&EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
EPA/600/R-01/084
September 2001
Innovative Technology
Verification Report
Field Measurement
Technologies for Total
Petroleum Hydrocarbons in Soil
Strategic Diagnostics Inc.
EnSys Petro Test System
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EPA/600/R-01/084
September 2001
Innovative Technology
Verification Report
Strategic Diagnostics Inc.
EnSys Petro Test System
Prepared by
Tetra Tech EM Inc.
200 East Randolph Drive, Suite 4700
Chicago, Illinois 60601
Contract No. 68-C5-0037
Dr. Stephen Billets
Characterization and Monitoring Branch
Environmental Sciences Division
Las Vegas, Nevada 89193-3478
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
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Notice
This document was prepared for the U.S. E nvironmental Protection Agency (EPA) Superfund
Innovative Technology Evaluation Program under Contract No. 68-C5-0037. The document has
been subjected to the EPA's peer and administrative reviews and has been approved for publication.
Mention of corporation names, trade names, or commercial products does not constitute endorsement
or recommendation for use.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
VERIFICATION STATEMENT
TECHNOLOGY TYPE: FIELD MEASUREMENT DEVICE
APPLICATION: MEASUREMENT OF TOTAL PETROLEUM HYDROCARBONS
TECHNOLOGY NAME: EnSys PETRO TEST SYSTEM
COMPANY: STRATEGIC DIAGNOSTICS INC.
ADDRESS: 111 PENCADER DRIVE
NEWARK, DE 19702
WEB SITE: http://www.sdix.com
TELEPHONE: (800) 544-8881
VERIFICATION PROGRAM DESCRIPTION
The U.S. Environmental Protection Agency (EPA) created the Superfund Innovative Tec hnology Evaluation (SITE) and
Environmental Technology Verification (ETV) Programs to facilitate deployment of innovative technologies through
performance verification and information dissemination. The goa 1 of these programs is to further environmental protection
by substantially accelerating the acceptance and use of improved and cost-effective technologies. These programs assist and
inform those involved in design, distribution, permitting, and purchase of environmental technologies. This document
summarizes results of a demonstration of the EnSys Petro Test System developed by Strategic Diagnostics Inc. (SDI).
PROGRAM OPERATION
Under the SITE and ETV Programs, with the full participa tion of the technology developers, the EPA evaluates and
documents the performance of innovative technologies by developi ng demonstration plans, conducting field tests, collecting
and analyzing demonstration data, and preparing reports. The technologies are evaluated under rigorous quality assurance
(Q A) protocols to produce well-documented data of known quality . The EPA National Exposure Research Laboratory, which
demonstrates field sampling, monitoring, and measurement tec hnologies, selected Terra Tech EM Inc. as the verification
organization to assist in field testing seven field measuremen t devices for total petroleum hydrocarbons (TPH) in soil. This
demonstration was funded by the SITE Program.
DEMONSTRATION DESCRIPTION
In June 2000, the EPA conducted a field demonstration of the EnSys Petro Test System and six other field measurement
devices for TPH in soil. This verification statement focuses on the EnSys Petro Test System; a similar statement has been
prepared for each of the other six devices. The performance and co st of the EnSys Petro Test System were compared to those
of an off-site laboratory reference method, "Test Methods for Evaluating Solid Waste" (SW-846) Method 8015B (modified).
To verify a wide range of performance attributes, the demons tration had both primary and secondary objectives. The primary
objectives included (1) determining the method detection limit, (2) evaluating the accuracy and precision of TPH
measurement, (3) evaluating the effect of interferents, and (4 ) evaluating the effect of moisture content on TPH measurement
for each device. Additional primary objectives were to m easure sample throughput and estimate TPH measurement costs.
Secondary objectives included (1) documenting the skills and training required to properly operate the device,
(2) documenting the portability of the device, (3) evaluating the device's durability, and (4) documenting the availability of
the device and associated spare parts.
The EnSys Petro Test System was demonstrated by using it to analyze 66 soil environmental samples, 89 soil performance
evaluation (PE) samples, and 36 liquid PE samples. In add ition to these 191 samples, 12 extract duplicates prepared using
the environmental samples were analyzed. The environmenta 1 samples were collected in four areas contaminated with
gasoline, diesel, or other petroleum products, and the PE sa mples were obtained from a commercial provider. SDI chose not
to analyze soil samples collected in a fifth area because accord ing to SDI, the EnSys Petro Test System was not designed to
measure the heavy lubricating oil present in the area.
The accompanying notice is an integral part of this verification statement. September 2001
iii
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Collectively, the environmental and PE samples provided the di fferent matrix types and the different levels and types of
petroleum hydrocarbon contamination needed to perform a comp rehensive evaluation of the EnSys Petro Test System. A
complete description of the demonstration and a summary of its results are available in the "Innovative Technology
Verification Report: Field Measurement Devices for Total Pe troleum Hydrocarbons in Soil—Strategic Diagnostics Inc.,
EnSys Petro Test System" (EPA/600/R-01/084).
TECHNOLOGY DESCRIPTION
The EnSys Petro Test System manufactured by SDI is based on a combination of immunoassay (specifically, enzyme-linked
immunosorbent assay) and colorimetry. The EnSys Petro Test System includes the SDI Sample Extraction Kit, the EnSys
Petro 12T Soil Test Kit, and the EnSys/EnviroGard * Common Accessory Kit. With this device, methanol is used for
extraction of petroleum hydrocarbons from soil samples. Each sa mple extract is mixed with an enzyme conjugate solution.
The reaction mixture is then transferred to an antibody-coated test tube. The hydrocarbons in the sample extract and those
in the enzyme conjugate competitively bind to specific antibody sites on the test tube. The test tube is rinsed with a dilute
detergent solution to remove any enzyme conjugate and hydro carbons not bound to the antibodies. A color developer solution
and hydrogen peroxide are added to the test tube in order to give yellow color to the enzymes that remain attached to the test
tube. The color intensity is inversely proportional to the c oncentration of hydrocarbons in the extract. To accomplish color
measurement, the absorbance of the antibody-coated tube c ontaining the sample extract and an antibody-coated tube
containing a reference standard (m-xylene) is compared using a differential photometer. A positive reading on the photometer
indicates that the total concentration of petroleum hydrocarbons in the sample extract is less than that in the reference
standard. Similarly, a negative reading on the photometer i ndicates that the total concentration of petroleum hydrocarbons
in the sample extract is greater th an that in the reference standard.
During the demonstration, extraction of petroleum hydrocarbons in a given soil sample was completed by adding 20 milliliters
of methanol to 10 grams of the sample. SDI performed each an alysis at three detection levels by diluting the sample extract
twice during sample and standard preparation. The refere nee standard concentrations for gasoline (10 milligrams per
kilogram [mg/kg]) and diesel (15 mg/kg) were multiplied by th e dilution factors used. Thus, the concentration ranges used
to estimate sample TPH concentrations were (1) less than (<)10; greater than (>)10 to <100; >100 to <1,000; and
> 1,000 mg/kg for samples containing gasoline range organics a nd (2) < 15; > 15 to < 100; > 100 to <1,000; and > 1,000 mg/kg
for samples containing extended diesel range organics.
VERIFICATION OF PERFORMANCE
To ensure data usability, data quality indicators for accuracy, precision, representativeness, completeness, and comparability
were assessed for the reference method based on project-s pecific QA objectives. Although the reference method results
generally exhibited a negative bias, based on the results for the data quality indicators, the reference method results were
considered to be of adequate quality. The bias was considered to be significant primarily for low- and medium-
concentration-range soil samples containing diesel, which made up only 13 percent of the total number of samples analyzed
during the demonstration. The reference method recoveries obs erved during the demonstration were typical of the recoveries
obtained by most organic analytical methods for environmental samples. In general, the user should exercise caution when
evaluating the accuracy of a field measurement device by comp aring it to reference methods because the reference methods
themselves may have limitations. Key demonstration fi ndings are summarized below for the primary objectives.
Method Detection Limit: Based on the TPH results for seven low-concentr ation-range diesel soil PE samples, the method
detection limit for the reference method was determined to be 6.32 mg/kg. Because the EnSys Petro Test System is a
semiquantitative device, a method detection limit could not be determined for the device; however, the device's TPH
concentration ranges for six of seven samp les overlapped the reference method results.
Accuracy and Precision: The EnSys Petro Test System results for 16 of 66 soil environmental samples were inconclusive.
Of the remaining 50 results, the device's TPH concentrati on ranges overlapped the reference method results for only
8 samples (16 percent); 3 6 EnSys Petro Test System results were biased high, and 6 results were biased low. The EnSys Petro
Test System results for 12 of 28 soil PE samples were inconclusive. Of the remaining 16 results, the device's TPH
concentration ranges overlapped the reference method results for only 5 samples (31 percent); 9 EnSys Petro Test System
results were biased high, and 2 results were biased low. The EnSys Petro Test System results for all 6 liquid PE samples were
inconclusive.
The EnSys Petro Test System results for 3 of 66 soil environmen tal samples used to draw conclusions regarding whether the
TPH concentrations in a given sampling area or sample type exceeded a specified action level were inconclusive. Of the
remaining 63 results, the device's conclusions agreed with those of the reference method for 41 samples (65 percent);
21 EnSys Petro Test System conclusions were false positives, and 1 was a false negative. The EnSys Petro Test System
results for 14 of 34 soil PE samples were inconclusive. Of the remaining 20 results, the device's conclusions agreed with
those of the reference method for 15 samples (75 percent); 3 En Sys Petro Test System conclusions were false positives, and
2 were false negatives.
The accompanying notice is an integral part of this verification statement. September 2001
iv
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Both the EnSys Petro Test System and reference method exhibited good precision. Specifically, for 17 of 19 soil sample
replicate sets and 2 of 2 liquid sample replicate sets, the En Sys Petro Test System TPH concentration ranges were the same
for each replicate set. For 12 of 12 extract duplicate sets, the device's TPH concentration ranges were the same for each
extract duplicate set. For the reference method, the median relative standard deviation ranged from 5.5 to 16 percent for
18 soil and 2 liquid sample replicate sets, and the median re lative percent difference was 3 for 12 extract duplicate sets.
Effect oflnterferents: The EnSys Petro Test System showed a mean response of at least 24 percent for neat tetrachloroethene
(PCE); Stoddard solvent; turpentine; and 1,2,4-trichlorobenzen e. The device showed no response for neat methyl-tert-butyl
ether (MTBE) or soil spiked with humic acid. The reference method showed varying mean responses for MTBE (39 percent);
PCE (17.5 percent); Stoddard solvent (85 percent); turpentine (52 percent); 1,2,4-trichlorobenzene (50 percent); and humic
acid (0 percent). For the demonstration, MTBE and St oddard solvent were included in the definition of TPH.
Effect of Moisture Content: The EnSys Petro Test System TPH results were in conclusive with regard to the effect of soil
moisture content. The reference method TPH results were unaffected when the soil moisture content was increased from
(1) 9 to 16 percent for weathered gasoline soil PE samples and (2) less than 1 to 9 percent for diesel soil PE samples.
Measurement Time: From the time of sample receipt, SDI required 39 hours, 35 minutes, to prepare a draft data package
containing TPH results for 191 samples and 12 extract duplicates compared to 30 days for the reference method, which was
used to analyze 199 samples and 13 extract duplicates.
Measurement Costs: For the EnSys Petro Test System, the TPH measurement cost for 191 samples and 12 extract duplicates
was estimated to be $10,210 (including the daily rental cost of the EnSys/EnviroGard * Common Accessory Kit, whose
purchase price is $1,999) compared to $41,290 for the reference method.
Key demonstration findings are summarized below for the secondary objectives.
Skill and Training Requirements: The EnSys Petro Test System can be opera ted by one person with basic wet chemistry
skills. The sample analysis procedure for the device can be learned in the field with a few practice attempts.
Portability: The EnSys Petro Test System is battery-operated and requires no alternating current power source. The device
can be easily moved between sampling areas in the field, if necessary.
Durability and Availability of the Device : All items in the EnSys Petro Test System are available from SDI. During a 1 -year
warranty period, SDI will supply replacement parts for the de vice by overnight courier service at no cost. During the
demonstration, none of the device's reus able items malfunctioned or was damaged.
In summary, during the demonstration, the EnSys Petro Test System exhibited the following desirable characteristics of a
field TPH measurement device: (1) good precision and (2) high sa mple throughput. In addition, the EnSys Petro Test System
exhibited moderate measurement costs. However, a signifi cant number of the EnSys Petro Test System TPH results were
determined to be inconclusive because the detection levels used by SDI were not appropriate to address the demonstration
objectives. Overall, the device's results did not compare well with those of the reference method; in general, the device
exhibited a high positive bias. Collectively, the demonstration findings indicated that the user should exercise caution when
considering the device for a site-specific field TPH measurement application.
Original
signed by
Gary J. Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
NOTICE: EPA verifications are based on an evaluation oft echnology performance under specific, predetermined criteria
and appropriate quality assurance procedures. The EPA make s no expressed or implied warranties as to the performance
of the technology and does not certify that a technology will always operate as verified. The end user is solely responsible
for complying with any and all applicable federal, state, and local requirements.
The accompanying notice is an integral part of this verification statement. September 2001
V
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation's natural resources. Under the 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, the EPA's Office
of Research and Development provides data and scientific support that can be used to solve
environmental problems, build the scientific knowle dge base needed to manage ecological resources
wisely, understand how pollutants affect public health, and prevent or reduce environmental risks.
The National Exposure Research Laboratory (NERL) is the agency's center for investigation of
technical and management approaches for identifyi ng and quantifying risks to human health and the
environment. Goals of the laboratory's research program are to (1) develop and evaluate methods
and technologies for characterizing and monitoring air, soil, and water; (2) support regulatory and
policy decisions; and (3) provide the scientific support needed to ensure effective implementation
of environmental regulations and strategies.
The EPA's Superfund Innovative Technology Evaluation (SITE) Program evaluates technologies
designed for characterization and remediation of contaminated Superfund and Resource
Conservation and Recovery Act sites. The SITE Program was created to provide reliable cost and
performance data in order to speed acceptance and use of innovative remediation, characterization,
and monitoring technologies by the regulatory and user community.
Effective measurement and monitoring technologies are needed to assess the degree of
contamination at a site, provide data that can be used to determine the risk to public health or the
environment, supply the necessary cost and performance data to select the most appropriate
technology, and monitor the success or failure of a remediation process. One component of the EPA
SITE Program, the Monitoring and Measurement Technology (MMT) Program, demonstrates and
evaluates innovative technologies to meet these needs.
Candidate technologies can originate within the fe deral government or the private sector. Through
the SITE Program, developers are given the opportun ity to conduct a rigorous demonstration of their
technologies under actual field conditions. By comp leting the demonstration and distributing the
results, the agency establishes a baseline for acceptance and use of these technologies. The MMT
Program is administered by the Environmental Sc iences Division of NERL in Las Vegas, Nevada.
Gary J. Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
VI
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Abstract
The EnSys Petro Test System developed by Strate gic Diagnostics Inc. (SDI) was demonstrated under
the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program
in June 2000 at the Navy Base Ventura County site in Port Hueneme, California. The purpose of
the demonstration was to collect reliable performan ce and cost data for the EnSys Petro Test System
and six other field measurement devices for total pe troleum hydrocarbons (TPH) in soil. In addition
to assessing ease of device operation, the key objectives of the demonstration included determining
the (1) method detection limit, (2) accuracy and precision, (3) effects of interferents and soil moisture
content on TPH measurement, (4) sample thr oughput, and (5) TPH measurement costs for each
device. The demonstration involved analysis of both performance evaluation samples and
environmental samples collected in four areas contam inated with gasoline, diesel, or other petroleum
products. The performance and cost results for a given field measurement device were compared to
those for an off-site laboratory reference method, "Test Methods for Evaluating Solid Waste"
(SW-846) Method 8015B (modified). During the de monstration, SDI required 39 hours, 3 5 minutes,
for TPH measurement of 191 samples and 12 extract duplicates. The TPH measurement costs for
these samples were estimated to be $10,210 for the EnSys Petro Test System compared to $41,290
for the reference method. The method detection limit for the reference method was determined to
be 6.32 milligrams per kilogram; a method detection limit could not be determined for the EnSys
Petro Test System because it is a semiquantitative device. During the demonstration, the device
exhibited good precision and lack of sensitivity to soil spiked with humic acid. The device showed
a mean response of at least 24 percent for interferents that are not petroleum hydrocarbons (neat
materials, including tetrachloroethene; turpentine; andl,2,4-trichlorobenzene). A significant number
of the EnSys Petro Test System TPH results we re determined to be inconclusive because the
detection levels used by SDI were not appropriate to address the demonstration objectives. Overall,
the device's results did not compare well with those of the reference method; in general, the device
exhibited a high positive bias. Collectively, the dem onstration findings indicated that the user should
exercise caution when considering the device for a site-specific field TPH measurement application.
vn
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Contents
Chapter Page
Notice ii
Verification Statement iii
Foreword vi
Abstract vii
Figures xi
Tables xii
Abbreviations, Acronyms, and Symbols xiv
Acknowledgments xvi
1 Introduction 1
1.1 Description of SITE Program 1
1.2 Scope of Demonstration 4
1.3 Components and Definition of TPH 4
1.3.1 Composition of Petroleum and Its Products 4
1.3.1.1 Gasoline 6
.3.1.2 Naphthas 6
.3.1.3 Kerosene 6
.3.1.4 JetFuels 6
.3.1.5 Fuel Oils 6
.3.1.6 Diesel 7
1.3.1.7 Lubricating Oils 7
1.3.2 Measurement of TPH 7
1.3.2.1 Historical Perspective 7
1.3.2.2 Current Options for TPH Measurement in Soil 8
1.3.2.3 Definition of TPH 9
2 Description of Immunoassay and Colorimetry and the EnSys Petro Test System 11
2.1 Description of Immunoassay and Colorimetry 11
2.1.1 Immunoassay 12
2.1.2 Colorimetry 15
2.2 Description of EnSys Petro Test System 16
vin
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Contents (Continued)
Chapter Page
2.2.1 Device Description 16
2.2.2 Operating Procedure 18
2.3 Developer Contact Information 18
3 Demonstration Site Descriptions 19
3.1 Navy Base Ventura County Site 20
3.1.1 Fuel Farm Area 20
3.1.2 Naval Exchange Service Station Area 21
3.1.3 Phytoremediation Area 21
3.2 Kelly Air Force Base Site 22
3.3 Petroleum Company Site 22
4 Demonstration Approach 24
4.1 Demonstration Objectives 24
4.2 Demonstration Design 24
4.2.1 Approach for Addressing Primary Objectives 25
4.2.2 Approach for Addressing Secondary Objectives 29
4.3 Sample Preparation and Management 33
4.3.1 Sample Preparation 33
4.3.2 Sample Management 35
5 Confirmatory Process 39
5.1 Reference Method Selection 39
5.2 Reference Laboratory Selection 41
5.3 Summary of Reference Method 41
6 Assessment of Reference Method Data Quality 50
6.1 Quality Control Check Results 50
6.1.1 GRO Analysis 50
6.1.2 EDRO Analysis 53
6.2 Selected Performance Evaluation Sample Results 59
6.3 Data Quality 62
7 Performance of the EnSys Petro Test System 63
7.1 Primary Objectives 63
7.1.1 Primary Objective PI: Method Detection Limit 65
7.1.2 Primary Objective P2: Accuracy and Precision 66
7.1.2.1 Accuracy 66
7.1.2.2 Precision 71
7.1.3 Primary Objective P3: Effect of Interferents 76
7.1.3.1 Interferent Sample Results 76
7.1.3.2 Effects of Interferents on TPH Results for Soil Samples 76
7.1.4 Primary Objective P4: Effect of Soil Moisture Content 83
7.1.5 Primary Objective P5: Time Required for TPH Measurement 83
7.2 Secondary Objectives 86
IX
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Contents (Continued)
Chapter
Page
7.2.1 Skill and Training Requirements for Proper Device Operation 86
7.2.2 Health and Safety Concerns Associated with Device Operation 87
7.2.3 Portability of the Device 87
7.2.4 Durability of the Device 88
7.2.5 Availability of the Device and Spare Parts 88
8 Economic Analysis 89
8.1 Issues and Assumptions 89
8. .1 Capital Equipment Cost 89
8. .2 Cost of Supplies 90
8. .3 Support Equipment Cost 90
8. .4 Labor Cost 90
8. .5 Investigation-Derived Waste Disposal Cost 90
8. .6 Costs Not Included 90
8.2 EnSys Petro Test System Costs 91
8.2.1 Capital Equipment Cost 91
8.2.2 Cost of Supplies 91
8.2.3 Support Equipment Cost 92
8.2.4 Labor Cost 92
8.2.5 Investigation-Derived Waste Disposal Cost 92
8.2.6 Summary of EnSys Petro Test System Costs 92
8.3 Reference Method Costs 93
8.4 Comparison of Economic Analysis Results 93
9 Summary of Demonstration Results 94
10 References 99
Appendix Supplemental Information Provided by the Developer 101
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Figures
Figure Page
1 -1. Distribution of various petroleum hy drocarbon types throughout boiling point range
of crude oil 5
2-1. Immunoglobulin G antibody structure and locations of antigen-binding sites 12
2-2. Enzyme-linked immunosorbent assay 14
5-1. Reference method selection process 40
7-1. Summary of statistical analysis of TPH results 64
XI
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Tables
Table Page
1-1. Summary of Calibration Information for Infrared Analytical Method 8
1-2. Current Technologies for TPH Measurement 9
2-1. EnSys Petro Test System Method Detection Limits 17
2-2. EnSys Petro Test System Components 17
3-1. Summary of Site Characteristics 20
4-1. Action Levels Used to Evaluate Analytical Accuracy 26
4-2. Demonstration Approach 30
4-3. Environmental Samples 34
4-4. Performance Evaluation Samples 36
4-5. Sample Container, Preservation, and Holding Time Requirements 38
5-1. Laboratory Sample Preparation and Analytical Methods 42
5-2. Summary of Project-Specific Procedures for GRO Analysis 43
5-3. Summary of Project-Specific Procedures for EDRO Analysis 47
6-1. Summary of Quality Control Check Results for GRO Analysis 54
6-2. Summary of Quality Control Check Results for EDRO Analysis 58
6-3. Comparison of Soil and Liquid Performance Evaluation Sample Results 60
6-4. Comparison of Environmental Resource Associates Historical Results to
Reference Method Results 62
7-1. TPH Results for Low-Concentration-Range Diesel Soil Performance Evaluation
Samples 65
7-2. Comparison of EnSys Petro Test Syst em and Reference Method TPH Results for
Environmental Samples 67
7-3. Comparison of EnSys Petro Test Syst em and Reference Method TPH Results for
Performance Evaluation Samples 69
7-4. Action Level Conclusions 71
7-5. Summary of EnSys Petro Test System and Reference Method Precision for Field
Triplicates of Environmental Samples 73
Xll
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Tables (Continued)
Table Page
7-6. Summary of EnSys Petro Test System and Reference Method Precision for
Extract Duplicates 74
7-7. Comparison of EnSys Petro Test System and Reference Method Precision for
Replicate Performance Evaluation Samples 75
7-8. Comparison of EnSys Petro Test System and Reference Method Results for
Interferent Samples 77
7-9. Comparison of EnSys Petro Test System and Reference Method Results for Soil
Performance Evaluation Samples Containing Interferents 79
7-10. Comparison of Results for Soil Performance Evaluation Samples at Different
Moisture Levels 84
7-11. Time Required to Complete TPH Measurement Activities Using the EnSys Petro
Test System 85
8-1. EnSys Petro Test System Cost Summary 92
8-2. Reference Method Cost Summary 93
9-1. Summary of EnSys Petro Test System Results for the Primary Objectives 95
9-2. Summary of EnSys Petro Test System Results for the Secondary Objectives 98
Xlll
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Abbreviations, Acronyms, and Symbols
"g
um
12T Soil Test Kit
AEHS
AFB
API
ASTM
bgs
BTEX
BVC
CCV
CFC
CFR
Common Accessory Kit
DER
DRO
EDRO
ELISA
EPA
EPH
ERA
FFA
FID
GC
GRO
ICV
row
Ig
ITVR
kg
L
LCS
LCSD
MCAWW
MDL
Means
Less than
Greater than
Less than or equal to
Plus or minus
Microgram
Micrometer
EnSys Petro 12T Soil Test Kit
Association for Environmental Health and Sciences
Air Force Base
American Petroleum Institute
American Society for Testing and Materials
Below ground surface
Benzene, toluene, ethylbenzene, and xylene
Base Ventura County
Continuing calibration verification
Chlorofluorocarbon
Code of Federal Regulations
EnSys/EnviroGard® Common Accessory Kit
Data evaluation report
Diesel range organics
Extended diesel range organics
Enzyme-linked immunosorbent assay
U.S. Environmental Protection Agency
Extractable petroleum hydrocarbon
Environmental Resource Associates
Fuel Farm Area
Flame ionization detector
Gas chromatograph
Gasoline range organics
Initial calibration verification
Investigation-derived waste
Immunoglobulin
Innovative technology verification report
Kilogram
Liter
Laboratory control sample
Laboratory control sample duplicate
"Methods for Chemical Analysis of Water and Wastes"
Method detection limit
R.S. Means Company
xiv
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Abbreviations, Acronyms, and Symbols (Continued)
mg
min
mL
MMT
MS
MSD
MTBE
n-Cx'
NERL
NEX
ng
ORD
ORO
OSWER
PC
PCB
PCE
PE
PHC
PPE
PRA
PRO
QA
QC
RPD
RSD
Sample Extraction Kit
SDI
SFT
SITE
STL Tampa East
SW-846
TPH
UST
VPH
Milligram
Minute
Milliliter
Monitoring and Measurement Technology
Matrix spike
Matrix spike duplicate
Methyl-tert-butyl ether
Alkane with "x" carbon atoms
National Exposure Research Laboratory
Naval Exchange
Nanogram
Office of Research and Development
Oil range organics
Office of Solid Waste and Emergency Response
Petroleum company
Polychlorinated biphenyl
Tetrachloroethene
Performance evaluation
Petroleum hydrocarbons
Personal protective equipment
Phytoremediation Area
Petroleum range organics
Quality assurance
Quality control
Relative percent difference
Relative standard deviation
SDI Sample Extraction Kit
Strategic Diagnostics Inc.
Slop Fill Tank
Superfund Innovative Technology Evaluation
Severn Trent Laboratories in Tampa, Florida
"Test Methods for Evaluating Solid Waste"
Total petroleum hydrocarbons
Underground storage tank
Volatile petroleum hydrocarbons
xv
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Acknowledgments
This report was prepared for the U. S. Environm ental Protection Agency (EPA) Superfund Innovative
Technology Evaluation Program under the direction and coordination of Dr. Stephen Billets of the
EPA National Exposure Research Laboratory (NERL)—Environmental Sciences Division in Las
Vegas, Nevada. The EPA NERL thanks Mr. Ernest Lory of Navy Base Ventura County, Ms. Amy
Whitley of Kelly Air Force Base, and Mr. Jay Simonds of Handex of Indiana for their support in
conducting field activities for the project. Mr. Eric Koglin of the EPA NERL served as the technical
reviewer of this report. Mr. Roger Claff of the American Petroleum Institute, Mr. Dominick
De Angelis of ExxonMobil Corporation, Dr. Ileana Rhodes of Equilon Enterprises, and Dr. Al
Verstuy ft of Chevron Research and Technology Comp any served as the peer reviewers of this report.
This report was prepared for the EPA by Dr. Kirankumar Topudurti and Mr. Eric Monschein of
Terra Tech EM Inc. Special acknowledgment is gi ven to Mr. Jerry Parr of Catalyst Information
Resources, L.L.C., for serving as the technical consultant for the project. Additional
acknowledgment and thanks are given to Ms. Jeanne Kowalski, Mr. Jon Mann, Mr. Stanley
Labunski, and Mr. Joe Abboreno of Terra Tech EM Inc. for their assistance during the preparation
of this report.
xvi
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Chapter 1
Introduction
The U.S. Environmental Protection Agency (EPA) Office
of Research and Development (ORD) National Exposure
Research Laboratory (NERL) conducted a demonstration
of seven innovative field measurement devices for total
petroleum hydrocarbons (TPH) in soil. The demonstration
was conducted as part of the EPA Superfund Innovative
Technology Evaluation (SITE) Monitoring and
Measurement Technology (MMT) Program using TPH-
contaminated soil from five areas located in three regions
of the United States. The demonstration was conducted at
Port Hueneme, California, during the week of June 12,
2000. The purpose of the demonstration was to obtain
reliable performance and cost data on field measurement
devices in order to provide (1) potential users with a better
understanding of the devices' performance and operating
costs under well-defined field conditions and (2) the
developers with documented results that will assist them in
promoting acceptance and use of their devices. The TPH
results obtained using the seven field measurement devices
were compared to the TPH results obtained from a
reference laboratory chosen for the demonstration, which
used a reference method modified for the demonstration.
This innovative technology verification report (ITVR)
presents demonstration performance results and associated
costs for the EnSys Petro Test System developed by
Strategic Diagnostics Inc. (SDI). Specifically, this report
describes the SITE Program, the scope of the
demonstration, and the components and definition of TPH
(Chapter 1); the innovative field measurement device and
the technology upon which it is based (Chapter 2); the
three demonstration sites (Chapter 3); the demonstration
approach (Chapter 4); the selection of the reference
method and laboratory (Chapter 5); the assessment of
reference method data quality (Chapter 6); the
performance of the field measurement device (Chapter 7);
the economic analysis for the field measurement device
and reference method (Chapter 8); the demonstration
results in summary form (Chapter 9); and the references
used to prepare the ITVR (Chapter 10). Supplemental
information provided by SDI is presented in the appendix.
1.1 Description of SITE Program
Performance verification of innovative environmental
technologies is an integral part of the regulatory and
research mission of the EPA. The SITE Program was
established by the EPA Office of Solid Waste and
Emergency Response (OSWER) and ORD under the
Superfund Amendments and Reauthorization Act of 1986.
The overall goal of the SITE Program is to conduct
performance verification studies and to promote the
acceptance of innovative technologies that may be used to
achieve long-term protection of human health and the
environment. The program is designed to meet three
primary objectives: (1) identify and remove obstacles to
the development and commercial use of innovative
technologies, (2) demonstrate promising innovative
technologies and gather reliable performance and cost
information to support site characterization and cleanup
activities, and (3) develop procedures and policies that
encourage the use of innovative technologies at Superfund
sites as well as at other waste sites or commercial facilities.
The intent of a SITE demonstration is to obtain
representative, high-quality performance and cost data on
one or more innovative technologies so that potential users
can assess the suitability of a given technology for a
specific application. The SITE Program includes the
following elements:
• MMT Program—Evaluates innovative technologies
that sample, detect, monitor, or measure hazardous
and toxic substances. These technologies are expected
to provide better, faster, or more cost-effective
-------
methods for producing real-time data during site
characterization and remediation studies than do
conventional technologies.
• Remediation Technology Program—Conducts
demonstrations of innovative treatment technologies to
provide reliable performance, cost, and applicability
data for site cleanups.
• Technology Transfer Program—Provides and
disseminates technical information in the form of
updates, brochures, and other publications that
promote the SITE Program and participating
technologies. The Technology Transfer Program also
offers technical assistance, training, and workshops to
support the technologies. A significant number of
these activities are performed by EPA's Technology
Innovation Office.
The TPH field measurement device demonstration was
conducted as part of the MMT Program, which provides
developers of innovative hazardous waste sampling,
detection, monitoring, and measurement devices with an
opportunity to demonstrate the performance of their
devices under actual field conditions. These devices may
be used to sample, detect, monitor, or measure hazardous
and toxic substances in water, soil gas, soil, and sediment.
The technologies include chemical sensors for in situ (in
place) measurements, soil and sediment samplers, soil gas
samplers, groundwater samplers, field-portable analytical
equipment, and other systems that support field sampling
or data acquisition and analysis.
The MMT Program promotes acceptance of technologies
that can be used to (1) accurately assess the degree of
contamination at a site, (2) provide data to evaluate
potential effects on human health and the environment, (3)
apply data to assist in selecting the most appropriate
cleanup action, and (4) monitor the effectiveness of a
remediation process. The program places a high priority
on innovative technologies that provide more cost-
effective, faster, and safer methods forproducing real-time
or near-real-time data than do conventional, laboratory-
based technologies. These innovative technologies are
demonstrated under field conditions, and the results are
compiled, evaluated, published, and disseminated by the
ORD. The primary objectives of the MMT Program are as
follows:
• Test and verify the performance of innovative field
sampling and analytical technologies that enhance
sampling, monitoring, and site characterization
capabilities
Identify performance attributes of innovative
technologies to address field sampling, monitoring,
and characterization problems in a more cost-effective
and efficient manner
• Prepare protocols, guidelines, methods, and other
technical publications that enhance acceptance of these
technologies for routine use
The MMT Program is administered by the Environmental
Sciences Division of the NERL in Las Vegas, Nevada.
The NERL is the EPA center for investigation of technical
and management approaches for identifying and
quantifying risks to human health and the environment.
The NERL mission components include (1) developing
and evaluating methods and technologies for sampling,
monitoring, and characterizing water, air, soil, and
sediment; (2) supporting regulatory and policy decisions;
and (3) providing the technical support needed to ensure
effective implementation of environmental regulations
and strategies. By demonstrating innovative field
measurement devices for TPH in soil, the MMT Program
is supporting the development and evaluation of methods
and technologies for field measurement of TPH
concentrations in a variety of soil types. Information
regarding the selection of field measurement devices for
TPH is available in American Petroleum Institute (API)
publications (API 1996,1998).
The MMT Program's technology verification process is
designed to conduct demonstrations that will generate
high-quality data so that potential users have reliable
information regarding device performance and cost. Four
steps are inherent in the process: (1) needs identification
and technology selection, (2) demonstration planning
and implementation, (3) report preparation, and
(4) information distribution.
The first step of the verification process begins with
identifying technology needs of the EPA and the regulated
community. The EPA regional offices, the U.S.
Department of Energy, the U.S. Department of Defense,
industry, and state environmental regulatory agencies are
asked to identify technology needs for sampling,
monitoring, and measurement of environmental media.
Once a need is identified, a search is conducted to identify
suitable technologies that will address the need. The
technology search and identification process consists of
-------
examining industry and trade publications, attending
related conferences, exploring leads from technology
developers and industry experts, and reviewing responses
to Commerce Business Daily announcements. Selection of
technologies for field testing includes evaluation of the
candidate technologies based on several criteria. A
suitable technology for field testing
Is designed for use in the field
Is applicable to a variety of environmentally
contaminated sites
• Has potential for solving problems that current
methods cannot satisfactorily address
• Has estimated costs that are lower than those of
conventional methods
• Is likely to achieve better results than current methods
in areas such as data quality and turnaround time
• Uses techniques that are easier or safer than current
methods
Is commercially available
Once candidate technologies are identified, their
developers are asked to participate in a developer
conference. This conference gives the developers an
opportunity to describe their technologies' performance
and to leam about the MMT Program.
The second step of the verification process is to plan and
implement a demonstration that will generate high-quality
data to assist potential users in selecting a technology.
Demonstration planning activities include a
predemonstration sampling and analysis investigation that
assesses existing conditions at the proposed demonstration
site or sites. The objectives of the predemonstration
investigation are to (1) confirm available information on
applicable physical, chemical, and biological
characteristics of contaminated media at the sites to justify
selection of site areas for the demonstration; (2) provide
the technology developers with an opportunity to evaluate
the areas, analyze representative samples, and identify
logistical requirements; (3) assess the overall logistical
requirements for conducting the demonstration; and
(4) provide the reference laboratory with an opportunity
to identify any matrix-specific analytical problems
associated with the contaminated media and to propose
appropriate solutions. Information generated through the
predemonstration investigation is used to develop the final
demonstration design and sampling and analysis
procedures.
Demonstration planning activities also include preparing
a detailed demonstration plan that describes the procedures
to be used to verify the performance and cost of each
innovative technology. The demonstration plan
incorporates information generated during the
predemonstration investigation as well as input from
technology developers, demonstration site representatives,
and technical peer reviewers. The demonstration plan also
incorporates the quality assurance (QA) and quality
control (QC) elements needed to produce data of sufficient
quality to document the performance and cost of each
technology.
During the demonstration, each innovative technology
is evaluated independently and, when possible and
appropriate, is compared to a reference technology. The
performance and cost of one innovative technology are not
compared to those of another technology evaluated in the
demonstration. Rather, demonstration data are used to
evaluate the individual performance, cost, advantages,
limitations, and field applicability of each technology.
As part of the third step of the verification process, the
EPA publishes a verification statement and a detailed
evaluation of each technology in an ITVR. To ensure its
quality, the ITVR is published only after comments from
the technology developer and external peer reviewers are
satisfactorily addressed. In addition, all demonstration
data used to evaluate each innovative technology are
summarized in a data evaluation report (DER) that
constitutes a complete record of the demonstration. The
DER is not published as an EPA document, but an
unpublished copy may be obtained from the EPA project
manager.
The fourth step of the verification process is to distribute
information regarding demonstration results. To benefit
technology developers and potential technology users, the
EPA distributes demonstration bulletins and ITVRs
through direct mailings, at conferences, and on the
Internet. The ITVRs and additional information on the
SITE Program are available on the EPA ORD web site
(http://www.epa.gov/ORD/SITE).
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1.2 Scope of Demonstration
The purpose of the demonstration was to evaluate field
measurement devices for TPH in soil in order to provide
(1) potential users with a better understanding of the
devices' performance and costs under well-defined field
conditions and (2) the developers with documented results
that will assist them in promoting acceptance and use of
their devices.
Chapter 2 of this ITVR describes both the technology upon
which the EnSys Petro Test System is based and the field
measurement device itself. Because TPH is a "method-
defined parameter," the performance results for the device
are compared to the results obtained using an off-site
laboratory measurement method—that is, a reference
method. Details on the selection of the reference method
and laboratory are provided in Chapter 5.
The demonstration had both primary and secondary
objectives. Primary objectives were critical to the
technology verification and required the use of quantitative
results to draw conclusions regarding each field
measurement device's performance as well as to estimate
the cost of operating the device. Secondary objectives
pertained to information that was useful but did not
necessarily require the use of quantitative results to draw
conclusions regarding the performance of each device.
Both the primary and secondary objectives are discussed
in Chapter 4.
To meet the demonstration objectives, samples were
collected from five individual areas at three sites. The first
site is referred to as the Navy Base Ventura County (BVC)
site; is located in Port Hueneme, California; and contained
three sampling areas. The Navy BVC site lies in EPA
Region 9. The second site is referred to as the Kelly Air
Force Base (AFB) site; is located in San Antonio, Texas;
and contained one sampling area. The Kelly AFB site lies
in EPA Region 6. The third site is referred to as the
petroleum company (PC) site, is located in north-central
Indiana, and contained one sampling area. The PC site lies
in EPA Region 5.
In preparation for the demonstration, a predemonstration
sampling and analysis investigation was completed at the
three sites in January 2000. The purpose of this
investigation was to assess whether the sites and sampling
areas were appropriate for evaluating the seven field
measurement devices based on the demonstration
objectives. Demonstration field activities were conducted
between June 5 and 18, 2000. The procedures used to
verify the performance and costs of the field measurement
devices are documented in a demonstration plan completed
in June 2000 (EPA 2000). The plan also incorporates the
QA/QC elements that were needed to generate data of
sufficient quality to document field measurement device
and reference laboratory performance and costs. The plan
is available through the EPA ORD web site
(http://www.epa.gov/ORD/SITE) or from the EPA project
manager.
1.3 Components and Definition of TPH
To understand the term "TPH," it is necessary to
understand the composition of petroleum and its products.
This section briefly describes the composition of petroleum
and its products and defines TPH from a measurement
standpoint. The organic compounds containing only
hydrogen and carbon that are present in petroleum and its
derivatives are collectively referred to as petroleum
hydrocarbons (PHC). Therefore, in this ITVR, the term
"PHC" is used to identify sample constituents, and the
term "TPH" is used to identify analyses performed and the
associated results (for example, TPH concentrations).
1.3.1 Composition of Petroleum and Its Products
Petroleum is essentially a mixture of gaseous, liquid, and
solid hydrocarbons that occur in sedimentary rock
deposits. On the molecular level, petroleum is a complex
mixture of hydrocarbons; organic compounds of sulfur,
nitrogen, and oxygen; and compounds containing metallic
constituents, particularly vanadium, nickel, iron, and
copper. Based on the limited data available, the elemental
composition of petroleum appears to vary over a relatively
narrow range: 83 to 87 percent carbon, 10 to 14 percent
hydrogen, 0.05 to 6 percent sulfur, 0.1 to 2 percent
nitrogen, and 0.05 to 1.5 percent oxygen. Metals are
present in petroleum at concentrations of up to 0.1 percent
(Speight 1991).
Petroleum in the crude state (crude oil) is a mineral
resource but when refined it provides liquid fuels,
solvents, lubricants, and many other marketable products.
The hydrocarbon components of crude oil include
paraffmic, naphthenic, and aromatic groups. Paraffins
(alkanes) are saturated, aliphatic hydrocarbons with
straight or branched chains but without any ring structure.
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Naphthenes are saturated, aliphatic hydrocarbons
containing one or more rings, each of which may have one
or more paraffinic side chains (alicyclic hydrocarbons).
Aromatic hydrocarbons contain one or more aromatic
nuclei, such as benzene, naphthalene, and phenanthrene
ring systems, that may be linked with (substituted)
naphthenic rings or paraffinic side chains. In crude oil, the
relationship among the three primary groups of
hydrocarbon components is a result of hydrogen gain or
loss between any two groups. Another class of
compounds that is present in petroleum products such as
automobile gasoline but rarely in crude oil is known as
olefins. Olefins (alkenes) are unsaturated, aliphatic
hydrocarbons.
The distribution of paraffins, naphthenes, and aromatic
hydrocarbons depends on the source of crude oil. For
example, Pennsylvania crude oil contains high levels of
paraffins (about 50 percent), whereas Borneo crude oil
contains less than (<) 1 percent paraffins. As shown in
Figure 1 -1, the proportion of straight or branched paraffins
decreases with increasing molecular weight or boiling
point fraction for a given crude oil; however, this is not
true for naphthenes or aromatic hydrocarbons. The
proportion of monocyclonaphthenes decreases with
increasing molecular weight or boiling point fraction,
whereas the opposite is true for polycyclonaphthenes (for
example, tetralin and decalin) and polynuclear aromatic
hydrocarbons; the proportion of mononuclear aromatic
hydrocarbons appears to be independent of molecular
weight or boiling point fraction.
Various petroleum products consisting of carbon and
hydrogen are formed when crude oil is subjected to
distillation and other processes in a refinery. Processing of
crude oil results in petroleum products with trace quantities
of metals and organic compounds that contain nitrogen,
sulfur, and oxygen. These products include liquefied
petroleum gas, gasoline, naphthas, kerosene, fuel oils,
lubricating oils, coke, waxes, and asphalt. Of these
products, gasoline, naphthas, kerosene, fuel oils, and
lubricating oils are liquids and may be present at
petroleum-contaminated sites. Except for gasoline and
some naphthas, these products are made primarily by
collecting particular boiling point fractions of crude oil
from a distillation column. Because this classification of
petroleum products is based on boiling point and not on
chemical composition, the composition of these products,
Lighter oils
100
> Heavier oils and residues
Increasing nitrogen, oxygen, sulfur, and metal content *•
o>
Polynuclear aromatic hydrocarbons
Mononuclear aromatic hydrocarbons
Monocyclonaphthenes •
Polycyclonaphthenes
Straight and branched paraffins
0
i • i • i •
0 100 200 300
Boiling point, °C
Source: Speight 1991
Figure 1-1. Distribution of various petroleum hydrocarbon types throughout boiling point range of crude oil.
400
500
-------
including the ratio of aliphatic to aromatic hydrocarbons,
varies depending on the source of crude oil. In addition,
specific information (such as boiling points and carbon
ranges) for different petroleum products, varies slightly
depending on the source of the information. Commonly
encountered forms and blends of petroleum products are
briefly described below. The descriptions are primarily
based on information in books written by Speight (1991)
and Gary and Handwerk (1993). Additional information
is provided by Dryoff(1993).
1.3.1.1
Gasoline
Gasoline is a major exception to the boiling point
classification described above because "straight-run
gasoline" (gasoline directly recovered from a distillation
column) is only a small fraction of the blended gasoline
that is commercially available as fuel. Commercially
available gasolines are complex mixtures of hydrocarbons
that boil below 180 °C or at most 225 °C and that contain
hydrocarbons with 4 to 12 carbon atoms per molecule. Of
the commercially available gasolines, aviation gasoline has
a narrower boiling range (38 to 170 °C) than automobile
gasoline (-1 to 200 °C). In addition, aviation gasoline may
contain high levels of paraffins (50 to 60 percent),
moderate levels of naphthenes (20 to 30 percent), a low
level of aromatic hydrocarbons (10 percent), and no
olefins, whereas automobile gasoline may contain up to
30 percent olefins and up to 40 percent aromatic
hydrocarbons.
Gasoline composition can vary widely depending on the
source of crude oil. In addition, gasoline composition
varies from region to region because of consumer needs for
gasoline with a high octane rating to prevent engine
"knocking." Moreover, EPA regulations regarding the
vapor pressure of gasoline, the chemicals used to produce
a high octane rating, and cleaner-burning fuels have
affected gasoline composition. For example, when use of
tetraethyl lead to produce gasoline with a high octane
rating was banned by the EPA, oxygenated fuels came into
existence. Production of these fuels included addition of
methyl-tert-butyl ether (MTBE), ethanol, and other
oxygenates. Use of oxygenated fuels also results in
reduction of air pollutant emissions (for example, carbon
monoxide and nitrogen oxides).
1.3.1.2 Naphthas
"Naphtha" is a generic term applied to petroleum solvents.
Under standardized distillation conditions, at least
10 percent of naphthas should distill below 175 °C, and at
least 95 percent of naphthas should distill below 240 °C.
Naphthas can be both aliphatic and aromatic and contain
hydrocarbons with 6 to 14 carbon atoms per molecule.
Depending on the intended use of a naphtha, it may be free
of aromatic hydrocarbons (to make it odor-free) and sulfur
(to make it less toxic and less corrosive). Many forms of
naphthas are commercially available, including Varnish
Makers' and Painters' naphthas (Types I and II), mineral
spirits (Types I through IV), and aromatic naphthas
(Types I and II). Stoddard solvent is an example of an
aliphatic naphtha.
1.3.1.3
Kerosene
Kerosene is a straight-run petroleum fraction that has a
boiling point range of 205 to 260 °C. Kerosene typically
contains hydrocarbons with 12 or more carbon atoms per
molecule. Because of its use as an indoor fuel, kerosene
must be free of aromatic and unsaturated hydrocarbons as
well as sulfur compounds.
1.3.1.4
Jet Fuels
Jet fuels, which are also known as aircraft turbine fuels,
are manufactured by blending gasoline, naphtha, and
kerosene in varying proportions. Therefore, jet fuels may
contain a carbon range that covers gasoline through
kerosene. Jet fuels are used in both military and
commercial aircraft. Some examples of jet fuels include
Type A, Type A-l, Type B, JP-4, JP-5, and JP-8. The
aromatic hydrocarbon content of these fuels ranges from
20 to 25 percent. The military jet fuel JP-4 has a wide
boiling point range (65 to 290 °C), whereas commercial jet
fuels, including JP-5 and Types A and A-l, have a
narrower boiling point range (175 to 290 °C) because of
safety considerations. Increasing concerns over combat
hazards associated with JP-4 jet fuel led to development of
JP-8 jet fuel, which has a flash point of 38 °C and a
boiling point range of 165 to 275 °C. JP-8 jet fuel
contains hydrocarbons with 9 to 15 carbon atoms per
molecule. Type B jet fuel has a boiling point range of
55 to 230 °C and a carbon range of 5 to 13 atoms per
molecule. A new specification is currently being
developed by the American Society for Testing and
Materials (ASTM) for Type B jet fuel.
1.3.1.5
Fuel Oils
Fuel oils are divided into two classes: distillates and
residuals. No. 1 and 2 fuel oils are distillates and include
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kerosene, diesel, and home heating oil. No. 4, 5, and 6
fuel oils are residuals or black oils, and they all contain
crude distillation tower bottoms (tar) to which cutter stocks
(semirefined or refined distillates) have been added. No. 4
fuel oil contains the most cutter stock, and No. 6 fuel oil
contains the least.
Commonly available fuel oils include No. 1,2,4,5, and 6.
The boiling points, viscosities, and densities of these fuel
oils increase with increasing number designation. The
boiling point ranges for No. 1,2, and 4 fuel oils are about
180 to 320, 175 to 340, and 150 to 480 °C, respectively.
No. 1 and 2 fuel oils contain hydrocarbons with 10 to 22
carbon atoms per molecule; the carbon range for No. 4 fuel
oil is 22 to 40 atoms per molecule. No. 5 and 6 fuel oils
have a boiling point range of 150 to 540 °C but differ in
the amounts of residue they contain: No. 5 fuel oil contains
a small amount of residue, whereas No. 6 fuel oil contains
a large amount. No. 5 and 6 fuel oils contain hydrocarbons
with 28 to 90 carbon atoms per molecule. Fuel oils
typically contain about 60 percent aliphatic hydrocarbons
and 40 percent aromatic hydrocarbons.
1.3.1.6
Diesel
Diesel is primarily used to operate motor vehicle and
railroad diesel engines. Automobile diesel is available in
two grades: No. 1 and 2. No. 1 diesel, which is sold in
regions with cold climates, has a boiling point range of 180
to 320 °C and a cetane number above 50. The cetane
number is similar to the octane number of gasoline; a
higher number corresponds to less knocking. No. 2 diesel
is very similar to No. 2 fuel oil. No. 2 diesel has a boiling
point range of 175 to 340 °C and a minimum cetane
number of 52. No. 1 diesel is used in high-speed engines
such as truck and bus engines, whereas No. 2 diesel is used
in other diesel engines. Railroad diesel is similar to No. 2
diesel but has a higher boiling point (up to 370 °C) and
lower cetane number (40 to 45). The ratio of aliphatic to
aromatic hydrocarbons in diesel is about 5. The carbon
range for hydrocarbons present in diesel is 10 to 28 atoms
per molecule.
1.3.1.7 Lubricating Oils
Lubricating oils can be distinguished from other crude oil
fractions by their high boiling points (greater than [>]
400 °C) and viscosities. Materials suitable for production
of lubricating oils are composed principally of
hydrocarbons containing 25 to 35 or even 40 carbon atoms
per molecule, whereas residual stocks may contain
hydrocarbons with 50 to 60 or more (up to 80 or so)
carbon atoms per molecule. Because it is difficult to
isolate hydrocarbons from the lubricant fraction of
petroleum, aliphatic to aromatic hydrocarbon ratios are not
well documented for lubricating oils. However, these
ratios are expected to be comparable to those of the source
crude oil.
1.3.2 Measurement of TPH
As described in Section 1.3.1, the composition of
petroleum and its products is complex and variable, which
complicates TPH measurement. The measurement of TPH
in soil is further complicated by weathering effects. When
a petroleum product is released to soil, the product's
composition immediately begins to change. The
components with lower boiling points are volatilized, the
more water-soluble components migrate to groundwater,
and biodegradation can affect many other components.
Within a short period, the contamination remaining in soil
may have only some characteristics in common with the
parent product.
This section provides a historical perspective on TPH
measurement, reviews current options for TPH
measurement in soil, and discusses the definition of TPH
that was used for the demonstration.
1.3.2.1 Historical Perspective
Most environmental measurements are focused on
identifying and quantifying a particular trace element (such
as lead) or organic compound (such as benzene).
However, for some "method-defined" parameters, the
particular substance being measured may yield different
results depending on the measurement method used.
Examples of such parameters include oil and grease and
surfactants. Perhaps the most problematic of the method-
defined parameters is TPH. TPH arose as a parameter for
wastewater analyses in the 1960s because of petroleum
industry concerns that the original "oil and grease"
analytical method, which is gravimetric in nature, might
inaccurately characterize petroleum industry wastewaters
that contained naturally occurring vegetable oils and
greases along with PHCs. These naturally occurring
materials are typically long-chain fatty acids (for example,
oleic acid, the major component of olive oil).
Originally, TPH was defined as any material extracted
with a particular solvent that is not adsorbed by the silica
gel used to remove fatty acids and that is not lost when the
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solvent is evaporated. Although this definition covers
most of the components of petroleum products, it includes
many other organic compounds as well, including
chlorinated solvents, pesticides, and other synthetic
organic chemicals. Furthermore, because of the
evaporation step in the gravimetric analytical method, the
definition excludes most of the petroleum-derived
compounds in gasoline that are volatile in nature. For
these reasons, an infrared analytical method was developed
to measure TPH. In this method, a calibration standard
consisting of three components is analyzed at a wavelength
of 3.41 micrometers (um), which corresponds to an
aliphatic CH2 hydrocarbon stretch. As shown in Table 1 -1,
the calibration standard is designed to mimic a petroleum
product having a relative distribution of aliphatic and
aromatic compounds as well as a certain percentage of
aliphatic CH2 hydrocarbons. The infrared analytical
method indicates that any compound that is extracted by
the solvent, is not adsorbed by silica gel, and contains a
CH2 bond is a PHC. Both the gravimetric and infrared
analytical methods include an optional, silica gel
fractionation step to remove polar, biogenic compounds
such as fatty acids, but this cleanup step can also remove
some petroleum degradation products that are polar in
nature.
In the 1980s, because of the change in focus from
wastewater analyses to characterization of hazardous
waste sites that contained contaminated soil, many parties
began to adapt the existing wastewater analytical methods
for application to soil. Unfortunately, the term "TPH" was
in common use, as many states had adopted this term
(and the wastewater analytical methods) for cleanup
activities at underground storage tank (UST) sites.
Despite efforts by the API and others to establish new
analyte names (for example, gasoline range organics
[GRO] and diesel range organics [DRO]), "TPH" is still
present in many state regulations as a somewhat ill-defined
term, and most state programs still have cleanup criteria
for TPH.
1.3.2.2 Current Options for TPH Measurement
in Soil
Three widely used technologies measure some form of
TPH in soil to some degree. These technologies were used
as starting points in deciding how to define TPH for the
demonstration. The three technologies and the analytes
measured are summarized in Table 1-2.
Of the three technologies, gravimetry and infrared are
discussed in Section 1.3.2.1. The third technology, the gas
chromatograph/flame ionization detector (GC/FID), came
into use because of the documented shortcomings of the
other two technologies. The GC/FID had long been used
in the petroleum refining industry as a product QC tool to
determine the boiling point distribution of pure petroleum
products. In the 1980s, environmental laboratories began
to apply this technology along with sample preparation
methods developed for soil samples to measure PHCs at
environmental levels (Zilis, McDevitt, and Parr 1988).
GC/FID methods measure all organic compounds that are
extracted by the solvent and that can be chromatographed.
However, because of method limitations, the very volatile
portion of gasoline compounds containing four or five
carbon atoms per molecule is not addressed by GC/FID
methods; therefore, 100 percent recovery cannot be
achieved for pure gasoline. This omission is not
considered significant because these low-boiling-point
aliphatic compounds (1) are not expected to be present in
environmental samples (because of volatilization) and
(2) pose less environmental risk than the aromatic
hydrocarbons in gasoline.
Table 1-1. Summary of Calibration Information for Infrared Analytical Method
Standard
Constituent
Hexadecane
Isooctane
Chlorobenzene
Constituent Type
Straight-chain aliphatic
Branched-chain aliphatic
Aromatic
Portion of Constituent
in Standard
(percent by volume)
37.5
37.5
25
Number of Carbon Atoms
Aliphatic
CH3
2
5
0
CH2
14
1
0
CH
0
1
0
Aromatic
CH
0
0
5
Average
Portion of Aliphatic CH2 in
Standard Constituent
(percent by weight)
91
14
0
35
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Table 1-2. Current Technologies for TPH Measurement
Technology
Gravimetry
Infrared
Gas chromatograph/flame ionization detector
What Is Measured
All analytes removed from the sample by the
extraction solvent that are not volatilized
All analytes removed from the sample by the
extraction solvent that contain an aliphatic CH2
stretch
All analytes removed from the sample by the
extraction solvent that can be chromatographed
and that respond to the detector
What Is Not Measured
Volatiles; very polar organics
Benzene, naphthalene, and other aromatic
hydrocarbons with no aliphatic group attached;
very polar organics
Very polar organics; compounds with high
molecular weights or high boiling points
The primary limitation of GC/FID methods relates to the
extraction solvent used. The solvent should not interfere
with the analysis, but to achieve environmental levels of
detection (in the low milligram per kilogram [mg/kg]
range) for soil, some concentration of the extract is needed
because the sensitivity of the FID is in the nanogram (ng)
range. This limitation has resulted in three basic
approaches for GC/FID analyses for GRO, DRO, and
PHCs.
For GRO analysis, a GC/FID method was developed as
part of research sponsored by API and was the subject of
an interlaboratory validation study (API 1994); the method
was first published in 1990. In this method, GRO is
defined as the sum of the organic compounds in the boiling
point range of 60 to 170 °C, and the method uses a
synthetic calibration standard as both a window-defining
mix and a quantitation standard. The GRO method was
specifically incorporated into EPA "Test Methods for
Evaluating Solid Waste" (SW-846) Method 8015B in 1996
(EPA 1996). The GRO method uses the purge-and-trap
technique for sample preparation, effectively limiting the
TPH components to the volatile compounds only.
For DRO analysis, a GC/FID method was developed under
the sponsorship of API as a companion to the GRO method
and was interlaboratory-validated in 1994. In the DRO
method, DRO is defined as the sum of the organic
compounds in the boiling point range of 170 to 430 °C. As
in the GRO method, a synthetic calibration standard is
used for quantitation. The DRO method was also
incorporated into SW-846 Method 8015B in 1996. The
technology used in the DRO method can measure
hydrocarbons with boiling points up to 540 °C. However,
the hydrocarbons with boiling points in the range of 430 to
540 °C are specifically excluded from SW-846
Method 8015B so as not to include the higher-boiling-
point petroleum products. The DRO method uses a
solvent extraction and concentration step, effectively
limiting the method to nonvolatile hydrocarbons.
For PHC analysis, a GC/FID method was developed by
Shell Oil Company (now Equilon Enterprises). This
method was interlaboratory-validated along with the GRO
and DRO methods in an API study in 1994. The PHC
method originally defined PHC as the sum of the
compounds in the boiling point range of about 70 to
400 °C, but it now defines PHC as the sum of the
compounds in the boiling point range of 70 to 490 °C.
The method provides options for instrument calibration,
including use of synthetic standards, but it recommends
use of products similar to the contaminants present at the
site of concern. The PHC method has not been specifically
incorporated into SW-846; however, the method has been
used as the basis for the TPH methods in several states,
including Massachusetts, Washington, and Texas. The
PHC method uses solvent microextraction and thus has a
higher detection limit than the GRO and DRO methods.
The PHC method also begins peak integration after elution
of the solvent peak for n-pentane. Thus, this method
probably cannot measure some volatile compounds (for
example, 2-methyl pentane and MTBE) that are measured
using the GRO method.
1.3.23
Definition of TPH
It is not possible to establish a definition of TPH that
would include crude oil and its refined products and
exclude other organic compounds. Ideally, the TPH
definition selected for the demonstration would have
Included compounds that are PHCs, such as paraffins,
naphthenes, and aromatic hydrocarbons
• Included, to the extent possible, the major liquid
petroleum products (gasoline, naphthas, kerosene, jet
fuels, fuel oils, diesel, and lubricating oils)
-------
• Had little inherent bias based on the composition of an
individual manufacturer's product
• Had little inherent bias based on the relative
concentrations of aliphatic and aromatic hydrocarbons
present
• Included much of the volatile portion of gasoline,
including all weathered gasoline
• Included MTBE
Excluded crude oil residuals beyond the extended
diesel range organic (EDRO) range
• Excluded nonpetroleum organic compounds (for
example, chlorinated solvents, pesticides,
polychlorinated biphenyls [PCB], and naturally
occurring oils and greases)
• Allowed TPH measurement using a widely accepted
method
• Reflected accepted TPH measurement practice in
many states
Several states, including Massachusetts, Alaska,
Louisiana, and North Carolina, have implemented or are
planning to implement a TPH contamination cleanup
approach based on the aliphatic and aromatic hydrocarbon
fractions of TPH. The action levels for the aromatic
hydrocarbon fraction are more stringent than those for the
aliphatic hydrocarbon fraction. The approach used in the
above-mentioned states involves performing a sample
fractionation procedure and two analyses to determine the
aliphatic and aromatic hydrocarbon concentrations in a
sample. However, in most applications of this approach,
only a few samples are subjected to the dual aliphatic and
aromatic hydrocarbon analyses because of the costs
associated with performing sample fractionation and two
analyses.
For the demonstration, TPH was not defined based on the
aliphatic and aromatic hydrocarbon fractions because
• Such a definition is used in only a few states.
Variations exist among the sample fractionation and
analysis procedures used in different states.
• The repeatability and versatility of sample
fractionation and analysis procedures are not well
documented.
• In some states, TPH-based action levels are still used.
• The associated analytical costs are high.
As stated in Section 1.3.2.2, analytical methods currently
available for measurement of TPH each exclude some
portion of TPH and are unable to measure TPH alone
while excluding all other organic compounds, thus making
TPH a method-defined parameter. After consideration of
all the information presented above, the GRO and DRO
analytical methods were selected for TPH measurement for
the demonstration. However, because of the general
interest in higher-boiling-point petroleum products, the
integration range of the DRO method was extended to
include compounds with boiling points up to 540 °C.
Thus, for the demonstration, the TPH concentration was
the sum of all organic compounds that have boiling points
between 60 and 540 °C and that can be chromatographed,
or the sum of the results obtained using the GRO and DRO
methods. This approach accounts for most gasoline,
including MTBE, and virtually all other petroleum
products and excludes a portion (25 to 50 percent) of the
heavy lubricating oils. Thus, TPH measurement for the
demonstration included PHCs as well as some organic
compounds that are not PHCs. More specifically, TPH
measurement did not exclude nonpetroleum organic
compounds such as chlorinated solvents, other synthetic
organic chemicals such as pesticides and PCBs, and
naturally occurring oils and greases. A silica gel
fractionation step used to remove polar, biogenic
compounds such as fatty acids in some GC/FID methods
was not included in the sample preparation step because,
according to the State of California, this step can also
remove some petroleum degradation products that are also
polar in nature (California Environmental Protection
Agency 1999). The step-by-step approach used to select
the reference method for the demonstration and the
project-specific procedures implemented for soil sample
preparation and analysis using the reference method are
detailed in Chapter 5.
10
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Chapter 2
Description of Immunoassay and Colorimetry and the EnSys Petro Test System
Measurement of TPH in soil by field measurement devices
generally involves extraction of PHCs from soil using an
appropriate solvent followed by measurement of the TPH
concentration in the extract using an optical method. An
extraction solvent is selected that will not interfere with the
optical measurement of TPH in the extract. Some field
measurement devices use light in the visible wavelength
range, and others use light outside the visible wavelength
range (for example, ultraviolet light).
The optical measurements made by field measurement
devices may involve absorbance, reflectance, or
fluorescence. In general, the optical measurement for a
soil extract is compared to a calibration curve in order to
determine the TPH concentration. Calibration curves may
be developed by (1) using a series of calibration standards
selected based on the type of PHCs being measured at a
site or (2) establishing a correlation between off-site
laboratory measurements and field measurements for
selected, site-specific soil samples.
Field measurement devices may be categorized as
quantitative, semiquantitative, and qualitative. These
categories are explained below.
• A quantitative measurement device measures TPH
concentrations ranging from its reporting limit through
its linear range. The measurement result is reported as
a single, numerical value that has an established
precision and accuracy.
• A semiquantitative measurement device measures
TPH concentrations above its reporting limit. The
measurement result may be reported as a concentration
range with lower and upper limits.
• A qualitative measurement device indicates the
presence or absence of PHCs above or below a
specified value (for example, the reporting limit or an
action level).
The EnSys Petro Test System is a field measurement
device capable of providing semiquantitative TPH
measurement results. Measurements made by the EnSys
Petro Test System are based on immunoassay and
colorimetry using light in the visible wavelength range.
Immunoassay and colorimetry are described in Section 2.1.
The EnSys Petro Test System does not require generation
of a calibration curve because it provides semiquantitative
results. A concentration range is reported by evaluating
whether the TPH concentration in a given sample is greater
or less than the concentration in one or more reference
standards; SDI does not report an absolute sample
concentration through interpolation of reference standard
concentrations.
Section 2.1 describes the technology upon which the
EnSys Petro Test System is based, Section 2.2 describes
the EnSys Petro Test System itself, and Section 2.3
provides SDI contact information. The technology and
device descriptions presented below are not intended to
provide complete operating procedures for measuring TPH
concentrations in soil using the EnSys Petro Test System.
Detailed operating procedures for the device, including soil
extraction, TPH measurement, and TPH concentration
range calculation procedures, are available from SDI.
Supplemental information provided by SDI is presented in
the appendix.
2.1 Description of Immunoassay and
Colorimetry
Measurement of TPH in soil using the EnSys Petro Test
System is based on a combination of immunoassay and
colorimetry. According to SDI, this combination of
technologies is suitable for measuring a large portion of
11
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the aromatic hydrocarbons and a few aliphatic
hydrocarbons in the C6 through C22 carbon range.
Immunoassay and colorimetry are described below.
2.1.1 Immunoassay
Immunoassay is a technique for measuring a target
compound's concentration using biologically engineered
antibodies. Antibodies are a class of proteins known as
immunoglobulins that are produced by the immune system
of animals in response to a foreign substance (an antigen).
The antibodies produced can bind with the antigen that
stimulated their production. Specifically, antibodies are
produced in response to localized, reactive sites called
antigenic determinants on the surface of the antigen.
Antigenic determinants consist of amino acid sequences
(Rittenburg 1990). Because an antigen may possess more
than one type of antigenic determinant, more than one type
of antibody may be produced by the immune system. In
general, the antibodies produced are structured in such a
way that they selectively bind to the antigenic
determinants on the antigen that stimulated their
production, resulting in formation of an antibody-antigen
complex.
Five major classes of antibodies (immunoglobulin [Ig] A,
IgD, IgE, IgG, and IgM) are produced by the immune
system. IgG is the most common type of antibody used in
immunoassay (Rittenburg 1990). IgG is a Y-shaped
molecule consisting of two identical heavy polypeptide
chains and two identical light polypeptide chains bound
together by disulfide bonds. Both the heavy and light
chains have variable and constant regions. The variable
regions at the ends of the two arms of the Y-shaped
antibody form areas called antigen-binding sites; therefore,
two antigen-binding sites are present on each antibody.
The general structure of the IgG antibody is shown in
Figure 2-1.
The dimensions and contours of antigen-binding sites are
determined by the sequence of amino acids in the variable
regions of the antibody. On a single antibody molecule,
the two binding sites have identical variable regions. As
a result, the two binding sites have identical specificity for
a particular antigenic determinant (Rittenburg 1990).
However, the binding sites of antibodies produced in
response to different antigenic determinants are not the
same.
The binding affinity between an antibody and antigen is
determined by (1) the sequence of amino acids in the
variable regions of the antibody, (2) the structure and
location of the antigenic determinant on the antigen, and
(3) the attractive forces that stabilize the antibody-antigen
complex. The attractive forces include a combination of
hydrogen bonds, hydrophobic bonds, coulombic
interaction, and van der Waals forces (Rittenburg 1990).
The closer the antigenic determinant is to the antigen-
binding site on the antibody, the higher the binding
affinity.
Immunoassays employ either polyclonal or monoclonal
antibodies. Because an antigen generally contains more
than one type of antigenic determinant, more than one type
of antibody may be produced in the immune response.
Therefore, the antibodies produced are not identical and
are called polyclonal antibodies. Because polyclonal
antibodies are not identical, they will, as a group, exhibit
varied specificities and binding affinities for antigenic
determinants. Monoclonal antibodies are produced by
isolating those antibodies produced in response to one type
of antigenic determinant. As a result, monoclonal
antibodies are structurally identical and exhibit the same
specificities and binding affinities for the antigenic
determinant that stimulated their production.
Although an antibody has a particular specificity and
binding affinity for the antigenic determinant that
produced the antibody, cross-reactivity with other
compounds may occur. For example, cross-reactivity may
occur when the antigenic determinant that stimulated the
antibody's production is present in other compounds (SDI
2000). Cross-reactivity may also occur with other
compounds that possess structurally similar antigenic
determinants (Rittenburg 1990).
Immunoassay effectiveness is primarily a function of
(1) the specificities and binding affinities of the polyclonal
or monoclonal antibodies used and (2) whether one
compound or a group of compounds is being measured.
For example, cross-reactivity will result in false positives
when only one compound is being measured. However,
cross-reactivity is desirable when a group of compounds,
such as PHCs, is being measured. Whether polyclonal or
monoclonal antibodies are better suited for measuring
PHCs depends on the individual antibodies used; for
example, highly cross-reactive, monoclonal antibodies can
be as effective as less cross-reactive, polyclonal
antibodies.
12
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Antigen-binding
sites
Heavy
chains
~
CH
-s-s-
-s-s-
•S J
-S J
-S J
•S J
k
%
5-
3-
^
Light
chain
Notes:
-S-S- = Disulfide bond
C = Constant region
H = Heavy polypeptide chain
L = Light polypeptide chain
V = Variable region
Figure 2-1. Immunoglobulin G antibody structure and locations of antigen-binding sites.
The EnSys Petro Test System is based on a type of
immunoassay called enzyme-linked immunosorbent assay
(ELISA). ELISA uses either polyclonal or monoclonal
antibodies adsorbed to the inside wall of a test tube in
order to facilitate separation of target compounds from
nontarget compounds during a washing step. In ELISA, an
enzyme conjugate solution is used to produce color whose
intensity is inversely proportional to the total
concentration of PHCs in a sample extract. ELISA
involves the following three steps: (1) enzyme conjugate
and sample extract addition, (2) washing, and (3) color
development. These steps are described below and are
illustrated in Figure 2-2. The intensity of the color
produced during color development is measured using
standard colorimetric principles as described in
Section 2.1.2.
Enzyme Conjugate and Sample Extract Addition . As
a first step, an enzyme conjugate solution is added to the
soil sample extract. An enzyme conjugate is an enzyme
13
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Step
Schematic
Description
Enzyme conjugate and sample extract addition
00...
A reaction mixture containing the sample
extract and enzyme conjugate solution is
added to an antibody-coated test tube. The
sample extract target compound and enzyme
conjugate compete for antigen-binding sites.
Washing
The unbound sample extract target
compound and enzyme conjugate are
removed from the test tube.
Color development
J-
A substrate and chromogen are added to the
test tube.
The substrate and chromogen react with the
enzyme in the enzyme conjugate to produce
color. The lower the color intensity, the
higher the sample extract target compound
concentration.
Notes:
Y = Antibody
• = Sample extract target compound
O = Enzyme conjugate
s* = Substrate
_i_ = Chromogen
Figure 2-2. Enzyme-linked immunosorbent assay.
bound to a target compound. The antigen used to initiate
antibody production is also used as the target compound
portion of the enzyme conjugate. The enzyme portion of
the enzyme conjugate plays its role in ELISA during the
color development step; the enzyme typically used in
ELISA is horseradish peroxidase. The reaction mixture
containing the sample extract and enzyme conjugate
solution is added to an antibody-coated test tube. Because
both the sample extract target compound and the enzyme
conjugate can bind with the antibodies, the sample extract
target compound and the enzyme conjugate compete for
the antigen-binding sites on the antibodies. The sample
extract target compound and the enzyme conjugate bind to
the antibodies in direct proportion to their relative
concentrations in the reaction mixture. For example, the
greater the ratio of the sample extract target compound
concentration to the enzyme conjugate concentration, the
greater the proportion of antigen-binding sites that are
occupied by the sample extract target compound.
Washing. The sample extract target compound and the
enzyme conjugate that are bound to the antibodies are
separated from the unbound sample extract target
compound and enzyme conjugate by emptying the reaction
mixture from the test tube and washing the test tube with
potable water or a dilute detergent solution.
Color Development. A substrate, such as hydrogen
peroxide, and a chromogen, such as tetramethylbenzidine
or orthophenylenediamine, are then added to the test tube
in order to produce color when they react with the enzyme
in the enzyme conjugate. For example, the enzyme
horseradish peroxidase reacts with the hydrogen peroxide
to release a proton, which in turn reduces the chromogen
14
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to form the colored product. After a specified period of
time, color development in the test tube is terminated using
a stopping solution such as hydrochloric acid. The amount
of color formed is directly proportional to the amount of
enzyme conjugate bound to the antibodies. Because the
sample extract target compound competes with the enzyme
conjugate for antigen-binding sites, ELISA results in
formation of color in the test tube whose intensity is
inversely proportional to the concentration of the sample
extract target compound; for example, less color indicates
a higher concentration of the sample extract target
compound.
2.1.2 Colorimetry
After completion of color development, the concentration
of PHCs in the sample extract is determined using
colorimetry. Colorimetry is a technique by which the
intensity of color is assessed using visual or
spectrophotometric means. Use of a spectrophotometer is
preferred over visual assessment of color charts because
the spectrophotometer provides a more accurate and
precise measurement and does not rely on a person's
skill in interpreting color charts. A reflectance
spectrophotometer measures the intensity of light reflected
from solid particles in a reaction mixture, and an
absorbance spectrophotometer measures the intensity of
light that passes through the liquid portion of a reaction
mixture. The EnSys Petro T est System uses an absorbance
spectrophotometer because the colored reaction product is
present in the liquid phase.
When a spectrophotometer is used in the visible
wavelength range, the reaction mixture is placed in a glass
or quartz cuvette that is then inserted into the
spectrophotometer. A beam of visible light is then passed
through the reaction mixture. The wavelength of the light
entering the reaction mixture is initially selected by
performing a series of absorbance measurements over a
range of wavelengths; the selected wavelength generally
provides maximum absorbance and allows target
compound measurement over a wide concentration range.
Some of the light is absorbed by the chemicals in the
reaction mixture, and the rest of the light passes through.
Absorbance, which is defined as the logarithm of the ratio
of the radiant power of the light source to that of the light
that passes through the reaction mixture, is measured by a
photoelectric detector in the spectrophotometer (Fritz and
Schenk 1987). Absorbance can be calculated using
Equation 2-1.
where
A
I =
A = 109(10/1) (2-1)
Absorbance
Intensity of light source
Intensity of light that passes through the
reaction mixture
Therefore, the intensity of the light that passes through
the reaction mixture is inversely proportional to the
concentration of the colored product in the reaction
mixture, or the intensity of the light absorbed by the
reaction mixture is directly proportional to the
concentration of the colored product in the reaction
mixture.
According to Beer-Lambert's law, Equation 2-1 may be
expressed as shown in Equation 2-2.
A=ebc
(2-2)
where
A
= Absorbance
e = Molar absorptivity (centimeter per mole per
liter [L])
b = Light path length (centimeter)
C = Concentration of absorbing species (mole
perL)
Thus, according to Beer-Lambert's law, the absorbance of
a chemical species is directly proportional to the
concentration of the absorbing chemical species (colored
reaction product) and the path length of the light that is not
absorbed by the reaction mixture and passes through the
mixture. In Equation 2-2, the molar absorptivity is a
proportionality constant, which is a characteristic of the
absorbing species and changes as the wavelength of the
light irradiating the reaction mixture changes. Therefore,
Beer-Lambert's law applies only to monochromatic light
(light energy of one wavelength).
For the EnSys Petro Test System, the absorbance of the
colored reaction mixture is assessed using a differential
photometer. The differential photometer is a double-beam
instrument in which two equivalent beams of light are
produced within the visible range of the electromagnetic
spectrum. One beam passes through the colored reaction
mixture developed using the sample extract, while the
other beam passes through a colored reaction mixture
developed using a reference standard. The photometer
15
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measures the difference in absorbance between the two
colored reaction mixtures. Because color intensity is
inversely proportional to the concentration of the sample
extract target compound, a positive reading on the
photometer indicates that the total concentration of PHCs
in the sample extract is less than that in the reference
standard. Similarly, a negative reading on the photometer
indicates that the total concentration of PHCs in the sample
extract is greater than that in the reference standard.
2.2 Description of EnSys Petro Test System
The EnSys Petro Test System is manufactured by SDI and
has been commercially available since 1992. The device
conforms to SW-846 Method 4030 for screening PHCs
using immunoassay detection (EPA 1996). This section
describes the device and summarizes its operating
procedure.
2.2.1 Device Description
The EnSys Petro Test System consists of three kits: the
(1) SDI Sample Extraction Kit (Sample Extraction Kit),
(2) EnSys Petro 12T Soil Test Kit (12T Soil Test Kit), and
(3) EnSys/EnviroGard® Common Accessory Kit (Common
Accessory Kit). The EnSys Petro Test System includes
antibody-coated test tubes containing monoclonal
antibodies, which are produced using m-xylene as the
antigen. The enzyme conjugate used to produce color is
composed of m-xylene as the target compound and
horseradish peroxidase as the enzyme. The washing step
is performed with a dilute detergent solution. Color
development is achieved using hydrogen peroxide as the
substrate and tetramethy Ibenzidine as the chromogen. The
stop solution added to terminate color development is
0.5 percent sulfuric acid. A differential photometer that
emits light in the visible range of the electromagnetic
spectrum at a 450-nanometer wavelength is used to
measure the absorbance of the sample extract and of a
reference standard containing 3 mg/L m-xylene during
color measurement. The total concentration of PHCs in
the sample extract is then determined by comparing the
absorbance readings associated with the sample extract and
reference standard.
According to SDI, the EnSys Petro Test System can be
used to measure the following petroleum products in soil:
gasoline, diesel, Jet A fuel, JP-4, kerosene, No. 2 fuel oil,
No. 6 fuel oil, and mineral spirits. The monoclonal
antibodies used in the device are specific to a subset of
petroleum product components, including a large portion
of the aromatic hydrocarbons and a few aliphatic
hydrocarbons in the C6 through C22 carbon range.
The method detection limits (MDL) of the EnSys Petro
Test System claimed by SDI for a variety of aromatic and
aliphatic hydrocarbons are presented hi Table 2-1. Except
for benzene, which has an MDL of 400 mg/kg, the
aromatic hydrocarbons listed in Table 2-1 have MDLs that
are less than or equal to (<.) 40 mg/kg, indicating a high
degree of selectivity. A few aliphatic hydrocarbons, such
as 2-methylpentane and isooctane, also have low MDLs.
Table 2-1 also presents the MDLs for various petroleum
products. These MDLs generally range from 10 mg/kg
(gasoline) to 40 mg/kg (mineral spirits). The MDLs for
machine oil, brake fluid, unused motor oil, grease, and
mineral oil are all > 1,000 mg/kg, indicating that the EnSys
Petro Test System is not as sensitive to these formulated
petroleum products.
According to SDI, the operating temperature range for the
12T Soil Test Kit is 16 to 38 °C and the test kit should be
stored at <.21 °C when not in use. SDI does not have an
operating humidity restriction for the test kit. The shelf
life of the test kit is typically 1 year after its date of
manufacture; lot-specific expiration date information is
provided on the test kit packaging. The chromogen and
substrate solutions should not be exposed to direct sunlight
during test kit operation or storage.
The components of the EnSys Petro Test System are listed
in Table 2-2. The Sample Extraction Kit contains enough
supplies to perform 12 soil sample extractions. The 12T
Soil Test Kit contains enough supplies to process up to
12 samples (for example, 10 soil sample extracts and
duplicate calibration standards). The Common Accessory
Kit contains multi-use items that do not require frequent
replacement. All Common Accessory Kit items are housed
in a hard-plastic carrying case to prevent damage to the
items during kit transport. The Sample Extraction Kit and
12T Soil Test Kit items are shipped in cardboard boxes.
The differential photometer (Artel DP™ Differential
Photometer) included in the Common Accessory Kit is
designed to provide an immediate, direct comparison of the
absorbance of two liquid samples (for example, a soil
sample extract and a reference standard) by means of a
digital display; the display indicates the difference in
16
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Table 2-1. EnSys Petro Test System Method Detection Limits
Table 2-2. EnSys Petro Test System Components
Compound or Substance
Method Detection Limit
(milligram per kilogram)8
Petroleum fuel product
Gasoline
Diesel
Jet A fuel
JP-4
Kerosene
No. 2 fuel oil
No. 6 fuel oil
Formulated petroleum product
Mineral spirits
Machine oil
Brake fluid
Unused motor oil
Grease
Mineral oil
Aromatic hydrocarbon
Benzene
Toluene
Ethylbenzene
o-Xylene
m-Xylene
p-Xylene
Styrene
1 ,2-Dichlorobenzene
Hexachlorobenzene
Naphthalene
Acenaphthalene
Biphenyl
Creosote
Aliphatic hydrocarbon
2-Methylpentane
Hexanes (mixed)
Heptane
Isooctane
Undecane
Trichloroethylene
Methyl-tert-butyl ether
Notes:
> = Greater than
10
15
15
15
15
15
25
40>
>1,000b
>1,000.
>1,000b
>1,000b
>1,000
400
40
7
8.5
8
4.5
7
2.5
10
0.8
0.5
10
1.5
35
65
130
8-5b
>1,000
>1,000b
>1,000
• Minimum soil concentration necessary to obtain a positive result
more than 95 percent of the time
b Highest concentration tested; positive result not obtained at this
concentration
Source: SD11999
SDI Sample Extraction Kit
• 12 extraction jars with screw caps (each jar contains 3 stainless-
steel mixing balls)
* 12 filter units (tops and bottoms)
• 12 ampule crackers
• 12 dilution ampules for each dilution level
• 12 wooden spatulas
• 12 plastic weigh canoes
• 12 disposable transfer pipettes
• 12 ampules containing 100 percent methanol solvent
• User guide
EnSys Petro 12T Soil Test Kit
• 48 monoclonal antibody-coated tubes
• 48 conjugate tubes
• 1 80-milliliter bottle of phosphate buffer solution
• 1 15-milliliter bottle of chromogen (tetramethylbenzidine)
• 1 15-milliliter bottle of substrate (hydrogen peroxide)
• 1 15-milliliter bottle of stop solution (0.5 percent sulfuric acid)
• 3 1-milliliter vials of Petro standard (3 milligrams per liter m-xylene)
• 24 Microman® positive displacement pipettor tips
• 3 5-milliliter Combitips® for the repeater pipettor
• 1 12.5-milliliterCombitip® for the repeater pipettor
• 12 plastic ampule crackers
• 3 amber vials (for storage of remnant solution from cracked
ampules)
• 3 disposable transfer pipettes
• 2 480-milliliter bottles of dilute detergent solution (Tween-20)
• User guide
EnSys/EnviroGard® Common Accessory Kit
• 1 battery-powered Artel DP™ Differential Photometer, including
4 rechargeable nickel-cadmium batteries and 1 battery recharger
• 1 battery-powered ACCULAB® digital balance, including 1 100-gram
calibration weight and 1 9-volt battery
• 1 battery-powered digital timer, including 1 G-13 cell button battery
• 1 Gilson M-25 Microman® positive displacement pipettor
• 1 Eppendorf™ repeater pipettor
• 3 5-milliliter Combitips* for the repeater pipettor
• 5 12.5-milliliter Combitips® for the repeater pipettor
• 1 50-milliliter Combitip* for the repeater pipettor
• 1 wash bottle
• 1 foam workstation
• 2 foam 30-position test tube racks
• User guides for differential photometer, balance, timer, and
pipettors
• Carrying case
absorbance between the two samples. The photometer is
3.4 inches long, 5.3 inches wide, and 2.6 inches high and
weighs 0.8 pound. The power supply for the photometer
consists of four rechargeable nickel-cadmium batteries; the
photometer cannot be operated using an alternating current
power source. The batteries require 8 to 10 hours to
achieve a full recharge after discharge and last for about
500 readings between recharges. According to SDI,
the operating temperature range for the photometer is
10 to 40 °C and the photometer should be stored at a
temperature between -20 and 66 °C when not in use. SDI
does not have an operating humidity restriction for the
photometer.
According to SDI, 12 samples (including soil sample
extracts and reference standards) can be analyzed as one
batch by one person using the EnSys Petro Test System in
approximately 45 minutes. The device is easy to operate
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and is designed to be used by those with basic wet
chemistry skills. In addition to the user guide or guides
that accompany each kit of the device, SDI provides
technical support over the telephone at no additional cost.
SDI also offers a 1-day, on-site training program.
According to SDI, the EnSys Petro Test System is
innovative because the device uses biologically engineered
antibodies to measure PHCs in soil. SDI also claims that
the device measures most aromatic hydrocarbons and
some aliphatic hydrocarbons in the C6 through C22 carbon
range.
2.2.2 Operating Procedure
During the demonstration, measuring TPH in soil using the
EnSys Petro Test System involved the following five steps:
(1) extraction, (2) sample and standard preparation,
(3) washing, (4) color development, and (5) color
measurement and estimation of TPH concentration.
Extraction of a given soil sample was completed by adding
20 milliliters (mL) of methanol to 10 grams of the sample.
During sample and standard preparation, the sample
extract and a reference standard were transferred to
conjugate tubes containing phosphate buffer solution. The
mixtures were then transferred from the conjugate tubes to
antibody-coated tubes. Washing was accomplished by first
discarding the contents of the antibody-coated tubes and
then washing each tube with dilute detergent solution.
Color development included addition of chromogen and
substrate to each antibody-coated tube; the addition of
substrate turned the reaction mixture blue. Stop solution
was then added to stop color development; the addition of
stop solution turned the reaction mixture yellow. To
accomplish color measurement, the absorbance of the
antibody-coated tubes containing the sample extract and of
the antibody-coated tube containing the reference standard
was compared using the differential photometer. Because
color intensity is inversely proportional to the
concentration of the sample extract target compound, a
positive reading on the photometer indicated that the total
concentration of PHCs in the sample extract was less than
that in the reference standard. Similarly, a negative
reading on the photometer indicated that the total
concentration of PHCs in the sample extract was greater
than that in the reference standard.
During the demonstration, SDI performed each analysis at
three detection levels by diluting the sample extract twice
during the sample and standard preparation step. The
reference standard concentrations for gasoline (10 mg/kg)
and diesel (15 mg/kg) were multiplied by the dilution
factors used. Thus, the concentration ranges used to
estimate sample TPH concentrations were (1) <10; >10 to
<100; >100 to < 1,000; and > 1,000 mg/kg for GRO-
containing samples and (2) <15; >15 to <100; >100 to
< 1,000; and > 1,000 mg/kg for EDRO-containing samples.
During the demonstration, a QC check was performed for
the EnSys Petro Test System during the fifth step (color
measurement and estimation of TPH concentration) of the
operating procedure. Two reference standard tubes
(duplicates) were switched in the photometer until the
photometer reading was negative or zero. Device
performance was considered to be acceptable if the
difference in the absorbance values between the standards
was <-0.30.
2.3 Developer Contact Information
Additional information about the EnSys Petro Test System
can be obtained from the following source:
Strategic Diagnostics Inc.
Mr. Joseph Dautlick
111 Pencader Drive
Newark, DEI 9702
Telephone: (800) 544-8881, extension 222
Fax: (302) 456-6770
E-mail: jdautlick@sdix.com
Internet: www.sdix.com
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Chapter 3
Demonstration Site Descriptions
This chapter describes the three sites selected for
conducting the demonstration. The first site is referred to
as the Navy BVC site; it is located in Port Hueneme,
California, and contains three sampling areas. The second
site is referred to as the Kelly AFB site; it is located in San
Antonio, Texas, and contains one sampling area. The third
site is referred to as the PC site; it is located in north-
central Indiana and contains one sampling area. After
review of the information available on these and other
candidate sites, the Navy BVC, Kelly AFB, and PC sites
were selected based on the following criteria:
Site Diversity—Collectively, the three sites contained
sampling areas with the different soil types and the
different levels and types of PHC contamination
needed to evaluate the seven field measurement
devices selected for the demonstration.
• Access and Cooperation—The site representatives
were interested in supporting the demonstration by
providing site access for collection of soil samples
required for the demonstration. In addition, the field
measurement devices were to be demonstrated at the
Navy BVC site using soil samples from all three sites,
and the Navy BVC site representatives were willing to
provide the site support facilities required for the
demonstration and to support a visitors' day during
the demonstration. As a testing location for the
Department of Defense National Environmental
Technology Test Site program, the Navy BVC site is
used to demonstrate technologies and systems for
characterizing or remediating soil, sediment, and
groundwater contaminated with fuel hydrocarbons or
waste oil.
To ensure that the sampling areas were selected based
on current site characteristics, a predemonstration
investigation was conducted. During this investigation,
samples were collected from the five candidate areas and
were analyzed for GRO and EDRO using SW-846
Method 8015B (modified) by the reference laboratory,
Severn Trent Laboratories in Tampa, Florida (STL Tampa
East). The site descriptions in Sections 3.1 through 3.3
are based on data collected during predemonstration
investigation sampling activities, data collected during
demonstration sampling activities, and information
provided by the site representatives. Physical character-
ization of samples was performed in the field by a
geologist during both predemonstration investigation and
demonstration activities.
Some of the predemonstration investigation samples were
also analyzed by the EnSys Petro Test System developer,
SDI, at its facility. SDI used reference laboratory and
EnSys Petro Test System results to gain a preliminary
understanding of the demonstration samples and to prepare
for the demonstration.
Table 3-1 summarizes key site characteristics, including
the contamination type, sampling depth intervals, TPH
concentration ranges, and soil type in each sampling area.
The TPH concentration ranges and soil types presented in
Table 3-1 and throughout this report are based on
reference laboratory TPH results for demonstration
samples and soil characterization completed during the
demonstration, respectively. TPH concentration range and
soil type information obtained during the demonstration
was generally consistent with the information obtained
during the predemonstration investigation except for the
B-38 Area at Kelly AFB. Additional information on
differences between demonstration and predemonstration
investigation activities and results is presented in
Section 3.2.
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Table 3-1. Summary of Site Characteristics
Site
Navy Base
Ventura
County
Kelly Air
Force
Base
Petroleum
company
Sampling Area
Fuel Farm Area
Naval Exchange
Service Station
Area
Phytoremediation
Area
B-38 Area
Slop Fill Tank
Area
Contamination Type8
EDRO (weathered diesel
with carbon range from
n-C,0 through n-C40)
GRO and EDRO (fairly
weathered gasoline with
carbon range from n-C6
through n-C14)
EDRO (heavy lubricating
oil with carbon range from
n-C14 through n-C40>)
GRO and EDRO (fresh
gasoline and diesel or
weathered gasoline and
trace amounts of
lubricating oil with carbon
range from n-C6 through
n-C40)
GRO and EDRO
(combination of slightly
weathered gasoline,
kerosene, JP-5, and diesel
with carbon range from
n-Cs through n-C32)
Approximate
Sampling Depth
Interval
(foot bgs)
Upper layer*
Lower layer6
7 to 8
8 to 9
9 to 10
10 to 11
1.5 to 2.5
23 to 25
25 to 27
2 to 4
4 to 6
6 to 8
8 to 10
TPH Concentration
Range (mg/kg)
44.1 to 93.7
8,0901015,000
28.1 to 280
144 to 2,570
617 to 3,030
9.56 to 293
1,130 to 2,140
43.8 to 193
41 .5 to 69.4
6.16 to 3,300
37.1 to 3,960
43.9 to 1,210
52.4 to 554
Type of Soil
Medium-grained sand
Medium-grained sand
Silty sand
Sandy clay or silty sand and gravel in
upper depth interval and clayey sand
and gravel in deeper depth interval
Silty clay with traces of sand and gravel
in deeper depth intervals
Notes:
bgs = Below ground surface
mg/kg = Milligram per kilogram
* The beginning or end point of the carbon range identified as "n-Cx" represents an alkane marker consisting of "x" carbon atoms on a gas
chromatogram.
* Because of soil conditions encountered in the Fuel Farm Area, the sampling depth intervals could not be accurately determined. Sample collection
was initiated approximately 10 feet bgs, and attempts were made to collect 4-foot-long soil cores. This approach resulted in varying degrees of
core tube penetration up to 17 feet bgs. At each location in the area, the sample cores were divided into two samples based on visual
observations. The upper layer of the soil core, which consisted of yellowish-brown, medium-grained sand, made up one sample, and the lower
layer of the soil core, which consisted of grayish-black, medium-grained sand and smelled of hydrocarbons, made up the second sample.
3.1 Navy Base Ventura County Site
The Navy BVC site in Port Hueneme, California, covers
about 1,600 acres along the south California coast. Three
areas at the Navy BVC site were selected as sampling areas
for the demonstration: (1) the Fuel Farm Area (FFA),
(2) the Naval Exchange (NEX) Service Station Area, and
(3) the Phytoremediation Area (PRA). These areas are
briefly described below.
3.1.1 Fuel Farm Area
The FFA is a tank farm in the southwest comer of the
Navy BVC site. The area contains five tanks and was
constructed to refuel ships and to supply heating fuel for
the Navy BVC site. Tank No. 5114 along the south edge
of the FFA was used to store marine diesel. After Tank
No. 5114 was deactivated in 1991, corroded pipelines
leading into and out of the tank leaked and contaminated
the surrounding soil with diesel.
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The horizontal area of contamination in the FFA was
estimated to be about 20 feet wide and 90 feet long.
Demonstration samples were collected within several
inches of the three predemonstration investigation
sampling locations in the FFA using a Geoprobe®.
Samples were collected at the three locations from east to
west and about 5 feet apart. During the demonstration, soil
in the area was found to generally consist of medium-
grained sand, and the soil cores contained two distinct
layers. The upper layer consisted of yellowish-brown,
medium-grained sand with no hydrocarbon odor and TPH
concentrations ranging from44.1 to 93.7 mg/kg; the upper
layer's TPH concentration range during the
predemonstration investigation was 38 to 470 mg/kg. The
lower layer consisted of grayish-black, medium-grained
sand with a strong hydrocarbon odor and TPH
concentrations ranging from 8,090 to 15,000 mg/kg; the
lower layer's TPH concentration range during the
predemonstration investigation was 7,700 to
11,000 mg/kg.
Gas chromatograms from the predemonstration
investigation and the demonstration showed that FFA soil
samples contained (1) weathered diesel, (2) hydrocarbons
in the n-C10 through n-C28 carbon range with the
hydrocarbon hump maximizing at n-C17, and
(3) hydrocarbons in the n-C 12 through n-C40 carbon range
with the hydrocarbon hump maximizing at n-C 20-
3.1.2 Naval Exchange Service Station Area
The NEX Service Station Area lies in the northeast portion
of the Navy BVC site. About 11,000 gallons of regular
and unleaded gasoline was released from UST lines in this
area between September 1984 and March 1985. Although
the primary soil contaminant in this area is gasoline,
EDRO is also of concern because (1) another spill north of
the area may have resulted in a commingled plume of
gasoline and diesel and (2) a significant portion of
weathered gasoline is associated with EDRO.
The horizontal area of contamination in the NEX Service
Station Area was estimated to be about 450 feet wide and
750 feet long. During the demonstration, samples were
collected at the three predemonstration investigation
sampling locations in the NEX Service Station Area from
south to north and about 60 feet apart using a Geoprobe ®.
Soil in the area was found to generally consist of
(1) brownish-black, medium-grained sand in the
uppermost depth interval and (2) grayish-black, medium-
grained sand in the three deeper depth intervals. Traces of
coarse sand were also present in the deepest depth interval.
Soil samples collected from the area had a strong
hydrocarbon odor. The water table in the area was
encountered at about 9 feet below ground surface (bgs).
During the demonstration, TPH concentrations ranged
from 28.1 to 280 mg/kg in the 7- to 8-foot bgs depth
interval; 144 to 3,030 mg/kg in the 8- to 9- and 9- to
10-foot bgs depth intervals; and 9.56 to 293 mg/kg in the
10- to 11-foot bgs depth interval. During the predemon-
stration investigation, the TPH concentrations in the
(1) top two depth intervals (7 to 8 and 8 to 9 feet bgs)
ranged from 25 to 65 mg/kg and (2) bottom depth interval
(10 to 11 feet bgs) ranged from 24 to 300 mg/kg.
Gas chromatograms from the predemonstration
investigation and the demonstration showed that NEX
Service Station Area soil samples contained (1) fairly
weathered gasoline with a high aromatic hydrocarbon
content and (2) hydrocarbons in the n-C6 through n-C14
carbon range. Benzene, toluene, ethylbenzene, and xylene
(BTEX) analytical results for predemonstration
investigation samples from the 9- to 10-foot bgs depth
interval at the middle sampling location revealed a
concentration of 347 mg/kg; BTEX made up 39 percent of
the total GRO and 27 percent of the TPH at this location.
During the predemonstration investigation, BTEX analyses
were conducted at the request of a few developers to
estimate the aromatic hydrocarbon content of the GRO;
such analyses were not conducted for demonstration
samples.
3.1.3 Phytoremediation Area
The PRA lies north of the FFA and west of the NEX
Service Station Area at the Navy BVC site. The PRA
consists of soil from a fuel tank removal project conducted
at the Naval Weapons Station in Seal Beach, California.
The area is contained within concrete railings and is
60 feet wide, 100 feet long, and about 3 feet deep. It
consists of 12 cells of equal size (20 by 25 feet) that have
three different types of cover: (1) un vegetated cover, (2) a
grass and legume mix, and (3) a native grass mix. There
are four replicate cells of each cover type.
In the PRA, demonstration samples were collected from
the 1.5- to 2.5-foot bgs depth interval within several inches
of the six predemonstration investigation sampling
locations using a split-core sampler. During the
demonstration, soil at four adjacent sampling locations
was found to generally consist of dark yellowish-brown,
silty sand with some clay and no hydrocarbon odor. Soil
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at the two remaining adjacent sampling locations primarily
consisted of dark yellowish-brown, clayey sand with no
hydrocarbon odor, indicating the absence of volatile PHCs.
The TPH concentrations in the demonstration samples
ranged from 1,130 to 2,140 mg/kg; the TPH concentrations
in the predemonstration investigation samples ranged from
1,500 to 2,700 mg/kg.
Gas chromatograms from the predemonstration
investigation and the demonstration showed that PRA soil
samples contained (1) heavy lubricating oil and
(2) hydrocarbons in the n-C H through n-C4(H carbon range
with the hydrocarbon hump maximizing at n-C 32.
SDI chose not to demonstrate the EnSys Petro Test System
using soil samples collected in the PRA because according
to SDI, its device was not designed to measure heavy
lubricating oil, the primary contaminant in the area.
3.2 Kelly Air Force Base Site
The Kelly AFB site covers approximately 4,660 acres and
is about 7 miles from the center of San Antonio, Texas.
One area at Kelly AFB, the B-38 Area, was selected as a
sampling area for the demonstration. The B-38 Area lies
along the east boundary of Kelly AFB and is part of an
active UST farm that serves the government vehicle
refueling station at the base. In December 1992,
subsurface soil contamination resulting from leaking diesel
and gasoline USTs and associated piping was discovered
in this area during UST removal and upgrading activities.
The B-38 Area was estimated to be about 150 square feet
in size. Based on discussions with site representatives,
predemonstration investigation samples were collected in
the 13- to 17- and 29- to 30-foot bgs depth intervals at four
locations in the area using a Geoprobe®. Based on
historical information, the water table in the area
fluctuates between 16 and 24 feet bgs. During the
predemonstration investigation, soil in the area was found
to generally consist of (1) clayey silt in the upper depth
interval above the water table with a TPH concentration
of 9 mg/kg and (2) sandy clay with significant gravel in
the deeper depth interval below the water table with
TPH concentrations ranging from 9 to 18 mg/kg. Gas
chromatograms from the predemonstration investigation
showed that B-38 Area soil samples contained (1) heavy
lubricating oil and (2) hydrocarbons in the n-C24 through
n-C30 carbon range.
Based on the low TPH concentrations and the type of
contamination detected during the predemonstration
investigation as well as discussions with site
representatives who indicated that most of the
contamination in the B-38 Area can be found at or near the
water table, demonstration samples were collected near the
water table. During the demonstration, the water table was
24 feet bgs. Therefore, the demonstration samples were
collected in the 23- to 25- and 25- to 27-foot bgs depth
intervals at three locations in the B-38 Area using a
Geoprobe®. Air Force activities in the area during the
demonstration prevented the sampling team from accessing
the fourth location sampled during the predemonstration
investigation.
During the demonstration, soil in the area was found to
generally consist of (1) sandy clay or silty sand and gravel
in the upper depth interval with a TPH concentration
between 43.8 and 193 mg/kg and (2) clayey sand and
gravel in the deeper depth interval with TPH
concentrations between 41.5 and 69.4 mg/kg. Soil samples
collected in the area had little or no hydrocarbon odor.
Gas chromatograms from the demonstration showed that
B-38 Area soil samples contained either (1) fresh gasoline,
diesel, and hydrocarbons in the n-C 6 through n-C25 carbon
range with the hydrocarbon hump maximizing at n-C 17;
(2) weathered gasoline with trace amounts of lubricating
oil and hydrocarbons in the n-C6 through n-C30 carbon
range with a hydrocarbon hump representing the
lubricating oil between n-C20 and n-C30; or (3) weathered
gasoline with trace amounts of lubricating oil
and hydrocarbons in the n-C6 through n-C40 carbon range
with a hydrocarbon hump representing the lubricating oil
maximizing at n-C31.
3.3 Petroleum Company Site
One area at the PC site in north-central Indiana, the Slop
Fill Tank (SFT) Area, was selected as a sampling area for
the demonstration. The SFT Area lies in the west-central
portion of the PC site and is part of an active fuel tank
farm. Although the primary soil contaminant in this area
is gasoline, EDRO is also of concern because of a heating
oil release that occurred north of the area.
The SFT Area was estimated to be 20 feet long and 20 feet
wide. In this area, demonstration samples were collected
from 2 to 10 feet bgs at 2-foot depth intervals within
several inches of the five predemonstration investigation
sampling locations using a Geoprobe®. Four of the
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sampling locations were spaced about 15 feet apart to form
the comers of a square, and the fifth sampling location was
at the center of the square. During the demonstration, soil
in the area was found to generally consist of brown to
brownish-gray, silty clay with traces of sand and gravel in
the deeper depth intervals. Demonstration soil samples
collected in the area had little or no hydrocarbon odor.
During the demonstration, soil in the three upper depth
intervals had TPH concentrations ranging from 6.16 to
3,960 mg/kg, and soil in the deepest depth interval had
TPH concentrations ranging from 52.4 to 554 mg/kg.
During the predemonstration investigation, soils in the
three upper depth intervals and the deepest depth interval
had TPH concentrations ranging from 27 to 1,300 mg/kg
and from 49 to 260 mg/kg, respectively.
Gas chromatograms from the predemonstration
investigation and the demonstration showed that SFT Area
soil samples contained (1) slightly weathered gasoline,
kerosene, JP-5, and diesel and (2) hydrocarbons in the
n-C5 through n-C20 carbon range. There was also evidence
of an unidentified petroleum product containing
hydrocarbons in the n-C24 through n-C32 carbon range.
BTEX analytical results for predemonstration
investigation samples from the deepest depth interval
revealed concentrations of 26, 197, and 67 mg/kg at the
northwest, center, and southwest sampling locations,
respectively. At the northwest location, BTEX made up
13 percent of the total GRO and 5 percent of the TPH. At
the center location, BTEX made up 16 percent of the total
GRO and 7 percent of the TPH. At the southwest location,
BTEX made up 23 percent of the total GRO and
18 percent of the TPH. BTEX analyses were not
conducted for demonstration samples.
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Chapter 4
Demonstration Approach
This chapter presents the objectives (Section 4.1), design
(Section 4.2), and sample preparation and management
procedures (Section 4.3) for the demonstration.
4.1 Demonstration Objectives
The primary goal of the SITE MMT Program is to develop
reliable performance and cost data on innovative, field-
ready technologies. A SITE demonstration must provide
detailed and reliable performance and cost data so that
potential technology users have adequate information to
make sound judgments regarding an innovative
technology's applicability to a specific site and to compare
the technology to conventional technologies.
The demonstration had both primary and secondary
objectives. Primary objectives were critical to the
technology evaluation and required the use of quantitative
results to draw conclusions regarding a technology's
performance. Secondary objectives pertained to
information that was useful but did not necessarily require
the use of quantitative results to draw conclusions
regarding a technology's performance.
The primary objectives for the demonstration of the
individual field measurement devices were as follows:
PI. Determine the MDL
P2. Evaluate the accuracy and precision of TPH
measurement for a variety of contaminated soil
samples
P3. Evaluate the effect of interferents on TPH
measurement
P4. Evaluate the effect of soil moisture content on TPH
measurement
P5. Measure the time required for TPH measurement
P6. Estimate costs associated with TPH measurement
The secondary objectives for the demonstration of the
individual field measurement devices were as follows:
S1. Document the skills and training required to properly
operate the device
S2. Document health and safety concerns associated with
operating the device
S3. Document the portability of the device
S4. Evaluate the durability of the device based on its
materials of construction and engineering design
S5. Document the availability of the device and associated
spare parts
The objectives for the demonstration were developed based
on input from MMT Program stakeholders, general user
expectations of field measurement devices, characteristics
of the demonstration areas, the time available to complete
the demonstration, and device capabilities that the
developers intended to highlight.
4.2 Demonstration Design
A predemonstration sampling and analysis investigation
was conducted to assess existing conditions and confirm
available information on physical and chemical
characteristics of soil in each demonstration area. Based
on information from the predemonstration investigation as
well as available historical data, a demonstration design
was developed to address the demonstration objectives.
Input regarding the demonstration design was obtained
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from the developers and demonstration site
representatives. The demonstration design is summarized
below.
The demonstration involved analysis of soil environmental
samples, soil performance evaluation (PE) samples, and
liquid PE samples. The environmental samples were
collected from three contaminated sites, and the PE
samples were obtained from a commercial provider,
Environmental Resource Associates (ERA) in Arvada,
Colorado. Collectively, the environmental and PE samples
provided the different matrix types and the different levels
and types of PHC contamination needed to perform a
comprehensive demonstration.
The environmental samples were soil core samples
collected from the demonstration areas at the Navy BVC,
Kelly AFB, and PC sites described in Chapter 3. The soil
core samples collected at the Kelly AFB and PC sites were
shipped to the Navy BVC site 5 days prior to the start of
the field analysis activities. Each soil core sample
collected from a specific depth interval at a particular
sampling location in a given area was homogenized and
placed in individual sample containers. Soil samples were
then provided to the developers and reference laboratory.
In addition, the PE samples were obtained from ERA for
distribution to the developers and reference laboratory.
Field analysis of all environmental and PE samples was
conducted near the PRA at the Navy BVC site.
The field measurement devices were evaluated based
primarily on how they compared with the reference
method selected for the demonstration. PE samples were
used to verify that reference method performance was
acceptable. However, for the comparison with the device
results, the reference method results were not adjusted
based on the recoveries observed during analysis of the PE
samples.
The sample collection and homogenization procedures
may have resulted in GRO losses of up to one order of
magnitude in environmental samples. Despite any such
losses, the homogenized samples were expected to contain
sufficient levels of GRO to allow demonstration objectives
to be achieved. Moreover, the environmental sample
collection and homogenization procedures implemented
during the demonstration ensured that the developers and
reference laboratory received the same sample material
for analysis, which was required to allow meaningful
comparisons of field measurement device and reference
method results.
To facilitate effective use of available information on both
the environmental and PE samples during the
demonstration, the developers and reference laboratory
were informed of (1) whether each sample was an
environmental or PE sample, (2) the area where each
environmental sample was collected, and (3) the
contamination type and concentration range of each
sample. This information was included in each sample
identification number. Each sample was identified as
having a low (< 100 mg/kg), medium (100 to 1,000 mg/kg),
or high (> 1,000 mg/kg) TPH concentration range. The
concentration ranges were based primarily on
predemonstration investigation results or the amount of
weathered gasoline or diesel added during PE sample
preparation. The concentration ranges were meant to be
used only as a guide by the developers and reference
laboratory. The gasoline used for PE sample preparation
was 50 percent weathered; the weathering was achieved by
bubbling nitrogen gas into a known volume of gasoline
until the volume was reduced by 50 percent. Some PE
samples also contained interferents specifically added to
evaluate the effect of interferents on TPH measurement.
The type of contamination and expected TPH
concentration ranges were identified; however, the specific
compounds used as interferents were not identified. All
PE samples were prepared in triplicate as separate, blind
samples.
During the demonstration, SDI field technicians operated
the EnSys Petro Test System, and EPA representatives
made observations to evaluate the device. All the
developers were given the opportunity to choose not to
analyze samples collected in a particular area or a
particular class of samples, depending on the intended uses
of their devices. SDI chose not to analyze soil samples
collected in the PRA because according to SDI, the EnSys
Petro Test System was not designed to measure the heavy
lubricating oil present in the PRA.
Details of the approach used to address the primary and
secondary objectives for the demonstration are presented
in Sections 4.2.1 and 4.2.2, respectively.
4.2.1 Approach for Addressing Primary Objectives
This section presents the approach used to address each
primary objective.
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Primary Objective PI: Method Detection Limit
To determine the MDL for each field measurement device,
low-concentration-range soil PE samples containing
weathered gasoline or diesel were to be analyzed. The
low-range PE samples were prepared using methanol,
which facilitated preparation of homogenous samples. The
target concentrations of the PE samples were set to meet
the following criteria: (1) at the minimum acceptable
recoveries set by ERA, the samples contained measurable
TPH .concentrations, and (2) when feasible, the sample
TPH concentrations were generally between 1 and
10 times the MDLs claimed by the developers and the
reference laboratory, as recommended by 40 Code of
Federal Regulations (CFR) Part 136, Appendix B,
Revision 1.1.1. SDI and the reference laboratory analyzed
seven weathered gasoline and seven diesel PE samples to
statistically determine the MDLs for GRO and EDRO soil
samples. However, during the preparation of low-range
weathered gasoline PE samples, significant volatilization
of PHCs occurred because of th e matrix used for preparing
these samples. Because of the problems associated with
preparation of low-range weathered gasoline PE samples,
the results for these samples could not be used to
determine the MDLs. Moreover, because the EnSys Petro
Test System is a semiquantitative device that does not
report absolute TPH concentrations, the device's MDL
was not to be determined using a statistical approach;
rather, the device MDL claimed by SDI was to be verified
using a nonstatistical approach. Specifically, the device's
MDL was to be verified by evaluating whether the TPH
concentration ranges reported by the device overlapped the
TPH results obtained using the reference method.
Primary Objective P2: Accuracy and Precision
To estimate the accuracy and precision of each field
measurement device, both environmental and PE samples
were analyzed. The evaluation of analytical accuracy was
based on the assumption that a field measurement device
may be used to (1) determine whether the TPH
concentration in a given area exceeds an action level or
(2) perform a preliminary characterization of soil in a
given area. To evaluate whether the TPH concentration in
a soil sample exceeded an action level, the developers and
reference laboratory were asked to determine whether
TPH concentrations in a given area or PE sample type
exceeded the action levels listed in Table 4-1. The action
levels chosen for environmental samples were based on
the predemonstration investigation analytical results and
state action levels. The action levels chosen for the PE
samples were based in part on the ERA acceptance limits
for PE samples; therefore, each PE sample was expected
to have at least the TPH concentration indicated in
Table 4-1. However, because of the problems associated
with preparation of the low-concentration-range weathered
Table 4-1. Action Levels Used to Evaluate Analytical Accuracy
Site
Navy Base Ventura
County
Kelly Air Force Base
Petroleum company
Fuel Farm Area
Naval Exchange Service Station Area
Phytoremediation Areab
B-38 Area
Slop Fill Tank Area
Performance evaluation samples (GRO analysis)
Performance evaluation samples (EDRO analysis)
Typical TPH Concentration Range"
Low and high
Low to high
High
Low
Medium
Medium
High
Low
Medium
High
Action Level (mg/kg)
100
50
1,500
100
500
200
2,000
15
200
2,000
Notes:
mg/kg = Milligram per kilogram
* The typical TPH concentration ranges shown cover all the depth intervals in each area. Table 4-2 shows the depth intervals that were sampled
in each area and the typical TPH concentration range for each depth interval. The action level for each area was used as the basis for evaluating
sample analytical results regardless of the typical TPH concentration ranges for the various depth intervals.
" SDI chose not to analyze soil samples collected in the Phytoremediation Area because according to SDI, the EnSys Petro Test System was not
designed to measure the heavy lubricating oil present in the Phytoremediation Area.
26
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gasoline PE samples, the results for these samples could
not be used to address primary objective P2.
In addition, neat (liquid) samples of weathered gasoline
and diesel were analyzed by the developers and reference
laboratory to evaluate accuracy and precision. Because
extraction of the neat samples was not necessary, the
results for these samples provided accuracy and precision
information strictly associated with the analyses and were
not affected by extraction procedures.
Sample TPH results obtained using each field
measurement device and the reference method were
compared to the action levels presented in Table 4-1 in
order to determine whether sample TPH concentrations
were above the action levels. The results obtained using
the device and reference method were compared to
determine how many times the device's results agreed with
those of the reference method for a particular area or
sample type. In addition, for each quantitative
measurement device, the ratio of the TPH results of the
device to the TPH results of the reference method was
calculated. The ratio was used to develop a frequency
distribution in order to determine how many of the device
and reference method results were within 30 percent,
within 50 percent, and outside the 50 percent window.
To complete a preliminary characterization of soil in a
given area using a field measurement device, the user may
have to demonstrate to a regulatory agency that (1) no
statistically significant difference exists between the results
of the laboratory method selected for the project (the
reference method) and the device results, indicating that
the device may be used as a substitute for the laboratory
method, or (2) a consistent correlation exists between the
device and laboratory method results, indicating that the
device results can be adjusted using the established
correlation. However, the statistical comparison and
correlation activities conducted for the demonstration were
limited to the evaluations of quantitative field
measurement devices.
To evaluate analytical precision, one set of blind field
triplicate environmental samples was collected from each
depth interval at one location in each demonstration area
except the B-38 Area, where site conditions allowed
collection of triplicates in the top depth interval only.
Blind triplicate low-, medium-, and high-concentration-
range PE samples were also used to evaluate analytical
precision because TPH concentrations in environmental
samples collected during the demonstration sometimes
differed from the analytical results for predemonstration
investigation samples. The low- and medium-range PE
samples were prepared using methanol as a carrier, which
facilitated preparation of homogenous samples.
Additional information regarding analytical precision was
collected by having the developers and reference
laboratory analyze extract duplicates. Extract duplicates
were prepared by extracting a soil sample once and
collecting two aliquots of the extract. For environmental
samples, one sample from each depth interval was
designated as an extract duplicate. Each sample designated
as an extract duplicate was co llected from a location where
field triplicates were collected. To evaluate a given
quantitative field measurement device's ability to precisely
measure TPH, the relative standard deviation (RSD) of the
device and reference method TPH results for triplicate
samples was calculated. In addition, to evaluate the
analytical precision of the device and reference method,
the relative percent difference (RPD) was calculated using
the TPH results for extract duplicates. For the EnSys Petro
Test System, a semiquantitative device, analytical
precision was assessed in a qualitative manner.
Specifically, to evaluate the overall precision, the device's
TPH concentration ranges for the triplicate samples were
compared to determine whether they were the same or
different. Similarly, to evaluate the analytical precision,
the TPH concentration ranges for the extract duplicates
were compared to determine whether they were the same
or different.
Primary Objective P3: Effect of Interferents
To evaluate the effect of interferents on each field
measurement device's ability to accurately measure TPH,
high-concentration-range soil PE samples containing
weathered gasoline or diesel with or without an interferent
were analyzed. As explained in Chapter 1, the definition
of TPH is quite variable. For the purposes of addressing
primary objective P3, the term "interferent" is used in a
broad sense and is applied to both PHC and non-PHC
compounds. The six different interferents evaluated during
the demonstration were MTBE; tetrachloroethene (PCE);
Stoddard solvent; turpentine (an alpha and beta pinene
mixture); 1,2,4-trichlorobenzene; and humic acid. The
boiling points and vapor pressures of (1) MTBE and PCE
are similar to those of GRO; (2) Stoddard solvent and
turpentine are similar to those of GRO and EDRO; and
(3) 1,2,4-trichlorobenzene and humic acid are similar to
those of EDRO. The solubility, availability, and cost of
the interferents were also considered during interferent
27
-------
selection. Specific reasons for the selection of the six
interferents are presented below.
• MTBE is an oxygenated gasoline additive that is
detected in the GRO analysis during TPH
measurement using a GC.
• PCE is not a petroleum product but is detected in the
GRO analysis during TPH measurement using a GC.
PCE may also be viewed as a typical halogenated
solvent that may be present in some environmental
samples.
• Stoddard solvent is an aliphatic naphtha compound
with a carbon range of n-C 8 through n-C H and is partly
detected in both the GRO and EDRO analyses during
TPH measurement using a GC.
• Turpentine is not a petroleum product but has a carbon
range of n-C9 through n-C15 and is partly detected in
both the GRO and EDRO analyses during TPH
measurement using a GC. Turpentine may also be
viewed as a substance that behaves similarly to a
typical naturally occurring oil or grease during TPH
measurement using a GC.
• The compound 1,2,4-trichlorobenzene is not a
petroleum product but is detected in the EDRO
analysis. This compound may also be viewed as a
typical halogenated semivolatile organic compound
that behaves similarly to a chlorinated pesticide or
PCB during TPH measurement using a GC.
• Humic acid is a hydrocarbon mixture that is
representative of naturally occurring organic carbon in
soil and was suspected to be detected during EDRO
analysis.
Based on the principles of operation of the field
measurement devices, several of the interferents were
suspected to be detected by the devices.
The PE samples containing MTBE and PCE were not
prepared with diesel and the PE samples containing
1,2,4-trichlorobenzene and humic acid were not prepared
with weathered gasoline because these interferents were
not expected to impact the analyses and because practical
difficulties such as solubility constraints were associated
with preparation of such samples.
Appropriate control samples were also prepared and
analyzed to address primary objective P3. These samples
included processed garden soil, processed garden soil and
weathered gasoline, processed garden soil and diesel, and
processed garden soil and humic acid samples. Because
of solubility constraints, control samples containing
MTBE; PCE; Stoddard solvent; turpentine; or
1,2,4-trichlorobenzene could not be prepared. Instead,
neat (liquid) samples of these interferents were prepared
and used as quasi-control samples to evaluate the effect of
each interferent on the field measurement device and
reference method results. Each PE sample was prepared in
triplicate and submitted to the developers and reference
laboratory as blind triplicate samples.
To evaluate the effects of interferents on a given field
measurement device's ability to accurately measure TPH
under primary objective P3, the means and standard
deviations of the TPH results for triplicate PE samples
were calculated. The mean for each group of samples was
qualitatively evaluated to determine whether the data
showed any trend—that is, whether an increase in the
interferent concentration resulted in an increase or decrease
in the measured TPH concentration. A one-way analysis
of variance was performed to determine whether the group
means were the same or different. For the EnSys Petro
Test System, a semiquantitative device, the effects of
interferents on TPH measurement were assessed in a
qualitative manner. Specifically, the device's TPH
concentration ranges for the control samples and the
samples containing interferents were qualitatively
evaluated to determine whether the data showed any trend.
Primary Objective P4: Effect of Soil Moisture Content
To evaluate the effect of soil moisture content, high-
concentration-range soil PE samples containing weathered
gasoline or diesel were analyzed. PE samples containing
weathered gasoline were prepared at two moisture levels:
9 percent moisture and 16 percent moisture. PE samples
containing diesel were also prepared at two moisture
levels: negligible moisture (<1 percent) and 9 percent
moisture. All the moisture levels were selected based on
the constraints associated with sample preparation. For
example, 9 percent moisture represents the minimum
moisture level for containerizing samples in EnCores and
16 percent moisture represents the saturation level of the
soil used to prepare PE samples. Diesel samples with
negligible moisture could be prepared because they did not
28
-------
require EnCores for containerization; based on vapor
pressure data for diesel and weathered gasoline, 4-ounce
jars were considered to be appropriate for containerizing
diesel samples but not for containerizing weathered
gasoline samples. Each PE sample was prepared in
triplicate.
To measure the effect of soil moisture content on a given
field measurement device's ability to accurately measure
TPH under primary objective P4, the means and standard
deviations of the TPH results for triplicate PE samples
containing weathered gasoline and diesel at two moisture
levels were calculated. A tw o-tailed, two-sample Student's
t-test was performed to determine whether the device and
reference method results were impacted by moisture—that
is, to determine whether an increase in moisture resulted in
an increase or decrease in the TPH concentrations
measured. For the EnSys Petro Test System, a
semiquantitative device, the effect of moisture was
assessed by qualitatively evaluating the device's TPH
concentration ranges at two different moisture levels.
Primary Objective P5: Time Required for TPH
Measurement
The sample throughput (the number of TPH measurements
per unit of time) was determined for each field
measurement device by measuring the time required for
each activity associated with TPH measurement, including
device setup, sample extraction, sample analysis, and data
package preparation. The EPA provided each developer
with investigative samples stored in coolers. The
developer unpacked the coolers and checked the chain-of-
custody forms to verify that it had received the correct
samples. Time measurement began when the developer
began to set up its device. The total time required to
complete analysis of all investigative samples was
recorded. Analysis was considered to be complete and
time measurement stopped when the developer provided
the EPA with a summary table of results, a run log, and
any supplementary information that the developer chose.
The summary table listed all samples analyzed and their
respective TPH concentrations.
For the reference laboratory, th e total analytical time began
to be measured when the laboratory received all the
investigative samples, and time measurement continued
until the EPA representatives received a complete data
package from the laboratory.
Primary Objective P6: Costs Associated with TPH
Measurement
To estimate the costs associated with TPH measurement
for each field measurement device, the following five cost
categories were identified: capital equipment, supplies,
support equipment, labor, and investigation-derived waste
(EDW) disposal. Chapter 8 of this ITVR discusses the
costs estimated for the EnSys Petro Test System based on
these cost categories.
Table 4-2 summarizes the demonstration approach used to
address the primary objectives and includes demonstration
area characteristics, approximate sampling depth intervals,
and the rationale for the analyses performed by the
reference laboratory.
4.2.2 Approach for Addressing Secondary
Objectives
Secondary objectives were addressed based on field
observations made during the demonstration. Specifically,
EPA representatives observed TPH measurement activities
and documented them in a field logbook. Each developer
was given the opportunity to review the field logbook at
the end of each day of the demonstration. The approach
used to address each secondary objective for each field
measurement device is discussed below.
• The skills and training required for proper device
operation (secondary objective SI) were evaluated by
observing and noting the skills required to operate the
device and prepare the data package and by discussing
necessary user training with developer personnel.
• Health and safety concerns associated with device
operation (secondary objective S2) were evaluated by
observing and noting possible health and safety
concerns during the demonstration, such as the types
of hazardous substances handled by developer
personnel during analysis, the number of times that
hazardous substances were transferred from one
container to another during the analytical procedure,
and direct exposure of developer personnel to
hazardous substances.
• The portability of the device (secondary objective S3)
was evaluated by observing and noting the weight and
size of the device and additional equipment required
29
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Table 4-2. Demonstration Approach
Site
Navy
BVC
Kelly
AFB
PC
Area
FFA
NEX
Service
Station
Area
PRA"
B-38
Area
SFT
Area
Approximate
Sampling Depth
Interval (foot bgs)
Upper \ayef
Lower layer5
7 to 8
8 to 9
9 to 10
10to 11
1.5 to 2.5
23 to 25
25 to 27
2 to 4
4 to 6
6 to 8
8 to 10
Sample Matrix
Ottawa sand
(PE sample)
Processed garden soil (PE sample)
Objective
Addressed1
P2
Objective
Addressed1
P1.P2
P2
Soil Characteristics
Medium-grained sand
Medium-grained sand
Silty sand
Sandy clay or silty sand and
gravel in upper depth interval and
clayey sand and gravel in deeper
depth interval
Silty clay with traces of sand in
deeper depth intervals
Soil Characteristics
Fine-grained sand
Sty sand
Contamination Type
Weathereddiesel with carbon range from
n-C10 through n-C40
Fairly weathered gasoline with carbon range
from n-Ce through n-C,4
Heavy lubricating oil with carbon range from
n-C14 through n-C40
Fresh gasoline and diesel or weathered
gasoline and trace amounts of lubricating oil
with carbon range from n-Q through n-C40
Combination of slightly weathered gasoline,
kerosene, JP-5, and diesel with carbon range
from n-C5 through n-Cj2
Contamination Type
Weathered gasoline
Diesel
Weathered gasoline
Diesel
Typical TPH
Concentration
Range6
Low
High
Low to
medium
Medium to
high
High
Low
High
Low
Medium
Typical TPH
Concentration
range"
Low
Medium and
high
Rationale for Analyses
by Reference Laboratory
Only EDRO because samples did not
contain PHCs in gasoline range
GRO and EDRO because samples
contained PHCs in both gasoline and
diesel ranges
Only EDRO because samples did not
contain PHCs in gasoline range
GRO and EDRO because samples
contained PHCs in both gasoline and
diesel ranges
Rationale for Analyses
by Reference Laboratory
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
U)
o
-------
Table 4-2. Demonstration Approach (Continued)
Sample Matrix
Not applicable (neat liquid PE
sample)
Processed garden soil (PE sample)
Objective
Addressed9
P2
(Continued)
P3
Soil Characteristics
Not applicable
Silty sand
Contamination Type
Weathered gasoline
Diesel
Blank soi(control sample)
Weathered gasoline
Weathered gasoline and MTBE (1,100 mg/kg)
PCE (2,810 mg/kg), Stoddard solvent
(2,900 mg/kg), or turpentine (2,730 mg/kg)
Weathered gasoline and MTBE (1 ,700 mg/kg)
PCE (13,100 mg/kg), Stoddard solvent
(15,400 mg/kg), or turpentine (12,900 mg/kg)
Diesel
Diesel and Stoddard solvent (3,650 mg/kg) or
turpentine (3,850 mg/kg)
Diesel and Stoddard solvent (18,200 mg/kg)
or turpentine (1 9,600 mg/kg)
Diesel and 1 ,2,4-trichlorobenzene
(3,350 mg/kg) or humic acid (3,940 mg/kg)
Diesel and 1 ,2,4-trichlorobenzene
(16,600 mg/kg) or humic acid (19,500 mg/kg)
Humic acid (3,940 mg/kg)
Humic acid (19,500 mg/kg)
Typical TPH
Concentration
range6
High
High
Trace
High
Trace
Rationale for Analyses
by Reference Laboratory
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
GRO and EDRO because processed
garden soil may contain trace
concentrations of PHCs in both gasoline
and diesel ranges
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
GRO and EDRO because (1) Stoddard
solvent contains PHCs in both gasoline
and diesel ranges and (2) turpentine
interferes with both analyses
Only EDRO because 1,2,4-trichloro-
benzene and humic acid do not interfere
with GRO analysis
Oily EDRO because humic acid does
not interfere with GRO analysis
The contribution oftrace concentrations
(less than 15 mg/kg) GRO found in
processed garden soil during the
predemonstration investigation was
considered to be insignificant evaluation
of the effect of humic acid interference,
which occurs in the diesel range.
-------
Table 4-2. Demonstration Approach (Continued)
Sample Matrix
Not applicable (neat liquid PE
sample)
Processed garden soil (PE sample)
Objective
Addressed1
P3
(Continued)
P4
Soil Characteristics
Not applicable
Silty and
Contamination Type
Weathered gasoline
Diesel
MTBE
PCE
Stoddard solvent
Turpentine
1 ,2,4-Trichlorobenzene
Weathered gasoline (samples prepared at
9 and 16 percent moisture levels)
Diesel (samples prepaid at negligible [less
than 1 percent] and 9 percent moisture levels)
Typical TPH
Concentration
rangeb
High
Not
applicable
High
Not
applicable
High
Rationale for Analyses
by Reference Laboratory
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
Only GRO because MTBE and PCE do
not interfere with EDRO analysis
GRO and EDRO because Stoddard
solvent contains PHCs in both gasoline
and diesel ranges
GRO and EDRO because turpentine
interferes with both analyses
Only EDRO because 1 ,2,4-trichloro-
benzene does not interfere with GRO
analysis
GRO and EDRO because weathered
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Only EDRO because diesel does not
contain PHCs in gasoline range
U)
to
Notes:
AFB
bgs
BVC
Air Force Base
Below ground surface
Base Ventura County
FFA = Fuel Farm Area
mg/kg = Milligram per kilogram
MTBE = Methyl-tert-butyl ether
NEX = Naval Exchange
PC = Petroleum company
PCE = Tetrachloroethene
PE = Performance evaluation
PHC = Petroleum hydrocarbon
PRA = Phytoremediation Area
SFT = Slop Fill Tank
Field observations of all sample analysesconducted during the demonstration were u&d to address primary objectives P5 and PGand the secondary objectives.
The typical TPH concentration range was basedbn reference laboratory results for the demonstration. The typical low, mediumand high ranges indicate TPH concentrations of less than
100 mg/kg; 100 to 1,000 mg/kg; and greater than 1,000 mg/kg, respectively.
Because of soil conditions encountered infte FFA during the demonstration, the samplhg depth intervals could not be accurate^ determined. Sample collector was initiated approximately
10 feet bgs, and attempts were made to collect 4-foot-long soil COBS. For each sampling location in the area, the sample core were divided into two samples based on visual observations.
The upper layer of the soil core made up one sample, and the lower layer of the soil core made up the second sample.
SDI chose not to analyze soil samples collected in the PRA becausaccording to SDI, the EnSys Petro Test System was not desiged to measure the heavy lubricating oil present in the
PRA.
Because of problems that arose during prepaation of PE samples with low concentrations of weathered gasoline, the results fothese samples were not used to evaluate the field
measurement devices.
-------
for TPH measurement as well as how easily the device
was set up for use during the demonstration.
• The durability of the device (secondary objective S4)
was evaluated by noting the materials of construction
of the device and additional equipment required for
TPH measurement. In addition, EPA representatives
noted likely device failures or repairs that may be
necessary during extended use of the device.
Downtime required to make device repairs during the
demonstration was also noted.
• The availability of the device and associated spare
parts (secondary objective S5) was evaluated by
discussing the availability of replacement devices with
developer personnel and determining whether spare
parts were available in retail stores or only from the
developer. In addition, the availability of spare parts
required during the demonstration was noted.
Field observations of the analyses of all the samples
described in Table 4-2 were used to address the secondary
objectives for the demonstration.
4.3 Sample Preparation and Management
This section presents sample preparation and management
procedures used during the demonstration. Specifically,
this section describes how samples were collected,
containerized, labeled, stored, and shipped during the
demonstration. Additional details about the sample
preparation and management procedures are presented in
the demonstration plan (EPA 2000).
4.3.1 Sample Preparation
The sample preparation procedures for both environmental
and PE samples are described below.
Environmental Samples
For the demonstration, environmental samples were
collected in the areas that were used for the
predemonstration investigation. For the EnSys Petro Test
System, the sampling areas were (1) FFA and NEX
Service Station Area at the Navy BVC site, (2) B-38 Area
at the Kelly AFB site, and (3) SFT Area at the PC site.
Samples were collected in all areas using a Geoprobe ®.
The liners containing environmental samples were
transported to the sample management trailer at the Navy
BVC site, where the liners were cut open longitudinally.
A geologist then profiled the samples based on soil
characteristics to determine where the soil cores had to be
sectioned. The soil characterization performed for each
demonstration area is summarized in Chapter 3.
Each core sample section was then transferred to a
stainless-steel bowl. The presence of any unrepresentative
material such as sticks, roots, and stones was noted in a
field logbook, and such material was removed to the extent
possible using gloved hands. Any lump of clay in the
sample that was greater than about 1/8 inch in diameter
was crushed between gloved fingers before
homogenization. Each soil sample was homogenized by
stirring it for at least 2 minutes using a stainless-steel
spoon or gloved hands until the sample was visibly
homogeneous. During or immediately following
homogenization, any free water was poured from the
stainless-steel bowl containing the soil sample into a
container designated for IDW. During the demonstration,
the field sampling team used only nitrile gloves to avoid
the possibility of phthalate contamination from handling
samples with plastic gloves. Such contamination had
occurred during the predemonstration investigation.
After sample homogenization, the samples were placed in
(1) EnCores of approximately 5-gram capacity for GRO
analysis; (2) 4-ounce, glass jars provided by the reference
laboratory for EDRO and percent moisture analyses; and
(3) EnCores of approximately 25-gram capacity for TPH
analysis. Using a quartering technique, each sample
container was filled by alternately spooning soil from one
quadrant of the mixing bowl and then from the opposite
quadrant until the container was full. The 4-ounce, glass
jars were filled after all the EnCores for a given sample
had been filled. After a sample container was filled, it was
immediately closed to minimize volatilization of
contaminants. To minimize the time required for sample
homogenization and filling of sample containers, these
activities were simultaneously conducted by four
personnel.
Because of the large number of containers being filled,
some time elapsed between the filling of the first EnCore
and the filling of the last. An attempt was made to
eliminate any bias by alternating between filling EnCores
33
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for the developers and filling EnCores for the reference
laboratory. Table 4-3 summarizes the demonstration
sampling depth intervals, numbers of environmental and
QA/QC samples collected, and numbers of environmental
sample analyses associated with the demonstration of the
EnSys Petro Test System.
Performance Evaluation Samples
All PE samples for the demonstration were prepared by
ERA and shipped to the sample management trailer at the
Navy B VC site. PE samples consisted of both soil samples
and liquid samples. ERA prepared soil PE samples using
two soil matrixes: Ottawa sand and processed garden soil
(silty sand).
To prepare the soil PE samples, ERA spiked the required
volume of soil based on the number of PE samples and the
quantity of soil per PE sample requested. ERA then
Table 4-3. Environmental Samples
homogenized the soil by manually mixing it. ERA used
weathered gasoline or diesel as the spiking material, and
spiking was done at three levels to depict the three TPH
concentration ranges: low, medium, and high. A
low-range sample was spiked to correspond to a TPH
concentration of < 100 mg/kg; a medium-range sample was
spiked to correspond to a TPH concentration range of 100
to 1,000 mg/kg; and a high-range sample was spiked to
correspond to a TPH concentration of more than
1,000 mg/kg. To spike each low- and medium-range soil
sample, ERA used methanol as a "carrier" to distribute the
contaminant evenly throughout the sample. Soil PE
samples were spiked with interferents at two different
levels ranging from 50 to 500 percent of the TPH
concentration expected to be present. Whenever possible,
the interferents were added at levels that best represented
real-world conditions. ERA analyzed the samples
containing weathered gasoline before shipping them to the
Site
Navy
BVC
Kelly
AFB
PC
Area
FFA
NEX
Service
Station
Area
B-38
Area
SFT
Area
Depth
Interval
(foot bgs)
Upper layer
Lower layer
7 to 8
8 to 9
9 to 10
10 to 11
23 to 25
25 to 27
2 to 4
4 to 6
6 to 8
8 to 10
Number of
Sampling
Locations
3
3
3
3
3
3
3
3
5
5
5
5
Total
Total Number of
Samples, Including
Field Triplicates, to
SDI and Reference
Laboratory8
5
5
5
5
5
5
5
3
7
7
7
7
66
Number of
MS/MSD"
Pairs
1
1
1
1
1
1
1
1
1
1
1
1
12
Number of
Extract
Duplicates
1
1
1
1
1
12
Number of
TPH Analyses
by SDI
6
6
6
6
6
6
6
4
8
8
8
8
78
Number of Analyses
by Reference
Laboratory0
GRO
0
0
8
8
8
8
8
6
10
10
10
10
86
EDRO
8
8
8
8
8
8
8
6
10
10
10
10
102
Notes:
AFB = Air Force Base
bgs = Below ground surface
BVC = Base Ventura County
FFA = Fuel Farm Area PC =
MS/MSD = Matrix spike and matrix spike duplicate SFT =
NEX = Naval Exchange
Petroleum company
Slop Fill Tank
Field triplicates were collected at a frequency of one per depth interval in each sampling area except the B-38 Area. Because of conditions in the
B-38 Area, triplicates were collected in the top depth interval only. Three separate, blind samples were prepared for each field triplicate.
MS/MSD samples were collected at a frequency of one per depth interval in each sampling area for analysis by the reference laboratory. MS/MSD
samples were not analyzed by SDI.
All environmental samples were also analyzed for moisture content by the reference laboratory.
34
-------
Navy BVC site. The analytical results were used to
confirm sample concentrations.
Liquid PE samples consisted of neat materials. Each liquid
PE sample consisted of approximately 2 mL of liquid in a
flame-sealed, glass ampule. During the demonstration, the
developers and reference laboratory were given a table
informing them of the amount of liquid sample to be used
for analysis.
ERA grouped like PE samples together in a resealable bag
and placed all the PE samples in a cooler containing ice for
overnight shipment to the Navy BVC site. When the PE
samples arrived at the site, the samples were labeled with
the appropriate sample identification numbers and placed
in appropriate coolers for transfer to the developers on site
or for shipment to the reference laboratory as summarized
in Section 4.3.2. Table 4-4 summarizes the contaminant
types and concentration ranges as well as the numbers of
PE samples and analyses associated with the demonstration
of the EnSys Petro Test System.
4.3.2 Sample Management
Following sample containerization, each environmental
sample was assigned a unique sample designation defining
the sampling area, expected type of contamination,
expected concentration range, sampling location, sample
number, and QC identification, as appropriate. Each
sample container was labeled with the unique sample
designation, date, time, preservative, initials of personnel
who had filled the container, and analysis to be performed.
Each PE sample was also assigned a unique sample
designation that identified it as a PE sample. Each PE
sample designation also identified the expected
contaminant type and range, whether the sample was soil
or liquid, and the sample number.
Sample custody began when samples were placed in iced
coolers in the possession of the designated field sample
custodian. Demonstration samples were divided into two
groups to allow adequate time for the developers and
reference laboratory to extract and analyze samples within
the method-specified holding times presented in Table 4-5.
The two groups of samples for reference laboratory
analysis were placed in coolers containing ice and chain-
of-custody forms and were sh ipped by overnight courier to
the reference laboratory on the first and third days of the
demonstration. The two groups of samples for developer
analysis were placed in coolers containing ice and chain-
of-custody forms and were hand-delivered to the
developers at the Navy BVC site on the same days that the
reference laboratory received its two groups of samples.
During the demonstration, each developer was provided
with a tent to provide shelter from direct sunlight during
analysis of demonstration samples. In addition, at the end
of each day, the developer placed any samples or sample
extracts in its custody in coolers, and the coolers were
stored in a refrigerated truck.
35
-------
Table 4-4. Performance Evaluation Samples
Sample Type
Typical TPH
Concentration
Range8
Total Number of
Samples to SDI
and Reference
Laboratory
Number of
MS/MSD"
Pairs
Number of
Analyses by
SDI
Number of
Analyses by Reference
Laboratory0
GRO
EDRO
Soil Samples (Ottawa Sand) , - " .'••'/'" -,;,,/ - •,-'"-,' ' ' -'•
Weathered gasoline
Diesel
Low
7
7
0
0
7
7
7
0
7
7
Soil Samples (Processed Garden Soil) • ,, ;", ,,X;;;; " ,Y'-
-------
Table 4-4. Performance Evaluation Samples (Continued)
Sample Type
Typical TPH
Concentration
Range'
Total Number of
Samples to SDI
and Reference
Laboratory
Number of
MS/MSD"
Pairs
Number of
Analyses by
SDI
Number of
Analyses by Reference
Laboratory0
GRO
EDRO
Liquid Samples (Neat Material) {Continued} „. , 7 -, •>'• .*•
PCE
Stoddard solvent
Turpentine
1 ,2,4-Trichlorobenzene
Not applicable
High
Not applicable
Total
6
6
6
6
125
0
0
0
0
6
6
6
6
6
125
6
6
6
0
90
0
6
6
6
125
Notes:
mg/kg = Milligram per kilogram
MS/MSD = Matrix spike and matrix spike duplicate
MTBE =
PCE =
Methyl-tert-butyl ether
Tetrachloroethene
The typical TPH concentration range was based on reference laboratory results for the demonstration. The typical low, medium, and high ranges
indicate TPH concentrations of less than 100 mg/kg; 100 to 1,000 mg/kg; and greater than 1,000 mg/kg, respectively. The typical TPH
concentration range for the liquid sample concentrations was based on the definition of TPH used for the demonstration and knowledge of the
sample (neat material).
MS/MSD samples were analyzed only by the reference laboratory.
All soil performance evaluation samples were also analyzed for moisture content by the reference laboratory.
-------
Table 4-5. Sample Container, Preservation, and Holding Time Requirements
Parameter0
GRO
EDRO
Percent moisture
TPH
GRO and EDRO
Medium
Soil
Soil
Soil
Soil
Liquid
Container
Two 5-gram EnCores
Two 4-ounce, glass jars with Teflon™-lined lids
Two 4-ounce, glass jars with Teflon™-lined lids
One 25-gram EnCore
One 2-milliliter ampule for each analysis
Preservation
4±2°C
4±2°C
4±2°C
4±2"C
Not applicable
Holding Time (days)
Extraction Analysis
2" 14
14" 40
Not applicable 7
Performed on site0
See note d
Notes:
± = Plus or minus
" The reference laboratory measured percent moisture using part of the soil sample from the container designated for EDRO analysis.
b The extraction holding time started on the day that samples were shipped.
° If GRO analysis of a sample was to be completed by the reference laboratory, the developers completed on-site extraction of the corresponding
sample within 2 days. Otherwise, all on-site extractions and analyses were completed within 7 days.
d The reference laboratory cracked open each ampule and immediately added the specified aliquot of the sample to methanol for GRO analysis
and to methylene chloride for EDRO analysis. This procedure was performed in such a way that the final volumes of the extracts for GRO and
EDRO analyses were 5.0 milliliters and 1.0 milliliter, respectively. Once the extracts were prepared, the GRO and EDRO analyses were performed
within 14 and 40 days, respectively.
38
-------
Chapter 5
Confirmatory Process
The performance results for each field measurement
device were compared to those for an off-site laboratory
measurement method—that is, a reference method. This
chapter describes the rationale for the selection of the
reference method (Section 5.1) and reference laboratory
(Section 5.2) and summarizes project-specific sample
preparation and analysis procedures associated with the
reference method (Section 5.3).
5.1 Reference Method Selection
During the demonstration, environmental and PE samples
were analyzed for TPH by the reference laboratory using
SW-846 Method 8015B (modified). This section
describes the analytical methods considered for the
demonstration and provides a rationale for the reference
method selected.
The reference method used was selected based on the
following criteria:
• It is not a field screening method.
• It is widely used and accepted.
It measures light (gasoline) to heavy (lubricating oil)
fuel types.
• It can provide separate measurements of GRO and
EDRO fractions of TPH.
• It meets project-specific reporting limit requirements.
The analytical methods considered for the demonstration
and the reference method selected based on the above-
listed criteria are illustrated in a flow diagram in
Figure 5-1. The reference method selection process is
discussed below.
Analytical methods considered for the demonstration were
identified based on a review of SW-846, "Methods for
Chemical Analysis of Water and Wastes" (MCAWW),
ASTM, API, and state-specific methods. The analytical
methods considered collectively represent six different
measurement technologies. Of the methods reviewed,
those identified as field screening methods, such as
SW-846 Method 4030, were eliminated from further
consideration in the reference method selection process.
A literature review was conducted to determine whether
the remaining methods are widely used and accepted in the
United States (Association for Environmental Health and
Sciences [AEHS] 1999). As a result of this review, state-
specific methods such as the Massachusetts Extractable
Petroleum Hydrocarbon (EPH) and Volatile Petroleum
Hydrocarbon (VPH) Methods (Massachusetts Department
of Environmental Protection 2000), the Florida Petroleum
Range Organic (PRO) Method (Florida Department of
Environmental Protection 1996), and Texas Method 1005
(Texas Natural Resource Conservation Commission 2000)
were eliminated from the selection process. Also
eliminated were the gravimetric and infrared methods
except for MCAWW Method 418.1 (EPA 1983). The use
and acceptability of MCAWW Method 418.1 will likely
decline because the extraction solvent used in this method
is Freon 113, a chlorofluorocarbon (CFC), and use of
CFCs will eventually be phased out under the Montreal
Protocol. However, because several states still accept the
use of MCAWW Method 418.1 for measuring TPH, the
method was retained for further consideration in the
selection process (AEHS 1999).
39
-------
Analytical methods considered (technology)
ASTM Method D 5831-96
(ultraviolet spectrophotometry)
State-specific methods such as
Massachusetts EPH and VPH Methods,
Florida PRO Method, and Texas Method
1005(GC/FID)
MCAWW Method 413.1
(gravimetric)
MCAWW Method 413.2
(infrared)
MCAWW Method 418.1
(infrared)
API PHC Method
(GC/FID)
SW-846 Method 4030
(immunoassay and colorimetry)
SW-846 Method 801 SB
(GC/FID)
SW-846 Method 8440
(infrared)
SW-846 Method 9071
(gravimetric)
SW-846 Method 9074
(emulsion turbidimetry)
Reference method selected
State-specific methods
MCAWW Method 413.1
MCAWW Method 413.2
SW-846 Method 8440
SW-846 Method 9071
No
Measures light
(gasoline) to heavy
(lubricating oil)
fuel types?
SW-846 Method 8015B (modified)
Yes
Yes->
MCAWW Method 41 8.1
API PHC Method
SW-846 Method 801 5B
^
r
Yes—»
MCAWW Method 418.1
API PHC Method
SW-846 Method 8015B
Meets
project-specific reporting limit
requirements?
State-specific methods
MCAWW Method 413.1
MCAWW Method 413.2
MCAWW Method 418.1
API PHC Method
SW-846 Method 8015B
SW-846 Method 8440
SW-846 Method 9071
Considered a field
screening method?
Yes—>
Provides
separate measurements
of GRO and EDRO
fractions of TPH?
MCAWW Method 418.1
API PHC Method
ASTM Method D 5831-96
SW-846 Method 4030
SW-846 Method 9074
reference method
Notes:
API = American Petroleum Institute, ASTM =American Society for Testing and MaterialspRO = diesel range organics, EPH = extrxtable petroleum hydrocarbon, GC/FID = gas chromatograph/flame
ionization detector, MCAWW = "Methods for Chemical Analysis of Water and Wastes," PHC = petroleum hydrocarbon, PRO = petroleurrange organics, SW-846 = "Test Methods for Evaluating
Solid Waste," VPH = volatile petroleum hydrocarbon
* SW-846 Method 8015B provides separateGRO and DRO measurements and, when modified,can also provide EDRO measurements.
Figure 5-1. Reference method selection process.
-------
Of the remaining methods, MCAWW Method 418.1, the
API PHC Method, and SW-846 Method 8015B can all
measure light (gasoline) to heavy (lubricating oil) fuel
types. However, GRO and EDRO fractions cannot be
measured separately using MCAWW Method 418.1. As
a result, this method was eliminated from the selection
process.
Both the API PHC Method and SW-846 Method 8015B
can be used to separately measure the GRO and DRO
fractions of TPH. These methods can also be modified to
extend the DRO range to EDRO by using a calibration
standard that includes even-numbered alkanes in the
EDRO range.
Based on a review of state-specific action levels for TPH,
a TPH reporting limit of 10 mg/kg was used for the
demonstration. Because the TPH reporting limit for the
API PHC Method (50 to 100 mg/kg) is >10 mg/kg, this
method was eliminated from the selection process (API
1994). SW-846 Method 8015B (modified) met the
reporting limit requirements for the demonstration. For
GRO, SW-846 Method 8015B (modified) has a reporting
limit of 5 mg/kg, and for EDRO, this method has a
reporting limit of 10 mg/kg. Therefore, SW-846
Method 8015B (modified) satisfied all the criteria
established for selecting the reference method. As an
added benefit, because this is a GC method, it also
provides a fingerprint (chromatogram) of TPH
components.
5.2 Reference Laboratory Selection
This section provides the rationale for the selection of the
reference laboratory. STL Tampa East was selected as the
reference laboratory because it (1) has been performing
TPH analyses for many years, (2) has passed many
external audits by successfully implementing a variety of
TPH analytical methods, and (3) agreed to implement
project-specific analytical requirements. In January 2000,
a project-specific audit of the laboratory was conducted
and determined that STL Tampa East satisfactorily
implemented the reference method during the
predemonstration investigation. In addition, STL Tampa
East successfully analyzed double-blind PE samples and
blind field triplicates for GRO and EDRO during the
predemonstration investigation. Furthermore, in 1998
STL Tampa East was one of four recipients and in 1999
was one of six recipients of the Seal of Excellence Award
issued by the American Council of Independent
Laboratories. In each instance, this award was issued
based on the results of PE sample analyses and client
satisfaction surveys. Thus, the selection of the reference
laboratory was based primarily on performance and not
cost.
5.3 Summary of Reference Method
The laboratory sample preparation and analytical methods
used for the demonstration are summarized in Table 5-1.
The SW-846 methods listed in Table 5-1 for GRO and
EDRO analyses were tailored to meet the definition of
TPH for the project (see Chapter 1). Project-specific
procedures for soil sample preparation and analysis for
GRO and EDRO are summarized in Tables 5-2 and 5-3,
respectively. Project-specific procedures were applied
(1) if a method used offered choices (for example, SW-846
Method 5035 for GRO extraction states that samples may
be collected with or without use of a preservative solution),
(2) if a method used did not provide specific details (for
example, SW-846 Method 5035 for GRO extraction does
not specify how unrepresentative material should be
handled during sample preparation), or (3) if a
modification to a method used was required in order to
meet demonstration objectives (for example, SW-846
Method 801 SB for EDRO analysis states that quantitation
is performed by summing the areas of all chromatographic
peaks eluting between the end of the
1,2,4-trimethylbenzene or n-C10 peak, whichever occurs
later, and the n-octacosane peak; however, an additional
quantitation was performed to sum the areas of all
chromatographic peaks eluting from the end of the
n-octacosane peak through the tetracontane peak in order
to meet demonstration objectives).
Before analyzing a liquid PE sample, STL Tampa East
added an aliquot of the liquid PE sample to the extraction
solvent used for soil samples. A specified aliquot of the
liquid PE sample was diluted in methanol for GRO
analysis and in methylene chloride for EDRO analysis
such that the final volume of the solution for GRO and
EDRO analyses was 5.0 and 1.0 mL, respectively. The
solution was then analyzed for GRO and EDRO using the
same procedures as are used for soil sample extracts.
41
-------
Table 5-1. Laboratory Sample Preparation and Analytical Methods
Parameter
Method Reference (Step)
Method Title
GRO
EDRO
Based on SW-846 Method 5035 (extraction)
Based on SW-846 Method 5030B (purge-and-trap)
Based on SW-846 Method 8015B (analysis)
Based on SW-846 Method 3540C (extraction)
Based on SW-846 Method 801 SB (analysis)
Percent moisture Based on MCAWW Method 160.3°
Closed-System Purge-and-Trap and Extraction for Volatile Organics
in Soil and Waste Samples
Purge-and-Trap for Aqueous Samples
Nonhalogenated Volatile Organics by Gas Chromatography
Soxhlet Extraction
Nonhalogenated Volatile Organics by Gas Chromatography
Residue, Total (Gravimetric, Dried at 103-105 °C)
Notes:
MCAWW = "Methods for Chemical Analysis of Water and Wastes"
SW-846 = "Test Methods for Evaluating Solid Waste"
° MCAWW Method 160.3 was modified to include calculation and reporting of percent moisture in soil samples.
42
-------
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis
SW-846 Method Reference (Step)
Project-Specific Procedures
5035 (Extraction)
Low-level (0.5 to 200 micrograms per kilogram) or high-level (greater
than 200 micrograms per kilogram) samples may be prepared.
Samples may be collected with or without use of a preservative
solution.
A variety of sample containers, including EnCores, may be used when
high-level samples are collected without use of a preservative.
Samples collected in EnCores should be transferred to vials containing
the extraction solvent as soon as possible or analyzed within 48 hours.
For samples not preserved in the field, a solubility test should be
performed using methanol, polyethylene glycol, and hexadecane to
determine an appropriate extraction solvent.
Removal of unrepresentative material from the sample is not discussed.
Procedures for adding surrogates to the sample are inconsistently
presented. Section 2.2.1 indicates that surrogates should be added to
an aliquot of the extract solution. Section 7.3.3 indicates that soil
should be added to a vial containing both the extraction solvent
(methanol) and surrogate spiking solution.
Nine ml of methanol should be added to a 5-gram (wet weight) soil
sample.
When practical, the sample should be dispersed to allow contact with
the methanol by shaking or using other mechanical means for 2 min
without opening the sample container. When shaking is not practical,
the sample should be dispersed with a narrow, metal spatula, and the
sample container should be immediately resealed.
Because the project-specific reporting limit for GRO was 5 milligrams
per kilogram, all samples analyzed for GRO were prepared using
procedures for high-level samples.
Samples were collected without use of a preservative.
Samples were containerized in EnCores.
Samples were weighed and extracted within 2 calendar days of their
shipment. The holding time for analysis was 14 days after extraction. A
full set of quality control samples (method blanks, MS/MSDs, and
LCS/LCSDs) was prepared within this time.
Because the reference laboratory obtained acceptable results for
performance evaluation samples extracted with methanol during the
predemonstration investigation, samples were extracted with methanol.
During sample homogenization, field sampling technicians attempted to
remove unrepresentative material such as sticks, roots, and stones if
present in the sample; the reference laboratory did not remove any
remaining unrepresentative material.
The soil sample was ejected into a volatile organic analysis vial, an
appropriate amount of surrogate solution was added to the sample, and
then methanol was quickly added.
Five ml of methanol was added to the entire soil sample contained in a
5-gram EnCore.
The sample was dispersed using a stainless-steel spatula to allow
contact with the methanol. The volatile organic analysis vial was then
capped and shaken vigorously until the soil was dispersed in methanol,
and the soil was allowed to settle.
5030B (Purge-and-Trap) . ,,.,,,., „„,,,,.,,':• s!S ,,
Screening of samples before the purge-and-trap procedure is
recommended using one of the two following techniques:
Use of an automated headspace sampler (see SW-846 Method 5021)
connected to a GC equipped with a photoionization detector in series
with an electrolytic conductivity detector
Extraction of the samples with hexadecane (see SW-846 Method 3820)
and analysis of the extracts using a GC equipped with a flame
ionization detector or electron capture detector
SW-846 Method 5030B indicates that contamination by carryover can
occur whenever high-level and low-level samples are analyzed in
sequence. Where practical, analysis of samples with unusually high
concentrations of analytes should be followed by an analysis of
organic-free reagent water to check for cross-contamination. Because
the trap and other parts of the system are subject to contamination,
frequent bake-out and purging of the entire system may be required.
Samples were screened with an automated headspace sampler (see
SW-846 Method 5021) connected to a GC equipped with a flame
ionization detector.
According to the reference laboratory, a sample extract concentration
equivalent to 1 0,000 ng on-column is the minimum concentration of
GRO that could result in carryover. Therefore, if a sample extract had
a concentration that exceeded the minimum concentration for
carryover, the next sample in the sequence was evaluated as follows:
(1) if the sample was clean (had no chromatographic peaks), no
carryover had occurred; (2) if the sample had detectable analyte
concentrations (chromatographic peaks), it was reanalyzed under
conditions in which carryover did not occur.
43
-------
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
5030B (Purge-and-Trap) (Continued)
The sample purge device used must demonstrate adequate
performance.
Purge-and-trap conditions for high-level samples are not clearly
specified. According to SW-846, manufacturer recommendations for
the purge-and-trap devices should be considered when the method is
implemented. The following general purge-and-trap conditions are
recommended for samples that are water-miscible (methanol extract):
Purge gas: nitrogen or helium
Purge gas flow rate: 20 mL/min
Purge time: 15 ± 0.1 min
Purge temperature: 85 ± 2 "C
Desorb time: 1 .5 min
Desorb temperature: 1 80 "C
Backflush inert gas flow rate: 20 to 60 mL/min
Bake time: not specified
Bake temperature: not specified
Multiport valve and transfer line temperatures: not specified
A Tekmar 2016 autosampler and a Tekmar LSC 2000 concentrator
were used. Based on quality control sample results, the reference
laboratory had demonstrated adequate performance using these
devices.
The purge-and-trap conditions that were used are listed below. These
conditions were based on manufacturer recommendations for the purge
device specified above and the VOCARB 3000 trap.
Purge gas: helium
Purge gas flow rate: 35 mL/min
Purge time: 8 min with 2-min dry purge
Purge temperature: ambient temperature
Desorb time: 1 min
Desorb temperature: 250 °C
Backflush inert gas flow rate: 35 mL/min
Bake time: 7 min
Bake temperature: 270 °C
Multiport valve and transfer line temperatures: 1 1 5 and 1 20 °C
801 SB (Analysis)
GC Conditions
The following GC conditions are recommended:
Column: 30-meter x 0.53-millimeter-inside diameter, fused-silica
capillary column chemically bonded with 5 percent methyl
silicone, 1 .5-micrometer field thickness
Carrier gas: helium
Carrier gas flow rate: 5 to 7 mL/min
Makeup gas: helium
Makeup gas flow rate: 30 mL/min
Injector temperature: 200 °C
Detector temperature: 340 °C
Temperature program:
Initial temperature: 45 "C
Hold time: 1 min
Program rate: 45 to 1 00 °C at 5 °C/min
Program rate: 100 to 275 °C at 8 °C/min
Hold time: 5 min
Overall time: 38.9 min
The HP 5890 Series II was used as the GC. The following GC
conditions were used based on manufacturer recommendations:
Column: 30-meter x 0.53-millimeter-inside diameter, fused-silica
capillary column chemically bonded with 5 percent methyl
silicone, 1. 5-micrometer field thickness
Carrier gas: helium
Carrier gas flow rate: 15 mL/min
Makeup gas: helium
Makeup gas flow rate: 15 mL/min
Injector temperature: 200 °C
Detector temperature: 200 °C
Temperature program:
Initial temperature: 25 °C
Hold time: 3 min
Program rate: 25 to 120 °C at 25 °C/min
Hold time: 4 min
Program rate: 120 to 245 °C at 25 °C/min
Hold time: 5 min
Overall time: 20.4 min
Calibration
The chromatographic system may be calibrated using either internal or
external standards.
Calibration should be performed using samples of the specific fuel type
contaminating the site. When such samples are not available, recently
purchased, commercially available fuel should be used.
The chromatographic system was calibrated using external standards
with a concentration range equivalent to 100 to 10,000 ng on-column.
The reference laboratory acceptance criterion for initial calibration was a
relative standard deviation less than or equal to 20 percent of the
average response factor or a correlation coefficient for the
least-squares linear regression greater than or equal to 0.990.
Calibration was performed using a commercially available,
10-component GRO standard that contained 35 percent aliphatic
hydrocarbons and 65 percent aromatic hydrocarbons.
44
-------
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
801 5B (Analysis) (Continued)
Calibration (Continued)
Initial calibration verification is not required.
CCV should be performed at the beginning of every 12-hour work shift
and at the end of an analytical sequence. CCV throughout the 12-hour
shift is also recommended; however, the frequency is not specified.
CCV should be performed using a fuel standard.
According to SW-846 Method 8000, CCV should be performed at the
same concentration as the midpoint concentration of the initial
calibration curve; however, the concentration of each calibration point is
not specified.
A method sensitivity check is not required.
Initial calibration verification was performed using a second-source
standard that contained a 10-component GRO standard made up of
35 percent aliphatic hydrocarbons and 65 percent aromatic
hydrocarbons at a concentration equivalent to 2,000 ng on-column. The
reference laboratory acceptance criterion for initial calibration
verification was an instrument response within 25 percent of the
response obtained during initial calibration.
CCV was performed at the beginning of each analytical batch, after
every tenth analysis, and at the end of the analytical batch. The
reference laboratory acceptance criteria for CCV were instrument
responses within 25 percent (for the closing CCV) and 1 5 percent
(for all other CCVs) of the response obtained during initial calibration.
CCV was performed using a commercially available, 10-component
GRO standard that contained 35 percent aliphatic hydrocarbons and
65 percent aromatic hydrocarbons.
CCV was performed at a concentration equivalent to 2,000 ng
on-column.
A method sensitivity check was performed daily using a calibration
standard with a concentration equivalent to 100 ng on-column. The
reference laboratory acceptance criterion for the method sensitivity
check was detection of the standard.
Retention Time Windows
The retention time range (window) should be established using
2-methylpentane and 1 ,2,4-trimethylbenzene during initial calibration.
Three measurements should be made over a 72-hour period; the results
should be used to determine the average retention time. As a minimum
requirement, the retention time should be verified using a midlevel
calibration standard at the beginning of each 12-hour shift. Additional
analysis of the standard throughout the 12-hour shift is strongly
recommended.
The retention time range was established using the opening CCV
specific to each analytical batch. The first eluter, 2-methylpentane, and
the last eluter, 1 ,2,4-trimethylbenzene, of the GRO standard were used
to establish each day's retention time range.
Quantitation
Quantitation is performed by summing the areas of all chromatographic
peaks eluting within the retention time range established using
2-methylpentane and 1 ,2,4-trimethylbenzene. Subtraction of the
baseline rise for the method blank resulting from column bleed is
generally not required.
Quantitation was performed by summing the areas of all
chromatographic peaks from 2-methylpentane through
1 ,2,4-trimethylbenzene. This range includes n-C,0. Baseline rise
subtraction was not performed.
Quality Control
Spiking compounds for MS/MSDs and LCSs are not specified.
According to SW-846 Method 8000, spiking levels for MS/MSDs are
determined differently for compliance and noncompliance monitoring
applications. For noncompliance applications, the laboratory may spike
the sample (1) at the same concentration as the reference sample
(LCS), (2) at 20 times the estimated quantitation limit for the matrix of
interest, or (3) at a concentration near the middle of the calibration
range.
The spiking compound. mixture for MS/MSDs and LCSs was the
10-component GRO calibration standard.
MS/MSD spiking levels were targeted to be between 50 and
150 percent of the unspiked sample concentration. The reference
laboratory used historical information to adjust spike amounts or to
adjust sample amounts to a preset spike amount. The spiked samples
and unspiked samples were prepared such that the sample mass and
extract volume used for analysis were the same.
45
-------
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
801 SB (Analysis) (Continued)
Quality Control (Continued)
According to SW-846 Method 8000, in-house laboratory acceptance
criteria for MS/MSDs and LCSs should be established. As a general
rule, the recoveries of most compounds spiked into a sample should fall
within the range of 70 to 130 percent, and this range should be used as
a guide in evaluating in-house performance.
The LCS should consist of an aliquot of a clean (control) matrix that is
similar to the sample matrix.
No LCSD is required.
The surrogate compound and spiking concentration are not specified.
According to SW-846 Method 8000, in-house laboratory acceptance
criteria for surrogate recoveries should be established.
The method blank matrix is not specified.
The extract duplicate is not specified.
The reference laboratory acceptance criteria for MS/MSDs and LCSs
were a relative percent difference less than or equal to 25 with 33 to
1 1 5 percent recovery. The acceptance criteria were based on
laboratory historical information. These acceptance criteria are similar
to those of the methods cited in Figure 5-1 .
The LCS/LCSD matrix was Ottawa sand.
The spiking compound mixture for LCSDs was the 10-component GRO
calibration standard.
The surrogate compound was 4-bromofluorobenzene. The reference
laboratory acceptance criterion for surrogates was 39 to 163 percent
recovery.
The method blank matrix was Ottawa sand. The reference laboratory
acceptance criterion for the method blank was less than or equal to the
project-specific reporting limit.
The extract duplicate was analyzed. The reference laboratory
acceptance criterion for the extract duplicate was a relative percent
difference less than or equal to 25.
Notes:
±
ccv
GC
LCS
LCSD
Plus or minus
Continuing calibration verification
Gas chromatograph
Laboratory control sample
Laboratory control sample duplicate
min = Minute
ml = Milliliter
MS = Matrix spike
MSD = Matrix spike duplicate
ng = Nanogram
SW-846 = Test Methods for Evaluating Solid Waste"
46
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Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis
SW-846 Method Reference (Step)
Project-Specific Procedures
3540C (Extraction), ' " ' "*', " " ' \" * , A- ' •' * ^,
Any free water present in the sample should be decanted and
discarded. The sample should then be thoroughly mixed, and any
unrepresentative material such as sticks, roots, and stones should be
discarded.
Ten grams of soil sample should be blended with 10 grams of
anhydrous sodium sulfate.
Extraction should be performed using 300 mL of extraction solvent.
Acetone and hexane (1:1 volume per volume) or methylene chloride
and acetone (1 :1 volume per volume) may be used as the extraction
solvent.
Note: Methylene chloride and acetone are not constant-boiling
solvents and thus are not suitable for the method. Methylene
chloride was used as an extraction solvent for method
validation.
The micro Snyder column technique or nitrogen blowdown technique
may be used to adjust (concentrate) the soil extract to the required final
volume.
Procedures for addressing contamination carryover are not specified.
During sample homogenization, field sampling technicians attempted to
remove unrepresentative material such as sticks, roots, and stones. In
addition, the field sampling technicians decanted any free water present
in the sample. The reference laboratory did not decant water or remove
any unrepresentative material from the sample. The reference
laboratory mixed the sample with a stainless-steel tongue depressor.
Thirty grams of sample was blended with at least 30 grams of
anhydrous sodium sulfate. For medium- and high-level samples, 6 and
2 grams of soil were used for extraction, respectively, and proportionate
amounts of anhydrous sodium sulfate were added. The amount of
anhydrous sodium sulfate used was not measured gravimetrically but
was sufficient to ensure that free moisture was effectively removed from
the sample.
Extraction was performed using 200 ml of extraction solvent.
Methylene chloride was used as the extraction solvent.
Kuderna Danish and nitrogen evaporation were used as the
concentration techniques.
According to the reference laboratory, a sample extract concentration of
100,000 micrograms per mL is the minimum concentration of EDRO
that could result in carryover. Therefore, if a sample extract had a
concentration that exceeded the minimum concentration for carryover,
the next sample in the sequence was evaluated as follows: (1 ) if the
sample was clean (had no chromatographic peaks), no carryover
occurred; (2) if the sample had detectable analyte concentrations
(chromatographic peaks), it was reanalyzed under conditions in which
carryover did not occur.
801 5B (Analysis) , , »
GC Conditions
The following GC conditions are recommended:
Column: 30-meter x 0.53-millimeter-inside diameter, fused-silica
capillary column chemically bonded with 5 percent methyl
silicone, 1 .5-micrometer field thickness
Carrier gas: helium
Carrier gas flow rate: 5 to 7 mL/min
Makeup gas: helium
Makeup gas flow rate: 30 mL/min
Injector temperature: 200 °C
Detector temperature: 340 °C
Temperature program:
Initial temperature: 45 °C
Hold time: 3 min
Program rate: 45 to 275 °C at 12 "C/min
Hold time: 12 min
Overall time: 34.2 min
An HP 6890 GC was used with the following conditions:
Column: 30-meter x 0.53-millimeter-inside diameter, fused-silica
capillary column chemically bonded with 5 percent methyl
silicone, 1 .5-micrometer field thickness
Carrier gas: hydrogen
Carrier gas flow rate: 1 .9 mL/min
Makeup gas: hydrogen
Makeup gas flow rate: 23 mL/min
Injector temperature: 250 °C
Detector temperature: 345 °C
Temperature program:
Initial temperature: 40 °C
Hold time: 2 min
Program rate: 40 to 345 °C at 30 "C/min
Hold time: 5 min
Overall time: 17.2 min
47
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Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
801 5B( Analysis) (Continued)
Calibration
The chromatographic system may be calibrated using either internal or
external standards.
Calibration should be performed using samples of the specific fuel type
contaminating the site. When such samples are not available, recently
purchased, commercially available fuel should be used.
ICV is not required.
CCV should be performed at the beginning of every 12-hour work shift
and at the end of an analytical sequence. CCV throughout the 12-hour
shift is also recommended; however, the frequency is not specified.
CCV should be performed using a fuel standard.
According to SW-846 Method 8000, CCV should be performed at the
same concentration as the midpoint concentration of the initial
calibration curve; however, the concentration of each calibration point is
not specified.
A method sensitivity check is not required.
The chromatographic system was calibrated using external standards
with a concentration range equivalent to 75 to 7,500 ng on-column. The
reference laboratory acceptance criterion for initial calibration was a
relative standard deviation less than or equal to 20 percent of the
average response factor or a correlation coefficient for the least-
squares linear regression greater than or equal to 0.990.
Calibration was performed using a commercially available standard that
contained even-numbered alkanes from C10 through C,0.
ICV was performed using a second-source standard that contained
even-numbered alkanes from C10 through C40 at a concentration
equivalent to 3,750 ng on-column. The reference laboratory
acceptance criterion for ICV was an instrument response within
25 percent of the response obtained during initial calibration.
CCV was performed at the beginning of each analytical batch, after
every tenth analysis, and at the end of the analytical batch. The
reference laboratory acceptance criteria for CCV were instrument
responses within 25 percent (for the closing CCV) and 15 percent
(for all other CCVs) of the response obtained during initial calibration.
CCV was performed using a standard that contained only
even-numbered alkanes from C,0 through Cia
CCV was performed at a concentration equivalent to 3,750 ng
on-column.
A method sensitivity check was performed daily using a calibration
standard with a concentration equivalent to 75 ng on-column. The
reference laboratory acceptance criterion for the method sensitivity
check was detection of the standard.
Retention Time Windows
The retention time range (window) should be established using
C,0 and C28 alkanes during initial calibration. Three measurements
should be made over a 72-hour period; the results should be used to
determine the average retention time. As a minimum requirement, the
retention time should be verified using a midlevel calibration standard at
the beginning of each 1 2-hour shift. Additional analysis of the standard
throughout the 12-hour shift is strongly recommended.
Two retention time ranges were established using the opening CCV for
each analytical batch. The first range, which was labeled diesel range
organics, was marked by the end of the 1 ,2,4-trimethylbenzene or n-C,0
peak, whichever occurred later, through the n-octacosane peak. The
second range, which was labeled oil range organics, was marked by the
end of the n-octacosane peak through the tetracontane peak.
Quantitation
Quantitation is performed by summing the areas of all chromatographic
peaks eluting between n-C,0 and n-octacosane.
Quantitation was performed by summing the areas of all
chromatographic peaks from the end of the 1 ,2,4-trimethylbenzene or
n-C,0 peak, whichever occurred later, through the n-octacosane peak.
A separate quantitation was also performed to sum the areas of all
chromatographic peaks from the end of the n-octacosane peak through
the tetracontane peak. Separate average response factors for the
carbon ranges were used for quantitation. The quantitation results were
then summed to determine the total EDRO concentration.
All calibrations, ICVs, CCVs, and associated batch quality control
measures were controlled for the entire EDRO range using a single
quantitation performed over the entire EDRO range.
48
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Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
801 SB (Analysis) (Continued)
Quantitation (Continued)
Subtraction of the baseline rise for the method blank resulting from
column bleed Is appropriate.
Because phthalate esters contaminate many types of products
commonly found in the laboratory, consistent quality control should be
practiced.
The reference laboratory identified occurrences of baseline rise in the
data package. The baseline rise was evaluated during data validation
and subtracted when appropriate based on analyst discretion.
Phthalate peaks were not noted during analysis.
Quality Control
Spiking compounds for MS/MSDs and LCSs are not specified.
According to SW-846 Method 8000, spiking levels for MS/MSDs are
determined differently for compliance and noncompliance monitoring
applications. For noncompliance applications, the laboratory may spike
the sample (1) at the same concentration as the reference sample
(LCS), (2) at 20 times the estimated quantitation limit for the matrix of
interest, or (3) at a concentration near the middle of the calibration
range.
According to SW-846 Method 8000, in-house laboratory acceptance
criteria for MS/MSDs and LCSs should be established. As a general
rule, the recoveries of most compounds spiked into a sample should fall
within the range of 70 to 130 percent, and this range should be used as
a guide in evaluating in-house performance.
The LCS should consist of an aliquot of a clean (control) matrix that is
similar to the sample matrix.
No LCSD is required.
The surrogate compound and spiking concentration are not specified.
According to SW-846 Method 8000, in-house laboratory acceptance
criteria for surrogate recoveries should be established.
The method blank matrix is not specified.
The extract duplicate is not specified.
The spiking compound for MS/MSDs and LCSs was an EDRO standard
that contained even-numbered alkanes from C,0 through C<0.
MS/MSD spiking levels were targeted to be between 50 and
1 50 percent of the unspiked sample concentration. The reference
laboratory used historical information to adjust spike amounts or to
adjust sample amounts to a preset spike amount. The spiked samples
and unspiked samples were prepared such that the sample mass and
extract volume used for analysis were the same.
The reference laboratory acceptance criteria for MS/MSDs and LCSs
were a relative percent difference less than or equal to 45 with 46 to
124 percent recovery. The acceptance criteria were based on
laboratory historical information. These acceptance criteria are similar
to those of the methods cited in Figure 5-1 .
The LCS/LCSD matrix was Ottawa sand.
The spiking compound for LCSDs was the EDRO standard that
contained even-numbered alkanes from C10 through C40.
The surrogate compound was o-terphenyl. The reference laboratory
acceptance criterion for surrogates was 45 to 143 percent recovery.
The method blank matrix was Ottawa sand. The reference laboratory
acceptance criterion for the method blank was less than or equal to the
project-specific reporting limit.
The extract duplicate was analyzed. The reference laboratory
acceptance criterion for the extract duplicate was a relative' percent
difference less than or equal to 45.
Notes:
CCV
GC
ICV
LCS
LCSD
min
Continuing calibration verification ml
Gas chromatograph MS
Initial calibration verification MSD
Laboratory control sample n-Cx
Laboratory control sample duplicate ng
Minute SW-846
= Milliliter
= Matrix spike
= Matrix spike duplicate
= Alkane with "x" carbon atoms
= Nanogram
= Test Methods for Evaluating Solid Waste"
49
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Chapter 6
Assessment of Reference Method Data Quality
This chapter assesses reference method data quality based
on QC check results and PE sample results. A summary of
reference method data quality is included at the end of this
chapter.
To ensure that the reference method results were of known
and adequate quality, EPA representatives performed a
predemonstration audit and an in-process audit of the
reference laboratory. The predemonstration audit findings
were used in developing the predemonstration design. The
in-process audit was performed when the laboratory had
analyzed a sufficient number of demonstration samples for
both GRO and EDRO and had prepared its first data
package. During the audit, EPA representatives
(1) verified that the laboratory had properly implemented
the EPA-approved demonstration plan and (2) performed
a critical review of the first data package. All issues
identified during the audit were fully addressed by the
laboratory before it submitted the subsequent data
packages to the EPA. The laboratory also addressed issues
identified during the EPA final review of the data
packages. Audit findings are summarized in the DER for
the demonstration.
6.1 Quality Control Check Results
This section summarizes QC check results for GRO and
EDRO analyses performed using the reference method.
The QC checks associated with soil sample analyses for
GRO and EDRO included method blanks, surrogates,
matrix spikes and matrix spike duplicates (MS/MSD), and
laboratory control samples and laboratory control sample
duplicates (LCS/LCSD). In addition, extract duplicates
were analyzed for soil environmental samples. The QC
checks associated with liquid PE sample analysis for GRO
included method blanks, surrogates, MS/MSDs, and
LCS/LCSDs. Because liquid PE sample analyses for
EDRO did not include a preparation step, surrogates,
MS/MSDs, and LCS/LCSDs were not analyzed; however,
an instrument blank was analyzed as a method blank
equivalent. The results for the QC checks were compared
to project-specific acceptance criteria. These criteria were
based on the reference laboratory's historical QC limits
and its experience in analyzing the predemonstration
investigation samples using the reference method. The
reference laboratory's QC limits were established as
described in SW-846 and were within the general
acceptance criteria recommended by SW-846 for organic
analytical methods.
Laboratory duplicates were also analyzed to evaluate the
precision associated with percent moisture analysis of soil
samples. The acceptance criterion for the laboratory
duplicate results was an RPD ^20. All laboratory
duplicate results met this criterion. The results for the
laboratory duplicates are not separately discussed in this
ITVR because soil sample TPH results were compared on
a wet weight basis except for those used to address primary
objective P4 (effect of soil moisture content).
6.1.1 GRO Analysis
This section summarizes the resu Its for QC checks used by
the reference laboratory during GRO analysis, including
method blanks, surrogates, MS/MSDs, extract duplicates,
and LCS/LCSDs. A summary of the QC check results is
presented at the end of the section.
Method Blanks
Method blanks were analyzed to verify that steps in the
analytical procedure did not introduce contaminants that
affected analytical results. Ottawa sand and deionized
water were used as method blanks for soil and liquid
50
-------
samples, respectively. These blanks underwent all the
procedures required for sample preparation. The results
for all method blanks met the acceptance criterion of being
less than or equal to the required project-specific reporting
limit (5 mg/kg). Based on method blank results, the GRO
analysis results were considered to be valid.
Surrogates
Each soil investigative and QC sample for GRO analysis
was spiked with a surrogate, 4-bromofluorobenzene,
before extraction to determine whether significant matrix
effects existed within the sample and to estimate the
efficiency of analyte recovery during sample preparation
and analysis. A diluted, liquid PE sample was also spiked
with the surrogate during sample preparation. The initial
surrogate spiking levels for soil and liquid PE samples
were 2 mg/kg and 40 micrograms per liter (ug/L),
respectively. The acceptance criterion was 39 to 163
percent surrogate recovery. For samples analyzed at a
dilution factor greater than four, the surrogate
concentration was diluted to a level below the reference
laboratory's reporting limit for the reference method;
therefore, surrogate recoveries for these samples were not
used to assess impacts on data quality.
A total of 101 surrogate measurements were made during
analysis of environmental and associated QC samples.
Fifty-six of these samples were analyzed at a dilution
factor less than or equal to four. The surrogate recoveries
for these 56 samples ranged from 43 to 345 percent with a
mean recovery of 150 percent and a median recovery of
136 percent. Because the mean and median recoveries
were > 100 percent, an overall positive bias was indicated.
The surrogate recoveries for 16 of the 56 samples did not
meet the acceptance criterion. In each case, the surrogate
was recovered at a concentration above the upper limit
of the acceptance criterion. Examination of the gas
chromatograms for the 16 samples revealed that some
PHCs or naturally occurring interferents present in these
environmental samples coeluted with the surrogate,
resulting in higher surrogate recoveries. Such coelution is
typical for hydrocarbon-containing samples analyzed using
a GC/FID technique, which was the technique used in the
reference method. The surrogate recoveries for QC
samples such as method blanks and LCS/LCSDs met
the acceptance criterion, indicating that the laboratory
sample preparation and analysis procedures were in
control. Because the coelution was observed only for
environmental samples and because the surrogate
recoveries for QC samples met the acceptance criterion,
the reference laboratory did not reanalyze the
environmental samples with high surrogate recoveries.
Calculations performed to evaluate whether the coelution
resulted in underreporting of GRO concentrations
indicated an insignificant impact of less than 3 percent.
Based on the surrogate results for environmental and
associated QC samples, the GRO analysis results for
environmental samples were considered to be valid.
A total of 42 surrogate measurements were made during
the analysis of soil PE and associated QC samples.
Thirty-four of these samples were analyzed at a dilution
factor less than or equal to four. The surrogate recoveries
for these 34 samples ranged from 87 to 108 percent with a
mean recovery of 96 percent and a median recovery of
95 percent. The surrogate recoveries for all 34 samples
met the acceptance criterion. Based on the surrogate
results for soil PE and associated QC samples, the GRO
analysis results for soil PE samples were considered to be
valid.
A total of 37 surrogate measurements were made during
the analysis of liquid PE and associated QC samples. Six
of these samples were analyzed at a dilution factor less
than or equal to four. All six samples were QC samples
(method blanks and LCS/LCSDs). The surrogate
recoveries for these six samples ranged from 81 to
84 percent, indicating a small negative bias. However, the
surrogate recoveries for all six samples met the acceptance
criterion. Based on the surrogate results for liquid PE and
associated QC samples, the GRO analysis results for liquid
PE samples were considered to be valid.
Matrix Spikes and Matrix Spike Duplicates
MS/MSD results were evaluated to determine the accuracy
and precision of the analytical results with respect to the
effects of the sample matrix. For GRO analysis, each soil
sample designated as an MS or MSD was spiked with the
GRO calibration standard at an initial spiking level of
20 mg/kg. MS/MSDs were also prepared for liquid PE
samples. Each diluted, liquid PE sample designated as an
MS or MSD was spiked with the GRO calibration standard
at an initial spiking level of 40 (ig/L. The acceptance
criteria for MS/MSDs were 3 3 to 115 percent recovery and
an RPD <;25. When the MS/MSD percent recovery
acceptance criterion was not met, instead of attributing the
failure to meet the criterion to an inappropriate spiking
51
-------
level, the reference laboratory respiked the sample at a
more appropriate and practical spiking level. Information
on the selection of the spiking level and calculation of
percent recoveries for MS/MSD samples is provided
below.
According to Provost and Elder (1983), for percent
recovery data to be reliable, spiking levels should be at
least five times the unspiked sample concentration. For the
demonstration, however, a large number of the unspiked
sample concentrations were expected to range between
1,000 and 10,000 mg/kg, so use of such high spiking levels
was not practical. Therefore, a target spiking level of 50
to 150 percent of the unspiked sample concentration was
used for the demonstration. Provost and Elder (1983) also
present an alternate approach for calculating percent
recoveries for MS/MSD samples (100 times the ratio of the
measured concentration in a spiked sample to the
calculated concentration in the sample). However, for the
demonstration, percent recoveries were calculated using
the traditional approach (100 times the ratio of the amount
recovered to the amount spiked) primarily because the
alternate approach is not commonly used.
For environmental samples, a total of 10 MS/MSD pairs
were analyzed. Four sample pairs collected in the NEX
Service Station Area were designated as MS/MSDs. The
sample matrix in this area primarily consisted of medium-
grained sand. The percent recoveries for all but one of the
MS/MSD samples ranged from 67 to 115 with RPDs
ranging from 2 to 14. Only one MS sample with a
162 percent recovery did not meet the percent recovery
acceptance criterion; however, the RPD acceptance
criterion for the MS/MSD and the percent recovery and
RPD acceptance criteria for the LCS/LCSD associated
with the analytical batch for this sample were met. Based
on the MS/MSD results, the GRO analysis results for the
NEX Service Station Area samples were considered to be
valid.
Two sample pairs collected in the B-38 Area were
designated as MS/MSDs. The sample matrix in this area
primarily consisted of sand and clay. The percent
recoveries for the MS/MSD samples ranged from 60 to 94
with RPDs of 1 and 13. Therefore, the percent recoveries
and RPDs for these samples met the acceptance criteria.
Based on the MS/MSD results, the GRO analysis results
for the B-38 Area samples were considered to be valid.
Four sample pairs collected in the SFT Area were
designated as MS/MSDs. The sample matrix in this area
primarily consisted of silty clay. The percent recoveries
for the MS/MSD samples ranged from 0 to 127 with RPDs
ranging from 4 to 21. Of the four sample pairs, two
sample pairs met the percent recovery acceptance criterion,
one sample pair exhibited percent recoveries less than the
lower acceptance limit, and one sample pair exhibited
percent recoveries greater than the upper acceptance limit.
For the two sample pairs that did not meet the percent
recovery acceptance criterion, the RPD acceptance
criterion for the MS/MSDs and the percent recovery and
RPD acceptance criteria for the LCS/LCSDs associated
with the analytical batches for these samples were met.
Because of the varied percent recoveries for the MS/MSD
sample pairs, it was not possible to conclude whether the
GRO analysis results for the SFT Area samples had a
negative or positive bias. Although one-half of the
MS/MSD results did not meet the percent recovery
acceptance criterion, the out-of-control situations alone did
not constitute adequate grounds for rejection of any of the
GRO analysis results for the SFT Area samples. The out-
of-control situations may have been associated with
inadequate spiking levels (0.7 to 2.8 times the unspiked
sample concentrations compared to the minimum
recommended value of 5 times the concentrations).
Three soil PE sample pairs were designated as MS/MSDs.
The sample matrix for these samples consisted of silty
sand. The percent recoveries for these samples ranged
from 88 to 103 with RPDs ranging from 4 to 6. The
percent recoveries and RPDs for these samples met the
acceptance criteria. Based on the MS/MSD results, the
GRO analysis results for the soil PE samples were
considered to be valid.
Two liquid PE sample pairs were designated as MS/MSDs.
The percent recoveries for these samples ranged from 77
to 87 with RPDs of 1 and 5. The percent recoveries and
RPDs for these samples met the acceptance criteria. Based
on the MS/MSD results, the GRO analysis results for the
liquid PE samples were considered to be valid.
Extract Duplicates
For GRO analysis, after soil sample extraction, extract
duplicates were analyzed to evaluate the precision
52
-------
associated with the reference laboratory's analytical
procedure. The reference laboratory sampled duplicate
aliquots of the GRO extracts for analysis. The acceptance
criterion for extract duplicate precision was an RPD $25.
Two or more environmental samples collected in each
demonstration area whose samples were analyzed for GRO
(the NEX Service Station, B-38, and SFT Areas) were
designated as extract duplicates. A total of 10 samples
designated as extract duplicates were analyzed for GRO.
The RPDs for these samples ranged from 0.5 to 11.
Therefore, the RPDs for all the extract duplicates met the
acceptance criterion. Based on the extract duplicate
results, the GRO analysis results were considered to be
valid.
Laboratory Control Samples and Laboratory
Control Sample Duplicates
For GRO analysis, LCS/LCSD results were evaluated to
determine the accuracy and precision associated with
control samples prepared by the reference laboratory. To
generate a soil LCS or LCSD, Ottawa sand was spiked
with the GRO calibration standard at a spiking level of
20 mg/kg. To generate an LCS or LCSD for liquid PE
sample analysis, deionized water was spiked with the GRO
calibration standard at a spiking level of 40 ug/L. The
acceptance criteria for LCS/LCSDs were 33 to 115 percent
recovery and an RPD <;25. The LCS/LCSD acceptance
criteria were based on the reference laboratory's historical
data.
Ten pairs of soil LCS/LCSD samples were prepared and
analyzed. The percent recoveries for these samples ranged
from 87 to 110 with RPDs ranging from 2 to 14. In
addition, two pairs of liquid LCS/LCSD samples were
prepared and analyzed. The percent recoveries for these
samples ranged from 91 to 92 with RPDs equal to 0 and 1.
Therefore, the percent recoveries and RPDs for the soil and
liquid LCS/LCSD samples met the acceptance criteria,
indicating that the GRO analysis procedure was in control.
Based on the LCS/LCSD results, the GRO analysis results
were considered to be valid.
Summary of Quality Control Check Results
Table 6-1 summarizes the QC check results for GRO
analysis. Based on the QC check results, the conclusions
presented below were drawn regarding the accuracy and
precision of GRO analysis results for the demonstration.
The project-specific percent recovery acceptance criteria
were met for most environmental samples and all PE
samples. As expected, the percent recovery ranges were
broader for the environmental samples than for the PE
samples. As indicated by the mean and median percent
recoveries, the QC check results generally indicated a
slight negative bias (up to 20 percent) in the GRO
concentration measurements; the exceptions were the
surrogate recoveries for environmental samples and the
LCS/LCSD recoveries for soil PE samples. The observed
bias did not exceed the generally acceptable bias (plus or
minus [±] 30 percent) stated in SW-846 for organic
analyses and is typical for most organic analytical methods
for environmental samples. Because the percent recovery
ranges were sometimes above and sometimes below 100,
the observed bias did not appear to be systematic.
The project-specific RPD acceptance criterion was met for
all samples. As expected, the RPD range and the mean and
median RPDs for MS/MSDs associated with the soil
environmental samples were greater than those for other
QC checks and matrixes listed in Table 6-1. The low
RPDs observed indicated good precision in the GRO
concentration measurements made during the
demonstration.
6.1.2 EDRO Analysis
This section summarizes the resu Its for QC checks used by
the reference laboratory during EDRO analysis, including
method and instrument blanks, surrogates, MS/MSDs,
extract duplicates, and LCS/LCSDs. A summary of the
QC check results is presented at the end of the section.
Method and Instrument Blanks
Method and instrument blanks were analyzed to verify that
steps in the analytical procedures did not introduce
contaminants that affected analytical results. Ottawa sand
was used as a method blank for soil samples. The method
blanks underwent all the procedures required for sample
preparation. For liquid PE samples, the extraction solvent
(methylene chloride) was used as an instrument blank.
The results for all method and instrument blanks met the
acceptance criterion of being less than or equal to the
required project-specific reporting limit (10 mg/kg).
Based on the method and instrument blank results, the
EDRO analysis results were considered to be valid.
53
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Table 6-1. Summary of Quality Control Check Results for GRO Analysis
QC Check8
Surrogate
MS/MSD
Extract
duplicate
LCS/LCSD
Matrix
Associated
with QC Check
Soil
environmental
samples
Soil PE
samples
Liquid PE
samples
Soil
environmental
samples
Soil PE
samples
Liquid PE
samples
Soil
environmental
samples
Soil
environmental
andPE
samples
Liquid PE
samples
No. of
Measurements
Used to
Evaluate Data
Quality
56
34
6
20 (10 pairs)
6 (3 pairs)
4 (2 pairs)
10 pairs
10 pairs
2 pairs
Accuracy (Percent Recovery)
Acceptance
Criterion
39 to 163
33 to 115
Actual
Range
43 to 345
87 to 108
81 to 84
0 to 162
88 to 103
77 to 87
No. of
Measurements
Meeting
Acceptance
Criterion
40
34
6
15
6
4
Mean
150
96
83
81
94
83
Median
136
95
84
80
92
85
Not applicable
33 to 115
87 to 110
91 to 92
20
4
100
92
100
92
Preciion (Relative Percent Difference)
Acceptance
Criterion
Actual
Range
No. of
Measurements
Meeting
Acceptance
Criterion
Mean
Median
Not applicable
s25
1 to 21
4 to 6
1 to 5
0.5 to 1 1
2 to 14
Oto1
10 pairs
3 pairs
2 pairs
10 pairs
10 pairs
2 pairs
11
5
3
5
6
0.5
12
5
3
4
6
0.5
Notes:
z = Less than or equal to
LCS/LCSD = Laboratory control sample andaboratory control sample duplicate
MS/MSD = Matrix spike and matrix spike duplicate
PE = Performance evaluation
QC = Quality control
During the demonstration, 12 method blanks (10 for soil samples and! for liquid samples) were analyzed. The method blank resits met the project-specifc acceptance criteria.
-------
Surrogates
Each soil investigative and QC sample for EDRO analysis
was spiked with a surrogate, o-terphenyl, before extraction
to determine whether significant matrix effects existed
within the sample and to estimate the efficiency of analyte
recovery during sample preparation and analysis. For a
30-gram sample, the spike concentration was 3.3 mg/kg.
For samples with higher EDRO concentrations, for which
smaller sample amounts were used during extraction,
the spiking levels were proportionately higher. The
acceptance criterion was 45 to 143 percent surrogate
recovery. Liquid PE samples for EDRO analysis were not
spiked with a surrogate because the analysis did not
include a sample preparation step.
A total of 185 surrogate measurements were made during
analysis of environmental and associated QC samples. Six
of these samples did not meet the percent recovery
acceptance criterion. Four of the six samples were
environmental samples. When the reference laboratory
reanalyzed the four samples, the surrogate recoveries for
the samples met the acceptance criterion; therefore, the
reference laboratory reported the EDRO concentrations
measured during the reanalyses. The remaining two
samples for which the surrogate recoveries did not meet
the acceptance criterion were LCS/LCSD samples; these
samples had low surrogate recoveries. According to the
reference laboratory, these low recoveries were due to the
extracts going dry during the extract concentration
procedure. Because two samples were laboratory QC
samples, the reference laboratory reanalyzed them as well
as all the other samples in the QC lot; during the
reanalyses, all surrogate recoveries met the acceptance
criterion. The surrogate recoveries for all results reported
ranged from 45 to 143 percent with mean and median
recoveries of 77 percent, indicating an overall negative
bias. The surrogate recoveries for all reported sample
results met the acceptance criterion. Based on the
surrogate results for environmental and associated QC
samples, the EDRO analysis results were considered to be
valid.
A total of 190 surrogate measurements were made during
analysis of soil PE and associated QC samples. Five of
these samples did not meet the percent recovery
acceptance criterion. In each case, the surrogate was
recovered at a concentration below the lower limit of the
acceptance criterion. Three of the five samples were soil
PE samples, and the remaining two samples were
LCS/LCSDs. The reference laboratory reanalyzed the
three soil PE samples and the LCS/LCSD pair as well as
all the other samples in the QC lot associated with the
LCS/LCSDs; during the reanalyses, all surrogate
recoveries met the acceptance criterion. The surrogate
recoveries for all results reported ranged from 46 to
143 percent with mean and median recoveries of
76 percent, indicating an overall negative bias. The
surrogate recoveries for all reported sample results met the
acceptance criterion. Based on the surrogate results for
soil PE and associated QC samples, the EDRO analysis
results were considered to be valid.
Matrix Spikes and Matrix Spike Duplicates
MS/MSD results were evaluated to determine the accuracy
and precision of the analytical results with respect to the
effects of the sample matrix. For EDRO analysis, each soil
sample designated as an MS or MSD was spiked with the
EDRO calibration standard at an initial spiking level of
50 mg/kg when a 30-gram sample was used during
extraction. The initial spiking levels were proportionately
higher when smaller sample amounts were used during
extraction. The acceptance criteria for MS/MSDs were 46
to 124 percent recovery and an RPD ^45. When the
MS/MSD percent recovery acceptance criterion was not
met, instead of attributing the failure to meet the criterion
to an inappropriate spiking level, the reference laboratory
respiked the samples at a target spiking level between
50 and 150 percent of the unspiked sample concentration.
Additional information on spiking level selection for
MS/MSDs is presented in Section 6.1.1. No MS/MSDs
were prepared for liquid PE samples for EDRO analysis
because the analysis did not include a sample preparation
step.
For environmental samples, a total of 13 MS/MSD pairs
were analyzed. Two sample pairs collected in the FFA
were designated as MS/MSDs. The sample matrix hi this
area primarily consisted of medium-grained sand. The
percent recoveries for the MS/MSD samples ranged from
0 to 183 with RPDs of 0 and 19. One of the two sample
pairs exhibited percent recoveries less than the lower
acceptance limit. In the second sample pair, one sample
exhibited a percent recovery less than the lower
acceptance limit, and one sample exhibited a percent
recovery greater than the upper acceptance limit. For both
sample pairs, the RPD acceptance criterion for the
MS/MSDs and the percent recovery and RPD acceptance
criteria for the LCS/LCSDs asso ciated with the analytical
55
-------
batches for these samples were met. Because of the varied
percent recoveries for the MS/MSD sample pairs, it was
not possible to conclude whether the EDRO analysis
results for the FFA samples had a negative or positive
bias. Although the MS/MSD results did not meet the
percent recovery acceptance criterion, the out-of-control
situations alone did not constitute adequate grounds for
rejection of any of the EDRO analysis results for the FFA
samples. The out-of-control situations may have been
associated with inadequate spiking levels (0.1 to 0.5 times
the unspiked sample concentrations compared to the
minimum recommended value of 5 times the
concentrations).
Four sample pairs collected in the NEX Service Station
Area were designated as MS/MSDs. The sample matrix in
this area primarily consisted of medium-grained sand. The
percent recoveries for the MS/MSD samples ranged from
81 to 109 with RPDs ranging from 4 to 20. The percent
recoveries and RPDs for these samples met the acceptance
criteria. Based on the MS/MSD results, the EDRO
analysis results for the NEX Service Station Area samples
were considered to be valid.
One sample pair collected in the PRA was designated as an
MS/MSD. The sample matrix in this area primarily
consisted of silty sand. The percent recoveries for the
MS/MSD samples were 20 and 80 with an RPD equal to
19. One sample exhibited a percent recovery less than the
lower acceptance limit, whereas the percent recovery for
the other sample met the acceptance criterion. The RPD
acceptance criterion for the MS/MSD and the percent
recovery and RPD acceptance criteria for the LCS/LCSD
associated with the analytical batch for this sample pair
were met. Although the percent recoveries for the
MS/MSD sample pair may indicate a negative bias,
because the MS/MSD results for only one sample pair
were available, it was not possible to conclude that the
EDRO analysis results for the PRA samples had a negative
bias. Although one of the percent recoveries for the
MS/MSD did not meet the acceptance criterion, the out-of-
control situation alone did not constitute adequate grounds
for rejection of any of the EDRO analysis results for the
PRA samples. The out-of-control situation may have been
associated with inadequate spiking levels (0.4 times the
unspiked sample concentration compared to the minimum
recommended value of 5 times the concentration).
Two sample pairs collected in the B:38 Area were
designated as MS/MSDs. The sample matrix in this area
primarily consisted of sand and clay. The percent
recoveries for the MS/MSD samples ranged from 25 to 77
with RPDs of 6 and 11. Of the two sample pairs, one
sample pair met the percent recovery acceptance criterion,
and one sample pair exhibited percent recoveries less than
the lower acceptance limit. For the sample pair that did
not meet the percent recovery acceptance criterion, the
RPD acceptance criterion for the MS/MSDs and the
percent recovery and RPD acceptance criteria for the
LCS/LCSDs associated with the analytical batch for the
sample pair were met. Although the percent recoveries for
one MS/MSD sample pair indicated a negative bias,
because the percent recoveries for the other sample pair
were acceptable, it was not possible to conclude that the
EDRO analysis results for the B-38 Area samples had a
negative bias. Although one-half of the MS/MSD results
did not meet the percent recovery acceptance criterion, the
out-of-control situations alone did not constitute adequate
grounds for rejection of any of the EDRO analysis results
for the B-38 Area samples. The out-of-control situations
may have been associated with inadequate spiking levels
(1.4 times the unspiked sample concentrations compared
to the minimum recommended value of 5 times the
concentrations).
Four sample pairs collected in the SFT Area were
designated as MS/MSDs. The sample matrix in this area
primarily consisted of silty clay. The percent recoveries
for the MS/MSD samples ranged from 0 to 223 with RPDs
ranging from 8 to 50. Of the four sample pairs, three
sample pairs had one sample each that exhibited a percent
recovery less than the lower acceptance limit and one
sample pair had one sample that exhibited a percent
recovery greater than the upper acceptance limit. The RPD
acceptance criterion was met for all but one of the
MS/MSDs. The percent recovery and RPD acceptance
criteria for the LCS/LCSDs asso ciated with the analytical
batches for these samples were met. Because of the varied
percent recoveries for the MS/MSD sample pairs, it was
not possible to conclude whether the EDRO analysis
results for the SFT Area samples had a negative or positive
bias. Although one-half of the MS/MSD results did not
meet the percent recovery acceptance criterion and one of
the four sample pairs did not meet the RPD acceptance
criterion, the out-of-control situations alone did not
constitute adequate grounds for rejection of any of the
EDRO analysis results for the SFT Area samples. The out-
of-control situations may have been associated with
inadequate spiking levels (0.4 to 0.7 times the unspiked
56
-------
sample concentrations compared to the minimum
recommended value of 5 times the concentrations).
Five soil PE sample pairs were designated as MS/MSDs.
The sample matrix for these samples primarily consisted of
silty sand. The percent recoveries for these samples
ranged from 0 to 146 with RPDs ranging from 3 to 17. Of
the five sample pairs, three sample pairs met the percent
recovery acceptance criterion, one sample pair exhibited
percent recoveries less than the lower acceptance limit, and
one sample pair exhibited percent recoveries greater than
the upper acceptance limit. For the two sample pairs that
did not meet the percent recovery acceptance criterion, the
RPD acceptance criterion for the MS/MSDs and the
percent recovery and RPD acceptance criteria for the
LCS/LCSDs associated with the analytical batches for
these samples were met. Because of the varied percent
recoveries for the MS/MSD sample pairs, it was not
possible to conclude whether the EDRO analysis results
for the soil PE samples had a negative or positive bias.
Although the percent recoveries for two of the five sample
MS/MSD pairs did not meet the acceptance criterion, the
out-of-control situations alone did not constitute adequate
grounds for rejection of any of the EDRO analysis results
for the soil PE samples.
Extract Duplicates
For EDRO analysis, after soil sample extraction, extract
duplicates were analyzed to evaluate the precision
associated with the reference laboratory's analytical
procedure. The reference laboratory sampled duplicate
aliquots of the EDRO extracts for analysis. The
acceptance criterion for extract duplicate precision was an
RPD s45. One or more environmental samples collected
in each demonstration area were designated as extract
duplicates. A total of 13 samples designated as extract
duplicates were analyzed for EDRO. The RPDs for these
samples ranged from 0 to 11 except for one extract
duplicate pair collected in the SFT Area that had an RPD
equal to 34. The RPDs for all the extract duplicates met
the acceptance criterion. Based on the extract duplicate
results, all EDRO results were considered to be valid.
Laboratory Control Samples and Laboratory
Control Sample Duplicates
For EDRO analysis, LCS/LCSD results were evaluated to
determine the accuracy and precision associated with
control samples prepared by the reference laboratory. To
generate a soil LCS or LCSD, Ottawa sand was spiked
with the EDRO calibration standard at a spiking level of
50 mg/kg. The acceptance criteria for LCS/LCSDs were
46 to 124 percent recovery and an RPD s45. The
LCS/LCSD acceptance criteria were based on the
reference laboratory's historical data. No LCS/LCSDs
were prepared for liquid PE samples for EDRO analysis
because the analysis did not include a sample preparation
step.
Twenty-two pairs of LCS/LCSD samples were prepared
and analyzed. The percent recoveries for these samples
ranged from 47 to 88 with RPDs ranging from 0 to 29.
Therefore, the percent recoveries and RPDs for these
samples met the acceptance criteria, indicating that the
EDRO analysis procedure was in control. Based on the
LCS/LCSD results, the EDRO analysis results were
considered to be valid.
Summary of Quality Control Check Results
Table 6-2 summarizes the QC check results for EDRO
analysis. Based on the QC check results, the conclusions
presented below were drawn regarding the accuracy and
precision of EDRO analysis results for the demonstration.
The project-specific percent recovery acceptance criteria
were met for all surrogates and LCS/LCSDs. About
one-half of the MS/MSDs did not meet the percent
recovery acceptance criterion. As expected, the MS/MSD
percent recovery range was broader for environmental
samples than for PE samples. The mean and median
percent recoveries for all the QC check samples indicated
a negative bias (up to 33 percent) in the EDRO
concentration measurements. Although the observed bias
was slightly greater than the generally acceptable bias
(± 30 percent) stated in SW-846 for organic analyses, the
observed recoveries were not atypical for most organic
analytical methods for environmental samples. Because
the percent recovery ranges were sometimes above and
sometimes below 100, the observed bias did not appear to
be systematic.
The project-specific RPD acceptance criterion was met for
all samples except one environmental MS/MSD sample
pair. As expected, the RPD range and the mean and
median RPDs for MS/MSDs associated with the soil
environmental samples were greater than those for other
QC checks and matrixes listed in Table 6-2. The low
RPDs observed indicated good precision in the EDRO
57
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Table 6-2. Summary of Quality Gbntrol Check Results for EDRO Analysis
QC Check6
Surrogate
MS/MSD
Extract
duplicate
LCS/LCSD
Matrix
Associated
with QC Check
Soil
environmental
samples
Soil PE
samples
Soil
environmental
samples
Soil PE
samples
Soil
environmental
samples
Soil
environmental
andPE
samples
No. of
Measurements
Used to
Evaluate Data
Quality
179
185
26 (13 pairs)
10 (5 pairs)
1 3 pairs
44 (22 pairs)
Accuracy (Percent Recovery)
Acceptance
Criterion
45 to 143
46 to 124
Actual
Range
45 to 143
46 to 143
0 to 223
0 to 146
No. of
Measurements
Meeting
Acceptance
Criterion
179
185
14
6
Mean
77
76
67
75
Median
77
76
79
78
Not applicable
46 to 124
47 to 88
44
77
80
Precsion (Relative Percent Difference)
Acceptance
Criterion
Actual
Range
No. of
Measurements
Meeting
Acceptance
Criterion
Mean
Median
Not applicable
5:45
OtoSO
3 to 17
Oto34
Oto29
12 pairs
5 pairs
13 pairs
22 pairs
17
7
6
6
16
4
2
5
Ul
oo
Notes:
£ = Less than or equal to
LCS/LCSD = Laboratory control sample andaboratory control sample duplicate
MS/MSD = Matrix spike and matrix spike duplicate
PE = Performance evaluation
QC = Quality control
During the demonstration, 22 method blanks for soil samples and 2 iatrument blanks for liquid samples were analyzed. The blah results met the project-specific acceptance criteria.
-------
concentration measurements made during the
demonstration.
6.2 Selected Performance Evaluation Sample
Results
Soil and liquid PE samples were analyzed during the
demonstration to document the reference method's
performance in analyzing samples prepared under
controlled conditions. The PE sample results coupled with
the QC check results were used to establish the reference
method's performance in such a way that the overall
assessment of the reference method would support
interpretation of the EnSys Petro Test System's
performance, which is discussed in Chapter 7. Soil PE
samples were prepared by adding weathered gasoline or
diesel to Ottawa sand or processed garden soil. For each
sample, an amount of weathered gasoline or diesel was
added to the sample matrix in order to prepare a PE sample
with a low (less than 100 mg/kg), medium (100 to
1,000 mg/kg), or high (> 1,000 mg/kg) TPH concentration.
Liquid PE samples consisted of neat materials. Triplicate
samples of each type of PE sample were analyzed by the
reference laboratory except for the low-concentration-
range PE samples, for which seven replicate samples were
analyzed.
As described in Section 4.2, some PE samples also
contained interferents. Section 6.2 does not discuss the
reference method results for PE samples containing
interferents because the results address a specific
demonstration objective. To facilitate comparisons, the
reference method results that directly address
demonstration objectives are discussed along with the
EnSys Petro Test System results in Chapter 7. Section 6.2
presents a comparison of the reference method's mean
TPH results for selected PE samples to the certified values
and performance acceptance limits provided by ERA, a
commercial PE sample provider that prepared the PE
samples for the demonstration. Although the reference
laboratory reported sample results for GRO and EDRO
analyses separately, because ERA provided certified values
and performance acceptance limits, the reference method's
mean TPH results (GRO plus EDRO analysis results) were
used for comparison.
For soil samples containing weathered gasoline, the
certified values used for comparison to the reference
method results were based on mean TPH results for
triplicate samples analyzed by ERA using a GC/FED
method. ERA extracted the PE samples on the day that PE
samples were shipped to the Navy BVC site for
distribution to the reference laboratory and developers.
The reference laboratory completed methanol extraction of
the demonstration samples within 2 days of receiving
them. Between 5 and 7 days elapsed between the time that
ERA and the time that the reference laboratory completed
methanol extractions of the demonstration samples. The
difference in extraction times is not believed to have had
a significant effect on the reference method's TPH results
because the samples for GRO analysis were containerized
in EPA-approved EnCores and were stored at 4 ± 2 °C to
minimize volatilization. After methanol extraction of the
PE samples, both ERA and the reference laboratory
analyzed the sample extracts within the appropriate
holding times for the extracts.
For soil samples containing diesel, the certified values
were established by calculating the TPH concentrations
based on the amounts of diesel spiked into known
quantities of soil; these samples were not analyzed by
ERA. Similarly, the densities of the neat materials were
used as the certified values for the liquid PE samples.
The performance acceptance limits for soil PE samples
were based on ERA's historical data on percent recoveries
and RSDs from multiple laboratories that had analyzed
similarly prepared ERA PE samples using a GC method.
The performance acceptance limits were determined at the
95 percent confidence level using Equation 6-1.
Performance Acceptance Limits = Certified Value
x (Average Percent Recovery +. 2(Average RSD)) (6-1)
According to SW-846, the 95 percent confidence limits
should be treated as warning limits, whereas the 99 percent
confidence limits should be treated as control limits. The
99 percent confidence limits are calculated by using three
times the average RSD in Equation 6-1 instead of two
times the average RSD.
When establishing the performance acceptance limits,
ERA did not account for variables among the multiple
laboratories, such as different extraction and analytical
methods, calibration procedures, and chromatogram
integration ranges (beginning and end points). For this
reason, the performance acceptance limits should be used
with caution.
59
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Performance acceptance limits for liquid PE samples were
not available because ERA did not have historical
information on percent recoveries and RSDs for the neat
materials used in the demonstration.
Table 6-3 presents the PE sample types, TPH concentration
ranges, performance acceptance limits, certified values,
reference method mean TPH concentrations, and ratios of
reference method mean TPH concentrations to certified
values.
In addition to the samples listed in Table 6-3, three blank
soil PE samples (processed garden soil) were analyzed to
determine whether the soil PE sample matrix contained a
significant TPH concentration. Reference method GRO
results for all triplicate samples were below the reporting
limit of 0.54 mg/kg. Reference method EDRO results
were calculated by adding the results for DRO and oil
range organics (ORO) analyses. For one of the triplicate
samples, both the DRO and ORO results were below the
reporting limits of 4.61 and 5.10 mg/kg, respectively. For
the remaining two triplicates, the DRO and ORO results
were 1.5 times greater than the reporting limits. Based on
the TPH concentrations in the medium- and high-
concentration-range soil PE samples listed in Table 6-3,
the contribution of the processed garden soil to the TPH
concentrations was insignificant and ranged between 0.5
and 5 percent.
The reference method's mean TPH results for the soil PE
samples listed in Table 6-3 were within the performance
acceptance limits except for the low-concentration-range
diesel samples. For the low-range diesel samples, (1) the
individual TPH concentrations for all seven replicates were
less than the lower performance acceptance limit and
(2) the upper 95 percent confidence limit for TPH results
was also less than the lower performance acceptance limit.
However, the reference method mean and individual TPH
results for the low-range diesel samples were within
the 99 percent confidence interval of 10.8 to 54.6 mg/kg,
indicating that the reference method results met the control
limits but not the warning limits. Collectively, these
observations indicated a negative bias in TPH
measurements for low-range diesel samples.
Table 6-3. Comparison of Soil and Liquid Performance Evaluation Sample Results
Sample Type8
TPH
Concentration
Range
Performance
Acceptance Limits
(mg/kg)
Certified Value
Reference Method Reference Method Mean
Mean TPH TPH Concentration/
Concentration Certified Value (percent)
Soil Sample (Ottawa Sand)
Diesel
Low
18.1 to 47.4
37.3 mg/kg
1 5.4 mg/kg
41
Soil Samples (Processed Garden Soil)
Weathered gasoline
Weathered gasoline at
16 percent moisture
Diesel
Diesel at less than 1 percent
moisture
Liquid Samples
Weathered gasoline
Diesel
Medium
High
High
Medium
High
High
High
High
389 to 1,548
1,110 to 4,430
992 to 3,950
220 to 577
1,900 to 4,980
2, 100 to 5,490
Not available
Not available
1 ,090 mg/kg
3,120 mg/kg
2,780 mg/kg
454 mg/kg
3,920 mg/kg
4,320 mg/kg
814,100 mg/L
851,900mg/L
705 mg/kg
2,030 mg/kg
1 ,920 mg/kg
252 mg/kg
2,720 mg/kg
2,910 mg/kg
* ;. "•>% -
648,000 mg/L
1,090,000 mg/L
65
65
69
56
69
67
80
128
Notes:
mg/kg = Milligram per kilogram
mg/L = Milligram per liter
° Soil samples were prepared at 9 percent moisture unless stated otherwise.
60
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As noted above, Table 6-3 presents ratios of the reference
method mean TPH concentrations to the certified values
for PE samples. The ratios for weathered gasoline-
containing soil samples ranged from 65 to 69 percent and
did not appear to depend on whether the samples were
medium- or high-range samples. The ratio for neat,
weathered gasoline (liquid sample) was 80 percent, which
was 11 to 15 percentage points greater than the ratios for
the soil samples. The difference in the ratios may be
attributed to (1) potential loss of volatiles during soil
sample transport and storage and during soil sample
handling when extractions were performed and (2) lower
analyte recovery during soil sample extraction. The less
than 100 percent ratios observed indicated a negative bias
in TPH measurement for soil and liquid samples
containing weathered gasoline. The observed bias for the
liquid samples did not exceed the generally acceptable bias
(±30 percent) stated in SW-846 for most organic analyses.
However, the bias for soil samples exceeded the acceptable
bias by up to 5 percentage points.
The ratios for diesel-containing soil samples ranged from
41 to 69 percent and increased with increases in the TPH
concentration range. The ratio for neat diesel (liquid
sample) was 128 percent, which was substantially greater
than the ratios for soil samples. Collectively, the negative
bias observed for soil samples and the positive bias
observed for liquid samples indicated a low analyte
recovery during soil sample extraction because the soil and
liquid samples were analyzed using the same calibration
procedures but only the soil samples required extraction
before analysis. The extraction procedure used during the
demonstration is an EPA-approved method that is widely
used by commercial laboratories in the United States.
Details on the extraction procedure are presented in
Table 5-3 of this ITVR.
The positive bias observed for liquid samples did not
exceed the generally acceptable bias stated in SW-846.
The negative bias observed for high-concentration-range
soil samples exceeded the acceptable bias by an average of
2 percentage points. However, the negative bias observed
for low- and medium-range samples exceeded the
acceptable bias by 29 and 14 percentage points,
respectively, indicating a negative bias.
Because the reference method results exhibited a negative
bias for soil PE samples when compared to ERA-certified
values, ERA's historical data on percent recoveries and
RSDs from multiple laboratories were examined.
Table 6-4 compares ERA's historical percent recoveries
and RSDs to the reference method percent recoveries and
RSDs obtained during the demons tration. Table 6-4 shows
that ERA's historical recoveries also exhibited a negative
bias for all sample types except weathered gasoline in
water and that the reference method recoveries were less
than ERA's historical recoveries for all sample types
except diesel in water. The ratios of reference method
mean recoveries to ERA historical mean recoveries for
weathered gasoline-containing samples indicated that the
reference method TPH results were 26 percent less than
ERA's historical recoveries. The reference method
recoveries for diesel-containing (1) soil samples were
34 percent less than the ERA historical recoveries and
(2) water samples were 63 percent greater than the ERA
historical recoveries. In all cases, the RSDs for the
reference method were significantly lower than ERA's
historical RSDs, indicating that the reference method
achieved significantly greater precision. The greater
precision observed for the reference method during the
demonstration may be associated with the fact that the
reference method was implemented by a single laboratory,
whereas ERA's historical RSDs were based on results
obtained from multiple laboratories that may have used
different analytical protocols.
In summary, compared to ERA-certified values, the TPH
results for all PE sample types except neat diesel exhibited
a negative bias to a varying degree; the TPH results for
neat diesel exhibited a positive bias of 28 percent. For
weathered gasoline-containing soil samples, the bias was
relatively independent of the TPH concentration range and
exceeded the generally acceptable bias stated in SW-846
by up to 5 percentage points. For neat gasoline samples,
the bias did not exceed the acceptable bias. For diesel-
containing soil samples, the bias increased with decreases
in the TPH concentration range, and the bias for low-,
medium-, and high-range samples exceeded the
acceptable bias by 29, 14, and 2 percentage points,
respectively. For neat diesel samples, the observed
positive bias did not exceed the acceptable bias. The low
RSDs (5 to 9 percent) associated with the reference
method indicated good precision in analyzing both soil and
liquid samples. Collectively, these observations suggest
that caution should be exercised during comparisons of
EnSys Petro Test System and reference method results for
low- and medium-range soil samples containing diesel.
61
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Table 6-4. Comparison of Environmental Resource Associates Historical Results to Reference Method Results
ERA Historical Results
Sample Type
Weathered gasoline in soil
Diesel in soil
Weathered gasoline in water
Diesel in water
Mean
Recovery
(percent)
88.7
87.7
109
78.5
Mean Relative
Standard Deviation
(percent)
26.5
19.6
22.0
22.8
Mean
Recovery8
(percent)
66
58
80
128
Reference Method Results
Reference Method Mean
Recovery/ERA Historical
Mean Recovery (percent)
75
66
73
163
Mean Relative
Standard Deviation0
(percent)
7
9
5
6
Notes:
ERA = Environmental Resource Associates
° The reference method mean recovery and mean relative standard deviation were based on recoveries and relative standard deviations observed
for all concentration ranges for a given type of performance evaluation sample.
6.3 Data Quality
Based on the reference method's performance in analyzing
the QC check samples and selected PE samples, the
reference method results were considered to be of
adequate quality for the following reasons: (1) the
reference method was implemented with acceptable
accuracy (± 30 percent) for all samples except low- and
medium-concentration-range soil samples containing
diesel, which made up only 13 percent of the total number
of samples analyzed during the demonstration, and (2) the
reference method was implemented with good precision
for all samples (the overall RPD range was 0 to 17). The
reference method results generally exhibited a negative
bias. However, the bias was considered to be significant
primarily for low- and medium-range soil samples
containing diesel because the bias exceeded the generally
acceptable bias of ± 30 percent stated in SW-846 by
29 percentage points for low-range and 14 percentage
points for medium-range samples. The reference method
recoveries observed were typical of the recoveries
obtained by most organic analytical methods for
environmental samples.
62
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Chapter 7
Performance of the EnSys Petro Test System
To verify a wide range of performance attributes, the
demonstration had both primary and secondary objectives.
Primary objectives were critical to the technology
evaluation and were intended to produce quantitative
results regarding a technology's performance. Secondary
objectives provided information that was useful but did not
necessarily produce quantitative results regarding a
technology's performance. This chapter discusses the
performance of the EnSys Petro Test System based on the
primary objectives (excluding costs associated with TPH
measurement) and secondary objectives. Costs associated
with TPH measurement (primary objective P6) are
presented in Chapter 8. The demonstration results for both
the primary and secondary objectives are summarized in
Chapter 9.
7.1 Primary Objectives
This section discusses the performance results for the
EnSys Petro Test System based on primary objectives PI
through P5, which are listed below.
PI. Determine the MDL
P2. Evaluate the accuracy and precision of TPH
measurement for a variety of contaminated soil
samples
P3. Evaluate the effect of interferents on TPH
measurement
P4. Evaluate the effect of soil moisture content on TPH
measurement
P5. Measure the time required for TPH measurement
To address primary objectives PI through P5, samples
were collected from four different sampling areas. In
addition, soil and liquid PE samples were prepared and
distributed to SDI and the reference laboratory. The
numbers and types of environmental samples collected in
each sampling area and the numbers and types of PE
samples prepared are discussed in Chapter 4.
Primary objectives PI through P4 were addressed using
statistical and nonstatistical approaches, as appropriate.
Because the EnSys Petro Test System is a semiquantitative
device, the TPH concentration in a sample cannot be
reported as an absolute value; therefore, statistical
approaches could not be used to address the primary
objectives for the EnSys Petro Test System. The statistical
tests performed to address primary objectives for the
reference method are illustrated in the flow diagram in
Figure 7-1. Before a parametric test was performed, the
Wilk-Shapiro test was used to determine whether the
reference method results were normally distributed at a
significance level of 5 percent. If the results were not
normally distributed, the Wilk-Shapiro test was performed
on transformed results (for example, logarithm and square
root transformations) to verify the normality assumption.
If the normality assumption was not met, a nonparametric
test was performed. Nonparametric tests are not as
powerful as parametric tests because the nonparametric
tests do not account for the magnitude of the difference
between sample results. Despite this limitation, when the
normality assumption was not met, performing a
nonparametric test was considered to be a better alternative
than performing no statistical comparison.
For the reference method, when the analyte concentration
in a given sample was reported as below the reporting
limit, one-half the reporting limit was used as the analyte
concentration forthat sample, as is commonly done, so that
necessary calculations could be performed without
rejecting the data. The appropriate reporting limits were
used in calculating the TPH concentration depending on
which TPH measurement components (GRO, DRO, and
ORO) were reported at concentrations below the reporting
63
-------
TPH results
Method detection limit
(primary objective P1)
Were
TPH results
normally distributed?
(Wik-Shapiro
Precision
(primary objective P2)
Determined method
detection limit using
approach recommended in
40 Code of Federal
Regulations Part 136,
Appendix B, Revision 1,1.1
Was unable to determine
method detection limit
Calculated relative
percent difference
for extract duplicate
TPH results
rgzss'jr; ~
Effect of interferents
{primary objective P3)
Were
TPH results
for three sample groups
normally distributed?
(Wilk-Shap
test)
Were
group variances
equal?
(Bartletfs test)
Performed one-way
analysis of variance
(parametric) and Tukey
(honest, significant
difference) comparison of
means (parametric) to
determine whether presence
of interferents resulted in
increase or decrease in
TPH results
Performed Kruskal-Wallis
one-way analysis of
variance (nonparametric)
and Kruskal-Wallis
comparison of means
(nonparametric) to
determine whether
presence of interferents
resulted in increase or
decrease in TPH results
Effect of soil moisture content
(primary objective P4)
TPH results
for both sample groups
normally distributed?
(Wilk-Shapiro^ :t
test)
*'"?j
^f./.'^iijiMi
Performed two-sample
Student's West
(parametric) to determine
whether increase in
moisture content resulted
in increase or decrease in
TPH results
'No
Performed Kruskal-Wallis
one-way analysis of
variance (nonparametric)
and Kruskal-Wallis
comparison of means
(nonparametric) to
determine whether
increase in moisture
content resulted in
increase or decrease in
TPH results
Figure 7-1. Summary of statistical analysis of TPH results.
-------
limits. Caution was exercised to ensure that these
necessary data manipulations did not alter the conclusions.
The reference method GRO results were adjusted for
solvent dilution associated with the soil sample moisture
content because the method required use of methanol, a
water-miscible solvent, for extraction of soil samples. In
addition, based on discussions with the reference
laboratory, all TPH results for the reference method were
rounded to three significant figures. No data
manipulations were required to evaluate EnSys Petro Test
System performance. The developer's perspective
regarding this ITVR's evaluation of EnSys Petro Test
System TPH results reported as >1,000 mg/kg is provided
in the appendix.
7.1.1 Primary Objective PI: Method Detection
Limit
To address primary objective PI, both SDI and the
reference laboratory analyzed seven low-concentration-
range weathered gasoline soil PE samples and seven low-
concentration-range diesel soil PE samples. As discussed
in Chapter 4, problems arose during preparation of the
low-range weathered gasoline samples; therefore, the
results for the soil PE samples containing weathered
gasoline could not be used to determine MDLs.
Because the EnSys Petro Test System is a semiquantitative
device, the TPH concentration in a sample cannot be
reported as an absolute value. Therefore, the device results
for the low-range soil PE diesel samples could not be used
to statistically determine the MDL. Instead, the EnSys
Petro Test System MDL was verified by evaluating
whether the TPH concentration ranges measured using the
device overlapped the TPH concentrations measured using
the reference method.
Because the reference method results were normally
distributed, the MDLs for the soil PE samples containing
diesel were calculated using Equation 7-1 (40 CFR
Part 136, Appendix B, Revision 1.1.1). An MDL thus
calculated is influenced by TPH concentrations because the
standard deviation will likely decrease with a decrease in
TPH concentrations. As a result, the MDL will be lower
when low-concentration samples are used for MDL
determination. Despite this limitation, Equation 7-1 is
commonly used and provides a reasonable estimate of the
MDL.
(7-1)
where
S = Standard deviation of replicate TPH results
(n-l,l-a=0.99) _
Student's t-value appropriate for a
99 percent confidence level and a
standard deviation estimate with n-1
degrees of freedom (3.143 for n = 7
replicates)
Because GRO compounds were not expected to be present
in the soil PE samples containing diesel, the reference
laboratory performed only EDRO analysis of these
samples and reported the sums of the DRO and ORO
concentrations as the TPH results. The EnSys Petro Test
System and reference method results for these samples are
presented in Table 7-1.
Table 7-1. TPH Results for Low-Concentration-Range Diesel Soil
Performance Evaluation Samples
EnSys Petro Test
System Result (mg/kg)
>15to<100
>15to<100
>15to<100
>15to<100
>100to<1,000
>15to<100
>15to<100
MDL Not calculated
Reference
Method Result
(mg/kg)
12.0
16.5
13.7
16.4
17.4
17.2
14.8
6.32
Did the EnSys Petro
Test System Result
Overlap the
Reference Method
Result?
No
Yes
No
Yes
No
Yes
No
Notes:
> = Greater than
< = Less than
MDL = Method detection limit
mg/kg = Milligram per kilogram
Based on the TPH results for the low-concentration-range
diesel soil PE samples, the MDL was determined to be
6.32 mg/kg for the reference method. Because the ORO
concentrations in all these samples were below the
reference laboratory's estimated reporting limit
(5.1 mg/kg), the MDL for the reference method was also
calculated using only DRO results. The MDL for the
reference method based on the DRO results was
6.29 mg/kg, whereas the MDL for the reference method
based on the EDRO results was 6.32 mg/kg, indicating that
65
-------
the ORO concentrations below the reporting limit did not
impact the MDL for the reference method. The MDL of
6.32 mg/kg for the reference method compares well with
the MDL of 4.72 mg/kg published in SW-846
Method 8015C for diesel samples extracted using a
pressurized fluid extraction method and analyzed for DRO.
Table 7-1 shows that the TPH results for the reference
method were near the detection limit for diesel (15 mg/kg)
claimed by SDI for the EnSys Petro Test System.
Specifically, three reference method results were below
and four were above 15 mg/kg; all seven results were
within 20 percent of the detection limit. Because the
reference method exhibited a significant negative bias
(59 percent) for the low-concentration-range diesel soil PE
samples (see Table 6-3), all the reference method results
for these samples could be considered to be in the
concentration range of >15 to <100 mg/kg, the reported
concentration range for six of the seven EnSys Petro Test
System results. Thus, the device's TPH results for six of
the samples could be considered to compare well with the
reference method TPH results; the device result of > 100 to
< 1,000 mg/kg for one sample cannot be explained. In
summary, the device was considered to have accurately
measured the TPH concentrations in six of seven low-
range diesel soil PE samples.
7.7.2 Primary Objective P2: Accuracy and
Precision
This section discusses the ability of the EnSys Petro Test
System to accurately and precisely measure TPH
concentrations in a variety of contaminated soils. The
EnSys Petro Test System TPH results were compared to
the reference method TPH results. Accuracy and precision
are discussed in Sections 7.1.2.1 and 7.1.2.2, respectively.
7.1.2.1 Accuracy
The accuracy of EnSys Petro Test System measurement of
TPH was assessed by determining
• Whether the EnSys Petro Test System TPH
concentration ranges overlapped the reference method
results
• Whether the conclusion reached using the EnSys Petro
Test System agreed with that reached using the
reference method regarding whether the TPH
concentration in a given sampling area or soil type
exceeded a specified action level
During examination of these two factors, the data quality
of the reference method and EnSys Petro Test System TPH
results was considered. For example, as discussed in
Chapter 6, the reference method generally exhibited a low
bias. However, the bias observed for all samples except
low- and medium-concentration-range diesel soil samples
did not exceed the generally acceptable bias of ±30 percent
stated in SW-846 for organic analyses. Therefore, caution
was exercised during comparison of the EnSys Petro Test
System and reference method results, particularly those for
low- and medium-range diesel soil samples.
The following sections discuss how the EnSys Petro Test
System results compared with the reference method
results by addressing each of the two factors identified
above.
Pairwise Comparison of TPH Results
To evaluate whether the EnSys Petro Test System and
reference method TPH results were the same or different,
the device's TPH concentration ranges were compared to
the reference method TPH results. Tables 7-2 and 7-3
present comparisons of the device and reference method
TPH results for environmental and PE samples,
respectively. The tables present the TPH results for each
sampling area or PE sample type.
Table 7-2 shows that the EnSys Petro Test System TPH
concentration ranges overlapped the reference method
results for only 8 of 50 (16 percent) environmental
samples. No conclusions could be drawn for 16 samples
for which the reference method TPH results were greater
than the highest detection level used by SDI
(1,000 mg/kg). The best agreement between the EnSys
Petro Test System and reference method results was
observed for B-38 Area samples (25 percent), followed by
samples from the SFT Area (21 percent), NEX Service
Station Area (8 percent), and FFA (0 percent). Lack of
agreement between an EnSys Petro Test System
concentration range and a reference method result did not
appear to be a function of the type of contamination
(gasoline or diesel), sample TPH concentration range (low,
medium, or high), or type of soil (sand, silt, or clay).
66
-------
Table 7-2. Comparison of EnSys Petro Test System and Reference Method TPH Results for Environmental Samples
Sampling Area
Fuel Farm Area
Naval Exchange Service Station
Area
B-38 Area
Slop Fill Tank Area
TPH Result (mg/kg)
EnSys Petro Test
System
<15
>1,000
<15
>1,000
<15
> 1,000
>15to<100
> 1,000
<15
> 1,000
>100to<1,000
>1,000
>1,000
>100to<1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
> 1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
> 1,000
>100to<1,000
>100to<1,000
>15to<100
>100to<1,000
>100to<1,000
>100to<1,000
>100to<1,000
>100to<1,000
>100to<1,000
>100to<1,000
>1,000
>1,000
> 1,000
<15
>1,000
>15to<100
Reference
Method
68.2
15,000
90.2
12,000
44.1
13,900
1,330
8,090
93.7
12,300
28.8
144
617
293
280
1,870
1,560
9.56
270
881
1,120
14.2
219
1,180
1,390
15.2
54.5
2,570
3,030
15.9
79.0
41.5
61.4
67.3
193
69.4
43.8
51.6
105
269
397
339
6.16
37.1
43.9
Analysis Summary
Did the EnSys Petro Test System
TPH Concentration Range Overlap
the Reference Method TPH Result?"
No
Inconclusive
No
Inconclusive
No
Inconclusive
No
Inconclusive
No
Inconclusive
No
No
No
Yes
No
Inconclusive
Inconclusive
No
No
No
Inconclusive
No
No
Inconclusive
Inconclusive
No
No
Inconclusive
Inconclusive
No
No
Yes
No
No
Yes
No
No
No
Yes
No
No
No
Yes
No
Yes
EnSys Petro Test System Bias
(minimum percent bias)
Low (78)
Low (83)
Low (66)
Low (92)
Low (84)
High (250)
High (590)
High (62)
High (260)
High (10,000)
High (270)
High (14)
High (6,900)
High (360)
High (6,500)
High (1,700)
High (530)
High (27)
High (63)
High (49)
High (44)
High (130)
High (94)
High (270)
High (150)
High (200)
High (2,600)
67
-------
Table 7-2. Comparison of EnSys Petro Test System and Reference Method TPH Results for Environmental Samples (Continued)
Sampling Area
Slop Fill Tank Area (continued)
TPH Result (mg/kg)
EnSys Petro Test
System
>15to<100
>1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>100to<1,000
>100to<1,000
Reference
Method
52.4
3,300
1,270
588
554
834
501
280
185
1,090
544
503
146
938
517
369
253
151
3,960
1,210
121
Analysis Summary
Did the EnSys Petro Test System
TPH Concentration Range Overlap
the Reference Method TPH Result?8
Yes
Inconclusive
Inconclusive
No
No
No
No
No
No
Inconclusive
No
No
No
No
No
No
No
No
Inconclusive
No
Yes
EnSys Petro Test System Bias
(minimum percent bias)
High (70)
High (81)
High (20)
High (100)
High (260)
High (440)
High (84)
High (99)
High (580)
High (7)
High (93)
High (170)
High (300)
High (560)
Low (17)
Notes:
> = Greater than
< = Less than
mg/kg = Milligram per kilogram
° No conclusion could be drawn for 16 samples for which the reference method TPH results were greater than the highest detection level used by
SDI during the demonstration (1,000 mg/kg). In these cases, SDI's results did not have the upper limits that defined concentration ranges.
68
-------
Table 7-3. Comparison of EnSys Petro Test System and Reference Method TPH Results for Performance Evaluation Samples
Sample Type
TPH Result
EnSys Petro
Test System
Reference
Method
Analysis Summary
Did the EnSys Petro Test System
TPH Concentration Range Overlap
the Reference Method TPH Result?8
Soil Samples (Processed Garden Soil) (TPH Results in Milligram per Kilogram)
Blank (9 percent moisture content)
Weathered
gasoline
Diesel
Medium-concentration range
(9 percent moisture content)
High-concentration range
(9 percent moisture content)
High-concentration range
(16 percent moisture
content)
Low-concentration range
(9 percent moisture content)
Medium-concentration range
(9 percent moisture content)
High-concentration range
(9 percent moisture content)
High-concentration range
(less than 1 percent
moisture content)
<10
<10
<10
> 1,000
> 1,000
> 1,000
> 1,000
> 1,000
> 1,000
> 1,000
>1,000
>1,000
>15to<100
>15to<100
>15to<100
>15to<100
>100to<1,000
>15to<100
>15to<100
>1,000
> 1,000
>100to<1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
5.12
13.1
13.5
702
743
671
1,880
2,020
2,180
1,740
1,980
2,050
12.0
16.5
13.7
16.4
17.4
17.2
14.8
226
265
267
2,480
2,890
2,800
2,700
2,950
3,070
Yes
No
No
No
No
No
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
No
Yes
No
Yes
No
Yes
No
No
No
Yes
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
EnSys Petro Test System Bias
(minimum percent bias)
Low (24)
Low (26)
High (42)
High (35)
High (49)
High (25)
High (9)
High (470)
High(1)
High (340)
High (280)
Liquid Samples (Neat Materials) (TPH Results in Milligram per Liter)
Weathered gasoline
Diesel
>200,500
>200,500
>200,500
>200,500
>200,500
>200,500
656,000
611,000
677,000
1,090,000
1,020,000
1,160,000
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Notes:
> = Greater than
< = Less than
" No conclusions could be drawn for 18 soil and liquid samples for which the reference method TPH results were greater than the highest detection
levels used by SDI during the demonstration (1,000 milligrams per kilogram for soil samples and 200,500 milligrams per liter for liquid samples).
In these cases, SDI's results did not have the upper limits that defined concentration ranges.
69
-------
When the EnSys Petro Test System concentration range
and reference method result did not agree, the device result
was biased high relative to the reference method result
except for all the FFA samples and one SFT Area sample.
As shown in Table 7-2, the minimum bias ranged from 14
to 10,000 percent for NEX Service Station Area samples;
27 to 130 percent for the B-38 Area samples; and 7 to
2,600 percent for the SFT Area samples. The minimum
median bias was 440, 56, and 150 percent for the NEX
Service Station, B-38, and SFT Area samples, respectively.
As a result, the high bias observed for the EnSys Petro Test
System results for environmental samples cannot be
explained based solely on the negative bias associated with
reference method TPH measurements for GRO-containing
samples (up to 20 percent) and EDRO-containing samples
(up to 33 percent) discussed in Chapter 6. The EnSys
Petro Test System results for the FFA samples were biased
low relative to the reference method results; the minimum
bias ranged from 66 to 92 percent with a median of
83 percent. The low bias observed for FFA samples is
inconsistent with the negative bias associated with
reference method TPH measurements for EDRO-
containing samples and cannot be explained.
Table 7-3 shows that the EnSys Petro Test System TPH
concentration ranges overlapped the reference method
results for only 5 of 16 (31 percent) soil PE samples. No
conclusions could be drawn for 12 soil PE samples for
which the reference method TPH results were greater than
the highest detection level used by SDI for soil samples
(1,000 mg/kg). Similarly, no conclusions could be drawn
for the six liquid PE samples because the reference method
TPH results were greater than the highest detection level
used by SDI for liquid samples (200,500 mg/L). When the
EnSys Petro Test System and reference method results did
not agree, the device results were biased (1) low for blank
soil samples and (2) high for medium-concentration-range
weathered gasoline soil samples and low- and medium-
range diesel soil samples.
The minimum low biases for blank soil samples were 24
and 26 percent with a median of 25 percent. The bias
observed for the blank samples may be explained by SDFs
selection of gasoline as the fuel product equivalent (see
Chapter 2). Had SDI used diesel as the fuel product
equivalent, the device results for these blank samples
would have been reported as <15 mg/kg, which would
have agreed with the reference method results.
The minimum high bias for the medium-concentration-
range weathered gasoline soil samples ranged from 35 to
49 percent with a median of 42 percent. A significant
portion of the bias may be explained by the negative bias
associated with the reference method results for medium-
range weathered gasoline soil samples (35 percent)
discussed in Section 6.2. The minimum high bias for the
low-range diesel soil samples ranged from 1 to 470 percent
with a median of 17 percent. The bias may be explained
by the significant negative bias associated with the
reference method results for the low-range diesel soil
samples (59 percent) discussed in Section 6.2. The
minimum high biases for medium-range diesel soil
samples were 280 and 340 percent with a median of
310 percent, which cannot be explained.
Action Level Conclusions
Table 7-4 compares action level conclusions reached using
the EnSys Petro Test System and reference method results
for environmental and soil PE samples. Section 4.2 of this
ITVR explains how the action levels were selected for the
demonstration. No conclusions could be drawn for 17 of
100 samples. Of the samples for which conclusions could
be drawn, the percentage of samples for which the
conclusions agreed ranged from 25 to 90 for environmental
samples and from 33 to 100 for PE samples. Overall, the
conclusions were the same for 67 percent of the samples.
The lack of agreement observed for B-38 Area soil
samples (25 percent) and for the blank soil PE samples
(33 percent) was not surprising because the sample TPH
concentrations were mostly near (within 30 percent) the
action levels and because the EnSys Petro Test System
detection levels were the same as the action levels for the
two sets of samples, making it difficult to accurately assess
whether a sample concentration was above or below the
action level.
When the action level conclusions did not agree, the TPH
results were further interpreted to assess whether the
EnSys Petro Test System conclusion was conservative.
The EnSys Petro Test System conclusion was considered
to be conservative when the device's result was above the
action level and the reference method result was below the
action level. A regulatory agency would likely favor a
field measurement device whose results are conservative;
however, the party responsible for a site cleanup might not
favor a device that is overly conservative because of the
cost associated with unnecessary cleanup.
EnSys Petro Test System conclusions that did not agree
with reference method conclusions were conservative for
NEX Service Station, B-38, and SFT Area samples and for
70
-------
Table 7-4. Action Level Conclusions
Sampling Area or Sample Type
Fuel Farm Area
Naval Exchange Service Station Area
B-38 Area
Slop Fill Tank Area
PE sample
PE sample
Soil PE
sample
containing
weathered
gasoline in
Soil PE
sample
containing
diesel in
Blank soil
(9 percent moisture content)
Blank soil and humic acid
(9 percent moisture content)
Medium-concentration range
(9 percent moisture content)
High-concentration range
(9 percent moisture content)
High-concentration range
(16 percent moisture content)
Low-concentration range
(9 percent moisture content)
Medium-concentration range
(9 percent moisture content)
High-concentration range
(less than 1 percent moisture
content)
High-concentration range
(9 percent moisture content)
Action
Level
(mg/kg)
100
50
100
500
10
200
200
2,000
2,000
15
200
2,000
2,000
Total
Total Number
of Samples
Analyzed
10
20
8
28
3
6
3
3
3
7
3
3
3
100
Total Number of
Samples for
Which Action
Level
Conclusions
Could Be Drawn"
10
20
8
25
3
5
3
0
0
7
2
0
0
83
Percentage of
Samples for Which
EnSys Petro Test
System and Reference
Method Conclusions
Agreed
90
75
25
60
33
100
100
57
100
67
When Conclusions Did
Not Agree, Were EnSys
Petro Test System
Conclusions
Conservative or Not
Conservative?1"
Not conservative
Conservative
Conservative
Conservative
Not conservative
Conservative
Notes:
mg/kg = Milligram per kilogram
PE = Performance evaluation
" Based on the detection levels selected by SDI during the demonstration (10,100, and 1,000 mg/kg for weathered gasoline-containing soil samples
and 15,100, and 1,000 mg/kg for diesel-containing soil samples), no conclusions could be drawn for 17 samples.
b A conclusion was considered to be conservative when the EnSys Petro Test System result was above the action level and the reference method
result was below the action level. A conservative conclusion may also be viewed as a false positive.
low-concentration-range soil PE samples containing
diesel. One conclusion for an FFA sample and two
conclusions for blank soil PE samples were not
conservative. The conclusion for the FFA sample appears
to be an outlier because the re ference method result for the
sample was 13 times the action level. The conclusions for
the blank soil PE samples may be attributed to difficulty in
accurately measuring TPH at trace levels. In summary, the
EnSys Petro Test System action level conclusions were
considered to be conservative because 24 of 27
conclusions (89 percent) were conservative.
7.1.2.2
Precision
Both environmental and PE samples were analyzed to
evaluate the precision associated with TPH measurements
using the EnSys Petro Test System and reference method.
The results of this evaluation are summarized below.
Environmental Samples
Blind field triplicates were analyzed to evaluate the overall
precision of the sampling, extraction, and analysis steps
71
-------
associated with TPH measurement. Each set of field
triplicates was collected from a well-homogenized sample.
Also, extract duplicates were analyzed to evaluate
analytical precision only. Each set of extract duplicates
was collected by extracting a given soil sample and
collecting two aliquots of the extract. Additional
information on field triplicate and extract duplicate
preparation is included in Chapter 4.
Tables 7-5 and 7-6 present the EnSys Petro Test System
and reference method results for 11 sets of field triplicates
and 12 sets of extract duplicates, respectively. EnSys
Petro Test System precision was evaluated by assessing the
comparability of the TPH concentration ranges reported for
field triplicates and extract duplicates. Reference method
precision was estimated using RSDs for field triplicates
and RPDs for extract duplicates.
As shown in Table 7-5, the TPH concentration ranges
reported by the EnSys Petro Test System were the same for
each field triplicate set. Of the 11 field triplicate sets,
two (18 percent) had a finite TPH concentration range of
< 15 mg/kg (field triplicate set 1) or > 100 to < 1,000 mg/kg
(field triplicate set 7). However, the TPH results for the
remaining field triplicate sets (82 percent) were reported
as > 1,000 mg/kg; the infinite concentration range
associated with these TPH results may have contributed to
the outcome that the results for a given set of field
triplicates were the same. Table 7-5 also shows that the
RSDs for the reference method ranged from 4 to
39 percent with a median of 16 percent, hi summary, the
field triplicate results for both the EnSys Petro Test
System and the reference method exhibited good overall
precision.
As shown in Table 7-6, the TPH concentration ranges
reported by the EnSys Petro Test System were the same for
each extract duplicate set. Three of the 12 extract
duplicate sets (25 percent) had a finite TPH concentration
range of <15 mg/kg (extract duplicate set 1), >15 to
<100 mg/kg (extract duplicate set 8), or >100 to
<1,000 mg/kg (extract duplicate set 7). However, the TPH
results for the remaining extract duplicate sets (75 percent)
were reported as > 1,000 mg/kg; the infinite concentration
range associated with the TPH result (> 1,000 mg/kg) may
have contributed to the outcome that the results for a given
set of extract duplicates were the same.
Table 7-6 also shows that the RPDs for the reference
method ranged from 0 to 11 with a median of 3. As
expected, the median RPD for extract duplicates was less
than the median RSD for field triplicates for the reference
method. This finding indicated that greater precision was
achieved when only the analysis step could have
contributed to TPH measurement error than when all three
steps (sampling, extraction, and analysis) could have
contributed to such error.
Because the EnSys Petro Test System TPH results for the
field triplicates exhibited the highest precision that can be
achieved by a semiquantitative device, no conclusions
could be drawn regarding whether greater precision was
achieved when only the analysis step could have
contributed to TPH measurement error.
Performance Evaluation Samples
Table 7-7 presents the EnSys Petro Test System and
reference method TPH results for eight sets of replicates
for soil PE samples and two sets of replicate liquid PE
samples.
For the EnSys Petro Test System, the TPH concentration
ranges were the same for 8 of the 10 sets of replicates. In
the remaining two sets of replicates for which the TPH
concentration ranges were not the same, only one of seven
(replicate set 5) and one of three (replicate set 6) TPH
results were different. Three of the 10 replicate sets
(30 percent) had a finite TPH concentration range of
<10 mg/kg (replicate set 1), >15 to <100 mg/kg (replicate
set 5), or >100 to < 1,000 mg/kg (one sample each in
replicate sets 5 and 6). However, the TPH results for the
remaining replicate sets (70 percent) were reported as
> 1,000 mg/kg or >200,500 mg/L; the infinite
concentration ranges associated with the TPH results
(> 1,000 mg/kg and >200,500 mg/L) may have contributed
to the outcome that the results for a given set of replicates
were the same.
For the reference method, the RSD calculated for the blank
soil samples was not considered in evaluating the
method's precision because one of the three blank soil
sample results (5.12 mg/kg) was estimated by adding one-
half the reporting limits for the GRO, DRO, and ORO
components of TPH measurement. The RSDs for the
remaining seven replicate sets ranged from 5 to 13 percent
with a median of 8 percent. The RSDs for the two
triplicate sets of liquid samples were 5 and 6 percent with
a median of 5.5 percent, hi summary, the EnSys Petro
Test System and reference method results for PE samples
exhibited good overall precision.
72
-------
Table 7-5. Summary of EnSys Petro Test System and Reference Method Precision for Field Triplicates of Environmental Samples
Sampling Area
Fuel Farm Area
Naval Exchange Service
Station Area
B-38 Area
Slop Fill Tank Area
Field Triplicate
Set
1
2
3
4
5
6
7
8
9
10
11
EnSys Petro Test System
TPH Result
(milligram per kilogram)
<15
<15
<15
> 1,000
>1,000
>1,000
> 1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
>1,000
>1,000
>100to<1,000
>100to<1,000
>100to<1,000
>1,000
> 1,000
> 1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
> 1,000
Were TPH
Concentration Ranges
for a Given Field
Triplicate the Same or
Different?
Same
Same
Same
Same
Same
Same
Same
Same
Same
Same
Same
Reference Method
TPH Result
(milligram per kilogram)
68.2
90.2
44.1
15,000
12,000
13,900
280
270
219
1,870
881
1,180
1,560
1,120
1,390
9.56
14.2
15.2
79
61.4
67.3
834
1,090
938
501
544
517
280
503
369
185
146
253
Relative Standard
Deviation (percent)
34
11
13
39
16
23
13
14
4
29
28
Notes:
Greater than
Less than
73
-------
Table 7-6. Summary of EnSys Petro Test System and Reference Method Precision for Extract Duplicates
Sampling Area
Fuel Farm Area
Naval Exchange Service
Station Area
B-38 Area
Slop Fill Tank Area
Extract
Duplicate
Set
1
2
3
4
5
6
7
8
9
10
11
12
EnSys Petro Test System
TPH Result
(milligram per
kilogram)
<15
<15
>1,000
>1,000
>1,000
> 1,000
>1,000
>1,000
>1.000
>1,000
>1,000
> 1,000
>100to<1,000
>100to<1,000
>15to<100
>15to<100
> 1,000
> 1,000
>1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
Were TPH Concentration
Ranges for a Given Extract
Duplicate Set the Same or
Different?
Same
Same
Same
Same
Same
Same
Same
Same
Same
Same
Same
Same
Reference Method
TPH Result
(milligram per kilogram)
44.1
44.1
13,700
14,000
226
213
1,190
1,170
1,420
1,360
15.5
14.9
79.6
78.4
41.4
41.5
829
838
528
473
271
289
189
181
Relative Percent
Difference
0
2
6
2
4
4
2
0
1
11
6
4
Notes:
= Greater than
= Less than
74
-------
Table 7-7. Comparison of EnSys Petro Test System and Reference Method Precision for Replicate Performance Evaluation Samples
Sample Type
Replicate
Set
EnSys Petro Test System
TPH Result
Were TPH Concentration
Ranges for a Given Replicate
Set the Same or Different?
Reference Method
TPH Result
Relative Standard
Deviation (percent)
Soil Samples (Processed Garden Soil) (TPH Results in Milligram per Kilogram)
Blank (9 percent moisture content)
Weathered
gasoline
Diesel
Medium-range TPH
concentration
(9 percent moisture
content)
High-range TPH
concentration
(9 percent moisture
content)
High-range TPH
concentration
(16 percent moisture
content)
Low-range TPH
concentration
(9 percent moisture
content)
Medium-range TPH
concentration
(9 percent moisture
content)
High-range TPH
concentration
(9 percent moisture
content)
High-range TPH
concentration
(<1 percent moisture
content)
1
2
3
4
5
6
7
8
<10
<10
<10
>1,000
>1,000
> 1,000
>1,000
> 1,000
>1,000
>1,000
> 1,000
> 1,000
>15to<100
>15to<100
>15to<100
>15to<100
> 1 00 to < 1,000
>15tO<100
>15to<100
>1,000
>1,000
>100to<1,000
>1,000
> 1,000
> 1,000
>1,000
> 1,000
>1,000
Same
Same
Same
Same
Same for six of seven
Same for two of three
Same
Same
5.12
13.1
13.5
702
743
671
1,880
2,020
2,180
1,740
1,980
2,050
12.0
16.5
13.7
16.4
17.4
17.2
14.8
226
265
267
2,480
2,890
2,800
2,700
2,950
3,070
45
5
7
8
13
9
8
6
Liquid Samples (Neat Materials) (TPH Results in Milligram per Liter)
Weathered gasoline
Diesel
9
10
>200,500
>200,500
>200,500
>200,500
>200,500
>200,500
Same
Same
656,000
611,000
677,000
1,090,000
1,020,000
1,160,000
5
6
Notes:
= Greater than
= Less than
75
-------
Finally, for the reference method, the median RSD for the
soil PE samples (8 percent) was less than that for the
environmental samples (16 percent), indicating that greater
precision was achieved for the samples prepared under
more controlled conditions (the PE samples). A similar
comparison could not be made for the EnSys Petro Test
System becaues the device' s results were semiquantitative.
7.7.3 Primary Objective P3: Effect of
Interferents
The effect of interferents on TPH measurement using the
EnSys Petro Test System and reference method was
evaluated through analysis of high-concentration-range
soil PE samples that contained weathered gasoline or
diesel with or without an interferent. The six interferents
used were MTBE; PCE; Stoddard solvent; turpentine;
1,2,4-trichlorobenzene; and humic acid. In addition, neat
(liquid) samples of each interferent except humic acid were
used as quasi-control samples to evaluate the effect of each
interferent on the TPH results obtained using the EnSys
Petro Test System and the reference method. Liquid
interferent samples were submitted for analysis as blind
triplicate samples. SDI and the reference laboratory were
provided with flame-sealed ampul es of each interferent and
were given specific instructions to prepare dilutions of the
liquid interferents for analysis. Two dilutions of each
interferent were prepared; therefore, there were six EnSys
Petro Test System and reference method TPH results for
each interferent. Blank soil was mixed with humic acid at
two levels to prepare quasi-control samples for this
interferent. Additional details regarding the interferents
are provided in Chapter 4. The results for the quasi-
control interferent samples are discussed first below,
followed by the effects of the interferents on the TPH
results for soil samples.
7.1.3.1 Interferent Sample Results
Table 7-8 presents the EnSys Petro Test System and
reference method TPH results, mean TPH results, and
mean responses for triplicate sets of liquid PE samples and
soil PE samples containing humic acid. Each mean
response was calculated by dividing the mean TPH result
for a triplicate set by the interferent concentration and
multiplying by 100. For liquid PE samples, the interferent
concentration was estimated using its density and purity.
The mean responses for the EnSys Petro Test System
ranged from 0 to >28 percent for the liquid interferent
samples; the mean response for humic acid was 0 percent.
The TPH results for a given triplicate set and between the
triplicate sets showed good agreement. Because SDI
performed TPH measurements for each liquid interferent
at two different dilutions, a conclusion regarding the effect
of each interferent on TPH results was drawn using (1) the
higher mean TPH result between triplicate sets when the
TPH results were reported as "greater than" values and
(2) the lower mean TPH resu It between triplicate sets when
the TPH results were reported as "less than" values.
Therefore, the mean response for MTBE (0 percent)
indicated that this compound cannot be measured as TPH
using the EnSys Petro Test System. However, the mean
responses for Stoddard solvent (>26 percent) indicated that
this compound can be measured as TPH using the device.
The mean responses for PCE (>25 percent); turpentine
(>24 percent); and 1,2,4-trichlorobenzene (>28 percent)
indicated that these interferents will likely result in false
positives during TPH measurement. Also, the mean
response of 0 percent for humic acid indicated that humic
acid would not result in either false positives or false
negatives during TPH measurement.
The mean responses for the reference method ranged from
17 to 92 percent for the liquid interferent samples; the
mean response for humic acid was 0 percent. The TPH
results for a given triplicate set and between the triplicate
sets showed good agreement. The mean responses for
MTBE (39 percent) and Stoddard solvent (85 percent)
indicated that these compounds can be measured as TPH
using the reference method. The mean responses for PCE
(17.5 percent); turpentine (52 percent); and 1,2,4-trichloro-
benzene (50 percent) indicated that these interferents will
likely result in false positives during TPH measurement.
The mean response of 0 percent for humic acid indicated
that humic acid would not result in either false positives or
false negatives during TPH measurement.
7.13.2 Effects of Interferents on TPH Results for
Soil Samples
The effects of interferents on TPH measurement for soil
samples containing weathered gasoline or diesel were
examined through analysis of PE samples containing
(1) weathered gasoline or diesel (control) and
(2) weathered gasoline or diesel plus a given interferent
at two levels. Information on the selection of interferents
is provided in Chapter 4.
Triplicate sets of control samples and samples containing
interferents were prepared for analysis using the EnSys
Petro Test System and reference method. Because the
76
-------
Table 7-8. Comparison of EnSys Petro Test System and Reference Method Results for Interferent Samples
Interferent and Concentration"
EnSys Petro Test System
TPH Result
Mean TPH
Result
Mean Response6
(percent)
Reference Method
TPH Result
Mean TPH
Result
Mean Response6
(percent)
Liquid Interferent Samples (TPH Results in Milligram per Liter)
Methyl-tert-butyl ether
(740,000 milligrams per liter)
Tetrachloroethene
(1,621,000 milligrams per liter)
Stoddard solvent
(771,500 milligrams per liter)
Turpentine
(845,600 milligrams per liter)
1 ,2,4-Trichlorobenzene
(1 ,439,000 milligrams per liter)
<2,005
<2,005
<2,005
>10,050to<100,500
<1,005
<1,005
>400,500
>400,500
>400,500
>80,500
>80,500
>80,500
>200,500
>200,500
>200,500
>40,500
>40,500
>40,500
>200,500
>200,500
>200,500
>40,500
>40,500
>40,500
>400,500
>400,500
>400,500
>80,500
>80,500
>80,500
<2,005
< 1,005°
>400,500
>80,500
>200,500
>40,500
>200,500
>40,500
>400,500
>80,500
0
0
>25
>5
>26
>5
>24
>5
>28
>6
309,000
272,000
270,000
303,000
313,000
282,000
269,000
270,000
277,000
290,000
288,000
307,000
561,000
628,000
606,000
703,000
Not reported
713,000
504,000
459,000
442,000
523,000
353,000
349,000
711,000
620,000
732,000
754,000
756,000
752,000
284,000
299,000
272,000
295,000
598,000
708,000
468,000
408,000
688,000
754,000
38
40
17
18
78
92
55
48
48
52
Interferent Samples (Processed Garden Soil) (TPH Results in Milligram per Kilogram)
Humic acid at 3,940 milligrams
per kilogram
Humic acid at 19,500
milligrams per kilogram
<15
<15
>100to<1,000
>15to<1,000
<15
<15
<15d
<15"
0
0
8.99
8.96
8.12
69.3
79.1
78.5
9.00
76.0
0
0
Notes:
> = Greater than < = Less than
° A given liquid interferent concentration was estimated using its density and purity.
" The mean response was calculated by dividing the mean TPH result for a triplicate set by the interferent concentration and multiplying by 100.
c Because the EnSys Petro Test System TPH results for five of six samples containing methyl-tert-butyl ether were below the lowest detection level
used by SDI, the device result of >10,050 to <100,500 milligrams per liter (an analytical outlier) was not considered.
" Because the EnSys Petro Test System TPH results for four of six samples containing humic acid were below the lowest detection level used by
SDI, the device results of >100 to <1,000 and >15 to <1,000 milligrams per kilogram (analytical outliers) were not considered.
77
-------
EnSys Petro Test System is a semiquantitative device, the
TPH concentration of a sample cannot be reported as an
absolute value, and a statistical approach could not be used
to evaluate the effect of interferents on TPH measurement.
For the reference method, a parametric or nonparametric
test was selected for statistical evaluation of the analytical
results using the approach presented in Figure 7-1.
TPH results for samples with and without interferents,
statistical tests performed, and statistical test conclusions
for the reference method are presented in Table 7-9. The
null hypothesis for the statistical tests was that mean TPH
results for samples with and without interferents were
equal. The effects of the interferents are discussed below
for both the EnSys Petro Test System and the reference
method.
Effect of Methyl-Tert-Butyl Ether
The effect of MTBE was evaluated for soil PE samples
containing weathered gasoline. Based on the liquid PE
sample (neat material) analytical results, MTBE was
expected to have no effect on the TPH results for the
EnSys Petro Test System; however, it was expected to bias
the reference method results high.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of MTBE on EnSys Petro Test System
TPH results for soil PE samples; the TPH concentrations
in soil PE samples containing weathered gasoline with and
without MTBE exceeded the highest detection level used
by SDI during the demonstration (1,000 mg/kg).
For the reference method, at the interferent levels used,
MTBE was expected to bias the TPH results high by
21 percent (low level) and 33 percent (high level). The
expected bias would be lower (17 and 27 percent,
respectively) if MTBE in soil samples was assumed to be
extracted as efficiently as weathered gasoline in soil
samples. However, no effect on TPH measurement was
observed for soil PE samples analyzed during the
demonstration. A significant amount of MTBE, a highly
volatile compound, may have been lost during PE sample
preparation, transport, storage, and handling, thus lowering
the MTBE concentrations to levels that would not have
increased the TPH results beyond the reference method's
precision (7 percent).
Effect of Tetrachloroethene
The effect of PCE was evaluated for soil PE samples
containing weathered gasoline. Based on the liquid PE
sample (neat material) analytical results, PCE was
expected to bias the EnSys Petro Test System and
reference method TPH results high.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of PCE on EnSys Petro Test System
TPH results for soil PE samples; the TPH concentrations
in soil PE samples containing weathered gasoline with and
without PCE exceeded the highest detection level used by
SDI during the demonstration (1,000 mg/kg).
For the reference method, at the interferent levels used,
PCE was expected to bias the TPH results high by
24 percent (low level) and 113 percent (high level). The
expected bias would be lower (20 and 92 percent,
respectively) if PCE in soil samples was assumed to be
extracted as efficiently as weathered gasoline in soil
samples. The statistical tests showed that the probability
of the three means being equal was < 5 percent. However,
the tests also showed that at the high level, PCE biased the
TPH results high, which appeared to be reasonable based
on the conclusions drawn from the analytical results for
neat PCE. As to the reason for PCE at the low level
having no effect on the TPH results, volatilization during
PE sample preparation, transport, storage, and handling
may have lowered the PCE concentrations to levels that
would not have increased the TPH results beyond the
reference method's precision (7 percent).
Effect of Stoddard Solvent
The effect of Stoddard solvent was evaluated for
weathered gasoline and diesel soil PE samples. Based on
the liquid PE sample (neat material) analytical results,
Stoddard solvent was expected to bias the EnSys Petro
Test System and reference method results high.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of Stoddard solvent on EnSys Petro
Test System TPH results for soil PE samples; the TPH
concentrations in soil PE samples containing weathered
gasoline and diesel with and without Stoddard solvent
exceeded the highest detection level used by SDI during
the demonstration (1,000 mg/kg).
78
-------
Table 7-9. Comparison of EnSys Petro Test System and Referece Method Results for Soil Performance Evaluation Samples Containftg Interferents
Sample Matrix and
Interferenf
EnSys Petro Test System"
TPH Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Reference Method
TPH
Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Statistical Tests
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Probability of Mean TPH
Results for Samples With
and Without Interferents
Being the Same (percent)
Soil Samples Without Interferents
Weathered gasoline
Diesel
> 1,000
> 1,000
>1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
Not applicable
Not applicable
1,880
2,020
2,180
2,480
2,890
2,800
2,030
2,720
Not applicable
Not applicable
Soil Samples With Interferents
Weathered
gasoline
MTBE
(1,100mg/kg)
MTBE
(1,700mg/kg)
PCE
(2,810mg/kg)
PCE
(13,100 mg/kg)
Stoddard
solvent
(2,900 mg/kg)
Stoddard
solvent
(15,400 mg/kg)
>1,000
>1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
> 1,000
> 1,000
> 1,000
> 1,000
> 1,000
>1,000
>1,000
> 1,000
> 1,000
>1,000
> 1,000
>1,000
> 1,000
> 1,000
>1 ,000
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
1,900
1,750
2,210
2,150
2,320
2,560
2,540
2,160
2,450
4,740
4,570
4,040
4,350
4,760
4,110
10,300
14,300
1 1 ,000
1,950
2,340
2,380
4,450
4,410
11,900
One-way analysis of
variance (parametric)
and Tukey (honest,
significant difference)
pairwise comparison
of means (parametric)
Same
Mean with interferent at
high level was different
from means without
interferent and with
interferent at low level
All three means (with and
without interferents) were
significantly different from
one another
11.21
0.00
0.00
-------
Table 7-9. Comparison of EnSys Petro Test System and Referace Method Results for Soil Performance Evaluation Samples Containig Interferents (Continued)
Sample Matrix and
Interferenf
EnSys Petro Test System6
TPH Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Reference Method
TPH
Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Statistical Tests
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Probability of Mean TPH
Results for Samples With
and Without Interferents
Being the Same (percent)
Soil Samples With Interferents (Continued) :
Diesel
Weathered
gasoline
Diesel
Stoddard
solvent
(3,650 mg/kg)
Stoddard
solvent
(18,200 mg/kg)
Turpentine
(2,730 mg/kg)
Turpentine
(12,900 mg/kg)
Turpentine
(3,850 mg/kg)
Turpentine
(19,600 mg/kg)
1 ,2,4-Trichloro-
benzene
(3,350 mg/kg)
1,2,4-Trichloro-
benzene
(16,600 mg/kg)
>1,000
>1,000
>1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
> 1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1 ,000
>1,000
>1,000
> 1,000
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
Inconclusive
4,390
4,640
4,520
8,770
6,580
8,280
4,410
3,870
4,440
12,800
11,200
14,600
5,860
5,810
5,610
15,000
13,300
13,300
3,220
3,750
3,550
7,940
6,560
6,690
4,520
7,880
4,240
12,900
5,760
13,900
3,510
7,060
One-way analysis of
variance (parametric)
and Tukey (honest,
significant difference)
pairwise comparison
of means (parametric)
Kruskal-Wallis one-
way analysis of
variance
(nonparametric) and
Kruskal-Wallis
pairwise comparison
of means
(nonparametric)
One-way analysis of
variance (parametric)
and Tukey (honest,
significant difference)
pairwise comparison
of means (parametric)
All three means (with and
without interferents) were
significantly different from
one another
All three means (with and
without interferents) were
significantly different from
one another
Mean without interferent
was same as mean with
interferent at low level;
mean with interferent at
low level was same as
mean with interferent at
high level
Mean with interferent at
high level was different
from means without
interferent and with
interferent at low level
0.00
0.00
2.65
0.01
oo
o
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Table 7-9. Comparison of EnSys Petro Test System and Referace Method Results for Soil Performance Evaluation Samples Containig Interferents (Continued)
Sample Matrix and
Interferenf
EnSys Petro Test Systemb
TPH Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Reference Method
TPH
Result
(mg/kg)
Mean TPH
Result
(mg/kg)
Statistical Tests
Were Mean TPH Results
for Samples With and
Without Interferents the
Same or Different?
Probability of Mean TPH
Results for Samples With
and Without Interferents
Being the Same (percent)
Soil Samples With Interferents (Continued)
Diesel
(Continued)
Humic acid
(3,940 mg/kg)
Humic acid
(19,500 mg/kg)
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
>1,000
Inconclusive
Inconclusive
2,150
2,080
2.360
2,660
2,420
2,270
2,200
2,450
One-way analysis of
variance (parametric)
and Tukey (honest,
significant difference)
pairwise companson
of means (parametric)
Mean without interferent
was same as mean with
interfered at high level;
mean with interferent at
low level was same as
mean with interferent at
high level
3.87
Notes:
> =
mg/kg =
MTBE =
PCE =
Greater than
Milligram per kilogram
Methyl-tert-butyl ether
Tetrachloroethene
All samples were prepared at a 9 percent moisture level.
Because the EnSys Petro Test System is a semiquantitative devicea statistical approach could not be used to draw conclusionsregarding the effect of a given interferent on TPH
measurement. In addition, based on the detection levels selectedby SDI during the demonstration, the TPH results for samplesArith and without interferents were reported as >1,000 mg/kg.
Therefore, no conclusions could bedrawn regarding the effect of a given interferent on TPH measurement.
-------
For the reference method, at the interferent levels used,
Stoddard solvent was expected to bias the TPH results high
by 121 percent (low level) and 645 percent (high level) for
weathered gasoline soil PE samples and by 114 percent
(low level) and 569 percent (high level) for diesel soil PE
samples. The expected bias would be lower (99 and
524 percent, respectively, for weathered gasoline soil PE
samples and 61 and 289 percent, respectively, for diesel
soil PE samples) if Stoddard solvent in soil samples was
assumed to be extracted as efficiently as weathered
gasoline and diesel hi soil samples. The statistical tests
showed that the mean TPH results with and without the
interferent were different for both weathered gasoline and
diesel soil PE samples, which confirmed the conclusions
drawn from the analytical results for neat Stoddard
solvent.
Effect of Turpentine
The effect of turpentine was evaluated for weathered
gasoline and diesel soil PE samples. Based on the liquid
PE sample (neat material) analy tical results, turpentine was
expected to bias the EnSys Petro Test System and
reference method results high.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of turpentine on EnSys Petro Test
System TPH results for soil PE samples; the TPH
concentrations in soil PE samples containing weathered
gasoline and diesel with and without turpentine exceeded
the highest detection level used by SDI during the
demonstration (1,000 mg/kg).
For the reference method, at the interferent levels used,
turpentine was expected to bias the TPH results high by
69 percent (low level) and 327 percent (high level) for
weathered gasoline soil PE samples and by 72 percent (low
level) and 371 percent (high level) for diesel soil PE
samples. The expected bias would be lower (56 and
266 percent, respectively, for weathered gasoline soil PE
samples and 39 and 200 percent, respectively, for diesel
soil PE samples) if turpentine in soil samples was assumed
to be extracted as efficiently as weathered gasoline and
diesel in soil samples. The statistical tests showed that the
mean TPH results with and without the interferent were
different for weathered gasoline soil PE samples, which
confirmed the conclusions drawn from the analytical
results for neat turpentine. However, for diesel soil PE
samples, (1) the mean TPH result without the interferent
and the mean TPH result with the interferent at the low
level were equal and (2) the mean TPH results with the
interferent at the low and high levels were equal,
indicating that turpentine at the low level did not affect the
TPH results for the diesel soil PE samples but that
turpentine at the high level did affect the TPH results. The
conclusion reached for the interferent at the low level was
unexpected and did not seem reasonable based on a simple
comparison of means that differed by a factor of three.
The anomaly might have been associated with the
nonparametric test used to evaluate the effect of turpentine
on TPH results for diesel soil PE samples, as
nonparametric tests do not account for the magnitude of
the difference between TPH results.
Effect of 1,2,4-TrichIorobenzene
The effect of 1,2,4-trichlorobenzene was evaluated for
diesel soil PE samples. Based on the liquid PE sample
(neat material) analytical results, 1,2,4-trichlorobenzene
was expected to bias the EnSys Petro Test System and
reference method results high.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of 1,2,4-trichlorobenzene on EnSys
Petro Test System TPH results for soil PE samples; the
TPH concentrations in soil PE samples containing diesel
with and without 1,2,4-trichlorobenzene exceeded the
highest detection level used by SDI during the
demonstration (1,000 mg/kg).
For the reference method, at the interferent levels used,
1,2,4-trichlorobenzene was expected to bias the TPH
results high by 62 percent (low level) and 305 percent
(high level). The expected bias would be lower (33 and
164 percent, respectively) if 1,2,4-trichlorobenzene in soil
samples was assumed to be extracted as efficiently as
diesel in soil samples. The statistical tests showed that the
probability of three means being equal was <5 percent.
However, the tests also showed that when the interferent
was present at the high level, TPH results were biased
high. The effect observed at the high level confirmed the
conclusions drawn from the analytical results for neat
1,2,4-trichlorobenzene. The statistical tests indicated that
the mean TPH result with the interferent at the low level
was not different from the mean TPH result without
the interferent, indicating that the low level of
1,2,4-trichlorobenzene did not affect TPH measurement.
However, a simple comparison of the mean TPH results
revealed that the low level of 1,2,4-trichlorobenzene
increased the TPH result to nearly the result based on the
expected bias of 33 percent. Specifically, the mean TPH
result with the interferent at the low level was 3,510 mg/kg
82
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rather than the expected value of 3,620 mg/kg. The
conclusions drawn from the statistical tests were justified
when the variabilities associated with the mean TPH
results were taken into account.
Effect of Humic Acid
The effect of humic acid was evaluated for diesel soil PE
samples. Based on the analytical results for soil PE
samples containing humic acid, this interferent was
expected to have no effect on the TPH results for the
EnSys Petro Test System and reference method.
Table 7-9 shows that no conclusions could be drawn
regarding the effect of humic acid on EnSys Petro Test
System TPH results for soil PE samples; the TPH
concentrations in soil PE samples containing diesel with
and without humic acid exceeded the highest detection
level used by SDI during the demonstration (1,000 mg/kg).
For the reference method, humic acid appeared to have
biased the TPH results low. However, the bias decreased
with an increase hi the humic acid level. Specifically, the
negative bias was 19 percent at the low level and
10 percent at the high level. For this reason, no conclusion
was drawn regarding the effect of humic acid on TPH
measurement using the reference method.
7.1.4 Primary Objective P4: Effect of Soil
Moisture Content
To measure the effect of soil moisture content on the
ability of the EnSys Petro Test System and reference
method to accurately measure TPH, high-concentration-
range soil PE samples containing weathered gasoline or
diesel at two moisture levels were analyzed. The EnSys
Petro Test System and reference method results were
converted from a wet weight basis to a dry weight basis in
order to evaluate the effect of moisture content on the
sample TPH results. Because the EnSys Petro Test
System is a semiquantitative device, the TPH
concentration in a sample cannot be reported as an
absolute value, and a statistical approach could not be used
to evaluate the effect of soil moisture content on TPH
measurement. Therefore, a qualitative evaluation was
performed to determine whether the device's TPH results
were impacted by soil moisture content—that is, to
determine whether an increase in soil moisture resulted in
an increase or decrease in the TPH concentrations
measured. The reference method dry weight TPH results
were normally distributed; therefore, a two-tailed, two-
sample Student's t-test was performed to determine
whether the reference method results were impacted by soil
moisture content. The null hypothesis for the t-test was
that the two means were equal or that the difference
between the means was equal to zero. Table 7-10 shows
the sample moisture levels, TPH results, mean TPH results
for sets of triplicate samples, whether the mean TPH
results at different soil moisture levels were the same, and
the probability of the null hypothesis being true.
Table 7-10 shows that no conclusions could be drawn
regarding the effect of soil moisture content on EnSys
Petro Test System TPH results for soil PE samples; the
TPH concentrations in soil PE samples containing
weathered gasoline and diesel exceeded the highest
detection level used by SDI during the demonstration,
which was 1,000 mg/kg on a wet weight basis. The
apparent differences in mean TPH concentrations resulted
from conversion of the concentrations to a dry weight
basis.
Table 7-10 also shows that reference method results for
weathered gasoline soil samples and diesel soil samples at
different moisture levels were statistically the same at a
significance level of 5 percent; therefore, the reference
method results were not Impacted by soil moisture content.
Based on a simple comparison of the results, this
conclusion appeared to be reasonable.
7.1.5 Primary Objective PS: Time Required for
TPH Measurement
During the demonstration, the time required for TPH
measurement activities, including EnSys Petro Test
System setup, sample extraction, sample analysis and data
package preparation, and device disassembly, was
measured. During the demonstration, either two or three
field technicians performed the TPH measurement
activities using the EnSys Petro Test System. Time
measurement began at the start of each demonstration day
when the technicians began to set up the device and ended
when they disassembled the device. Time not measured
included (1) the time spent by the technicians verifying
that they had received all the demonstration samples
indicated on chain-of-custody forms, (2) the times when
the technicians took breaks, and (3) the time that the
technicians spent away from the demonstration site
preparing and analyzing calibration standards. In addition
to the total time required for TPH measurement, the time
required to perform sample extraction and the time
required to perform sample analysis and prepare the data
83
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Table 7-10. Comparison of Results for Soil Performaice Evaluation Samples at Different Moisture Levels
Sample Type and Moisture Level
Weathered gasoline at 9 percent
moisture level
Weathered gasoline at 16 percent
moisture level
Diesel at less than 1 percent
moisture level
Diesel at 9 percent moisture level
EnSys Petro Test System
TPH Result on Dry
Weight Basis
(milligram per
kilogram)
>1,100
>1,100
>1,100
>1,200
>1.200
>1.200
> 1.000
> 1,000
> 1.000
>1,100
>1,100
>1,100
Mean TPH Result
(milligram per
kilogram)
>1,100
>1,200
> 1,000
>1,100
Were Mean TPH
Results at Different
Moisture Levels the
Same or Different?8
Inconclusive
Inconclusive
Reference Method
TPH Result on Dry
Weight Basis
(milligram per
kilogram)
2,070
2,220
2,400
2,070
2,390
2,440
2,740
3,180
3,070
2,720
2,970
3,100
Mean TPH Result
(milligram per
kilogram)
2,230
2,300
3,000
2,930
Were Mean TPH
Results at Different
Moisture Levels the
Same or Different?1
Same
Same
Probability of Null
Hypothesis Being
Truec
(percent)
66.52
71.95
Notes:
> = Greater than
1 Because the EnSys Petro Test System is a semiquantitative devfe, a statistical approach could notbe used to draw conclusions regarding the effect of soil moisture content on TPH
measurement. In addition, based on the detection levels selectedby SDI during the demonstration, the TPH results for samplesvith different moisture levels were reported as >1,000 milligrams
per kilogram on a wet weight basis. The small differences in the mean TPH concentradris resulted from conversion of the conceitrations to a dry weight basis. Therefore, no conclusions could
be drawn regarding the effect of moisture content on TPH measurement.
b A two-tailed, two-sample Student's t-test parametric) was used to evaluate the effect of soil moisture content on TPH results.
c The null hypothesis for the t-test was that the two means wereequal or that the difference between the two means was equal taero.
-------
package for the first analytical batch of soil samples
during each day of the demonstration were measured. The
number and type of samples in a batch were selected by
SDL
The time required to complete TPH measurement activities
using the EnSys Petro Test System is shown in Table 7-11.
When a given activity was performed by two or three field
technicians simultaneously, the time measurement for the
activity was the total time spent by the technicians. The
time required for each activity was rounded to the nearest
5 minutes.
Overall, SDI required 39 hours, 35 minutes, for TPH
measurement of 66 soil environmental samples, 89 soil PE
samples, 36 liquid PE samples, and 12 extract duplicates.
In addition, SDI performed m-xylene reference standard
duplicate QC checks at a rate of one per analytical batch
(five samples). Information regarding the time required for
each measurement activity during the 2-day demonstration
and for extraction and analysis of the first analytical batch
of soil samples during each day of the demonstration is
provided below.
EnSys Petro Test System setup required 15 minutes each
day, totaling 30 minutes for the entire demonstration. This
activity included device setup; performing calibration
checks for the differential photometer and digital balance;
and organization of extraction, analysis, and waste
disposal supplies. The setup time was not separately
measured for the first sample batch on the first day of the
demonstration; instead, the setup time recorded for the first
sample batch on the second day of the demonstration was
used as an estimate.
The sample extraction time and the sample analysis and
data package preparation time were not separately
measured for each analytical batch during the
demonstration because these activities were performed
concurrently by two or more SDI technicians. A total of
38 hours, 45 minutes, was required to perform 155 soil
sample extractions and 210 TPH analyses using the EnSys
Petro Test System. The 210 analyses included analyses of
155 soil samples, 36 liquid samples, and 12 extract
duplicates as well as reanalyses of 7 samples. During most
of the demonstration, two SDI technicians performed
measurement activities. On the first day of the
demonstration, a third SDI technician assisted with sample
extractions for 2 hours, 25 minutes, and with sample
analyses for 1 hour, 30 minutes.
The time required for extraction of the first analytical batch
of soil samples during each day of the demonstration was
recorded. SDI designated five samples for each analytical
batch. The number of samples was based on the capacity
of the foam workstation provided in the Common
Accessory Kit. A total of 20 minutes was required to
extract the first batch of soil samples on the first day of
Table 7-11. Time Required to Complete TPH Measurement Activities Using the EnSys Petro Test System
Time Required3
Measurement Activity
EnSys Petro Test System setup
Sample extraction
Sample analysis and data package
preparation11
EnSys Petro Test System disassembly
Total
First Sample Batch, First Day
1 5 minutes"
20 minutes
35 minutes
10 minutes'
1 hour, 20 minutes
First Sample Batch, Second Day
15 minutes
15 minutes
25 minutes
1 0 minutes'
1 hour, 5 minutes
2-Day Demonstration Period
30 minutes
38 hours, 45 minutes0
20 minutes
39 hours, 35 minutes
Notes:
The time required for each activity was rounded to the nearest 5 minutes.
The device setup time was not separately measured for the first sample batch on the first day of the demonstration; instead, the setup time recorded
for the first sample batch on the second day of the demonstration was used as an estimate.
The sample extraction time and the sample analysis and data package preparation time were not separately measured for each analytical batch
during the demonstration because two or three SDI technicians concurrently performed these activities.
The data package preparation time was not separately measured during the demonstration because the raw TPH results recorded on the field data
form constituted the data package submitted by SDI; no additional calculations were required in the field.
The device disassembly time was not separately measured during the demonstration. The disassembly time reported was estimated based on
field observations. Specifically, this estimate was based on the device setup time, excluding the time required for (1) differential photometer and
digital balance calibration checks and (2) organization of extraction, analysis, and waste disposal supplies.
85
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first day of the demonstration; therefore, an average of
4 minutes was required for extraction of a sample. A total
of 15 minutes was required to extract the first batch of
samples on the second day of the demonstration; therefore,
an average of 3 minutes was required for extraction of a
sample. The decrease in the average extraction time for
the first batch of soil samples on the second day of the
demonstration suggested that the field technicians became
more familiar with the EnSys Petro Test System extraction
procedures as the demonstration progressed.
The time required to analyze samples and prepare the data
package for the first analytical batch of soil samples during
each day of the demonstration was also recorded. On the
first day of the demonstration, a total of 35 minutes was
required to analyze the first batch of samples and record
the TPH result in the data package, or an average of
7 minutes per sample. On the second day of the
demonstration, a total of 25 minutes was required to
analyze the first batch of samples and record the TPH
result in the data package, or an average of 5 minutes per
sample. The decrease in the average sample analysis and
data recording time for the first batch of soil samples on
the second day of the demonstration suggested that the
field technicians became more familiar with the EnSys
Petro Test System analysis procedures as the
demonstration progressed.
The EnSys Petro Test System disassembly time was
estimated to be 10 minutes on each day, or a total of
20 minutes for the entire demonstration. Disassembly
included packing the reusable items of the EnSys Petro
Test System required for TPH measurement. The
disassembly time was not separately measured during the
demonstration but was estimated based on field
observations. Specifically, this estimate was based on the
device setup time, excluding the time required for
(1) differential photometer and digital balance calibration
checks and (2) organization of extraction, analysis, and
waste disposal supplies.
For the reference method, time measurement began when
the reference laboratory received all the investigative
samples and continued until the EPA received the first
draft data package from the laboratory. The reference
laboratory took 30 days to deliver the first draft data
package to the EPA. Additional time taken by the
reference laboratory to address EPA comments on all the
draft laboratory data packages was not included as part of
the time required for TPH measurement.
7.2 Secondary Objectives
This section discusses the performance results for the
EnSys Petro Test System in terms of the secondary
objectives stated in Section 4.1. The secondary objectives
were addressed based on (1) observations of the EnSys
Petro Test System's performance during the demonstration
and (2) information provided by SDL
7.2.1 Skill and Training Requirements for
Proper Device Operation
The EnSys Petro Test System is easy to operate, requiring
one field technician with basic wet chemistry skills
acquired on the job or in a university. Because the sample
extraction time may need to be adjusted based on soil type,
basic knowledge of soil types is also recommended so that
the technician can differentiate among sand, silt, and clay
soil types and adjust the extraction time accordingly. For
the demonstration, SDI chose to conduct sample analyses
using either two or three technicians in order to increase
the sample throughput. One or two technicians performed
sample extraction while one technician concurrently
performed multiple analyses.
To simplify sample analysis for the user, SDI customizes
the EnSys Petro Test System to include dilution ampules
that allow the user to obtain semiquantitative results in
order to meet project-specific requirements. SDI has 20
preset dilution ampules readily available for gasoline and
diesel analyses but develops nonstandard dilution ampules
upon request. For the demonstration, SDI used 100- and
1,000-mg/kg preset dilution ampules to analyze gasoline-
and diesel-containing soil samples.
Each item in the EnSys Petro Test System is labeled to
assist the user with sample analysis activities. Containers
that are similar in appearance but contain different
reagents are color-coded. For example, dilution ampules
used for gasoline-containing soil samples are color-coded
blue and green for 100- and 1,000-mg/kg dilutions,
respectively. Also, the labels on the 15-mL bottles
containing chromogen, substrate, and stop solution are
color-coded yellow, green, and red, respectively.
Methanol for use in sample extraction and extract dilution
is provided in premeasured, sealed ampules. In addition,
items included in the Sample Extraction Kit and the 12T
Soil Test Kit are kept organized within the foam
workstation provided in the Common Accessory Kit. As
a result, the likelihood of user error during sample analysis
is minimized.
86
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Each foam workstation has the capacity to allow five
samples to be analyzed in one batch at up to three dilution
levels. More than five samples can be analyzed at a given
time by setting up multiple workstations, but the
advisability of doing so depends on the user's experience
with the EnSys Petro Test System. Because the SDI field
technicians have extensive experience with the EnSys
Petro Test System, SDI used up to three workstations, at
any given time, during the demonstration.
The sample analysis procedure for the EnSys Petro Test
System can be learned in the field with a few practice
attempts. The system contains user guides that must be
followed to properly operate the system. In addition,
during regular business hours, SDI provides technical
support over the telephone at no additional cost.
According to SDI, the user guides supplemented by
technical support over the telephone are adequate for a
user to learn the sample analysis procedure. However, SDI
also offers a 1-day, on-site training program for $999,
which includes the cost of instructor travel and per diem
and the cost of one EnSys Petro Test System for training
purposes. SDI does not provide a training video for the
system.
With the EnSys Petro Test System, the user can easily
estimate TPH concentrations by measuring the difference
in color intensities between the reference standard and the
sample extract or multiple dilutions of the sample extract.
During the demonstration, SDI analyzed each sample at
three detection levels by diluting the sample extract twice
using the 100- and 1,000-mg/kg dilution ampules. The
resulting TPH concentration ranges used to estimate
sample concentrations were <10; >10 to <100; >100 to
< 1,000; and > 1,000 mg/kg for GRO-containing samples
and<15;>15to<100;>100tol,000mg/kg
for EDRO-containing samples. No calculations are
required to compensate for the extract dilutions.
After the demonstration, SDI made minimal revisions to
the TPH results reported in the field. Specifically, of the
203 TPH results reported in the field at the end of the
demonstration, fewer than 5 percent were corrected based
on EPA review of the data package. The corrections
primarily involved data entry errors.
7.2.2 Health and Safety Concerns Associated
with Device Operation
Sample analysis using the EnSys Petro Test System
requires handling of small quantities of multiple,
potentially hazardous reagents supplied in
sealed containers. These reagents include methanol
(100 percent); N,N-dimethylformamide (2 percent), the
hazardous component of tetramethylbenzidine; and sulfuric
acid (0.5 percent). Therefore, the user should employ good
laboratory practices during sample analysis. Example
guidelines for good laboratory practices are described in
ASTM's "Standard Guide for Good Laboratory Practices
in Laboratories Engaged in Sampling and Analysis of
Water" (ASTM 1998).
During the demonstration, SDI field technicians operated
the EnSys Petro Test System in modified Level D personal
protective equipment (PPE) to prevent eye and skin contact
with reagents. The PPE included safety glasses, disposable
gloves, and work boots as well as work clothes with long
sleeves and long pants. Sample analyses were performed
outdoors in a well-ventilated area; therefore, exposure to
volatile reagents through inhalation was not a concern.
Health and safety information for reagents in the EnSys
Petro Test System is included in material safety data sheets
available from SDI.
The user should also exercise caution when handling the
dilution ampules, which are made of glass. During the
demonstration, one SDI field technician received a minor
cut on a finger after accidentally touching the sharp edge
of an open dilution ampule.
7.2.3 Portability of the Device
The EnSys Petro Test System is easily transported
between sampling areas in the field. As stated in
Table 2-2, the system consists of three kits: the (1) Sample
Extraction Kit, (2) 12T Soil Test Kit, and (3) Common
Accessory Kit. Each Sample Extraction Kit weighs about
3 pounds and is housed in a cardboard box that is
19 inches long, 7.25 inches wide, and 5 inches high. Each
12T Soil Test Kit weighs about 5 pounds and is housed in
a cardboard box that is 18.5 inches long, 7.5 inches wide,
and 5 inches high. Each Common Accessory Kit weighs
about 19 pounds and is housed in a hard-plastic carrying
case that is 19.5 inches long, 15 inches wide, and 6 inches
high. The differential photometer, which is included in
the Common Accessory Kit, weighs 0.8 pound and is
5.3 inches long, 3.4 inches wide, and 2.6 inches high. The
differential photometer, digital balance, and digital timer
are battery-operated. Because no AC power source is
required, the system can be easily transported between
sampling areas.
87
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To operate the EnSys Petro Test System, a shaded sample
preparation and analysis area is required. The area must be
large enough to accommodate the items in one Sample
Extraction Kit and one Common Accessory Kit.
Disposable items in the 12T Soil Test Kit have designated
positions in the foam workstation included in the Common
Accessory Kit. According to SDI, the sample preparation
and analysis area must be shaded because the chromogen
(tetramethylbenzidine) and substrate (hydrogen
peroxide) added during the color development step are
photosensitive and should be kept out of direct sunlight.
A staging area may also be required to store Sample
Extraction Kits and 12T Soil Test Kits; the size of
the staging area depends on the number of samples
to be analyzed and is thus project-specific. For the
demonstration, SDI performed sample preparation and
analysis under one 8- by 8-foot tent that housed two
8-foot-long, folding tables; three folding chairs; one
20-gallon laboratory pack for flammable waste; and one
55-gallon drum for general refuse.
7.2.4 Durability of the Device
The Common Accessory Kit of the EnSys Petro Test
System contains several reusable items, including the
Artel DP™ differential photometer, ACCULAB ® digital
balance, Gilson M-25 Microman® positive displacement
pipettor, and Eppendorf™ repeater pipettor. Based on
observations made during the demonstration, the EnSys
Petro Test System is a durable field measurement device;
none of the system's reusable items malfunctioned or was
damaged. These items are manufactured or distributed by
established scientific equipment suppliers and are housed
by SDI in a hard-plastic carrying case to prevent damage
to the items during transport of the Common Accessory
Kit. The items were also unaffected by the varying
temperature and humidity conditions encountered between
8:00 a.m. and 5:00 p.m. on any given day of the
demonstration. During the daytime, the temperature
ranged from about 17 to 24 °C, while the relative humidity
ranged from 53 to 88 percent. During sample analysis, the
light, disposable items in the system were housed in the
foam workstation, so wind speeds up to 20 miles per hour
also did not affect system operation.
7.2.5 A variability of the Device and Spare Parts
During the demonstration, none of the reusable items in
the EnSys Petro Test System required replacement. Had
one of these items required replacement, it would not have
been available in local stores. A replacement item can be
obtained from SDI by overnight courier service if the order
is placed by 2:00 p.m. eastern time. If the need for a
replacement item is identified after 2:00 p.m. eastern time
and the item is needed the next day, the item might be
obtained from various scientific equipment suppliers,
depending on then- shipping procedures and locations.
Spare parts for reusable items such as the differential
photometer are not included in the EnSys Petro Test
System. SDI recommends that malfunctioning reusable
items be returned to SDI for service; according to SDI,
repairs should not be attempted in the field by the user.
Because SDI provides a 1-year warranty for reusable
items, SDI will replace such items and supply them to the
user by overnight courier service at no additional cost
during the warranty period.
The power supply for the differential photometer consists
of four rechargeable, nickel-cadmium batteries. The
batteries require 8 to 10 hours to achieve a full recharge
after discharge, and they supply enough power for about
500 readings between recharges. Because the batteries are
hard-wired into the differential photometer, it should be
returned to SDI for service if the batteries malfunction.
The power supplies for the digital balance (one 9-volt
battery) and digital timer (one G-13 cell button battery)
can be purchased from local stores and replaced in the field
if necessary.
Disposable items in the EnSys Petro Test System should be
obtained from SDI. All the disposable items, including the
antibody-coated test tubes, are manufactured only by SDI.
The disposable items provided to a given user on a given
occasion all come from the same lot. Because SDI
conducts QC checks for each lot individually, if the user
performs analyses with items from more than one lot or
uses reagents obtained from a scientific supply store, SDI
assumes no responsibility for the quality of the sample
analysis results.
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Chapter 8
Economic Analysis
As discussed throughout this ITVR, the EnSys Petro Test
System was demonstrated by using it to analyze soil
environmental samples, soil PE samples, and liquid PE
samples. The environmental samples were collected from
three contaminated sites, and the PE samples were
obtained from a commercial provider, ERA. Collectively,
the environmental and PE samples provided the different
matrix types and the different levels and types of PHC
contamination needed to perform a comprehensive
economic analysis for the EnSys Petro Test System.
During the demonstration, the EnSys Petro Test System
and the off-site laboratory reference method were each
used to perform more than 200 TPH analyses. The
purpose of the economic analysis was to estimate the total
cost of TPH measurement for the EnSys Petro Test
System and then compare this co st to that for the reference
method. The cost per analysis was not estimated for the
EnSys Petro Test System because the cost per analysis
would increase as the number of samples analyzed
decreased. This increase would be primarily the result of
the distribution of the initial capital equipment cost across
a smaller number of samples. Thus, this increase in the
cost per analysis cannot be fairly compared to the reference
laboratory's fixed cost per analysis.
This chapter provides information on the issues and
assumptions involved in the economic analysis
(Section 8.1), discusses the costs associated with using the
EnSys Petro Test System (Section 8.2), discusses the costs
associated with using the reference method (Section 8.3),
and presents a comparison of the economic analysis results
for the EnSys Petro Test System and the reference method
(Section 8.4).
8.1 Issues and Assumptions
Several factors affect TPH measurement costs. Wherever
possible in this chapter, these factors are identified in such
a way that decision-makers can independently complete a
project-specific economic analysis. The following five
cost categories were included in the economic analysis for
the demonstration: capital equipment, supplies, support
equipment, labor, and IDW disposal. The issues and
assumptions associated with these categories and the costs
not included in the analysis are briefly discussed below.
Because the reference method costs were based on a fixed
cost per analysis, the issues and assumptions discussed
below apply only to the EnSys Petro Test System unless
otherwise stated.
8.1.1 Capital Equipment Cost
The capital equipment cost was the cost associated with the
rental of the Common Accessory Kit, one of the three
primary components of the EnSys Petro Test System used
during the demonstration. The Common Accessory Kit is
available for purchase or rental from SDI; the kit can be
rented from SDI on a daily, weekly, or monthly basis. The
kit can be rented on a daily basis for 9 percent of the
purchase price; as a result, the break-even point between
the purchase price and the daily rental cost is 12 days.
Because the kit was used for 2 days during the
demonstration, the capital equipment cost was the cost
associated with the rental of the kit for 2 days, the less
expensive alternative. The purchase price and rental cost
information was obtained from a standard price list
provided by SDI.
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8.1.2 Cost of Supplies
The cost of supplies was estimated based on the supplies
required to analyze all demonstration samples using the
EnSys Petro Test System that were not included in the
capital equipment cost category. Supplies used by SDI
during the demonstration included the disposable items of
two primary components of the EnSys Petro Test System:
the Sample Extraction Kit and 12T Soil Test Kit. During
the demonstration, the quantities of kits used by SDI were
noted each day. The purchase price of each kit was
obtained from a standard price list provided by SDI.
Because a user cannot return unused supplies, no salvage
value for supplies that were not used during the
demonstration was included in the cost of supplies.
8.1.3 Support Equipment Cost
Because the EnSys Petro Test System contains
photosensitive reagents (chromogen and substrate), SDI
required a shelter such as a tent to perform sample
analyses. In addition, because of the large number of
samples analyzed during the demonstration, the EPA
provided support equipment, including tables and chairs,
for the field technicians' comfort during sample extraction
and analysis. For the economic analysis, the support
equipment costs were estimated based on price quotes from
independent sources.
8.1.4 Labor Cost
The labor cost was estimated based on the time required
for EnSys Petro Test System setup, sample preparation,
sample analysis, and summary data package preparation.
The data package included, at a minimum, a result
summary table, a run log, and any supplementary
information submitted by SDI. The measurement of the
time required for SDI to complete all analyses and submit
the data package to the EPA was rounded to the nearest
half-hour. For the economic analysis, it was assumed that
a field technician who had worked for a fraction of a day
would be paid for an entire 8-hour day. Based on this
assumption, a daily rate for a field technician was used in
the analysis.
During the demonstration, EPA representatives evaluated
the skill level required for the field technicians to complete
analyses and calculate TPH concentrations. Based on the
field observations, a field technician with basic wet
chemistry skills acquired on the job or in a university and
a few hours of device-specific training was considered to
be qualified to operate the EnSys Petro Test System. For
the economic analysis, an hourly rate of $16.63 was used
for a field technician (R.S. Means Company [Means]
2000), and a multiplication factor of 2.5 was applied to
labor costs in order to account for overhead costs. Based
on this hourly rate and multiplication factor, a daily rate of
$332.60 was used for the economic analysis.
8.1.5 Investigation-Derived Waste Disposal Cost
During the demonstration, SDI was provided with two
20-gallon laboratory packs for collecting hazardous wastes
generated (one for flammable wastes and one for corrosive
wastes) and was charged for each laboratory pack used.
Unused samples and sample extracts, residual solvent from
sample extractions and dilutions, used EnCores, and
unused chemicals that could not be returned to SDI were
disposed of in a laboratory pack. SDI was required to
provide any containers necessary to containerize individual
wastes prior to then: placement in a laboratory pack;
however, SDI did not need additional containers.
During the demonstration, SDI generated an additional
4 gallons of liquid waste. This waste, which consisted
of spent sample extract, detergent solution,
tetramethylbenzidine, hydrogen peroxide, and sulfuric
acid, was collected in a 5-gallon bucket provided by the
demonstration site representatives. Because the liquid
waste was determined to be noncorrosive, the contents of
the bucket were disposed of on site hi accordance with
demonstration site waste disposal guidelines, and the cost
for disposing of this waste was not included in the IDW
disposal cost estimate.
Items such as used plastic weigh boats, wooden spatulas,
and PPE were disposed of with municipal garbage in
accordance with demonstration site waste disposal
guidelines; the associated waste disposal cost was not
included in the IDW disposal cost estimate.
8.1.6 Costs Not Included
Items whose costs were not included in the economic
analysis are identified below along with a rationale for the
exclusion of each.
Oversight of Sample Analysis Activities. A typical user
of the EnSys Petro Test System would not be required to
pay for customer oversight of sample analysis. EPA
90
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representatives audited all activities associated with
sample analysis during the demonstration, but costs for
EPA oversight were not included in the economic analysis
because these activities were project-specific. For the
same reason, costs for EPA oversight of the reference
laboratory were also not included in the analysis.
Travel and Per Diem for Field Technicians. Field
technicians may be available locally. Because the
availability of field technicians is primarily a function of
the location of the project site, travel and per diem costs
for field technicians were not included in the economic
analysis.
Sample Collection and Management. Costs for sample
collection and management activities, including sample
homogenization and labeling, were not included in the
economic analysis because these activities were project-
specific and were not device- or reference method-
dependent.
Shipping. Costs for shipping (1) the EnSys Petro Test
System to the demonstration site and (2) sample coolers to
the reference laboratory were not included in the economic
analysis because such costs vary depending on the
shipping distance and the service used (for example, a
courier or overnight shipping versus economy shipping).
Items Costing Less Than $10. The cost of inexpensive
items such as ice used for sample preservation in the field
was not included in the economic analysis because the
estimated cost was less than $10.
8.2 EnSys Petro Test System Costs
This section presents information on the individual costs of
capital equipment, supplies, support equipment, labor, and
IDW disposal for the EnSys Petro Test System as well as
a summary of these costs. Additionally, Table 8-1
summarizes the EnSys Petro Test System costs.
8.2.1 Capital Equipment Cost
The capital equipment cost was the cost associated with
the rental of the Common Accessory Kit (Item
No. 6997020) for 2 days. Table 2-2 lists the items in the
Common Accessory Kit, which are reusable. The
Common Accessory Kit can be purchased for $ 1,999 or
rented on a daily ($175), weekly ($450), or monthly
($800) basis. Because daily rental was the cheapest option
in the context of the demonstration, the daily rental cost
was used to calculate the capital equipment cost for the kit.
Thus, the capital equipment cost of the Common
Accessory Kit for the demonstration was $350.
Items in the Common Accessory Kit that can be purchased
separately from SDI if additional quantities are needed
include the Artel DP™ Differential Photometer ($1,000),
ACCULAB® digital balance ($135), digital timer ($29),
Eppendorf™ repeater pipettor ($507), and Gilson M-25
Microman® positive displacement pipettor ($325). During
the demonstration, the photometer batteries required
recharging. Because the batteries could not be recharged
when the photometer was in use, SDI used a spare
photometer to complete TPH measurements. Because the
initial photometer was not damaged and did not require
repair, the cost of the spare photometer was not included in
the economic analysis. Also, during the demonstration,
SDI used three foam workstations to conduct sample
analyses, but only one foam workstation is included hi the
Common Accessory Kit. Because SDI provides spare
foam workstations to users at no additional cost, no cost
for the two additional workstations was included in the
economic analysis.
8.2.2 Cost of Supplies
The cost of supplies was associated with the purchase of
Sample Extraction Kits (Item No. 70423 01EA) and 12T
Soil Test Kits (Item No. 7042301). Table 2-2 lists the
items in the Sample Extraction Kit and 12T Soil Test Kit,
which are disposable. During the demonstration, SDI used
18 Sample Extraction Kits at $120 each and 15 12T Soil
Test Kits at $366 each. Thus, the total cost of the supplies
used by SDI during the demonstration was $7,650.
Of the items in the Sample Extraction Kit and 12T Soil
Test Kit, only a few items in the 12T Soil Test Kit can be
purchased separately if additional quantities are needed.
Items in the 12T Soil Test Kit that can be purchased
separately include the 5- and 12.5-mL Combitips ® for the
repeater pipettor at $1.20 each and the 50- to 250-uL
Microman® positive displacement pipettor tips, which can
be purchased in packages of 12 ($10), 24 ($15), 60 ($25),
and 200 ($70). During the demonstration, no additional
quantities of these items were required; all items required
to perform TPH measurements were included in the
Sample Extraction Kits and 12T Soil Test Kits used.
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Table 8-1. EnSys Petro Test System Cost Summary
Item
Capital equipment
Rental of Common Accessory Kit
Supplies
Sample Extraction Kit
12T Soil Test Kit
Support equipment
Tent
Tables and chairs (two each)
Labor
Field technicians
Investigation-derived waste disposal
Total Cost*
Quantity
1 unit for 2 days
18 units
1 5 units
1 unit
1 set for 1 week
5 person-days
1 20-gallon container
Unit Cost ($)
175/day
120
366
159
39
332.60
345.00
Itemized Cost ($)
350
2,160
5,490
159
39
1,663
345
$10,210
Note:
The total dollar amount was rounded to the nearest $10.
8.2.3 Support Equipment Cost
SDI was provided with one 8- by 8-foot tent to prevent
decomposition of photosensitive reagents (chromogen and
substrate) and to protect the EnSys Petro Test System and
the field technicians from inclement weather during the
demonstration. SDI was also provided two tables and two
chairs for use during sample preparation and analysis
activities. The purchase cost for the tent ($159) and the
rental cost for two tables and two chairs for 1 week ($39)
totaled $198.
8.2.4 Labor Cost
To complete all sample analyses and prepare the summary
data package, three field technicians were required during
the first day of the demonstration, and two field
technicians were required during the second day. Based on
a daily labor rate of $332.60 pe r person, the total labor cost
for the EnSys Petro Test System was $1,663.
8.2.5 Investigation-Derived Waste Disposal Cost
SDI used one laboratory pack to collect flammable
hazardous waste generated during the demonstration. The
IDW disposal cost included the purchase cost of the
laboratory pack ($38) and the cost associated with disposal
of the laboratory pack in a landfill ($307) (Means 2000).
The total IDW disposal cost was $345.
8.2.6 Summary of EnSys Petro Test System
Costs
The total cost for performing more than 200 TPH analyses
using the EnSys Petro Test System and for preparing a
summary data package was $10,210 (rounded to the
nearest $10). The TPH analyses were performed for
66 soil environmental samples, 89 soil PE samples, and
36 liquid PE samples. In addition to these 191 samples,
12 extract duplicates were analyzed for specified soil
environmental samples. When SDI performed multiple
dilutions or reanalyses for a sample, these were not
included in the number of samples analyzed.
During the demonstration, SDI analyzed five samples in a
given analytical batch at three detection levels. Five
samples were the maximum number that could be analyzed
using one foam workstation. In addition to analyzing all
demonstration samples in such a manner, SDI reanalyzed
seven sample extracts. Collectively, these activities
required SDI to use one additional Sample Extraction Kit
and 10 additional 12T Soil Test Kits, or 6 and 200 percent
more of these components, respectively, than would
otherwise have been needed. The additional Sample
Extraction Kit was required only to reanalyze the seven
sample extracts, whereas the additional 12T Soil Test Kits
were required to perform all the TPH measurement
activities.
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The total cost of $10,210 for analyzing the demonstration
samples using the EnSys Petro Test System included $350
for capital equipment; $7,650 for supplies; $198 for
support equipment; $1,663 for labor; and $345 for IDW
disposal. Of these five costs, the two largest were the cost
of supplies (75 percent of the total cost) and the labor cost
(16 percent of the total cost).
8.3 Reference Method Costs
This section presents the costs associated with the
reference method used to analyze the demonstration
samples for TPH. Depending on the nature of a given
sample, the reference laboratory analyzed the sample for
GRO, EDRO, or both and calculated the TPH
concentration by adding the GRO and EDRO
concentrations, as appropriate. The reference method costs
were calculated using unit cost information from the
reference laboratory invoices. To allow an accurate
comparison of the EnSys Petro Test System and reference
method costs, the reference method costs were estimated
for the same number of samples as was analyzed by SDL
For example, although the reference laboratory analyzed
MS/MSD samples for TPH and all soil samples for percent
moisture, the associated sample analytical costs were not
included in the reference method costs because SDI did not
analyze MS/MSD samples for TPH or soil samples for
percent moisture during the demonstration.
Table 8-2 summarizes the reference method costs, which
totaled $41,290. This cost covered preparation of
demonstration samples and then" analysis for TPH. In
addition, at no additional cost, the reference laboratory
provided (1) analytical results for internal QC check
samples such as method blanks and LCS/LCSDs and (2) an
electronic data deliverable and two paper copies of full,
EPA Contract Laboratory Program-style' data packages
within 30 calendar days of the receipt of the last
demonstration sample by the reference laboratory.
8.4 Comparison of Economic Analysis Results
The total costs for the EnSys Petro Test System ($10,210)
and the reference method ($41,290) are listed in
Tables 8-1 and 8-2, respectively. The total TPH
measurement cost for the EnSys Petro Test System was
75 percent less than that for the reference method.
Although the EnSys Petro Test System analytical results
did not have the same level of detail (for example,
quantitative data) as the reference method analytical
results or comparable QA/QC data, the EnSys Petro Test
System provided semiquantitative TPH analytical results
on site at significant cost savings. In addition, use of the
EnSys Petro Test System in the field will likely produce
additional cost savings because the results will be
available within a few hours of sample collection;
therefore, critical decisions regarding sampling and
analysis can be made in the field, resulting in a more
complete data set. However, these savings cannot be
accurately estimated and thus were not included in the
economic analysis.
Table 8-2. Reference Method Cost Summary
Item
Soil environmental samples
GRO
Extract duplicates
EDRO
Extract duplicates
Soil performance evaluation samples
GRO
EDRO
Liquid performance evaluation samples
GRO
EDRO
Total Cost*
Number of Samples Analyzed
56
10
66
12
55
89
27
24
Cost per Analysis ($)
111
55.50
142
71
111
142
111
106.50
Itemized Cost ($)
6,216
555
9,372
852
6,105
12,638
2,997
2,556
$41,290
Note:
The total dollar amount was rounded to the nearest $10.
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Chapter 9
Summary of Demonstration Results
As discussed throughout this ITVR, the EnSys Petro Test
System was demonstrated by using it to analyze 66 soil
environmental samples, 89 soil PE samples, and 36 liquid
PE samples. In addition to these 191 samples, 12 extract
duplicates prepared using the environmental samples were
analyzed. The environmental samples were collected from
four individual areas at three contaminated sites, and the
PE samples were obtained from a commercial provider,
ERA. Collectively, the environmental and PE samples
provided the different matrix types and the different levels
and types of PHC contamination needed to perform a
comprehensive evaluation of the EnSys Petro Test System.
The EnSys Petro Test System performance and cost data
were compared to those for an off-site laboratory reference
method, SW-846 8015B (modified). As discussed in
Chapter 6, the reference method results were considered to
be of adequate quality for the following reasons: (1) the
reference method was implemented with acceptable
accuracy (±30 percent) for all the samples except low- and
medium-concentration-range soil samples containing
diesel, which made up only 13 percent of the total number
of samples analyzed during the demonstration, and (2) the
reference method was implemented with good precision
for all samples. The reference method results generally
exhibited a negative bias. However, the bias was
considered to be significant primarily for low- and
medium-range soil samples containing diesel. The
reference method recoveries observed during the
demonstration were typical of the recoveries obtained by
most organic analytical methods for environmental
samples.
This chapter compares the performance and cost results
for the EnSys Petro Test System with those for the
reference method, as appropriate. The performance and
cost results are discussed in detail in Chapters 7 and 8,
respectively. Tables 9-1 and 9-2 summarize the results for
the primary and secondary objectives, respectively. As
shown in these tables, during the demonstration, the EnSys
Petro Test System exhibited the following desirable
characteristics of a field TPH measurement device:
(1) good precision and (2) high sample throughput. In
addition, the EnSys Petro Test System exhibited moderate
measurement costs.
A significant number of the EnSys Petro Test System TPH
results were determined to be inconclusive because the
detection level used by SDI were not appropriate to
address the demonstration objectives. Overall, the device's
results did not compare well with those of the reference
method; in general, the device exhibited a high positive
bias. In addition, the device showed a significant response
to several interferents that are not PHCs—for example,
>25 percent to PCE; >24 percent to turpentine; and
>28 percent to 1,2,4-trichlorobenzene. These findings
indicated that the accuracy of TPH measurement using the.
device will likely be impacted by the presence of
halogenated solvents, naturally occurring oil and grease,
and chlorinated semivolatile organic contaminants such as
chlorinated pesticides and PCBs in soil samples.
Collectively, the demonstration findings indicated that the
user should exercise caution when considering the device
for a site-specific field TPH measurement application.
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Table 9-1. Summary of EnSys Petro TestSystem Results for the Primary Objectives
Primary Objective
Evaluation Basis'
Performance Results
EnSys Petro Test System
Reference Method
P1
Determine the method
detection limit
Method detection limit based on TPH analysis of
seven low-concentration-range diesel soil PE
samples
The device's TPH concentation ranges for six
of seven samples overlapped the reference
method results.
6.32 mg/kg
P2 Evaluate the accuracy
and precision of TPH
measurement
Pairwise comparison of EnSys Petro Test System and
reference method TPH results for (1) 66 soil
environmental samples collected from four areas;
(2) 28 soil PE samples, including blank, weathered
gasoline, and diesel soil samples; and (3) 6 liquid PE
samples consisting of neat weathered gasoline and
diesel
The EnSys Petro Test System results for 16 of 66 sd environmental samples were inconclusive. Of the
remaining 50 results, the device's TPH concentraton ranges overlapped the reference method results
for only 8 samples (16 percent); 36 EnSys Petro Test System results were biased high, and 6 results
were biased low.
The EnSys Petro Test System results for 12 of 28 sd PE samples were inconclusive. Of the remaining
16 results, the device's TPH concentration rangesoverlapped the reference method results for only
5 samples (31 percent); 9 EnSys Petro Test Systenresults were biased high, and 2 results were biased
low.
The EnSys Petro Test System results for £ 6 liquid PE samples were inconclusive.
Comparison of project-specific action level
conclusions of the EnSys Petro Test System with
those of the reference method for 66 soil
environmental and 34 soil PE samples
The EnSys Petro Test System results for 3 of 66 sd environmental samples were inconclusive. Of the
remaining 63 results, the device's conclusions agreed/vith those of the reference method for 41 samples
(65 percent); 21 EnSys Petro Test System concluains were false positives, and 1 was a false negative.
The EnSys Petro Test System results for 14 of 34 sd PE samples were inconclusive. Of the remaining
20 results, the device's conclusions agreed wittthose of the reference method for 15 samples
(75 percent); 3 EnSys Petro Test System conclusiona/vere false positives, and 2 were false negatives.
Overall precision for soil environmental, soil PE, and
liquid PE sample replicates
Soil environmental samples (11 triplicate sets)
The TPH concentration ranges were the
same for each field triplicate set.
Soil PE samples (8 replicate sets)
The TPH concentration ranges were the
same for 6 of the 8 sets of replicates. Of
the remaining 2 replicate sets, only one
sample TPH concentration range in each
set was different from the others.
Liquid PE samples (2 triplicate sets)
The TPH concentration ranges were the
same for each triplicate set.
Analytical precision forextract duplicates for soil
environmental samples (12 for the EnSys Petro Test
System and 12 for the reference method)
The TPH concentration ranges were the same
for each extract duplicate set.
Soil environmental samples (11 triplicate sets)
RSD range: 4 to 39 percent
Median RSD: 16 percent
Soil PE samples (7 replicate sets)
RSD range: 5 to 13 percent
Median RSD: 8 percent
Liquid PE samples (2 triplicate sets)
RSDs: 5 and 6 percent
Median RSD: 5.5 percent
RPD range: 0 to 11
Median RPD: 3
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Table 9-1. Summary of EnSys Petro Test Sysfem Results for the Primary Objectives (Continued)
Primary Objective
P3 Evaluate the effect of
interferents on TPH
measurement
P4 Evaluate the effect of
soil moisture content
on TPH measurement
P5 Measure the time
required for TPH
measurement (sample
throughput)
P6 Estimate TPH
measurement costs
Evaluation Basis'
Mean responses for neat materials, including MTBE;
PCE; Stoddard solvent; turpentine; and
1 ,2,4-trichlorobenzene, and for soil spiked with
humic acid (two triplicate sets each)
Comparison of TPH results (simple, nonstatistical
comparison for the EnSys Petro Test System and
one-way analysis of variance for the reference
method) for weathered gasoline and diesel soil PE
samples without and with interferents at two levels
Interferents for weathered gasoline soil PE samples:
MTBE, PCE, Stoddard solvent, and turpentine
Interferents for diesel soil PE samples: Stoddard
solvent; turpentine; 1 ,2,4-trichlorobenzene; and
humic acid
Comparison of TPH results (simple, nonstatistical
comparison for the EnSys Petro Test System and
two-sample Student's t-test for the reference method)
for weathered gasoline and diesel soil PE samples at
two moisture levels: 9 and 16 percent for weathered
gasoline samples and less than 1 and 9 percent for
diesel samples
Total time from sample receipt through preparation of
the draft data package
Total cost (costs of capital equipment, supplies,
support equipment, labor, andlDW disposal) for TPH
measurement of 66 soil environmental samples,
89 soil PE samples, 36 liquid PE samples, and
12 extract duplicates
Performance Results
EnSys Petro Test System
MTBE: 0 percent
PCE: >25 percent
Stoddard solvent: >26 percent
Turpentine: >24 percent
1,2,4-Trichlorobenzene: >28 percent
Humic acid: 0 percent
The TPH results were inconclusive for all
interferents.
The TPH results were inconclusive for both
weathered gasoline and diesel soil PE
samples.
39 hours, 35 minutes, for TPH measurement
of 66 soil environmental samples, 89 soil PE
samples, 36 liquid PE samples, and 12 extract
duplicates
$10,210 (including the daily rental cost of the
EnSys/EnviroGard* Common Accessory Kit,
which can be purchased for $1 ,999)
Reference Method
MTBE: 39 percent
PCE: 17.5 percent
Stoddard solvent: 85 percent
Turpentine: 52 percent
1 ,2,4-Trichlorobenzene: 50 percent
Humic acid: 0 percent
MTBE, a petroleum hydrocarbon, did not cause
statistically significant interference at either of the two
levels.
PCE caused statistically significant interference only at
the high level.
Stoddard solvent, a petroleum hydrocarbon, caused
statistically significant interference at both levels for
weathered gasoline and diesel samples.
Turpentine caused statisticallysignificant interference
(1 ) at both levels for weathered gasoline samples and
(2) only at the high level for diesel samples.
1,2,4-Trichlorobenzene causedstatistically significant
interference only at the high level.
Humic acid results were inconclusive.
Soil moisture content did not have a statistically
significant impact.
30 days for TPH measurement of 74 soil environmental
samples, 89 soil PE samples, 36 liquid PE samples, and
13 extract duplicates
$41,290
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Table 9-1. Summary of EnSys Petro Test Sysfem Results for the Primary Objectives (Continued)
Notes:
> = Greater than PCE
IDW = Investigation-derived waste PE
mg/kg = Milligram per kilogram RPD
MTBE = Methyl-tert-butyl ether RSD
Tetrachloroethene
Performance evaluation
Relative percent difference
Relative standard deviation
All statistical comparisons were madeat a significance level of 5 percent.
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Table 9-2. Summary of EnSys Petro Test System Results for the Secondary Objectives
Secondary Objective
S1
S2
S3
S4
S5
Skill and training
requirements for proper
device operation
Health and safety concerns
associated with device
operation
Portability of the device
Durability of the device
Availability of device and
spare parts
Performance Results
The device can be operated by one person with basic wet chemistry skills.
The device's user guides are considered to be adequate training materials for proper device operation.
The sample analysis procedure for the device can be learned in the field with a few practice attempts.
Minimal effort is required to estimate a TPH concentration range using the device; the sign (negative or
positive) associated with the differential photometer reading allows the user to determine the TPH
concentration range for a given sample. At the end of the demonstration, SDI reported 203 TPH results.
Of these, fewer than 5 percent required corrections, which primarily involved data entry errors.
No significant health and safety concerns were noted; when the device is used in a well-ventilated area,
basic eye and skin protection (safety glasses, disposable gloves, work boots, and work clothes with long
sleeves and long pants) should be adequate for safe device operation.
The device is battery-operated and requires no alternating current power source. The device can be easily
moved between sampling areas in the field, if necessary.
The device is housed in a hard-plastic carrying case to prevent damage to the device. During the
demonstration, none of the device's reusable items malfunctioned or was damaged. The moderate
temperatures (17 to 24 °C) and high relative humidities (53 to 88 percent) encountered during the
demonstration did not affect device operation.
All items in the device are available from SDI. During a 1-year warranty period, SDI will supply replacement
parts for the device by overnight courier service at no cost unless the reason for a part failure involves
misuse of the device.
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Chapter 10
References
AEHS. 1999. "State Soil Standards Survey." Soil &
Groundwater. December 1999/January 2000.
API. 1994. Intel-laboratory Study of Three Methods for
Analyzing Petroleum Hydrocarbons in Soils. API
Publication Number 4599. March.
API. 1996. "Compilation of Field Analytical Methods for
Assessing Petroleum Product Releases." Publication
Number 463 5. December.
API. 1998. "Selecting Field Analytical Methods: A
Decision-Tree Approach." Publication Number 4670.
August.
ASTM. 1998. "Standard Guide for Good Laboratory
Practices in Laboratories Engaged in Sampling and
Analysis of Water." Designation: D 3586-95. Annual
Book of ASTM Standards. Volume 11.01.
California Environmental Protection Agency. 1999.
Memorandum Regarding Guidance for Petroleum
Hydrocarbon Analysis. From Bart Simmons, Chief,
Hazardous Materials Laboratory. To Interested
Parties. October 21.
Dryoff, George V. Editor. 1993. "Manual of Significance
of Tests for Petroleum Products." 6th Edition.
American Society for Testing and Materials. ASTM
Manual Series: MNL 1.
EPA. 1983. "Methods for Chemical Analysis of Water
and Waste." Revision. Environmental Monitoring
and Support Laboratory. Cincinnati, OH. EPA
600-4-79-020. March.
EPA. 1996. "Test Methods for Evaluating Solid Waste."
Volumes 1A through 1C. SW-846. Third Edition.
Update HI. OSWER. Washington, DC. December.
EPA. 2000. "Field Measurement Technologies for Total
Petroleum Hydrocarbons in Soil Demonstration Plan."
Office of Research and Development. Washington,
DC. EPA/600/R-01/060. June.
Florida Department of Environmental Protection. 1996.
"FL-PRO Laboratory Memorandum." Bureau of
Waste Cleanup. Accessed on April 21. On-Line
Address: www.dep.state.fl.us/labs/docs/flpro.htm
Fritz, James S., and George H. Schenk. 1987.
Quantitative Analytical Chemistry. Allyn and Bacon,
Inc. Boston, Massachusetts. Fifth Edition.
Gary, J.H., and G.E. Handwerk. 1993. Petroleum
Refining: Technology and Economics. Marcel Dekker,
Inc. New York, New York.
Massachusetts Department of Environmental Protection.
2000. "VPH/EPH Documents." Bureau of Waste Site
Cleanup. Accessed on April 13. On-Line Address:
www.state.ma.us/dep/bwsc/vp eph.htm
Means. 2000. Environmental Remediation
Data-Unit Price. Kingston, Massachusetts.
Cost
Provost, Lloyd P., and Robert S. Elder. 1983.
"Interpretation of Percent Recovery Data." American
Laboratory. December. Pages 57 through 63.
Rittenburg, James H. 1990. Development and
Application of Immunoassay for Food Analysis.
Elsevier Applied Science. London, England, and New
York, New York.
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SDI. 1999. "PETRO Soil Test Technical Guide." Zilis, Kimberly, Maureen McDevitt, and Jerry Parr. 1988.
"A Reliable Technique for Measuring Petroleum
SDI. 2000. "Harnessing the Antibody—The Hydrocarbons in the Environment." Paper Presented
Fundamentals of Enzyme Immunoassay." at the Conference on Petroleum Hydrocarbons and
Organic Chemicals in Groundwater. National Waste
Speight, J.G. 1991. The Chemistry and Technology of Water Association. Houston, Texas.
Petroleum. Marcel Dekker, Inc. New York, New
York.
Texas Natural Resource Conservation Commission. 2000.
"Waste Updates." Accessed on April 13. On-Line
Address: www.tnrcc.state.tx.us/permitting/
wastenews.htm#additional
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Appendix
Supplemental Information Provided by the Developer
This appendix contains supplemental information provided
by SDL After the introduction, this appendix discusses
sample screening and device specificity.
Introduction
The EnSys Petro Test System used in the SITE
demonstration is one of 10 distinctly different devices that
SDI offers for on-site TPH measurement. The selection of
the "best" device for a particular application depends on
the type of contamination present, the contaminant
concentrations expected, the data quality objective (such as
semiquantitative or quantitative data), the number of
samples to be analyzed, cost, and other considerations.
Usually most of these variables are known before on-site
analysis begins, and an SDI representative assists the user
in selecting the appropriate device.
For the demonstration, the EnSys Petro Test System was
chosen because it responds well to a variety of fuel types,
particularly gasoline and diesel. The EnSys Petro Test
System does not detect heavier fuels or measure aliphatic
hydrocarbon compounds. The device has a wide dynamic
range and is listed in EPA SW-846 Method 4030.
Sample Screening (Erring on the Positive Side)
The EnSys Petro Test System is a semiquantitative device
that rapidly screens soil samples for the presence of
petroleum fuel compounds; the device effectively detects
the presence of PHCs. Because the antibody employed in
this device has a different sensitivity to each of the various
petroleum products, if the device is calibrated using a
"typical" fuel calibrator, the device will not quantitatively
report results for a specific petroleum product. Where
there are mixtures of fuels, such as in the samples used in
the SITE demonstration, the EnSys Petro Test System is
calibrated to the least reactive fuel known to be present in
order to ensure that all PHCs are detected. This approach
can lead to elevated results for those PHCs to which the
device is most sensitive. To perform a quantitative
determination for a petroleum product, the fuel type
present must be known and the device must be calibrated
accordingly.
The EnSys Petro Test System is set up to have a positive
bias of about 30 percent in order to ensure that even when
the device is calibrated with the specific petroleum product
of interest, the concentrations present will not be
underreported. This is particularly important in screening
scenarios where a nondetect or low-level result could have
serious consequences; an elevated result is clearly a
positive and at worst will trigger additional testing. Not all
SDI measurement devices are biased high; however, it is
important to be conservative with a device frequently
employed in screening for hot spots.
Device Specificity
The ORO or heavy-range petroleum products will
probably not be detected with the EnSys Petro Test
System. The device is used almost exclusively for GRO
and DRO measurement.
This appendix was written solely by SDI. The statements presented in this appendix represent the developer's point of view and summarize the
claims made by the developer regarding the EnSys Petro Test System. Publication of this material does not represent the EPA's approval or
endorsement of the statements made in this appendix; performance assessment and economic analysis results for the EnSys Petro Test System are
discussed in the body of this ITVR.
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If a site contains a mixture of gasoline and diesel
compounds, a simple correlation between device and
laboratory results for the same samples will allow
appropriate device calibration prior to field analysis.
The liquid samples analyzed in the demonstration clearly
had high TPH concentrations. Despite the high TPH
concentrations, the device could not detect PHCs in some
samples. Until SDI understands the exact nature of these
samples, it cannot address the device's performance during
the demonstration.
During the demonstration, SDI used three detection levels
to estimate the TPH concentration ranges for all samples.
These detection levels were not always consistent with the
project-specific action levels, which varied depending on
sample source and type. As a result, many TPH results
that were reported as > 1,000 mg/kg were determined to
be inconclusive when compared to the action levels
(1,500 and 2,000 mg/kg) that were above the highest
detection level (1,000 mg/kg).
For several samples analyzed dur ing the demonstration, the
EnSys Petro Test System exhibited a more consistent
response than the reference method, as was indicated by
the precision associated with the replicate sample TPH
measurements.
Soil samples analyzed during the demonstration were
collected from different locations around the country and
thus were not typical of a single site. A preliminary
comparison of EnSys Petro Test System and reference
method TPH results would allow the user to develop a
conversion factor that would take into account site-specific
factors, including soil type and contamination weathering.
Application of such a conversion factor would result in
better comparability between the device and reference
method TPH results.
This appendix was written solely by SDI. The statements presented in this appendix represent the developer's point of view and summarize the
claims made by the developer regarding the EnSys Petro Test System. Publication of this material does not represent the EPA's approval or
endorsement of the statements made in this appendix; performance assessment and economic analysis results for the EnSys Petro Test System are
discussed in the body of this ITVR.
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