCS analysis reported a recovery of 160 percent for dieldrin, above QC limits of 57 to 123 percent.
All dieldrin results are flagged "J" to indicate that they are estimates biased high.
In most analyses, surrogate recoveries could not be determined due to the high dilutions. No
qualifications are warranted for these data gaps.
As noted above, sample extracts were diluted for analysis due to the high concentrations of pesticides.
The results in Table 5 are derived from dilutions ranging from 200-fold to 200,000-fold. Two or three
dilutions were used for each sample, so no results exceeded the calibration range. However, some results
were below the calibration range in the least diluted analysis. These extrapolations are flagged "J" to
indicate that they are estimates.
16
-------
TABLE 5
VALIDATED RESULTS FOR ORGANOCHLORINE PESTICIDE ANALYSES (jig/kg)
Sample:
4,4 '-ODD
4,4 '-ODD
Aldrin
alpha-BHC
3eta-BHC
Dieldrin
Endrin
Endrin ketone
Herjtachlor
PRE-S-1 (0-2)
3,600 U
3,600 U
7,400
3,600 U
3,600 U
85,000 J
3,700
3,900
3.600 U
PRE-S-1 (10-12)
3,700 U
3,700 U
26,000
4,700
3,700 U
150,000 J
3,700 U
3,700 U
3.700 U
PRE-S-1 (12-13)
940 U
940 U
7,000
940 U
940 U
59,000 J
940 U
940 U
940 U
PRE-S-2 (0-2)
21,000 U
21,000 U
140,000
21,000 U
21,000 U
4,500,000 J
53,000
6,500 J
21.000 U
PRE-S-2 (10-12)
8,200
940 U
15,000
940 U
940 U
63,000 J
940 U
8,300
940 U
PRE-S-2 (12-13)
4,900
940 U
9,900
940 U
940 U
34,000 J
940 U
2,700
940 U
PRE-S-3 (0-2)
360 U
360 U
1,300
360 U
360 U
13,000 J
1,200
2,500
360 U
PRE-S-3-(10-12)
1,100 U
1,100 U
3,200
1,100 U
1,100 U
21,000 J
1,100 U
1,100 U
1.100 U
Sample:
4,4 '-ODD
4,4 '-ODD
Aldrin
alpha-BHC
3eta-BHC
Dieldrin
Endrin
Endrin ketone
Hetrtachlor
PRE-W-1
3,900 U
3,900 U
110,000 J
3,900 U
3,900 U
1,300,000 J
25,000
14,000
3.900 U
PRE-W-2
52,000
4,000 U
700,000
4,000 U
11,000
1,700,000 J
62,000
14,000
15.000
PRE-W-3
51,000
11,000 U
110,000
11,000 U
11,000 U
360,000 J
11,000 U
11,000 U
4.400 J
PRE-W-4
1,300 U
1,300 U
40,000 J
1,300 U
1,300 U
280,000 J
9,400
4,500
1.300 U
PRE-W-5
4,000 U
14,000
1,400,000
4,000 U
4,000 U
1,500,000 J
63,000
47,000
20.000
PRE-W-6
3,900 U
3,900 U
3,800 J
3,900 U
3,900 U
23,000 J
3,900 U
3,900 U
3.900 U
PRE-W-201"
23,000
4,000 U
490,000
4,000 U
4,000 U
1,200,000 J
47,000
8,900
11.000
PRE-W-202"
29,000
10,000
570,000
4,000 U
4,000 U
1,200,000 J
53,000
11,000
11.000
Notes:
U
J
a
Micrograms per kilogram
The compound was not detected. The reported numerical value is the sample quantitation limit.
The compound was detected, but the result is considered to be estimated for quality control reasons.
Field replicate of sample PRE-W-2
17
-------
5.0 OVERALL EVALUATION
Given the nature of the samples, analytical results and laboratory analyses appear to be acceptable, as
qualified. Some laboratory errors (such as an apparent miscommunication that led to misspiking the first
SVOC LCS) made little difference in the results. The samples contain many organic compounds, and
many of the samples exhibit high concentrations of these contaminants. This complexity tends to produce
significant matrix interferences, seen as irregularities in MS/MSD analyses, surrogate recoveries, and
internal standard results. Some such problems were seen, but they were not severe enough to render the
results unusable. Highly contaminated samples like these often have irregular distributions of the
contaminants because the samples are a physical mixture of organic particles (containing most of the
contaminants) within the bulk matrix of soil or water.
18
-------
February 10, 2003
Memo to: ISTD File
From: Harry Ellis
Re: Data Validation for Pre-Demonstration Samples (Dioxin Analyses)
This memorandum documents a data validation of the analytical results from soil samples collected
during the pre-demonstration sampling for the In Situ Thermal Destruction (ISTD) Technology carried
out at the "Hex Pit" of the Rocky Mountain Arsenal, Adams County, Colorado, under the auspices of the
U.S. Environmental Protection Agency (EPA) Field Evaluation and Technical Support (FEATS) program
by Tetra Tech EM Inc. (Tetra Tech) and its subcontractor, Kemron Environmental Services (Kemron). A
total of 12 composite soil samples and two replicate soil samples were collected by Tetra Tech on July 18
through 25, 2001, and sent in three shipments by overnight courier to Triangle Laboratories, Inc.
(Triangle), of Durham, North Carolina. Triangle analyzed the samples for polychlorinated
dibenzo(p)dioxins and polychlorinated dibenzofurans (dioxins) by EPA Test Methods for Evaluating
Solid Wastes (SW-846) Method 8290. Each shipment was analyzed as a separate sample delivery group
(SDG), Nos. 54747, 54763, and 54787. Additional samples were sent to another laboratory for other
analyses; those analyses have been discussed in a separate memorandum.
The data were evaluated in general accordance with the EPA Contract Laboratory Program National
Functional Guidelines (NFG) for dioxin review, dated August 2002. When differences exist between the
SW-846 method and the NFG, the data validation followed the acceptance criteria given in the method.
In addition, when Triangle gave laboratory-specific acceptance criteria, then these criteria were used to
evaluate the data. The evaluation of the data was based on the following quality control (QC) parameters.
Data package completeness
Holding times
Instrument performance check
Initial and continuing calibrations
Blanks
Matrix spike/matrix spike duplicate (MS/MSD) analyses
Laboratory control samples (LCS)
Internal standards
Surrogate recoveries
Compound quantitation
-------
The following sections discuss, in turn, the three SDGs. A final section provides an overall evaluation of
the analyses and is followed by tables summarizing the validated analytical results.
1.0 SDG No. 54747
SDGNo. 54747 included four soil samples collected July 18 and 19. There were no problems with data
package completeness, holding times, instrument performance checks, LCS results, and surrogate
recoveries. Validated analytical results are summarized in Table 1.
The closing continuing calibration performed after the analysis of the undiluted extracts had some
unacceptable results due to carryover from the samples. Since the affected analytes were quantitated from
diluted reanalyses, no qualifications are required.
Some of the laboratory blanks contained low-level concentrations of analytes. The samples contained
much higher concentrations of the analytes (or of interfering nontargets), so no qualifications are
required.
This SDG included no MS/MSD analyses. Duplicate LCS analyses provided adequate checks of
accuracy and precision, so no qualifications are warranted for this data gap.
In a few cases, such as hexachlorodibenzofurans (HxCDF) and heptachlorodibenzofurans (HpCDF) in the
undiluted analysis of sample PRE-S-1 (0-2), co-eluting nontarget compounds gave the internal standards
an ion ratio outside QC limits. No such results were used for quantitation, so no qualifications are
required for this problem. In addition, some internal standards had recoveries outside their QC limits,
usually above the limits due to the presence of nontarget compounds. In most cases, the sample was
reanalyzed at a different dilution with acceptable recoveries so no qualifications are required. The
exception was sample PRE-S-1 (10-12) where three internal standards were outside their QC limits in the
undiluted analysis. For instance, the recovery for 13C12-2,3,7,8-tetrachlorodibenzo(p)dioxin (TCDD) was
197 percent, versus QC limits of 25 to 164 percent. Therefore, the results for 2,3,7,8-TCDD and other
similarly affected analytes are flagged "J" to indicate that they are estimated, biased low.
These samples produced numerous problems with quantitation, which Triangle worked diligently to
minimize. First, all samples were analyzed undiluted. Many analytes exceeded their calibration range
and most of those saturated the detector. Therefore, Triangle reextracted the samples (using a smaller
-------
portion of soil) and diluted those extracts to reach 1,000-fold dilutions. One sample was analyzed a third
time at a 12,000-fold dilution and one at a 25-fold dilution. Due to these repeated attempts, almost all of
the results in Table 1 are within the calibration range of one dilution, so they are not qualified. A few
results are above the calibration range from a less diluted sample but below the range for a more diluted
one (calibration standards cover a 200-fold range), so these extrapolations are flagged "J" to indicate that
they are estimated.
In this analysis, the detection limits are generally calculated from the definition of a peak, namely that it
has a signal-to-noise ratio of 2.5 or more. This applies to the nondetect result for 2,3,4,7,8-
pentachlorodibenzofuran (PeCDF) in sample PRE-S-1 (0-2). But in a number of cases, such as 2,3,7,8-
tetrachlorodibenzofuran (TCDF) in that same sample, a peak was present in the window for the analyte
but it was outside the acceptable range of isotope ratios. Therefore, the peak was partially or completely
nontarget compounds. When this occurs, the detection limit is calculated from the interfering peak and is
called in the laboratory report the "estimated maximum possible concentration" or EMPC. Table 1 does
not distinguish between these two types of detection limits.
Finally, in a few cases, such as total TCDF in sample PRE-S-1 (0-2), polychlorinated diphenyl ethers
(PCDPE) are contributing to the apparent mass of analytes. The laboratory sorted out the PCDPE from
the dioxins as much as possible, but the results are flagged "J" to indicate that they are estimated.
2.0 SDG No. 54763
SDG No. 54763 includes four soil samples collected on 20 and 23 July. There were no problems with
data package completeness, holding times, instrument performance check, LCS results, and surrogate
recoveries. Validated analytical results are summarized in Table 2.
Almost all calibration results were acceptable. The initial analyses of these samples were performed in
the same analytical run as the samples in SDG No. 54747. The closing continuing calibration had results
outside QC limits due to carryover from some of the samples. No qualifications are applied for this
irregularity.
Some of the laboratory blanks contained low-level concentrations of a few analytes. The samples
contained much higher concentrations, so no qualifications are warranted.
-------
No MS/MSD analyses were included in this SDG. Duplicate LCS analyses provided adequate evidence
of acceptable accuracy and precision, so no qualifications are warranted for this data gap.
A few of the internal standard recoveries exceeded QC limits. For instance, in the original analysis of
sample PRE-S-3 (10-12), the recovery of 13C12-l,2,3,6,7,8-HxCDF was 170 percent versus QC limits of
26 to 123 percent. The HxCDF analytes were quantitated from a more diluted analysis (with acceptable
internal standard recoveries), so no qualifications were warranted. However, 13C12-1,2,3,6,7,8-
hexachlorodibenzo(p)dioxin (HxCDD) had a 198 percent recovery, versus QC limits of 28 to 130 percent.
Since all three HxCDD isomers were quantitated against this internal standard, they are flagged "J" to
indicate that they are estimated, biased low. Similar considerations apply to other internal standards in
this and other samples.
These samples contained many target analytes and even more nontarget compounds, which interfered
with the analyses. All samples were reextracted and reanalyzed at a dilution. Sample PRE-S-3 (10-12)
was also analyzed at a third, intermediate dilution. Despite this, a few results were above the calibration
range at one dilution and below it in the next higher dilution. These extrapolations are flagged "J" to
indicate that they are estimated. In some cases, peaks appeared in the windows for analytes, but the
isotope ratios were outside the acceptable range. Therefore, the peaks were partially or completely
nontarget compounds. These results are flagged "U" to indicate that the analyte was not detected and the
size of the nontarget peak was used to calculate the sample quantitation limit (called an EMPC by the
laboratory).
Finally, it is well known that 2,3,7,8-TCDF cannot be separated from some (relatively nontoxic) isomers,
especially 2,3,4,7-TCDF and 1,2,3,9-TCDF, on the primary chromatography column. Therefore, the
extract is reanalyzed on a second column to confirm the identity. With sample PRE-S-3 (10-12), the
second column did not confirm the presence of 2,3,7,8-TCDF. Therefore, the result is flagged "U" to
indicate that it is a false positive.
3.0 SDG No. 54787
SDG No. 54787 includes four soil samples and two replicate samples (a field triplicate) collected on 24
and 25 July. There were no problems with data package completeness, holding times, instrument
performance checks, initial and continuing calibrations, LCS results, internal standards, and surrogate
recoveries. Validated analytical results are summarized in Table 3.
-------
Some of the laboratory blanks contained low-level concentrations of some analytes. However, all
samples contained much higher concentrations of analytes, interferents, or both, so no qualifications are
warranted.
MS/MSD analyses were performed on two samples, PRE-S-2 (10-12) and PRE-W-3. In both cases,
accuracy could not be determined from the percent recovery data since the field sample concentrations
were much more (generally orders of magnitude more) than the amounts spiked. Since all LCS results
were acceptable, no qualifications are warranted for this data gap. The precision results (determined from
the relative percent difference data) were quite good for the MS/MSD analyses on sample PRE-S-2 (10-
12). In contrast, precision was poor for the MS/MSD analyses on sample PRE-W-3, with all MSD results
about twice the MS results. This same sort of irregularity was seen with the field triplicate samples, since
the primary sample (PRE-W-2) contained considerably more than the first replicate sample (PRE-W-
201), which contained somewhat more than the second replicate sample (PRE-W-202). These results
show that in many places there may be considerable local variations in the dioxin content of the soil,
giving different quantitative results for different 12 to 13 gram portions from the field sample.
As with earlier SDGs, Triangle worked to get usable results. The initial analyses were performed at
1,000- or 2,000-fold dilutions. Some samples were reanalyzed at a greater dilution to bring higher
concentrations within calibration range and some were reanalyzed at a 50-fold dilution to bring lower
concentration results within calibration range. Despite all this work, some positive results [such as
1,2,3,7,8-pentachlorodibenzo-p-dioxin in sample PRE-S-2 (0-2)] were still below the calibration range.
These extrapolations are flagged "J" to indicate that they are estimated. As defined in the method, there
are two types of sample quantitation limits shown in the results. When there is no peak in the analyte
window that has a signal-to-noise level of 2.5 or more, the listed value is the "detection level" of 2.5 times
the noise. This applies to results such as 2,3,7,8-TCDD in sample PRE-S-2 (0-2). When there is a peak
in the window but it fails the mass ratio test (indicating that it is, at least in part, a nontarget compound)
the peak size is used to calculate an EMPC, as for 1,2,3,4,7,8-HxCDD in the same sample.
4.0 OVERALL EVALUATION
On the whole, the laboratory did as well as could be expected from the characteristics of the samples
(highly contaminated, heterogenous) and the need to produce some usable numbers without delaying to
carry out a research project on each sample. The results are usable as qualified for any purpose.
-------
As summarized in Tables 1 through 3, about half the samples contained measurable concentrations of all
17 individual 2,3,7,8-substituted analytes. The others contained most of the target analytes. To provide a
measure of the total adverse effects of these analytes, one uses the procedures in the method to calculate
the "toxicity equivalent" for each sample. This is essentially the concentration of 2,3,7,8-TCDD that
would have the same adverse effects as the entire mixture of contaminants because 2,3,7,8-TCDD has a
toxicity equivalent factor of 1.00. These toxicity equivalents are generally used in risk assessments and
other risk-based decision making. Table 4 summarizes the results of the toxicity equivalent calculation
for these samples. For samples with one or more nondetect results, three calculations are presented. The
first (labeled "maximum") calculation assumes that nondetected analytes are actually present at their
quantitation limits, whether that is an actual detection limit or an estimated maximum possible
concentration, as discussed for this SDG. The second calculation (labeled "minimum") assumes the
nondetected analytes are completely absent. The third calculation (labeled "median") assumes that the
true concentrations of nondetected analytes are half their quantitation limits. This "median" estimation is
routinely used in risk assessment and is probably the most realistic. These samples have such high
concentrations that the differences in the toxicity equivalent calculations produce negligible differences in
biological effect estimates.
The primary technical problem with these analyses was interference from high concentrations of both
target analytes and other compounds. The nontarget compounds are apparently closely related to the
target ones since they respond readily to the detectors. The source of these samples is the disposal site for
wastes from the manufacture of hexachlorocyclopentadiene. The manufacturing processes include
heating various compounds in the presence of some oxygen sources, which may result in the generation
of target compounds, especially highly chlorinated dibenzofurans. As discussed above for the MS/MSD
analyses, there is good evidence of local heterogeneity in the dioxin concentrations. However, the
relative concentrations of the various analytes within different portions of the same sample are essentially
consistent. The simplest explanation for this is that the waste composition, in terms of dioxin compounds
and their proportions, was relatively consistent over the years of production. One would expect this from
a single manufacturing process and highly stable products. Therefore, the inconsistencies are practically
limited to the total concentrations (expressed as toxicity equivalents) over space.
There is one significant consequence of this spatial heterogeneity. No single sample can be considered
fully "representative" of its source area. Many samples, more than those discussed here, are needed to
define an "average" concentration of dioxins in the pit. Therefore, it will be difficult to compare the post-
demonstration results to these pre-demonstration results. Even if post-demonstration samples are taken
-------
within a few centimeters of the locations used here, differences between the results may be due to
heterogeneity. To minimize the probability of error, it would be reasonable to consider a change of less
than 10-fold in the toxicity equivalent to be a "no effect" response.
-------
TABLE 1
SUMMARY OF VALIDATED DIOXIN RESULTS FROM SDG NO. 54747
(nanograms per kilogram)
Sample Location:
2,3,7,8-Tetrachlorodibenzo(p)dioxin
1 ,2,3 ,7,8-Pentachlorodibenzo(p)dioxin
l,2,3,4,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,6,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,7,8,9-Hexachlorodibenzo(p)dioxin
l,2,3,4,6,7,8-Heptachlorodibenzo(p)dioxin
Octachlorodibenzo(p)dioxin
2,3 ,7,8-Tetrachlorodibenzofuran
1 ,2,3 ,7,8-Pentachlorodibenzofuran
2,3,4,7,8-Pentachlorodibenzofuran
1,2,3,4,7,8-Hexachlorodibenzofuran
1,2,3,6,7,8-Hexachlorodibenzofuran
2,3,4,6,7,8-Hexachlorodibenzofuran
1,2,3,7,8,9-Hexachlorodibenzofuran
1,2,3,4,6,7,8-Heptachlorodibenzofuran
1,2,3,4,7,8,9-Heptachlorodibenzofuran
Octachlorodibenzofuran
Total tetrachlorodibenzo(p)dioxins
Total pentachlorodibenzo(p)dioxins
Total hexachlorodibenzo(p)dioxins
Total heptachlorodibenzo(p)dioxins
Total tetrachlorodibenzofurans
Total pentachlorodibenzofurans
Total hexachlorodibenzofurans
Total heptachlorodibenzofurans
PRE-S-1 (0-2)
11.2
83
180
200
220
1,150
2,400 J
880 U
7,500 J
133 U
14,600 J
5,000
1,750
2,700
26,000 J
14,800 U
280,000
500
1,110
2,300
2,000
7,000 J
17,000
29,000
37,000
PRE-S-1 (10-12)
600 J
4,900 J
11,100
10,700 J
11,800 J
68,000 J
75,000 J
76,200
420,000
94,000
950,000
600,000
170,000
145,000
2,000,000
1,140,000
12,500,000
27,000
39,000
146,000
142,000
750,000
1,360,000
2,900,000
3,900,000
PRE-W-1
940
7,600
21,000
22,000
19,000
171,000
330,000
91,000 U
670,000
156,000
1,840,000
1,130,000
300,000
250,000
4,500,000
2,500,000
30,000,000
55,000
71,000
230,000
320,000
610,000
1,900,000
5,200,000
8,600,000
PRE-W-6
500 U
4,600
10,600
11,600
12,300
70,000
105,000
128,000
660,000
94,000
1,240,000
740,000
250,000
210,000
2,200,000
1,300,000
52,000,000
34,000
50,000
137,000
139,000
1,400,000
2,400,000
3,900,000
4,500,000
Notes:
J
U
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
-------
TABLE 2
SUMMARY OF VALIDATED DIOXIN RESULTS FROM SDG NO. 54763
(nanograms per kilogram)
Sample Location:
2,3,7,8-Tetrachlorodibenzo(p)dioxin
1 ,2,3 ,7,8-Pentachlorodibenzo(p)dioxin
l,2,3,4,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,6,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,7,8,9-Hexachlorodibenzo(p)dioxin
l,2,3,4,6,7,8-Heptachlorodibenzo(p)dioxin
Octachlorodibenzo(p)dioxin
2,3 ,7,8-Tetrachlorodibenzofuran
1 ,2,3 ,7,8-Pentachlorodibenzofuran
2,3,4,7,8-Pentachlorodibenzofuran
1,2,3,4,7,8-Hexachlorodibenzofuran
1,2,3,6,7,8-Hexachlorodibenzofuran
2,3,4,6,7,8-Hexachlorodibenzofuran
1,2,3,7,8,9-Hexachlorodibenzofuran
1,2,3,4,6,7,8-Heptachlorodibenzofuran
1,2,3,4,7,8,9-Heptachlorodibenzofuran
Octachlorodibenzofuran
Total tetrachlorodibenzo(p)dioxins
Total pentachlorodibenzo(p)dioxins
Total hexachlorodibenzo(p)dioxins
Total heptachlorodibenzo(p)dioxins
Total tetrachlorodibenzofurans
Total pentachlorodibenzofurans
Total hexachlorodibenzofurans
Total heptachlorodibenzofurans
PRE-S-3 (0-2)
560
3,700
7,700
9,400
9,400
60,000
75,000
36,000
148,000
48,000
200,000
104,000
80,000
84,000
340,000
180,000
2,800,000
43,000
51,000
117,000
109,000
270,000
380,000
540,000
680,000
PRE-S-3 (10-12)
60
40
70 J
80 J
80 J
840 J
2,500 J
2,500 U
16,200
1,100
16,100
11,400
3,100
3,200
27,000 U
19,400
245,000
610
770
880
840
30,000
61,000
56,000
27,000
PRE-W-4
290
2,000
4,100
4,800
5,000
31,000
39,000
82,000
300,000
24,000
490,000
280,000
43,000
47,000
860,000
560,000
8,500,000
25,000
24,000
60,000
61,000
870,000
1,220,000
1,520,000
1,830,000
PRE-W-5
670 U
4,500 U
6,400
10,600
11,000
66,000
78,000
81,000
500,000
57,000
440,000 J
270,000 J
69,000 J
86,000 J
780,000
390,000
13,700,000
46,000
53,000
139,000
132,000
1,180,000
1,810,000
1,390,000
1,530,000
Notes:
J
U
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
-------
TABLE 3
SUMMARY OF VALIDATED ANALYTICAL RESULTS FROM SDG NO. 54787
(nanograms per kilogram)
Sample Location:
2,3,7,8-Tetrachlorodibenzo(p)dioxin
l,2,3,7,8-Pentachlorodibenzo(p)dioxin
l,2,3,4,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,6,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,7,8,9-Hexachlorodibenzo(p)dioxin
l,2,3,4,6,7,8-Heptachlorodibenzo(p)dioxin
Octachlorodibenzo(p)dioxin
2,3,7,8-Tetrachlorodibenzofuran
1,2,3,7,8-Pentachlorodibenzofuran
2,3,4,7,8-Pentachlorodibenzofuran
1,2,3,4,7,8-Hexachlorodibenzofuran
1,2,3,6,7,8-Hexachlorodibenzofuran
2,3,4,6,7,8-Hexachlorodibenzofuran
1,2,3,7,8,9-Hexachlorodibenzofuran
1,2,3,4,6,7,8-Heptachlorodibenzofuran
1,2,3,4,7,8,9-Heptachlorodibenzofuran
Octachlorodibenzofuran
Total tetrachlorodibenzo(p)dioxins
Total pentachlorodibenzo(p)dioxins
Total hexachlorodibenzo(p)dioxins
Total heptachlorodibenzo(p)dioxins
Total tetrachlorodibenzofurans
Total pentachlorodibenzofurans
PRE-S-2 (0-2)
18.9 U
119 J
198 U
270
240
1,900
4,200
4,400
14,700
1,420
20,000
10,000
3,900
3,100
36,000
26,000
480,000
290
730
2,300
3,200
26,000
50,000
PRE-S-2 (10-12)
190
1,350
2,300
3,500
3,300
23,000
43,000
27,000
146,000
16,100
250,000
176,000
32,210
33,000
490,000
183,000
4,500,000
16,700
28,000
41,000
41,000
500,000
730,000
PRE-W-2
1,200 U
8,300 J
13,900
21,000
19,100 U
106,000
257,000
73,000
720,000
57,000
1,340,000
650,000
195,000
164,000
2,200,000
1,240,000
24,000,000
31,000
133,000
210,000
191,000
1,890,000
2,700,000
PRE-W-201"
600 U
5,200 J
9,800 J
12,500
10,200
65,000
146,000
32,000
480,000
37,000
900,000
480,000
142,000
115,000
1,550,000
880,000
19,600,000
48,000
73,000
140,000
119,000
1,160,000
1,880,000
PRE-W-202a
1,800 U
2,100 U
8,400 J
10,100
6,300 J
51,600 U
156,000
32,000
390,000
30,000
860,000
430,000
109,000
59,000
1,480,000
690,000
14,200,000
36,000
60,000
128,000
51,000
1,070,000
1,700,000
PRE-W-3
2,000 J
14,100
71,000
45,000
33,000
420,000
910,000
94,000
1,550,000
73,000
1,330,000
1,620,000
290,000
330,000
2,400,000
3,900,000
24,000,000
109,000
240,000
720,000
680,000
2,300,000
5,700,000
10
-------
TABLE 3 (Continued)
SUMMARY OF VALIDATED ANALYTICAL RESULTS FROM SDG NO. 54787
(nanograms per kilogram)
Sample Location:
Total hexachlorodibenzofurans
Total heptachlorodibenzofurans
PRE-S-2 (0-2)
63,000
79,000
PRE-S-2 (10-12)
770,000
910,000
PRE-W-2
3,600,000
4,600,000
PRE-W-2013
2,700,000
3,200,000
PRE-W-202"
2,500,000
2,800,000
PRE-W-3
4,100,000
5,000,000
Notes:
a
J
U
Field replicate of sample PRE-W-2
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
11
-------
TABLE 4
SUMMARY OF TOXICITY EQUIVALENTS
(nanograms per kilogram)
Sample
PRE-S-1 (0-2)
PRE-S-1 (10-12)
PRE-W-1
PRE-W-6
PRE-S-3 (0-2)
PRE-S-3 (10-12)
PRE-W-4
PRE-W-5
PRE-S-2 (0-2)
PRE-S-2 (10-12)
PRE-W-2
PRE-W-201d
PRE-W-202d
PRE-W-3
Toxicity Equivalents
Maximum3
3,750
313,000
586,000
430,000
95,700
5,890
147,400
179,900
6,890
80,200
378,000
260,000
226,000
596,000
Minimum15
3,450
313,000
577,000
430,000
95,700
5,370
147,400
177,000
6,850
80,200
374,000
260,000
222,000
596,000
Median0
3,600
313,000
581,000
430,000
95,700
5,630
147,400
178,400
6,870
80,200
376,000
260,000
224,000
596,000
Notes:
a
b
c
d
"Maximum" calculated with nondetect results assumed to be equal to the sample reporting limits
"Minimum" calculated with nondetect results assumed to be zero
"Median" calculated with nondetect results assumed to be half the sample reporting limits
Field replicates of sample PRE-W-2
12
-------
January 15, 2003
Memo to: ISTD File
From: Harry Ellis
Re: Data Validation for Post-Demonstration Samples (All Analyses)
This memorandum documents a data validation of the analytical results from soil samples collected
during the post-demonstration sampling for the In Situ Thermal Destruction (ISTD) Technology carried
out at the "Hex Pit" of the Rocky Mountain Arsenal, Adams County, Colorado, under the auspices of the
U.S. Environmental Protection Agency (EPA) Field Evaluation and Technical Support (FEATS) program
by Tetra Tech EM Inc. (Tetra Tech) and its subcontractor, Kemron Environmental Services (Kemron). A
total of 14 soil samples were collected by Tetra Tech on October 15 through 17, 2002. These were sent
by overnight courier to Accura Analytical Laboratory (AAL) of Norcross, Georgia. AAL analyzed the
samples as sample delivery group (SDG) No. 2846. The seven grab samples were analyzed by EPA Test
Methods for Evaluating Solid Wastes (SW-846) Method 8260B for volatile organic compounds (VOC).
AAL analyzed the seven composite samples for semivolatile organic compounds (SVOC) by SW-846
Method 8270C and for organochlorine pesticides by SW-846 Method 8081 A. About a week after sample
collection, AAL also analyzed the composite samples for pH by SW-846 Method 9045 C. Tetra Tech also
sent portions of the composite samples to Triangle Laboratories, Inc. (Triangle), of Durham, North
Carolina. Triangle analyzed the samples for polychlorinated dibenzo(p)dioxins and polychlorinated
dibenzofurans (dioxins) by SW-846 Method 8290, under SDG No. 58676.
The data were evaluated in general accordance with the EPA Contract Laboratory Program National
Functional Guidelines (NFG) for organic data review, dated October 1999, and the draft NFG for dioxin
data review, dated August 2002. The various methods provide guidance on procedures and method
acceptance criteria that, in some cases, differ from those in the NFG. When differences exist between the
methods and the NFG, the data validation followed the acceptance criteria given in the methods. In
addition, if the data package presented laboratory-specific acceptance criteria, then these criteria were
used to evaluate the data unless the criteria were considered inadequate. Finally, in cases where the
criteria in Section 6.0 of the quality assurance project plan (QAPP) are different from the others, the
QAPP criteria are used in the validation. The evaluation of the data was based on the following
parameters:
Data package completeness
Holding times
Instrument performance check
-------
Initial and continuing calibrations
Blanks
Matrix spike/matrix spike duplicate (MS/MSD) analyses
Laboratory control samples (LCS)
Internal standards
Surrogate recoveries
Compound quantitation
The following sections discuss, in turn, the analyses for VOCs, SVOCs, organochlorine pesticides, pH,
and dioxins. A final section provides an overall evaluation of the analyses and is followed by an
attachment containing a series of tables summarizing the validated analytical results
1.0 VOLATILE ORGANIC COMPOUND ANALYSES
The VOC analyses had no problems with data package completeness, holding times, instrument
performance check, LCS results, internal standards, and surrogate recoveries. Validated results are on
Table 1 of the attachment.
In the VOC initial calibrations, some analytes had an average relative response factor (RRF) less than the
usual data validation minimum of 0.05. Accura compensated for this by using appropriately higher
quantitation limits for these compounds, so no qualifications are warranted. In the continuing calibration
performed before most of the sample analytical runs, the RRF for 1,2,3-trichlorobenzene, 1,2,4-
trichlorobenzene, 1,4-dioxane, and acetone had an excessive percent difference (over 25 percent) from the
average RRF from the initial calibration. Therefore, all results for those compounds from the associated
runs are flagged "J" or "UJ," as appropriate, to indicate that they are estimated. In the last continuing
calibration, acrolein had an excessive percent difference. Since all acrolein results are derived from
earlier analyses, no qualifications are warranted.
VOC blanks contained traces of chloromethane and xylenes. Similar low concentrations in some samples
are flagged "U" to indicate that they are considered to be artifacts.
The MS/MSD analyses were performed using sample POST-HVJ6. That sample was diluted so much to
bring the major contaminants within calibration range in the parent sample that spike recoveries could not
-------
be reliably determined. However, the precision results (relative percent differences between the two
spiked sample results) were acceptable. No qualifications are warranted for the missing data.
Accura found it difficult to bring all positive results within the calibration range, despite the use of
multiple dilutions and both low-level and medium-level analytical procedures. Table 1 (in the
attachment) reflects the best available results. When a concentration from the least diluted
chromatographic run is below the calibration range (such as 1,1-dichloroethane, 1,2,3-trichlorobenzene,
and other compounds in sample POST-HVH4), that extrapolation is flagged "J" to indicate that it is
estimated.
Carbon tetrachloride and chloroform in sample POST-HVJ6 are illustrative examples of inconsistent
results. Although the upper end of the calibration range is 20 times the lower end, the results for those
compounds exceed the range in the undiluted run but are below it in the 5-fold diluted run. This may be a
consequence of a highly variable distribution of contaminants within the sample. The tabulated results
are those from the undiluted run and are flagged "J" to indicate that they are estimated.
2.0 SEMIVOLATILE ORGANIC COMPOUND ANALYSES
The SVOC analyses had no problems with data package completeness, holding times, instrument
performance check, LCS results, and internal standards. Validated results are summarized in Table 2 of
the attachment.
All initial calibration results were within QC limits. One continuing calibration had an excessive percent
difference for 2,4-dinitrophenol. The sample quantitation limits for that compound are flagged "UJ" to
indicate that they are estimated. The other continuing calibration had an excessive percent difference for
pentachlorophenol. Since all results for that compound were associated with the first continuing
calibration, no further qualifications are warranted.
The laboratory blank contained traces of hexachlorocyclopentadiene and several polynuclear aromatic
hydrocarbons (PAH). The samples contained much more hexachlorocyclopentadiene but none of the
PAHs, so no qualifications are required.
-------
As with the VOC analyses, sample POST-HVJ6 was used for MS/MSD analyses and recoveries could not
be calculated due to the excessive dilution of the sample required to bring contaminants within calibration
range. The precision results were all acceptable. No qualifications will be applied for the data gaps.
Surrogate recoveries could not be determined in many analytical runs because of the high dilution factors.
In the less diluted runs, most surrogate recoveries were within Accura's limits. However, two of the three
acidic surrogates in the less diluted analytical run of sample POST-HVH8 were below their limits.
Therefore, the results for all acidic analytes in that sample are flagged "UJ" to indicate that the
quantitation limits are estimated, biased low.
As with the VOC analyses, samples were analyzed at multiple dilutions. The positive results below the
calibration range in the least diluted run are flagged "J" to indicate that they are estimated.
3.0 ORGANOCHLORINE PESTICIDE ANALYSES
The organochlorine pesticide analyses had no problems with data package completeness, holding times,
instrument performance check, blanks, and LCS results. The method uses no internal standard. Validated
results are summarized in Table 3 in the attachment.
All initial calibration results met QC requirements. A number of compounds had an excessive percent
difference on the primary column or the secondary column, but not both, during the continuing
calibrations. No qualifications are warranted for these irregularities. However, delta-BHC had
differences above the QC limit of 15 percent on both columns during the closing continuing calibration.
The results for that compound are flagged "UJ" to indicate that they are estimated.
No MS/MSD analyses were performed. In view of the results from the SVOC analyses, it is probable that
such analyses would have provided little, if any, useful information. No qualifications will be applied for
this data gap.
Due to the high dilution factor required by the presence of large amounts of various organochlorine
compounds in the samples, surrogate recoveries could not be determined. No qualifications are warranted
for these data gaps.
-------
As with other analyses, some positive results, such as endrin ketone in sample POST-HVH8, were below
the calibration range in the least diluted analysis. These extrapolations are flagged "J" to indicate that
they are estimated. A number of other results, such as aldrin and endrin in that same sample, had
relatively high differences between the results on the primary and secondary columns. These
irregularities may be a result of varying amounts of nontarget compounds eluting with the analytes. All
such results are flagged "J" to indicate that they are estimated.
4.0 pH ANALYSES
The pH analyses had no problems with data package completeness, calibration, and sample duplicate
results. The only other QC parameter relevant to these analyses is sample quantitation. The instrument
was calibrated with standard buffers over the range of 4 to 10. However, all sample results were at least 2
standard units outside this range. Therefore, the validated results, listed on Table 3 in the attachment, are
flagged "J" to indicate that these extrapolations are estimated.
5.0 POLYCHLORINATED DIBENZO(P)DIOXIN AND
POLYCHLORINATED DIBENZOFURAN ANALYSES
The dioxin analyses had no problems with holding times, instrument performance checks, initial and
continuing calibrations, LCS and LCS duplicate analyses, internal standards, and surrogate recoveries.
Validated analytical results are summarized in Table 4.
As received, the data package was missing two pages, the results summary for one sample. The data were
available elsewhere, in both the raw data and the introductory data summary. Triangle furnished copies
of the pages when requested.
The laboratory (method) blank and the cleanup blank contained low-level concentrations of several of the
more chlorinated analytes. The samples contained much higher concentrations, so no qualifications are
warranted.
MS/MSD analyses were performed on sample POST-HVJ6. For most analytes, the sample contained so
much more compound than the spike that recoveries could not be reliably measured. Even for 2,3,7,8-
tetrachlorodibenzo(p)dioxin (TCDD), which was not reported in the unspiked sample, the interfering
material dominated analytical results. Therefore, there is no sample-specific information on accuracy. In
-------
addition, precision results were not satisfactory since the MSB sample contained more of every analyte
than the MS sample. These results are probably due to a heterogenous distribution of the analytes within
the material collected for the sample. All results for the parent sample are flagged "J" or "UJ" to indicate
that they are estimated due to sample heterogeneity.
The initial analyses of these samples used the undiluted extracts. Most, if not all, of the analytes in every
sample were above the calibration range, with many being high enough to saturate the detector. Triangle
then reanalyzed all samples at a 100-fold dilution. In six of the seven sample extracts, one or more
analytes still exceeded the calibration range, so these were reanalyzed at a 1000-fold dilution. Even then,
the octachlorodibenzofuran (OCDF) concentration in four samples still exceeded calibration range.
Further dilutions are not practical, since the internal standards would be difficult to separate cleanly from
other material. Most tabulated results (Table 4) are derived from the 100-fold dilution. Some low
concentration results (primarily TCDD) come from the original, undiluted analyses. The 1000-fold
dilution results are used for the highest concentrations. The OCDF results that were extrapolated beyond
the calibration range are flagged "J" to indicate that they are estimated.
The few nondetected results have rather high quantitation limits. All samples contained compounds that
eluted in the same range as some target analytes. These peaks failed the ion abundance ratio criteria (for
number of chlorine atoms per molecule), had the characteristics of poly chlorinated diphenyl ethers, or
both, and were deemed to be nondetected results. However, the presence of these extraneous peaks
means that the sample quantitation limits, what the method calls "estimated maximum possible
concentrations" which are calculated from the interferent concentrations, are therefore relatively high.
Table 5 summarizes the total toxicity equivalents of the samples. A sample containing 2,3,7,8-TCDD at a
listed concentration on the table and none of the other target analytes would have the same toxic effects as
a sample with several positives because 2,3,7,8-TCDD has a toxicity equivalent factor of 1.00. When one
or more analytes has nondetected results, there are many possible assumptions one could make about the
actual concentration, and therefore many possible toxicity equivalent estimates. The table shows the
results of the three most common assumptions. The "maximum" values are based on the assumption that
the nondetected results are equal to the sample reporting limits. The "minimum" values are based on the
assumption that the nondetected results are actually zero. The "median" values are based on the
assumption that the nondetected results are half the sample reporting limits. Risk assessment usually uses
the "median" values. When there are no nondetected results, as is the case for most samples, the three
-------
toxicity equivalent values are identical. When there are few nondetected results, as in the other samples,
the differences are small.
6.0 OVERALL EVALUATION
These analyses went as well as could be expected, given the nature of the analytical methods and the
samples. The methods (except for the pH method) are designed to identify and quantitate extremely low
concentrations of organic compounds in relatively uncontaminated matrices of soil minerals. The
samples, accurately labeled "nasty" by Accura's preparation chemist, have low to high concentrations of
many organic compounds, mostly chlorinated compounds. The collision between those characteristics
produced many failures of QC measures. The matrix interferences seen in these samples can produce
both false positives and false negatives and did produce extremely high sample quantitation limits in
many cases. As a result, all of the quantitative results are somewhat uncertain, although not all have been
formally qualified in the tables in the attachment.
All the samples have similar sorts of matrix interference, so the relative degrees of contamination are
probably accurate. With these caveats, the validated results can be used, as qualified, for any purpose.
One notable aspect of these analyses is evidence of heterogeneity within samples, seen especially in the
VOC and dioxin analyses. This adds to the uncertainty caused by the matrix interferences. Therefore, it
would be difficult to compare these analytical results to the pre-demonstration results. A 10-fold
difference in a parameter would represent a definite change. However, a lesser difference may only
represent sample heterogeneity and analytical variation.
Since all samples were taken from borings in a single disposal unit, it is anticipated that all pH results
would be either acidic or basic. Therefore the observed situation, with five highly acidic samples and two
highly basic samples, is rather surprising. However, a review of the post-demonstration sampling
borehole logs indicates that thick layers of probable lime material occurred in the borings producing the
highly basic samples. In addition, there are differences in the organic chemistry of the two sets of
samples. As shown in Tables 2, 4, and 5, the basic samples have much lower concentrations (usually one
or more orders of magnitude) of SVOCs and dioxins than the acidic samples. The extreme differences in
pH should be considered real.
-------
The most unexpected part of this demonstration was finding that the stainless steel tubing and well points
installed in the contaminated soil were practically destroyed. In chemical terms, at least one component
of the iron-chromium-minor metals alloy was oxidized and then dissolved. All of the soil samples
exhibited extreme pH values, either acidic or basic. Most commonly used oxidizing agents, including
nitrate, sulfate, and perchlorate, are active in acidic conditions. A few, such as peroxide, are active in
basic conditions. And a few, including both hypochlorite and elemental chlorine, are active at both pH
extremes. The presence of suitable inorganic oxidants, of which hypochlorite is the one most likely to be
associated with the wastes in the Hex Pit, plus the observed pH conditions, would be adequate to explain
the dissolution of the metal.
-------
TABLE 1
SUMMARY OF VALIDATED VOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
1,1, 1 ,2-Tetrachloroethane
1,1,1 -Trichloroethane
1 , 1 ,2,2-Tetrachloroethane
1,1,2-Trichloroethane
1 , 1 -Dichloroethane
1 , 1 -Dichloroethene
1 , 1 -Dichloropropene
1 ,2,3 -Trichlorobenzene
1 ,2,3 -Trichloropropane
1 ,2,4-Trichlorobenzene
1 ,2,4-Trimethylbenzene
1 ,2-Dibromo-3 -chloropropane
1 ,2-Dichlorobenzene
1 ,2-Dichloroethane
1 ,2-Dichloropropane
1 ,3 ,5-Trimethylbenzene
1 ,3 -Dichlorobenzene
1 ,3 -Dichloropropane
1 ,4-Dichlorobenzene
1,4-Dioxane
2,2-Dichloropropane
2-Butanone
POST-HVH4
12.6
3.7 U
3.7 U
3.7 U
3.7 U
0.54 J
3.7 U
3.7 U
3.3 J
3.7 U
11 J
7.5
3.7 U
1.8 J
3.7 U
3.7 U
2.5 J
1.2 J
3.7 U
3.7 U
73 UJ
3.7 U
25 J
POST-HVP4
7.8
300 U
300 U
300 U
300 U
300 U
300 U
300 U
230 J
300 U
780
170 J
300 U
190 J
300 U
300 U
300 U
110 J
300 U
300 U
6,000 U
300 U
3,000 U
POST-HVL4
8.5
270 U
270 U
160 J
110 J
270 U
270 U
270 U
260 J
270 U
1,600
270 U
110 J
200 J
74 J
270 U
270 U
79 J
94 J
600
5,300 U
270 U
2,700 U
POST-HVL4013
8.5
3.9 U
3.9 U
3.9 U
3.9 U
3.9 U
3.9 U
3.9 U
3.9 UJ
3.9 U
1.7 J
3.6 J
3.9 U
3.9 U
3.9 U
3.9 U
1.1 J
3.9 U
3.9 U
1.0 J
79 UJ
3.9 U
2.9 U
POSTHVJ6
8.7
8.9 U
8.9 U
8.9 U
3.1 J
1.9 J
8.9 U
8.9 U
13 J
8.9 U
25 J
5.7 J
8.9 U
11
1.1 J
8.9 U
1.9 J
5.8 J
8.9 U
13
180 UJ
8.9 U
47 J
POST-HVH8
8.8
7.6 U
7.6 U
7.6 U
7.6 U
7.6 U
7.6 U
7.6 U
3.1 J
7.6 U
4.1 J
5.3 J
7.6 U
4.8 J
7.6 U
7.6 U
1.6 J
7.6 U
7.6 U
7.6 U
150 UJ
7.6 U
19 J
POST-HVP8
7.5
3.6 U
3.6 U
3.6 U
2.4 J
3.6 U
3.6 U
3.6 U
3.6 UJ
3.6 U
3.6 UJ
2.7 J
3.6 U
3.6 U
3.6 U
3.6 U
0.83 J
3.6 U
3.6 U
3.6 U
71 UJ
3.6 U
4.7 J
-------
TABLE 1 (Continued)
SUMMARY OF VALIDATED VOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
2-Chlorotoluene
2-Hexanone
4-Chlorotoluene
4-Methyl-2-pentanone
Acetone
Acetonitrile
Acrolein
Acrylonitrile
Allyl chloride
Benzene
Bromobenzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
POST-HVH4
12.6
3.7 U
37 U
3.7 U
37 U
1,200
37 U
7.3 U
7.3 U
3.7 U
45
3.7 U
3.7 U
3.7 U
3.7 U
11
3.7 U
5,200
5.3
12
4,400
24
POST-HVP4
7.8
300 U
3,000 U
300 U
3,000 U
1,700 J
3,000 U
600 U
600 U
300 U
150 J
300 U
300 U
300 U
300 U
600 U
300 U
3,800
170 J
600 U
2,300
200 J
POST-HVL4
8.5
270 U
2,700 U
270 U
2,700 U
2,700 U
2,700 U
530 U
270 J
270 U
65 J
33 J
270 U
270 U
110 J
530 U
270 U
870
57 J
530 U
1,100
410 J
POST-HVL4013
8.5
3.9 U
39 U
3.9 U
39 U
780
39 U
7.9 U
7.9 U
3.9 U
5.4
3.9 U
3.9 U
3.9 U
3.9 U
16
3.9 U
54
3.9 U
15
2,600
60
POSTHVJ6
8.7
8.9 U
89 U
8.9 U
89 U
1,200
89 U
18 U
18 U
8.9 U
27
8.9 U
8.9 U
8.9 U
8.9 U
18 U
7.4 J
830 J
9.4
29
670 J
47
POST-HVH8
8.8
7.6 U
76 U
7.6 U
76 U
560 J
76 U
15 U
15 U
7.6 U
23
7.6 U
7.6 U
7.6 U
7.6 U
15 U
8.8
63
2.2 J
15 U
180
15 U
POST-HVP8
7.5
3.6 U
36 U
3.6 U
36 U
69 J
3.6 U
7.1 U
7.1 U
3.6 U
4.3
3.6 U
3.6 U
3.6 U
3.6 U
7.1 U
3.6 U
100
0.73 J
9.4
4,400
7.1 U
10
-------
TABLE 1 (Continued)
SUMMARY OF VALIDATED VOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
cis- 1 ,2-Dichloroethene
cis- 1 ,3 -Dichloropropene
Dibromochloromethane
Dibromomethane
Ethyl Methacrylate
Ethylbenzene
Hexachlorobutadiene
lodomethane
Isobutanol
Isopropylbenzene
Isopropyltoluene
Methyl Methacrylate
Methyl tert-butyl ether
Methylacrylonitrile
Methylene chloride
Naphthalene
n-Butylbenzene
Pentachloroethane
Propionitrile
sec-Butylbenzene
Styrene
POST-HVH4
12.6
3.7 U
3.7 U
3.7 U
3.7 U
3.7 U
11
68
3.7 U
73 U
3.7 U
3.7 U
3.7 U
3.7 U
37 U
15
4.1
1.2 J
3.7 U
37 U
3.7 U
3.7 U
POST-HVP4
7.8
300 U
300 U
300 U
300 U
300 U
300 U
7,500
300 U
6,000 U
300 U
300 U
300 U
300 U
3,000 U
78 J
300 J
300 U
300 U
3,000 U
300 U
300 U
POST-HVL4
8.5
270 U
270 U
71 J
90 J
140 J
270 U
8,600
270 U
5,300 U
270 U
270 U
150 J
130 J
1,500 J
110 J
190 J
270 U
270 U
2,700 U
270 U
270 U
POST-HVL4013
8.5
3.9 U
3.9 U
3.9 U
3.9 U
3.9 U
3.9 U
5.7
3.9 U
79 U
3.9 U
3.9 U
3.9 U
3.9 U
39 U
30
3.9 U
3.9 U
3.9 U
39 U
3.9 U
3.9 U
POSTHVJ6
8.7
8.9 U
8.9 U
8.9 U
8.9 U
8.9 U
2.2 J
120
8.9 U
180 U
8.9 U
8.9 U
8.9 U
8.9 U
89 U
130
1.6 J
8.9 U
8.9 U
89 U
8.9 U
8.9 U
POST-HVH8
8.8
7.6 U
7.6 U
7.6 U
7.6 U
7.6 U
2.9 J
21
7.6 U
150 U
7.6 U
7.6 U
7.6 U
7.6 U
76 U
100
7.6 U
7.6 U
7.6 U
76 U
7.6 U
7.6 U
POST-HVP8
7.5
3.6 U
3.6 U
3.6 U
3.6 U
3.6 U
0.68 J
23
3.6 U
71 U
3.6 U
3.6 U
3.6 U
3.6 U
36 U
9.6
3.6 U
3.6 U
3.6 U
36 U
3.6 U
3.6 U
11
-------
TABLE 1 (Continued)
SUMMARY OF VALIDATED VOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
tert-Butylbenzene
Tetrachloroethene
Toluene
trans-l,2-Dichloroethene
trans- 1 , 3 -Dichloropropene
Trichloroethene
Trichlorofluoromethane
Vinyl acetate
Vinyl chloride
Xylenes (total)
POST-HVH4
12.6
3.7 U
3,700
3.9
3.7 U
3.7 U
9.9
3.7 U
73 U
3.7 U
47
POST-HVP4
7.8
300 U
2,500
300 U
300 U
300 U
68 J
300 U
300 U
300 U
130 J
POST-HVL4
8.5
270 U
1,400
270 U
270 U
63 J
270 U
270 U
270 U
270 U
270 U
POST-HVL4013
8.5
3.9 U
28
1.2 J
3.9 U
3.9 U
2.4 J
3.9 U
79 U
2.5 J
3.9 U
POSTHVJ6
8.7
8.9 U
100
4.2 J
8.9 U
8.9 U
11
8.9 U
8.9 U
8.9 U
11
POST-HVH8
8.8
7.6 U
55
2.9 J
7.6 U
7.6 U
7.1 J
7.6 U
7.6 U
7.6 U
15
POST-HVP8
7.5
3.6 U
90
11
3.6 U
3.6 U
8.2
3.6 U
3.6 U
3.6 U
3.6 U
Notes:
J
U
UJ
a
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
The analyte was not detected. The reported sample quantitation limit is considered estimated for quality control reasons.
Field duplicate sample
12
-------
TABLE 2
SUMMARY OF VALIDATED SEMIVOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
l,l'-Biphenyl
1 ,2,4-Trichlorobenzene
1 ,2-Dichlorobenzene
1 ,3 -Dichlorobenzene
1 ,4-Dichlorobenzene
1 -Methy Inaphthalene
2,3 ,4,6-Tetrachlorophenol
2,4,5-Trichlorophenol
2,4,6-Trichlorophenol
2,4-Dichlorophenol
2,4-Dimethylphenol
2,4-Dinitrophenol
2,4-Dinitrotoluene
2,6-Dinitrotoluene
2-Chloronaphthalene
2-Chlorophenol
2-Methy Inaphthalene
2-Methylphenol
2-Nitro aniline
2-Nitrophenol
3,3' -Dichlorobenzidine
3 ,4-Dimethylphenol
3-Nitroaniline
POST-HVH4
7.6 - 15.6
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
1,300,000 UJ
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
530,000 U
270,000 U
530,000 U
530,000 U
530,000 U
POST-HVP4
4.8 - 12.8
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
5,500,000 UJ
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
2,200,000 U
1,100,000 U
2,200,000 U
2,200,000 U
2,200,000 U
POST-HVL4
5.5 - 13.5
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
5,300,000 UJ
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
2,100,000 U
1,100,000 U
2,100,000 U
2,100,000 U
2,100,000 U
POST-HVL401a
5.5 - 13.5
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
5,200,000 UJ
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
2,100,000 U
1,000,000 U
2,100,000 U
2,100,000 U
2,100,000 U
POSTHVJ6
5.7 - 13.7
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
600,000 UJ
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
240,000 U
120,000 U
240,000 U
240,000 U
240,000 U
POST-HVH8
5.8 - 13.8
390 J
1,400 J
6,100 U
6,100 U
6,100 U
6,100 U
6,100 UJ
6,100 UJ
6,100 UJ
6,100 UJ
6,100 UJ
30,000 UJ
6,100 U
6,100 U
6,100 U
6,100 UJ
6,100 U
6,100 UJ
12,000 U
6,100 UJ
12,000 U
12,000 UJ
12,000 U
POST-HVP8
6-14
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
13,000,000 UJ
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
5,300,000 U
2,700,000 U
5,300,000 U
5,300,000 U
5,300,000 U
13
-------
TABLE 2 (Continued)
SUMMARY OF VALIDATED SEMIVOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
4,6-Dinitro-2-methylphenol
4-Bromophenyl-phenyl ether
4-Chloro-3 -methylphenol
4-Chloroaniline
4-Chlorophenyl-phenylether
4-Nitro aniline
4-Nitrophenol
Acenaphthene
Acenaphthylene
Acetophenone
Anthracene
Atrazine
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Benzoic acid
Benzyl alcohol
Benzylbutylphthalate
bis(2-Chloroethoxy)methane
bis(2-Chloroethyl)ether
POST-HVH4
7.6 - 15.6
1,300,000 U
270,000 U
270,000 U
270,000 U
270,000 U
530,000 U
530,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
1,300,000 U
270,000 U
270,000 U
270,000 U
270,000 U
POST-HVP4
4.8 - 12.8
5,500,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
2,200,000 U
2,200,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
5,500,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
POST-HVL4
5.5 - 13.5
5,300,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
2,100,000 U
2,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
5,300,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
POST-HVL401a
5.5 - 13.5
5,200,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
2,100,000 U
2,100,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
5,200,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
POSTHVJ6
5.7 - 13.7
600,000 U
120,000 U
120,000 U
120,000 U
120,000 U
240,000 U
240,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
600,000 U
120,000 U
120,000 U
120,000 U
120,000 U
POST-HVH8
5.8 - 13.8
30,000 UJ
6,100 U
6,100 UJ
6,100 U
6,100 U
12,000 U
12,000 UJ
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
30,000 UJ
6,100 U
6,100 U
6,100 U
6,100 U
POST-HVP8
6-14
13,000,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
5,300,000 U
5,300,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
13,000,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
14
-------
TABLE 2 (Continued)
SUMMARY OF VALIDATED SEMIVOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
bis(2-Chloroisopropyl)ether
bis(2-Ethylhexyl)phthalate
Caprolacram
Chrysene
Dibenz(a,h)anthracene
Dibenzofuran
Diethylphthalate
Dimethylphthalate
Di-n-butylphthalate
Di-n-octylphthalate
Fluoranthene
Fluorene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Indeno( 1 ,2,3 -cd)pyrene
Isodrin
Isophorone
Methyl methanesulfonate
Naphthalene
Nitrobenzene
POST-HVH4
7.6 - 15.6
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
2,300,000
56,000 J
4,700,000
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
270,000 U
POST-HVP4
4.8 - 12.8
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
2,400,000
1,100,000 U
5,000,000
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
POST-HVL4
5.5 - 13.5
1,100,000 U
88,000 J
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
7,400,000
1,100,000 U
190,000 J
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
1,100,000 U
POST-HVL401a
5.5 - 13.5
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
6,400,000
1,000,000 U
93,000 J
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
1,000,000 U
POSTHVJ6
5.7 - 13.7
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
740,000
120,000 U
1,500,000
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
120,000 U
POST-HVH8
5.8 - 13.8
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
42,000
3,400 J
4,100 J
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
6,100 U
POST-HVP8
6-14
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
4,300,000
2,700,000 U
7,300,000
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
2,700,000 U
15
-------
TABLE 2 (Continued)
SUMMARY OF VALIDATED SEMIVOLATILE ORGANIC COMPOUND ANALYTICAL RESULTS
(micrograms per kilogram)
Sample Location:
Depth (feet):
N-Nitrosodi-n-propylamine
N-Nitrosodiphenylamine
Pentachlorophenol
Phenanthrene
Phenol
Pyrene
Notes:
J
U
UJ
a
POST-HVH4
7.6 - 15.6
270,000
270,000
530,000
270,000
270,000
270,000
U
U
U
U
U
U
POST-HVP4
4.8 - 12.8
1,100,000
1,100,000
2,200,000
1,100,000
1,100,000
1,100,000
U
U
U
U
U
U
POST-HVL4
5.5 - 13.5
1,100,000
1,100,000
2,100,000
1,100,000
1,100,000
100,000
U
U
U
U
U
J
POST-HVL401a
5.5 - 13.5
1,000,000
1,000,000
2,100,000
1,000,000
1,000,000
1,000,000
U
U
U
U
U
U
POSTHVJ6
5.7 - 13.7
120,000
120,000
240,000
120,000
120,000
120,000
U
U
U
U
U
U
POST-HVH8
5.8 - 13.8
6,100
6,100
12,000
6,100
6,100
6,100
U
U
UJ
U
UJ
U
POST-HVP8
6-14
2,700,000 U
2,700,000 U
5,300,000 U
2,700,000 U
2,700,000 U
2,700,000 U
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
The analyte was not detected. The reported sample quantitation limit is considered estimated for quality control reasons.
Field duplicate sample
16
-------
TABLE 3
SUMMARY OF VALIDATED ORGANOCHLORINE PESTICIDE AND pH ANALYTICAL RESULTS
(microgram per kilogram)
Sample Location:
Depth (feet):
4,4 '-ODD
4,4 '-DDE
4,4 '-DDT
Aldrin
alpha-BHC
alpha-Chlordane
beta-BHC
Chlordane (technical)
delta-BHC
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Endrin ketone
gamma-BHC (Lindane)
gamma-Chlordane
Heptachlor
Heptachlor epoxide
Methoxychlor
Toxaphene
POST-HVH4
7.6 - 15.6
14,000 U
35,000 J
14,000 U
21,000
14,000 U
14,000 U
14,000 U
140,000 U
14,000 UJ
190,000
14,000 U
120,000
14,000 U
14,000 U
14,000 U
14,000 U
19,000
14,000 U
14,000 U
14,000 U
72,000 U
720,000 U
POST-HVP4
4.8 - 12.8
14,000 U
110,000
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
140,000 U
14,000 UJ
14,000 U
14,000 U
190,000
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
72,000 U
720,000 U
POST-HVL4
5.5 - 13.5
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
140,000 U
14,000 UJ
14,000 U
160,000
14,000 U
14,000 U
14,000 U
14,000 U
200,000 J
14,000 U
14,000 U
14,000 U
14,000 U
70,000 U
700,000 U
POST-HVL401a
5.5 - 13.5
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
140,000 U
14,000 UJ
14,000 U
150,000
14,000 U
14,000 U
14,000 U
14,000 U
210,000 J
14,000 U
14,000 U
14,000 U
14,000 U
69,000 U
690,000 U
POSTHVJ6
5.7 - 13.7
16,000 U
180,000 J
16,000 U
16,000 U
16,000 U
16,000 U
16,000 U
160,000 U
16,000 UJ
40,000
16,000 U
16,000 U
16,000 U
16,000 U
16,000 U
16,000 U
16,000 U
9,200 J
7,400 J
16,000 U
81,000 U
810,000 U
POST-HVH8
5.8 - 13.8
16,000 U
16,000 U
16,000 U
68,000 J
16,000 U
16,000 U
16,000 U
160,000 U
16,000 UJ
480,000
16,000 U
16,000 U
16,000 U
19,000 J
16,000 U
4,500 J
16,000 U
16,000 U
16,000 U
16,000 U
81,000 U
810,000 U
POST-HVP8
6-14
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
140,000 U
14,000 UJ
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
14,000 U
72,000 U
720,000 U
17
-------
TABLE 3 (Continued)
SUMMARY OF VALIDATED ORGANOCHLORINE PESTICIDE AND pH ANALYTICAL RESULTS
(microgram per kilogram)
Sample Location:
Depth (feet):
pH (standard units)
POST-HVH4
7.6 - 15.6
2.0 J
POST-HVP4
4.8 - 12.8
2.0 J
POST-HVL4
5.5 - 13.5
2.0 J
POST-HVL4013
5.5 - 13.5
1.0 J
POSTHVJ6
5.7 - 13.7
12 J
POST-HVH8
5.8 - 13.8
12 J
POST-HVP8
6-14
2.0 J
Notes:
J
U
UJ
a
The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
The analyte was not detected. The reported numerical value is the sample quantitation limit.
The analyte was not detected. The reported sample quantitation limit is considered estimated for quality control reasons.
Field duplicate sample
18
-------
TABLE 4
SUMMARY OF VALIDATED DIOXIN RESULTS
(nanograms per kilogram)
Sample Location:
Depth (feet):
2,3,7,8-Tetrachlorodibenzo(p)dioxin
l,2,3,7,8-Pentachlorodibenzo(p)dioxin
l,2,3,4,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,6,7,8-Hexachlorodibenzo(p)dioxin
l,2,3,7,8,9-Hexachlorodibenzo(p)dioxin
l,2,3,4,6,7,8-Heptachlorodibenzo(p)dioxin
Octachlorodibenzo(p)dioxin
2,3 ,7,8-Tetrachlorodibenzofuran
1 ,2,3 ,7,8-Pentachlorodibenzofuran
2,3,4,7,8-Pentachlorodibenzofuran
1,2,3,4,7,8-Hexachlorodibenzofuran
1,2,3,6,7,8-Hexachlorodibenzofuran
2,3,4,6,7,8-Hexachlorodibenzofuran
1,2,3,7,8,9-Hexachlorodibenzofuran
1,2,3,4,6,7,8-Heptachlorodibenzofuran
1,2,3,4,7,8,9-Heptachlorodibenzofuran
Octachlorodibenzofuran
Total tetrachlorodibenzo(p)dioxins
Total pentachlorodibenzo(p)dioxins
Total hexachlorodibenzo(p)dioxins
Total heptachlorodibenzo(p)dioxins
Total tetrachlorodibenzofurans
POST-HVH4
7.6 - 15.6
1,190
9,500
21,000
25,000
24,000
197,000
440,000
55,000
351,000
38,000
1,120,000
380,000
149,000
86,000
1,800,000
1,110,000
46,500,000 J
58,000
130,000
240,000
330,000
860,000
POST-HVP4
4.8 - 12.8
825 U
11,200
24,000
23,000
17,400
167,000
340,000
88,130
700,000
64,000
1,600,000
620,000
250,000
200,000
2,060,000
1,460,000
38,100,000
55,000
144,000
230,000
270,000
1,710,000
POST-HVL4
5.5 - 13.5
1,340
23,000
48,000
58,000
42,000
380,000
710,000
194,000
1,370,000
143,000
3,000,000
1,140,000
480,000
290,000
3,300,000
2,500,000
57,000,000 J
37,000
197,000
450,000
620,000
1,740,000
POST-HVL401a
5.5 - 13.5
1,830
28,000
59,000
73,000
58,000
490,000
880,000
240,000
1,610,000
200,000
3,200,000
1,300,000
570,000
350,000
3,500,000
2,900,000
64,000,000 J
46,000
188,000
600,000
760,000
2,000,000
POSTHVJ6
5.7 - 13.7
471 UJ
11,400 J
31,000 J
74,000 J
55,000 J
540,000 J
740,000 J
5,500 J
25,000 J
12,300 J
250,000 J
106,000 J
45,000 J
4,800 J
940,000 J
86,000 J
4,100,000 J
23,000 J
130,000 J
530,000 J
950,000 J
71,000 J
POST-HVH8
5.8 - 13.8
430
3,700
3,200
5,900
6,200
18,700
11,000
13,700
24,200
7,300
58,000
32,000
10,600
4,500 J
154,000
32,000
270,000
17,100
40,000
48,000
33,000
106,000
POST-HVP8
6-14
970
5,400 U
14,800
16,000
14,400
140,000
280,000
68,000
1,150,000
62,000
2,100,000
1,350,000
360,000
280,000
5,200,000
2,900,000
79,000,000 J
18,400
50,000
155,000
240,000
1,310,000
19
-------
TABLE 4 (Continued)
SUMMARY OF VALIDATED DIOXIN RESULTS
(nanograms per kilogram)
Sample Location:
Depth (feet):
Total pentachlorodibenzofurans
Total hexachlorodibenzofurans
Total heptachlorodibenzofurans
POST-HVH4
7.6 - 15.6
1,330,000
2,600,000
3,940,000
POST-HVP4
4.8 - 12.8
2,700,000
4,200,000
4,800,000
POST-HVL4
5.5 - 13.5
4,300,000
7,400,000
7,900,000
POST-HVL401a
5.5 - 13.5
5,000,000
7,800,000
8,700,000
POSTHVJ6
5.7 - 13.7
290,000 J
810,000 J
1,180,000 J
POST-HVH8
5.8 - 13.8
148,000
210,000
230,000
POST-HVP8
6-14
3,600,000
6,600,000
10,000,000
Notes:
J = The analyte was detected. The reported numerical value is considered to be estimated for quality control reasons.
U = The analyte was not detected. The reported numerical value is the sample quantitation limit.
ng/kg = nanograms per kilogram
a Field duplicate sample
20
-------
TABLE 5
SUMMARY OF TOXICITY EQUIVALENTS
(nanograms per kilogram)
Sample
POST-HVH4
POST-HVP4
POST-HVL4
POSTHVL40P
POST-HVJ6
POST-HVH8
POST-HVP8
Toxicity Equivalents
Maximum15
305,000
432,000
798,000
910,000
62,000
18,600
675,000
Minimum0
305,000
431,000
798,000
910,000
62,000
18,600
673,000
Mediand
305,000
432,000
798,000
910,000
62,000
18,600
674,000
Notes:
a
b
c
d
Field Duplicate Sample
"Maximum" calculated with nondetected results assumed to be equal to the sample reporting limit
"Minimum" calculated with nondetected results assumed to be zero
"Median" calculated with nondetected results assumed to be half the sample reporting limits
21
-------
APPENDIX D
SITE SOIL BOREHOLE LOGS
61
-------
Tetra Tech EM Inc.
A
N-
E4=
E3=ป
Sample Top
0=
2=
6=
10=
Sample Bottom
2=
6=
10=
13=
Recovered
1.35=
?=
4=
3=
0)
P
737=
802=
804=
810=
3=
6=
9= 10=
Hex Pit lnterior=
CD
c
m
0)
K.
Q
LL
0.05:
2.26:
4=
2.5=
0.7=
9.5=
0.1 =
1.4=
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
CL
t
"5
w
w
o
w
SW=
ML=
SM=
ML=
SP=
SM=
ML=
TD=
Borehole ID: 1
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-18-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 1 : Sand with silt and qravel: med. qrained: brown: poorly sorted: loose: soft: =
moist; VOC sample collected from 1 ft. interval at 0738.=
1 to 2: Same as above with black staininq throuqhout: moist. Note: offset ~6 inches
to the NW. After moving the drillers encounter apparent void spaces from 2 to 6 ft.,
incomplete recovery. =
2 to 6: Sandy silt: rust color patches and black color patches throuqhout (Hex): soft:
6 to 7.4: Silty sand: brown: fine qrained: loose: soft=
7.4 to 8.2: Silt: loose: soft: sliqhtly plastic: liqht brown=
8.2 to 10: Sand: trace fines: fine qrained: subrounded: well sorted: very soft: very =
loose; "clean". =
10 to 11: Silty sand: brown: med. qrained: moderately firm: moderately dense: =
moist; slightly plastic=
11 to 13: Sandy silt with some clay: brown: moderately dense: moderately firm: =
some black staining at ~13 ft. (the staining seems wet).=
TD = 13ft.=
Hex Pit Borehole Log 1
-------
Tetra Tech EM Inc.
A5
8
11 12
Hex Pit Interior
Sample Top
0
2
6
Sample Bottom
2
6
10
Recovered
2
2
3
7
3
4
3.15
3
0)
P
1125
1128
1135
1145
>
E9
h
E10
CD
C
T3
us
0)
K.
Q
LL
0.1
5
6
0.3
0.5
1.4
1.5
1
7
11.2
3.1
1.4
3
3.4
0.4
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
L
J
0)
CL
t
"5
w
w
o
w
D
Borehole ID: 5
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-17-01
Logged By: Erika Herreria
Soil Description
0 to 0.6: Sand with some fines: liaht brown: medium sand: well sorted: loose: soft:
"clean fill"; subrounded to rounded.
0.6 to 1 : Gravel sand mix: poorly sorted: fine qravel: loose: soft: dark brown: qravel
is subrounded to subangular; "clean".
1 to 2: Sandy silt: brown: fine to med. sand: moderately sorted: med. dense: sliahtly
plastic; "clean".
2 to 4.5: Sandy silt: brown: fine sand: well sorted: loose: soft: sliahtly plastic: with
coal like material throughout.
4.5 to 6.8: Sandy silt: with lots of rust and black hex/tar material throuahout the
whole interval.
6.8 to 7.5: Silty sand: dark brown: fine sand: well sorted: very loose: very soft:
"clean".
7.5 to 8.5: Sandy silt: brown: fine sand: well sorted: loose: soft: sliahtly plastic:
"clean".
8.5 to 1 1 .2: Sand with fines: liaht brown: fine sand: well sorted: very loose: very soft:
"clean".
1 1 .2 to 1 1 .8: Silty sand: liaht brown: med. sand: well sorted: loose: soft:
subrounded; slightly plastic; "clean".
1 1 .8 to 13: Clay silt with fines: liaht brown: plastic: med. dense: moderately firm:
with white sand pockets throughout; "clean".
Hex Pit Borehole Log 5
-------
Tetra Tech EM Inc.
i k
N-
CL
|2
0)
Q.
CT3
W
o-
2=
6=
10=
A.6=
E4=* ซ ซ
9= 10=
E3ซ
Hex Pit lnterior=
Sample Bottom
?-
6=
10=
13=
Recovered
2=
2.5=
3.6=
3.2=
0)
p
808=
815=
820=
830=
CD
_C
T3
CT3
0)
cc
Q
LL
0.4=
0.35:
2.5=
3.2=
76=
97-
91 =
20=
35=
30=
Lab Analysis
"33
ฃ
c
.c
"S.
0)
Q
1 =
2=
3=
4=
6
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
Q.
t
"o
W
W
O
w
D
SP=
SM=
i~
52-
JD
U)
1
Hex=
ML=
SP=
_i
S
S
w
TD=
Borehole ID: 6
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/25/01 =
Logged By: David West=
Soil Description=
0.0 to 1 .1 : Sand: moderately sorted fine to medium qrained: yellowish brown, dry =
loose; abundant rock fragments to 1/3" to 1/2" at 0.8 ft; new surfical fill; sharp -
contact below. =
1 .1 to 3.8: Silty sand: fine qrained moderately sorted: silt to 25%: sliahtly moist: stiff:
dark yellowsih brown to dark grayish brown.
Collected VOC sample at 1 ft. @ 0814 PRE-S-6(VOC)=
Collected VOC sample at 5 ft. @ 0819 PRE-W-6(VOC)=
Moderate recovery in 2 to 6 ft. run (2.5/4.0), depths are approx. 3 to 3.8 silty sand =
becomes strongly mixed with black (hex) staining; sharp contact at 3.8 with obvious =
color change in waste. =
3.8 to 6.2: waste: liqht bluish qray silty waste with qreasy (qraphite-like) texture to -
. . r .^ ... _. .. . . . . . . . . . r
fibrous material; black liquid hex at 5.9 to 6.1 ft.=
6.2 to 8.4: Silt: stronqly stained very dark brown to dark reddish brown from hex -
waste above; uniform soft texture; moist to slightly moist; becomes sandy below 7.5 =
ft; relatively sharp contact with sand below; streaked with hex.=
8.4 to 10.0: Sand: well sorted fine to medium fine qrained: dark brown to dark
yellowish brown; moderately loose; streaked/stained with hex (hex sheen); slightly =
moist to moist.=
10.0 to 13.0: Silty sand and sandy silt: uniform yellowish brown to dark yellowish
brown with some tan mattles; sparse hex staining throughout; moderately stiff; very =
fine to fine grained sand, slightly moist.
* sparse hex staining and "micro stringers" throughout 10-13=
TD = 13ft=
Collect 3-point composite at 2-10 for sample PRE-W-2=
Collected 6-point composite at 0-2, 10-12, 12-13 for sample PRE-S-2=
Hex Pit Borehole 6
-------
Tetra Tech EM Inc.
A
N-
CL
|2
0)
Q.
CT3
W
0=
2=
6=
10=
W
E4=*
E3ซ
Sample Bottom
2=
6=
10=
13=
Recovered
2=
1.1 =
2.8=
0)
p
850=
855=
900=
6=
^.
9= 10=
Hex Pit lnterior=
CD
_c
T3
CT3
0)
cc
Q
LL
0.12=
1.9=
1.8=
27=
97-
52=
13
16=
32=
Lab Analysis
"33
ฃ
c
.c
"S.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11~
12=
13=
14=
15=
16=
17=
18=
19=
20=
7=
0)
Q.
t
"o
V)
w
o
w
D
sw=
SM=
S
52-
m
w
1
ML
SP=
S
w
_i
S
TD=
Borehole ID: 7
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/25/01 =
Logged By: David West=
Soil Description=
0.0 to 1 .0: Surficial fill: poorly sorted sand with qravel/rock fraaments to 3/4" =
(granite); dry; loose. =
1 .0 to 2.0: Silty sand: poorly sorted very fine to medium sand and abundant (> 25%) :
silt; stiff but "plastic"; dark reddish brown to orange-brown; slightly moist; reddish -
brown (oxidized) clasts but no hex is visible. =
2.0 to 6.0: Poor recovery (1 .1/4.0); some poorly sorted silty sand yellowish brown -
til -j u -r * * r u* ui u *,j -i -i *. -i i *. / *~i
brown silty sand with strong hex staining at bottom of intervals
6.0 to 7.4: Silt: dark qrayish brown to dark reddish brown stained from waste above, =
,..,,. UlCUf ''kifl " h\ **** h tt'th
sand.=
7.4 to 10.0: Sand: well sorted very fine to fine qrained. very moist: dark reddish -
. , . . . ... . . - . , ... , ,, , , .,,
content =
10.0 to 13.0: Silt and Silty Sand: uniform pale brown to yellowish brown with liqht -
yellow to tan mottles/partings in silt; stiff to moderately stiff; very slightly moist; minor
above; very slightly moist; very spurse black (hex) staining throughout interval (not =
obvious). =
TD = 13ft=
Collect 3-point composite at 2-10 for sample PRE-W-2=
Collect 6-point composite at 0-2, 10-12, 12-13 for sample PRE-S-2=
Hex Pit Borehole 7
-------
Tetra Tech EM Inc.
A
E49 A. 9
E3ซ * *
"W 13 14
N E2ซ
Hex Pit Interior
CL
|2
0)
CL
CT3
W
0
2
6
10
Sample Bottom
2
6
10
13
Recovered
2.0/2.0
2.7/4.0
2.4/4.0
3.3/3.0
0)
p
1047
1051
1055
1058
CD
_C
T3
CT3
0)
cc
Q
LL
0.7
0.2
1.5
3.1
4.5
59
167
25
22.4
14.8
Lab Analysis
"33
ฃ
c
.c
"S.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
0)
CL
t
"o
W
w
o
w
D
GM
SM
ML
SM
Borehole ID: 9
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7/24/01
Logged By: David West
Soil Description
0.0 to 1 .2: Surface fill; sand, silty sand, gravel; and rock fragments; dry to very
slightly moist; yellowish brown; rock fragments to 1 1/2 inch; poorly sorted.
1.2 to 2.0: Silty sand; well sorted fine grained sand, yellowish brown; moist; stiff;
grades to silt below.
2.0 to 3.8: Silt; grayish brown; very slightly moist; stiff; some greenish brown to pale
yellow mottles;
3.8 to 4.6: Silty sand; dark yellowish brown with abundant dark gray to black hex
patches/streaks, also black (hex) granules; moderate sorting fine to medium grains.
4.6 to 8.0: Waste material; concrete rubble and rock/flbroes fragments with litlle fine
grained matrix 4.6 to 5.5 ft; dry to very slightly moist; sharp contact at 5.5 ft with
rusted metalic band (drum) with distinct bright orange to ruby red crystalline hex
waste material (drum contents) to about 7 ft. (poor recovery at top of 6 to 10 run),
7.7 to 8 ft. is black liquid hex within clayey silt matrix; running liquid is black, matrix
is dark gray to blak becoming less stained at 8 to 8.5 ft.
8.0 to 9.1 : Silt; no sand; dark brown with dark gray to black hex smears throughout;
very slightly moist; moderately stiff; moderately sharp contact with sand below.
9.1 to 10.5: sand; uniform sorting very fine to medium fine grained; yellowish brown
to dark yellowish brown, very slightly moist; moderately stiff; moderately sharp
contact with silt below.
10.5 to 13.0: silt; grading to silty sand at 12.5; uniform pale yellowish brown to dark
yellowsih brown; slightly moist; yellowish white mottles; no obvoius hex staining;
very stiff.
Collect 3-Point composite at 2-10 ft. for sample PRE-W-2
Collect 6-Point composite at 0-2, 10-12, and 12-13 for sample PRE-S-2
Hex Pit Borehole Log 9
-------
Tetra Tech EM Inc.
A
E4ซ
E3* 13= f=
N= E2ป
Hex Pit lnterior=
Sample Top
0=
2=
6-
10=
Sample Bottom
2=
6=
10=
13=
Recovered
2=
2.3=
3.1 =
3=
01
F
808=
820=
827=
835=
FID Reading
0.2=
3.9
4.9=
4.3=
40=
48=
23=
35=
36=
42=
24=
w
'w
_>*
ro
<
,Q
ro
_i
0)
0)
u_
c
,c
"o.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
USCS Soil Type
GM=
_0)
w
ro
S
SM=
_0)
w
to
ML/
SM=
SP=
ML/SM/SP
TD=
Borehole ID: 14
Job Number: G1093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/24/01 =
Logged By: David West=
Soil Description=
0.0 to 0.8: surface fill: dry siltv sand and gravel/ rock fragments: loose: vellowish =
brown; quartz rock fragments to 3/4 inc.; sharp contact below.=
0.8 to 1.4: waste material: wood fragments/chunks: dark brown siltv sand matrix: no =
obvious contamination; slightly moist to moist; sharp contact and obvious color =
change to light gray (lime?) below; collect sample PRE-S-14(VOC) at 1 ft at 0809.-
1.4 to 5.6: silty sand with some clay; obvious light bluish gray; indurated (cemented) =
uniform silt with minor clay; collect sample PRE-W-14(voc) at 5 ft (0823); very sharp =
contact with wood fragments/waste at 5.6 ft.=
Photo: 4-22, 4-23.=
5.6 to 7.3: wood fragments and mixed granular hex waste to 6 ft.: wet: dark reddish =
brown becoming dark brownish gray below 6 ft.; clayey silt with some wood fragments
from 6 to 7.3, also wet; 40 ppm FID signature; typical hex sheen throughout, but no =
"flowing" hex; grades into less stained silt below; hex creates sheen on water.=
?.3 to 8.2: silt/siltv sand: mostlv "clean" dark vellowish brown silt, grading to siltv =
sand; slightly moist, moderately dense; uniform sorting; native materials
10.0 to 13.0: silt, siltv sand, and sand interbedded: uniform (light) vellowish brown: -
interbeds; slightly moist; sands are well sorted fine to medium fine grained; native -
12.5 to 13.0 may be minor hex contamination. -
TD = 1 3 ft=
Note: 3 point composite collected at 2-10 for sample PRE-W-3 and a 6-point =
compsites collected at 0-2, 10-12, 12-13 for sample PRE-S-2=
Hex Pit Borehole 14=
-------
Tetra Tech EM Inc.
**
Hex Pit lnterior=
* .
15= 16=
Q.
O
(-
01
Q.
ro
W
0=
2=
5=
6=
10=
Sample Bottom
2=
5=
6=
10=
13=
Recovered
1.8=
2.6=
1 =
3.4=
3=
0)
F
1100=
1105=
1106=
1120=
1125=
E9=
E10=
CD
C
T3
ro
8.
Q
u_
n 7-
2.1 =
4=
1.4=
4.1 =
4.5=
41 =
8.5=
4.9=
6.9=
8.1 =
9.4=
1
h
Lab Analysis
0)
0)
u_
_c
,c
"S.
0)
Q
1
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
k
1=
K
>*
H
'o
W
W
O
w
3
S
O
S
w
SM
WASTE (CL)
HEX
ML=
SP/
SM=
qyi-
TD=
Borehole ID: 15
Job Number: G1093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/23/01 =
Logged By: David West=
Soil Description
0.0 to 0.8: siltv sand and aravel/rock fragments: surface fill: drv: loose: qravish brown:
sharp contact with silty sand below.=
0.8 to 2.0: siltv sand: moderate sorting, fine to medium fine drained: vellowish brown. :
moist; moderately loose; sharp color change at 1 .6 ft to dark brown poorly sorted silty
sand; 1 1/2 inch wood fragments at 2 ft.; collected VOC sample PRE-S-15 (VOC) at =
1.0ft. at 1107.=
2.0 to 6.0: clav: cemented sands and waste material: distinct liqht qrav color =
throughout (lime?); upper 0.2 ft. is indurated cemented sands, sharp contact with clay
of identical color; uniform; distinct greasy/graphite texture; dark brown silty sand and =
mottled light gray to gray, also distinct at 5.0 ft.; collected VOC sample PRE-W
15(VOC)at5ft. at 1111.=
6.0 to 7.8 : clav as above: verv strong mottling light qrav to dark qrav. wet at 7.6 to -
7 7 ft f" H H" t A-t h t t t 7 O "th I h K I
wood fragments at 7.7 to 7.8.=
7.8 to 8.2: hex waste: granules of industrial hex and obvious orange to reddish =
orange staining in clayey silt matrix; moist; some tar-like hex in fine grained matrix; =
graded to "clean" silt below.=
8.2 to 9.1: silt: vellowish brown: moderatelv stiff: "clean": sliqhtlv moist to moist: =
grades to silty sand below.=
9.1 to 13.0: siltv sand to sand with minor silt: well sorted fine to medium fine drained:
uniform pale brown to light yellowish brown; overall maintains silty sand; slightly moist
throughout; stiff to moderately stiff; native material.
TD= 13ft=
6 pt. Composite collected at 0-2, 10-12, 12-13 feet.=
3 pt. Composite collected at 2-10 feet.=
Several photos of Kevin & Neil Collecting VOC samples. =
Note: obvious reddish-orange hex coloration below 8.0 ft. (to 8.2 ft) was a "smearing"
of waste along liner.=
Hex Pit Borehole Log 15=
-------
Tetra Tech EM Inc.
Sample Top
0
2
6
10
HexF
15
Sample Bottom
2
6
10
13
Dit Interio
A
16
Recovered
2.2
4
3.75
ซ
r
O
0)
P
930
936
940
946
E9
E10
CD
C
T3
us
0)
CC
Q
LL
0.3
0.15
0.25
0.65
51.2
24.8
63.4
10.3
8.8
Lab Analysis
A
h
IE
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
k
J
0)
d.
t
"5
w
w
o
w
D
SP
GW
ML
CM
Ml
cp
SM
ML
TD
Borehole ID: 16
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-18-01
Logged By: Erika Herreria
Soil Description
Take VOC sample at the 1 ft. interval at 0933
0 to 0.5: Sand with fines: med. qrained: brown: well sorted: loose: soft: subrounded:
"clean"
0.5 to 1 .6: Sand with qravel: med. drained sand with coarse qravel: poorly sorted:
loose; soft; subrounded gravel.
1 .6 to 2: Sandy silt with some clay: brown: moderately dense: moderately firm:
moderately plastic; "clean".
2 to 4.2: Silty sand: brown: fine to med. qrained: moderately soft: moderately dense
color changes to a rust color and at 4.2 ft to a black color.
(no visible liquid product) Note* Take VOC sample at the 5 ft interval at 0938
6 to 9: Sandy silt: dark brown: soft: moderately dense: sliqhtly plastic: wet (no
visible liquid product); with black staining throughout.
brown color
10 to 1 1 .2: Same as above: color chanqe toward to bottom at 1 1 .1 ft. to a liqhter
brown.
1 1 .8 to 13: Sandy silt: liqht brown: loose: soft: sliqhtly plastic: with white sand
pockets; "clean".
Sample 2-10 taken at 1015 from a composite of borings 1, 16, 4.
Hex Pit Borehole Log 16
-------
Tetra Tech EM Inc.
N-
CL
|2
0)
Q.
CT3
W
0=
2=
6=
10=
Sample Bottom
2=
6=
10=
13=
E4
E3
E2
E1
Recovered
2=
1.8=
2.9=
3.3=
0)
p
900=
907=
912=
918=
13
*
CD
_C
T3
CT3
0)
cc
Q
LL
0.5=
0.25=
9.6=
7.3=
20.9=
48=
24=
27=
22=
10.1 =
17=
L
17=
Lab Analysis
14=
"33
ฃ
c
.c
"S.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
Q.
t
"o
W
W
O
w
D
SM/
SM
LJJ
s?
ง
X
I
ML
gp-
5
w
TD=
Borehole ID: 17
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/24/01 =
Logged By: David West=
Soil Description
0 to 1 .1 : surface fill: siltv sand and qravel/rock fraqments to 1/2 inch: dark yellowish =
brown; loose; dry.=
1.1 ro 1 .8: silty sand: well sorted find to very fine sand: dark yellowish brown: sliqhtly
moist; stiff; appears "clean", sharp contact below.=
1 .8 to 4.4: (?) (poor recovery at 2 to 6 ft.): silty sand, poorly sorted sand, fine to -
.. . . . . , . ... . . , , f ... ,
slightly moist; sharp contact below.=
4.4 to 7.3: waste material: briqht reddish oranqe industrial sand 0.6 ft. thick at about =
4.4 to 5.0 ft.; mixed silty sand and distinct light grayish white silt (lime?); slightly =
moist; poorly sorted, rock fragments to 1 inch; minor wood fragments; wet at 6 ft. -
and sharp contact with dark grayish brown clayey silt with obvious hex sheen/smear;
slippery; texture; grades to less stained silt below.
brown becoming yellowish brown at 10 ft * slightly moist" moderately loose ~
10.3 to 13: silty sand/sandy silt interbedded; light yellowish brown to pale brown with
throughout; some pale yellow/white mottles in silt.=
9:36 completed sampling;
Note: several photos of sample collection/drilling=
TD = 13ft=
o-point composite collected at 2-10 tor sample HKt-w-o and b-point composite -
collected at 0-2, 10-12, 12-13 for sample PRE-S-2=
Hex Pit Borehole 17
-------
Tetra Tech EM Inc.
N=
Q.
|2
,
05
<
.Q
05
^.
"5
5
O
OT
SM =
ML
(GM)=
white:
ML/
CL
QM
M|
TD=
Borehole ID: 21
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7/23/01 =
Logged By: David West=
Soil Description=
0.0 to 1 .2: Sand with rock/aravel fraaments: arayish brown; dry; loose: rock/aravel =
sharp contact with silty sand below.=
1 .2 to 2: silty sand: well sorted fine to medium fine drained: silt to 10%: sliaht moist: :
moderately dense; strong brown to dark yellowish brown. =
strong black (hex) mottling; some black granular (hex?) coal-like fragments: some =
rock fragments to 1 inch at middle of interval. ~3.0 to 4.0: sandy silt; moist; soft; =
rubber 3/4 inch round; fibrous dark grayish brown material (0.1 ft. thick); waste =
material; sharp contact and obvious color change to light gray to pale white (lime?), :
silty sand below waste layer approximately 5 to 6 ft (')' moderately sorting fine to =
medium grained; strongly mottled light gray/pale white/medium to dark gray: moist; =
6.0 to 7.8: Silt/clayey silt: mottled dark aray to liaht aray with distinct band of pale =
white clay at 7.2 to 7.5 with slippery, graphite texture (lime?); very dark gray silty =
clay/clayey silt below 7.5; sharp contact with "clean" material below 7.8 ft-
7.8 to 9.0: Silty sand with minor clay: well sorted fine to very fine drained sand: dark
10 ft; "clean" yellowish brown, slightly moist, well sorted, fine to medium fine =
grained; minor silt (< 5%).=
9.0 to 10.8: sand, as described above: moderately sharp contact with silt below.=
10. 8 to 13.0: silt and sandy silt: "clean" liaht yellowish brown; sliahtly moist: stiff: =
native material: intervedded silt and sand content up to 25-35% with increased =
moisture; pale brown to light yellowish color is uniform throughout.=
TD= 13ft.=
Hex Pit Borehole Log 21 =
-------
Tetra Tech EM Inc.
N=
CL
O
0)
CL
us
W
0=
2=
6=
10=
Sample Bottom
?=
6=
10=
13=
E4
E3
E2
E1
Recovered
2=
1.6=
2.2=
3.5=
*
ซ ,
"*
0)
JZ
1038=
1042=
1048=
1054=
13=
A
23=
CD
C
T3
CT3
0)
cc
Q
LL
0.8=
1.0=
0.8=
4.0=
45.5=
94.5=
8.5=
105.0=
83.0=
14=
17=
20=
Lab Analysis
"5
0)
LL
_C
.c
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
S.
>>
"o
W
w
o
w
D
GM=
ML-
CR/I-
MI -
TD=
Borehole ID: 23
Job Number: G1093-24Q-
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1 .125 in. PETG plastic liners=
Drilling Date(s): 07/20/01 =
Logged By: Erika Herreria=
Soil Description=
0 to 0.2: silty aravel: fine, poorly sorted, loose, soft. "clean".=
ฃ,.,.,. ... -it
0.2 to 2.0: bandy silt: brown: loose: soft: with black coal-like material tnrouanout -
intervals
Note: Sample PRE-S-23 (VOC) was collected at the 1 foot interval at 1040=
2.0 to 5.0: same as above. At approximately 5.0' feet hit a rock.=
Note: Sample PRE-W-23 (VOC) was collected at the 5 foot interval at 1044=
5.0 to 6.0: Silt: white arey blue color: very fine: soft: dense: moist (lime?)=
6.0 to 10.0: Silty sand: very dark brown: fine qrained: well sorted: loose: soft: at 6.0" =
feet there was about 2" inches of liquid hex.=
1 0.0 to 1 1 .0: Clayey silt: brown: moderately stiff: moderately dense: plastic: moist: =
with black staining throughout intervals
1 1 .0 to 13.0: Sandy silt: brown: loose: soft: moist: with black staininq and very moist :
spots throughout intervals
TD= 13ft.=
Hex Pit Borehole Log 23'
-------
Tetra Tech EM Inc.
Sample Top
0
2
6
10
HexF
'
A
25*
Sample Bottom
2
6
10
13
3it Interio
16<
19
22
L
Recovered
2.0/2.0
3.3/4.0
3.4/4.0
2.5/3.0
r ซ
*
01
F
8:40
8:45
8:50
8:55
>E9
>E10
ฃ11
0)
c
T3
ro
0)
Ct
Q
LL
0.9
1.6
2.4
3.0
2.4
5.9
14.3
102.0
75.4
31.1
14.8
11.5
w
'w
_>*
ro
<
,Q
ro
_i
A
h
"55
0)
U_
c
,c
"o.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
L
1
USCS Soil Type
SMI
GM
SM
CL
white
ML
SM
SP
SM/
ML
MI
TD
Borehole ID: 25
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Steve Mitchell & Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7/23/01
Logged By: David West
Soil Description
0 to 1.2: silty sand and gravel/rock fragments; dry surface fill; grayish brown; loose;
below.
1.2 to 2.0: silty sand; poorly sorted very fine to medium grained but uniform
otherwise; silt from 10 to 15%; dark yellowish brown; slightly moist; moderately
dense.
2.0 to 5.3: silty sand (as above); mostly clean to 3.5 ft, becomes variable mottled with
black hex 3.5 to 5.3 with black granular coal-like band at 4.3 to 4.5 ft; moderately
sorted fine to medium fine sand below 4.5 ft; increased moisture at 4.5 to 5.3 to
mearly wet; sharp contact at 5.3 to gray stained waste material.
5.3 to 5.6: waste material; silty sand matrix; fiboroous and wood fragments; strong
gray to dark gray staining with no significant FID signature; grades to light gray clay
below.
5.6 to 6.0: clay; obvious light gray to pale white mottles, very greasy graphite-like
texture, moist.
white to light gray Band at 7 1 to 7 3 ft" moist" greasy/graphite texture remains
throughout; grades to silt below.
7.6 to 8.5: silt; stained dark gray from above, becoming dark yellowish brown; uniform
texture; moderately stiff; slightly moist; grades to silty sand.
8.5 to 9.0: silty sand; uniform dark yellowish brown, "clean" native material; slightly
moist; graades to sand with minor silt.
yellowish brown uniform "clean" native material" sharp contact
11.1 to 13.0: silty sand and silt interbedded; light yellowish brown to pale brown;
slightly moist; moderately stiff, uniform "clean" native material.
Photo 4-24 taken of kevin P. sampling.
Note: Sample collected from entire borehole used in 6-point composite sample PRE-
S-3
Hex Pit Borehole Log 25
-------
Tetra Tech EM Inc.
Sample Top
0
2
6
10
HexF
15ซ
25*
Sample Bottom
2
6
10
13
Dit Interio
16<
19
22
A
26
Recovered
2
2
2.5
4
2.6
4
3.1
3
r
k
L
0)
p
1104
1108
1111
1117
>E9
>E10
E11
>
CD
C
T3
us
0)
CC
Q
LL
1.5
6
0.3
0.45
2.1
23
9.7
9.4
12.9
5.1
Lab Analysis
A
h
IE
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
k
J
0)
d.
t
"5
w
w
o
w
D
SP
GW
ML
CM
SP
Ml
Borehole ID: 26
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-18-01
Logged By: Erika Herreria
Soil Description
0 to 0.4: Sand: liaht brown: med. sand: well sorted: very loose: very soft: rounded:
"clean"; dry.
0.4 to 1 .5: Sand with qravel: med. sand: coarse aravel: poorly sorted: loose: soft:
subrounded to subangular gravel; dry; "clean".
1 .5 to 2: Sandy silt: liaht brown: fine sand: well sorted: moderately firm: moderately
dense; dry; "clean".
2 to 6: Sandy silt: fine to med. sand: moderately sorted: loose: soft: with black coal
like material throughout; From 2 to 5 ft interval was a brown color at 5 ft the color
changed to a rust color.
6 to 6.3: Black liquid Hex: sticky: hiqh viscosity.
6.3 to 7: Silty sand: fine sand: very loose: very soft: well sorted: moist: color chanqe
at 6.5 ft from black to dark brown.
7 to 9: Sandy silt: brown: fine sand: well sorted: loose: soft: sliahtly plastic: moist.
9 to 10: Sand with some fines: very fine sand: well sorted: very loose: very soft:
moist; brown; "clean".
moderately firm* plastic* with white sand color pocket throughout" moist
12.3 to 13: Sandy silt; brown; fine sand; well sorted; soft; moderately dense; sliahtly
plastic; moist.
Hex Pit Borehole Log 26
-------
Tetra Tech EM Inc.
N
Sample Top
0
2
6
10
..J
r
E4A ป
13
E3ป
17
E20 20
E1ป
Sample Bottom
2
6
10
13
Recovered
2.0/2.0
2.0/4.0
2.15/4.0
3.2/3.0
0)
P
7:42
7:47
7:52
8:00
CD
C
m
0)
Q
LL
0.3
0.8
0.7
2.5
29.7
97
11.3
16.8
....!---
i
24
28
Lab Analysis
14
"5
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
0)
CL
t
"5
w
w
o
w
GM
ML
SP
SM
Borehole ID: 28
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason & Zack
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 07/20/01
Logged By: Erika Herreria
Soil Description
0.0 to 1 .0: silty sand with gravel; brown color; fine sand; poorly sorted; coarse gravel;
loose; soft; "clean".
1.0 ro 2.0: sandy silt; brown color; fine sand; well sorted; medium stiff; medium
dense; with some coal like materials throughout interval.
2.0 to 4.0: same as above; at 3.5' to 4.0' feet the color changes to a rust color.
4.0 to 6.0: silt; white grey blue color; very fine, well sorted, soft, dense, moist, sligtly
plastic.
6.0 to 7.0: silt with fines; black color (hex), very fine, well sorted, soft, dense, moist
to wet.
7.0 to 8.5: silt; very dark brown, very fine, well sorted, soft, dense, moist, hex shim
throughout interval.
8.5 to 10.0: sand with fines; dark brown, fine sand, well sorted, soft, loose, moist.
10.0 to 13.0: silty sand; light brown, medium sand, well sorted, soft, loose, moist,
with black staining throughout.
Hex Pit Borehole Log 28'
-------
Tetra Tech EM Inc.
N
Sample Top
0
2
6
10
Sample Bottom
2
6
10
13
E4
E3
E2
E1
Recovered
2
2
2.7
4
2.3
3.1
3
..i
.
r
0)
p
1040
1044
1102
....
23
27
CD
C
T3
us
0)
CC
Q
LL
2.3
3
3.8
44.5
96.5
8.4
12.7
....
^.
31
Lab Analysis
....
IE
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
24
28
0)
d.
t
"5
w
w
o
w
D
GW
Ml
SM
ML
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-18-01
Logged By: Erika Herreria
Soil Description
Note: took sample PRE-S-31 (VOC) from 1 ft. at 1045
0 to 1 : Sand with qravel: some fines: poorly sorted: loose: soft: fine to coarse
gravel; brown sand.
1 to 2.7: Sandy silt: brown: fine sand: well sorted: soft: med. dense: sliqhtyly plastic:
with coal like material throughout.
2.7 to 4.5: Sandy silt with qravel: fine qravel: poorly sorted: dense: firm: ranqe in
color at firm dark gray 2.7 to 3.5 ft.; white gray with fibers from 3.5 to 3.9 ft.; rust
color from 3.9 to 4.5 ft; moist.
4.5 to 6.2: Black liquid Hex. Note: took sample PRE-W-31 (VOC) from 5 foot
interval at 1050.
plastic" moist
moderately dense* moderately firm* moist* with some coal like material throughout
12 to 13: Clayey silt: liqht brown: dense: firm: plastic: some black staininq: with
fines; moist.
Hex Pit Borehole Log 31
-------
Tetra Tech EM Inc.
N
Sample Top
0
2
6
10
Sample Bottom
2
6
10
13
E4
E3
E2
E1
Recovered
2.0/2.0
2.45/4.0
2.5/4.0
3.0/3.0
i
.
r
0)
p
8:12
8:17
8:48
8:52
23
27
CD
C
T3
ss
0)
CC
Q
LL
-0.2
3.9
2.4
28.2
87.6
56
38.4
34.4
19.1
24
28
31
Lab Analysis
I
1
1
1
i
1
1
ill
1
i
1
1
111
i
i
i
1
1
i
i
A
"5
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
t,
32
0)
d.
t
"5
w
w
o
w
D
fiM
ML
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain
Drilling Method: Direct push
Continuous core in 4 ft. X 1 .125 in. PETG plastic liners
Drilling Date(s): 07/20/01
Logged By: Erika Herreria
Soil Description
0 to 1 : silty sand with gravel; poorly sorted; fine to medium sand; fine to coarse
gravel; loose; soft; with coal like material in the center of the interval.
coal like material (a 10 mm size coal like material found at the bottom of the
interval).
2 to 3.5: sandy silt; light brown; fine sand; well sorted; loose; soft; moist; with lots of
coal like material throughout.
3.5 to 6.0: sandy silt; fine to medium sand, moderately sorted, soft, dense, moist,
range in color at the top of interval is a rust color then it trasitions to a very dark
6.0 to 6.7: silt; black color (hex shim); very fine; well sorted; soft; dense; moist; with
a few coarse gravels throughout.
6.7 to 7.2: sandy silt; very dark brown (with some hex shim); fine; well sorted; soft;
moderately dense; moist; with some black staining.
7.2 to 9.0: no recovery (the drillers hit a void space)
9.0 to 1 1 .0: sandy silt; dark brown; fine sand; well sorted; soft; dense; moist; with
some coal like material and black staining throughout.
11.0 to 13.0: sandy silt; brown; medium sand; well sorted; soft; moderately dense;
moist; with some black staining throughout.
Hex Pit Borehole log 32
-------
Tetra Tech EM Inc.
Sample Top
0
2
6
10
HexF
29
Sample Bottom
2
6
10
13
Dit Interio
30
33 A
36
Recovered
2
2
3.2
4
2.65
4
2.6
3
r
0)
P
0745
0750
0755
0903
E9
E10
E11
E12
CD
C
T3
us
0)
CC
Q
LL
0.1
0.1
0.2
0.57
0.3
9.5
Lab Analysis
I
h
IE
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
^
J
0)
d.
t
"5
w
w
o
w
D
GW
ML
SM
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-18-01
Logged By: Erika Herreria
Soil Description
Note: sample PRE-S-33 (VOC) collected from the 1 ft. interval at 0753.
0 to 1 : Sand with fravel: med. sand: poorly sorted: loose: soft: coarse:aravel: with
coal like material spots throughout.
1 to 2: Sandy silt: med. to fine sand: dark brown: well sorted: soft: moderately
dense; slightyly plastic; with coal like material modules throughout.
2 to 3.2: Same as above.
3.2 to 5.8: Sandy silt: fine sand: well sorted: loose: soft: sliqhtly plastic: rust color
from 3.2 to 4 ft then transition to a brown color from 4 to 5.8 ft; with coal like material
throughout.
5.8 to 6.9: Sandy silt: same as above: chanqe color to very dark brown with black
staining throughout.
moist
10.2 to 13: Silty sand: liaht brown: med. sand: loose: soft: moist.
Hex Pit Borehole Log 33
-------
Tetra Tech EM Inc.
Sample Top
0
2
6
10
HexF
29
Sample Bottom
2
6
10
13
Dit Interio
30
33 *
36 A
Recovered
2
2
2.7
4
0.4
4
1
3
r
0)
P
0813
0818
0825
0834
E9
E10
E11
E12
CD
C
T3
us
0)
CC
Q
LL
Lab Analysis
>
h
IE
0)
LL
C
.C
"5.
0)
Q
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
^
J
0)
d.
t
"5
w
w
o
w
D
GW
ML
NR
ML
SM
Job Number: G1 093-240
Site: Rocky Mountain Arsenal - Hex Pit
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck
Drilling Method: Direct push
Continuous core in 4 ft. X 1.125 in. PETG plastic liners
Drilling Date(s): 7-18-01
Logged By: Erika Herreria
Soil Description
Note: Sample PRE-S-36 (VOC) from 1 ft. at 0838
0 to 1 : Sand with qravel: med. sand: fine to coarse aravel: poorly sorted: loose: soft:
brown color sand.
1 to 2: Sandy silt: brown color: fine sand: well sorted: med. stiff: medium dense:
slightly plastic; with coal like material throughout.
from 2 to 4 ft then change to redish brown from 4 to 4 5" moist
4.5 to 6: Sandy silt: fine sand: well sorted: moderately dense: soft: very dark brown
(VOC) taken at 5 feet at 0855 and FID stopped working.
6 to 9.8: No recovery: drillers noted possible water.
9.8 to 10: Silt: brown: moderately dense: moderately stiff: with fines: moist sliqhtly
plastic.
sorted* loose* soft" moist" "clean looking"
Hex Pit Borehole Log 36
-------
Tetra Tech EM Inc.
A
N-
Sample Top
0=
2=
7=
E3
E2
E1
Sample Bottom
2=
7=
10=
Recovered
1.5=
3.6=
Hex Pit lnterior=
0)
P
1133=
1206=
CD
C
m
0)
Q
LL
0=
0=
0=
0=
0=
0=
0=
0=
1=
1=
0=
0=
0=
0=
0=
0=
0=
0=
0=
0=
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8-
9=
1ง=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
CL
t
"5
w
w
o
w
SP=
SM=
SP=
SM=
SP=
SM=
SP=
TD=
Borehole ID: E1
Job Number. oi09o-240-
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain Steve Mitchell and Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1 .125 in. PETG plastic liners=
Drilling Date(s): 7-12-01 =
Logged By: David West, Erica Herreria assisting=
Soil Description
0 to 2 Poor recovery in loose surficial sands. Fill material: sand with minor silt=
with fine to medium gravel; moderate sorting; moist; dark brown to brown; loose;
"clean"; offset < 1 ft. west and redrive with good recovery (1.5/2.0); sand, as=
decribed above; sharp contact at 1 ft. to dark brown very fine silty sand;
slighty moist to wet; minor silt at 2 ft; silty sand is stiff/dense; no FID detection=
throughout; wet at 1 ft contact. =
2 to 6 (no recovery on 1st and 2nd attempt: offset to 3rd location) Obvious=
surficial saturation "silty" on sharp contact at 1 ft with dense silty sand.
2 to 7 (3rd attempt): sand with minor silt: fine to medium qrained moderately =
well sorted (SP); loose; slightly to very little moisture; yellowish brown; grades=
to dark brown silty sand at 5.5 to 6.5 ft.: sand with minor silt =
6.5 to 7 Sand: loose: no moisture: well sorted: yellowish brown and "clean" =
7 to 10 Silty sand: very fine qrained 7 to 8 ft: sliqhtly moist well sorted sand=
with abundant silt; dark yellowish brown; grades to very well-sorted=
fine qrained sand with minor silt at 8 to 10 ft: loose: yellowish brown, "clean"
(as above), very slightly to slightly moist.=
TD= 10ft=
Collect 2 to 10 ft composite and split for agent screening at 1220; composite=
mixed in disposable aluminum pan; sanple ID = PRE-S-E2=
Background FID readings = -.0.68
E1 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
A
N-
Sample Top
0=
2=
fi-
E4ซ
Hex Pit lnterior=
E3ป
E2ซ
E1ซ
Sample Bottom
7-
6=
in-
Recovered
1.7=
3.6=
3.3=
0)
P
817=
824=
826=
CD
C
T3
ss
0)
CC
Q
LL
0=
0=
0=
0=
0=
0=
0=
0=
0=
0=
0=
0=
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
sw=
SM
SP=
SM=
SP=
TD=
Borehole ID: E2
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain Steve Mitchell and Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: David West; Erica Herreria assisting=
Soil Description=
0 to 0.5 Surficial qravel and sand, loose, dry. liqht brown=
0.5 to 2 Silty sand: fine to medium qrained dark brown, sliahtly moist=
2 to 5.8 Sand with minor silt, uniform, well sorted fine to medium fine qrained. =
moderately loose, slightly moist, yellowish brown, "clean," grades to silty sand=
below.=
5.8 to 6.5 Silty sand, very fine to flne-qrained. dark yellowish brown=
moderately stiff, slightly moist, grades to sand below=
6.5 to 10 Sand, minor silt, modertly well sorted, fine to medium qrained. =
"clean," loose, yellowish brown, slightly moist, silt content increases to 5 - 10=
% at 10 ft; overall very uniform native materials
TD = 10ft=
Background FID = -0.66 ppm =
0835 collect 2 to 10 ft composite and split sample for agent screening; sample=
composited in disposable aluminum tray; sample ID = PRE-S-E2=
E2 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
A
N-
Sample Top
0=
2=
7=
E4ซ
Hex Pit lnterior=
E3ป
E2ซ
E1ซ
Sample Bottom
2=
7=
10=
Recovered
1.9=
3.85=
2.6=
0)
P
909=
914=
920=
CD
C
T3
ss
0)
CC
Q
LL
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
PW-
ML=
SM=
ML=
SM=
TD=
Borehole ID: E3=
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: Erica Herreria=
Soil Description=
0 to 0.7 Gravel-sand mixture, poorly sorted, med. Sand, loose, soft, with fines. =
gravel size range fine to coarse=
0.7 to 1 .5 Clayey silt with fines, moderately dense, dark brown, moderately firm. =
slightly plastic, with black, coal-like materiaN
1.5 to 2 Silty sand, liaht brown, fine sand, loose, soft, well sorted. "clean"=
6.2 to 7 Sandy silt, liaht brown, very fine sand, loose, soft, well sorted, "clean." =
slightly plastic=
7 to 7.5: Sandy silt: same as above=
7.5 to 10 Silty sand, liaht brown, very loose, very soft, well sorted, fine sand. =
rounded, "clean"=
TD = 10ft=
Sample PRE-S-E3 taken from 2 to 1 0 ft at 0930=
E3 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
A
N-
Sample Top
0=
2=
7=
E4ซ
Hex Pit lnterior=
E3ป
E2ซ
E1ซ
Sample Bottom
2=
7
10=
Recovered
2=
3.8=
3=
0)
P
933=
937=
942=
CD
C
T3
ss
0)
CC
Q
LL
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
PW-
ML=
SM=
ML
SM=
TD=
Borehole ID: E4
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer and Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: Erica Herreria=
Soil Description=
0 to 1 .3 Sand with fines: med. sand: liaht brown: soft: loose: well sorted: rounded to
subrounded; "clean"=
6.2 to 7.5: Sandy silt: liaht brown: fine sand: loose: soft: well sorted: sliahtly plastic: =
"clean". =
TD = 10ft=
Sample PRE-S-E4 taken from 0 to 2 ft at 0950.=
E4 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
*
*
Sample Top
0=
2=
7=
Sample Bottom
2=
7=
10=
E5= E6= E7= E8= T
I
IN
*
Hex Pit lnterior=
Recovered
2.1 =
3.9=
2.7=
0)
P
935=
941 =
947=
CD
C
T3
ss
0)
CC
Q
LL
0.1 =
0.4=
0.5=
0.4=
0.6=
1.3=
0.6=
0.8=
1.6=
0.5=
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
sw=
SP=
SM=
ML=
SP=
TD=
Borehole ID: E5
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit-
Drilling Company: ESN - Rocky Mountain Steve Mitchell; Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: David West; Erica Herreria assisting=
Soil Description=
0 to 2 Sand, little to no silt, poorly sorted, fine to medium qrained.=
modertly loose; slightly moist; appears "clean" throughout; yellowish brown=
grades to well-sorted medium to fine silty sand at 1 .9 ft.=
2 to 5.5 Sand with little silt: silt content 5-10 %: well-sorted fine to=
medium grained, modertly compact; moist; yellowish brown; "clean, "=
grades to more dense silty sand/sandy silt below=
5.5 to 7 Silty sand/sandy silt: very fine qranied (well sorted) sand with =
abundant silt, becoming sandy silt at 6.5 to 7 ft.; more dense (stiff) but still=
crumbles easily; dark yellowish brown; moist to slightly moist; "clean" native =
soil=
7 to 9 Silt: uniform: soft: moist: dark yellowish brown to dark brown: "clean"=
native material; interbed of sandy silt 0.2 ft thick at 7.5 ft.=
9 to 10 Sand: well sorted fine qrained: loose: yellowish brown: "clean"=
T.D.= 10ft.=
FID background = 1 to 0.3 ppm=
0955 Collect 2 to 10 ft. composite sample "PRE-S-E5" in 8 OZ jar; collect split=
sample for agent screenings
0955 Borehole E5 grouted; move rig to E6=
0958 Start E6=
E5 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
Sample Top
0=
2=
6=
E5= E6= E7= E8= T
1
:
' Hex Pit Interior=
Sample Bottom
2=
6=
in-
Recovered
1.8=
3.4=
3.6=
0)
P
1000=
1009=
1014=
CD
C
T3
ss
0)
CC
Q
LL
0.8=
0.8=
0.6=
0.5=
1 =
0.2=
0.8=
1.8=
1.6=
2=
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
sw=
SP=
SM=
ML=
SP =
TD=
Borehole ID: E6
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit-
Drilling Company: ESN - Rocky Mountain Steve Mitchell; Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: David West=
Soil Description=
0 to 1 Sand: moderately sorted: fine to medium qrained: yellowish brown:=
loose "clean" cover material; slightly moist to moist; sharp contact at 1 ft.=
1 to 6 Sand: well sorted: fine qrained: no silt, uniform yellowish =
brown; modertly loose native soil; slightly moist; "clean;" grades to silty sand=
below=
6 to 8.4 Silty sand: very fine to fine qrained: well sorted: silt to =
approximately 10 %; loose; yellowish brown; slightly moist; 'clean"=
native material; relatively sharp contact with silt below=
8.4 to 9 Silt/sandy silt: sand is very fine qrained: about equal percent sand and=
silt; dark yellowish brown to dark brown; moist; sharp contact with sand below.=
9 to 10 Sand: well sorted fine qrained: loose: yellowish brown: "clean", no silt.=
T.D. = 10ft=
FID background = 0.10 ppm=
1026 Collect 2 to 10 ft composite sample "PRE-S-E6" and split sample for agent=
screening=
Borehole E-6 grouted to surface. =
E6 Hex Pit Borehole Log'
-------
Tetra Tech EM Inc.
j>
CL
E
CT3
W
E5=
_O
"o
m
j>
CL
E
CT3
W
E6= E7= E8=
0= 2=
2= 7=
Hex Pit lnterior=
I
0)
0)
CC
2=
4=
o>
cc
Q
LL
_>,
us
o>
P
1137=
1144= 1.4=
t
N=
2=
Borehole ID: E7
Job Number: G1093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain Steve Mitchell; Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-13-01 =
Logged By: David West=
o
v>
o
5 Soil Description
0 to 1.6: Sand; minor silt (<5%); moderately sorted very fine to med. coarse =
SW=grained; loose; moist; uniform yellowish brown; "clean" surface fill; sharp contact to
mostly dry well sorted fine grained sand 1.5 to 1.6 ft.; orange survey tape in sample :
at 1.6 ft. (at contact).=
1.5=
2=
3- 1.6 to 5.1: Sand; well sorted fine to very fine grained; moderately dense; very =
SP= slightly moist; very uniform yellowish brown; "clean" native material; grades to silty =
4=
sand at 5.1 ft.=
1.3=
3.1 =
5=
0.9= 6=
5.1 to 8.5: Silty sand; uniform well sorted very fine to fine grained sand; slightly =
moist; more dense than above; dark yellowish brown; remains clean native soil;:
grades to silt at 8.5 ft.=
7= 10= 2.6= 1149= 0.7= 7= SM=
8.5 to 9.1: Silt; uniform grayish brown; moist; moderately dense; remains "clean";:
8= very sharp contact at 9.1 ft. to sand.=
9= ML=9,1 to 10: Sand; uniform grayish brown; moist; moderately dense; remains "clean"
_ very well sorted fine to very fine grined; yellowish brown; slightly moist; loose; =
1 Q= "clean" native (?)
TD=TD = 10ft=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
1158: Collect 2 to 10 ft. composite sample "PRE-S-E7" (1, 8-oz. jar) for Hex =
analysis. Sample composited in disposable aluminum tray. Borehole E7 grouted to =
surface.=
E7 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
*
*
Sample Top
0=
2=
6=
Sample Bottom
2=
6=
10=
E5= E6= E7= E8= T
I
IN
*
Hex Pit lnterior=
Recovered
2=
3.7=
3.45=
0)
P
850=
856=
906=
CD
C
T3
ss
0)
CC
Q
LL
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
0)
d.
t
"5
w
w
o
w
D
sw=
ML=
SM=
ML
SM=
TD=
Borehole ID: E8
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit-
Drilling Company: ESN - Rocky Mountain; Jason Lauer & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-16-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 1 .75 Sand: little fines: moderately sorted: med. qrained: liaht brown: =
subrounded; "clean;" dry; loose; soft.=
1 .75 to 2 Sandy silt: brown: moderately dense: moderately firm: sliahtly plastic.=
7 to 9.25 Sandy silt; brown; loose; soft; sliqhtly plastic; moist.=
TD = 10ft=
Sample PRE-S-E8 taken from 2 to 10 ft. at 0914=
E8 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
ซ
Hex Pit lnterior= _
Sample Top
0=
2=
7=
Sample Bottom
2=
7=
10=
Recovered
2=
2.7=
2.55=
0)
F
1014=
1021 =
1024=
E9=
p-t n
E11 =
E12-
CD
c
T3
ra
0)
CC
Q
LL
0=
-0.15
-0.05
-0.1 =
-0.21
0.05:
o.oa
-0.2=
-0.2=
-0.05
0.21'
0.2&
i
h
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
L
J=
CD
CL
t
"o
w
w
o
w
D
SP=
NR=
SP=
SM=
ML=
SP=
TD=
Borehole ID: E9
Job Number' G1 093-240"
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-16-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 2 Sand: very little fines, med. qrained: well sorted: loose: soft: subrounded: liaht
brown; "clean".=
2 to 4.5 No recovery.=
4.5 to 5 Sand: same as above with some orqanic matter (roots): "clean". =
5 to 5.25 Sandy silt with black, charcoal-like material: moist: moderately dense: =
slightly plastic; brown =
TD = 10ft=
PRE-S-E9 taken from 2 to 1 0 ft at 1 040.=
E9 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
Hex Pit lnterior=
Sample Top
0=
2=
6=
Sample Bottom
2=
6=
10=
Recovered
1.5=
2.6=
3=
0)
P
1044=
1050=
1058=
E9=
Fin-
E11 =
E12-
CD
c
T3
ra
0)
K.
Q
LL
0.05:
0.05:
0.3=
0.2=
0.1 =
0.1 =
0.2=
0.2=
0.1 5:
i
h
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
L
j-
0)
CL
t
"5
w
w
o
w
D
SP=
NR=
SP=
SM=
SP=
ML
TD=
Borehole ID: E10
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-16-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 0.25 Sand with some fines: med. qrained: loose:! soft: brown: moist: some =
roots and qrass: well sorted. =
0.25 to 2: Sand; light brown; little fines; med. grained; well sorted; loose; soft; =
"clean"; subrounded.
2 to 3.4: No recovery. =
3.4 to 4: Sand: same as above. =
4 to 4.5: Silty sand: brown: loose: soft: fine sand: well sorted: moist: "clean". =
4.5 to 7.5 Sand: fine qrained: some fines: loose: soft: liqht brown: well sorted: =
increasing fines with depth=
7.5 to 10: Sandy silt: brown: sliqhtly plastic: soft: moderately dense: moist=
TD = 10ft=
Sample PRE-S-E10 collected from 2 to 10 ft at 1103.=
E10 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
Hex Pit lnterior=
Sample Top
0=
2=
7=
Sample Bottom
2=
7=
10=
Recovered
2=
3.8=
2.5=
0)
P
1150=
1155=
1201 =
E9=
Fin-
E11 =
E12-
CD
c
T3
ra
0)
K.
Q
LL
0.05:
0.05:
0.3=
0.2=
0.1 =
0.1 =
0.2=
0.2=
0.1 5:
i
h
Lab Analysis
0)
0)
LL
C
.C
"5.
0)
Q
1 =
2=
3=
4=
5=
6=
7=
8=
9=
10=
11 =
12=
13=
14=
15=
16=
17=
18=
19=
20=
L
j-
0)
CL
t
"5
w
w
o
w
D
SP=
NR=
SM=
NR=
ML=
SM=
ML
TD=
Borehole ID: E11
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauer & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-16-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 2 Sand, trace fines: med. qrained: liaht brown: well sorted: subrounded: soft:
loose; "clean". =
7 to 7.5 No recovery. =
8.5 to 9 Silty sand: liaht brown: loose: soft: moist=
TD = 10ft=
Sample PRE-S-E11 collected from 2 to 10 ft at 1206.=
E11 Hex Pit Borehole Log
-------
Tetra Tech EM Inc.
Hex Pit lnterior=
Sample Top
0=
2=
7=
Sample Bottom
2=
7=
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Borehole ID: E12
Job Number: G1 093-240=
Site: Rocky Mountain Arsenal - Hex Pit=
Drilling Company: ESN - Rocky Mountain; Jason Lauel & Zack Beck=
Drilling Method: Direct push=
Continuous core in 4 ft. X 1.125 in. PETG plastic liners=
Drilling Date(s): 7-17-01 =
Logged By: Erika Herreria=
Soil Description=
0 to 2 Sand: some fines: liaht brown: med. arained: moderately sorted: loose: med. =
2 to 4 Sandy silt: liaht brown: soft: loose:=
4 to 6.5: Silty sand: liaht brown: fine arained: subrounded: very loose: very soft=
6.5 to 7: Silty sand: dark brown: fine to med. arained: moderately sorted: loose: soft:
with rust color nodule and with black color nodules (coal like). Note: Took a picture =
of a section of the internal. -
7 to 8.4: Sandy silt: liaht brown: loose: soft=
8.4 to 10: Silt: liaht brown: loose: soft: sliahtly plastic: moist=
TD = 10ft=
Sample PRE-S-E12 taken at 0819 from 2 to 10 ft.=
E12 Hex Pit Borehole Log
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