USEPA ETV/SITE Program report

USEPA ETV/SITE Program report
United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
EPA/600/R-01/082
September 2001
Innovative Technology
Verification Report
Field Measurement
Technologies for Total
Petroleum Hydrocarbons in Soil
CHEMetrics, Inc., and AZUR
Environmental Ltd
RemediAid™ Total Petroleum
Hydrocarbon Starter Kit
EPA/600/R-01/082
September 2001
Innovative Technology
Verification Report
CHEMetrics, Inc., and AZUR Environmental Ltd
RemediAid™ Total Petroleum Hydrocarbon
Starter Kit
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
Notice
This document was prepared for the U.S. Environmental 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.
ii
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
VERIFICATION STATEMENT
TECHNOLOGY TYPE:
FIELD MEASUREMENT DEVICE
APPLICATION:
MEASUREMENT OF TOTAL PETROLEUM HYDROCARBONS
TECHNOLOGY NAME:
RemediAid™ TOTAL PETROLEUM HYDROCARBON
STARTER KIT
COMPANY:
ADDRESS:
CHEMetrics, INC.
ROUTE 28
CALVERTON, VA 20138
WEB SITE:
http://www.chemetrics.com
TELEPHONE:
(800) 356-3072
VERIFICATION PROGRAM DESCRIPTION
The U.S. Environmental Protection Agency (EPA) created the Superfund Innovative Technology Evaluation (SITE) and
Environmental Technology Verification (ETV) Programs to facilitate deployment of innovative technologies through
performance verification and information dissemination. The goal 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 RemediAid™ Total Petroleum Hydrocarbon Starter Kit (RemediAid™ kit)
developed by CHEMetrics, Inc. (CHEMetrics), and AZUR Environmental Ltd.
PROGRAM OPERATION
Under the SITE and ETV Programs, with the full participation of the technology developers, the EPA evaluates and
documents the performance of innovative technologies by developing demonstration plans, conducting field tests, collecting
and analyzing demonstration data, and preparing reports. The technologies are evaluated under rigorous quality assurance
(QA) protocols to produce well-documented data of known quality. The EPA National Exposure Research Laboratory, which
demonstrates field sampling, monitoring, and measurement technologies, selected Tetra Tech EM Inc. as the verification
organization to assist in field testing seven field measurement 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 RemediAid™ kit and six other field measurement devices for
TPH in soil. This verification statement focuses on the RemediAid™ kit; a similar statement has been prepared for each of
the other six devices. The performance and cost of the RemediAid™ kit 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 demonstration 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 measure 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 RemediAid™ kit was demonstrated by using it to analyze 74 soil environmental samples, 89 soil performance evaluation
(PE) samples, and 36 liquid PE samples. In addition to these 199 samples, 10 extract duplicates prepared using the
environmental samples were analyzed. The environmental samples were collected in five areas contaminated with gasoline,
diesel, lubricating oil, or other petroleum products, and the PE samples were obtained from a commercial provider.
The accompanying notice is an integral part of this verification statement.
iii
September 2001
Collectively, the environmental and PE samples provided the different matrix types and the different levels and types of
petroleum hydrocarbon contamination needed to perform a comprehensive evaluation of the RemediAid™ kit. 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 Petroleum Hydrocarbons in Soil—CHEMetrics, Inc., and AZUR Environmental Ltd
RemediAid™ Total Petroleum Hydrocarbon Starter Kit” (EPA/600/R-01/082).
TECHNOLOGY DESCRIPTION
The RemediAid™ kit is based on a combination of the modified Friedel-Crafts alkylation reaction and colorimetry. The
Friedel-Crafts alkylation reaction involves reaction of an alkyl halide with an aromatic compound in the presence of a metal
halide. With the RemediAid™ kit, dichloromethane is used as both the alkyl halide and the solvent to extract petroleum
hydrocarbons from soil samples. Anhydrous aluminum chloride is used as the metal halide because it is the most sensitive
metal halide and because it provided the most accurate recoveries for various types of hydrocarbons during laboratory tests
performed by CHEMetrics. An excess amount of dichloromethane is used, resulting in a colored reaction product that
remains in the liquid phase. Because the colored reaction product is in the liquid phase, an absorbance photometer can be
used to measure the color intensity and determine the TPH concentration in a sample extract.
During the demonstration, 5 grams of soil sample was added to an appropriate amount of anhydrous sodium sulfate in order
to remove sample moisture. Then 20 milliliters of solvent (dichloromethane) was added to a test tube along with the soil,
and the tube was shaken. The soil was allowed to settle to the bottom of the tube. Florisil was added to remove any natural
organic material from the extract and minimize associated interference. Color development was completed by combining
anhydrous aluminum chloride with the extract in an ampule. Depending on the concentration and type of hydrocarbon
present, the reaction mixture turned yellow to orange-brown. Color measurement was completed by inserting the ampule
into the photometer and recording the absorbance at a wavelength of 430 nanometers. The absorbance value was converted
to milligrams per kilogram TPH in the soil sample using predetermined calibration curve slope and intercept values.
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-specific 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 mediumconcentration-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 observed 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 comparing it to reference methods because the reference methods
themselves may have limitations. Key demonstration findings are summarized below for the primary objectives.
Method Detection Limit: Based on the TPH results for seven low-concentration-range diesel soil PE samples, the method
detection limits were determined to be 60 and 4.79 milligrams per kilogram for the RemediAid™ kit and reference method,
respectively.
Accuracy and Precision: Eighty-four of 102 RemediAid™ kit results (82 percent) used to draw conclusions regarding
whether the TPH concentration in a given sampling area or sample type exceeded a specified action level agreed with those
of the reference method; 10 RemediAid™ kit conclusions were false positives, and 8 were false negatives.
Of 102 RemediAid™ kit results used to assess measurement bias, 34 were within 30 percent, 15 were within 30 to 50 percent,
and 53 were not within 50 percent of the reference method results; 39 RemediAid™ kit results were biased low, and 63 were
biased high.
For soil environmental samples, the RemediAid™ kit results were statistically (1) the same as the reference method results
for four of the five sampling areas and (2) different from the reference method results for one sampling area. For soil PE
samples, the RemediAid™ kit results were statistically (1) the same as the reference method results for blank and mediumand high-concentration-range weathered gasoline samples and (2) different from the reference method results for low-,
medium-, and high-concentration-range diesel samples. For liquid PE samples, the RemediAid™ kit results were statistically
(1) the same as the reference method results for diesel samples and (2) different from the reference method results for
weathered gasoline samples.
The RemediAid™ kit results correlated highly with the reference method results for weathered gasoline soil PE samples and
diesel soil PE samples (the square of the correlation coefficient [R2] values were 0.95 and 0.98, respectively, and F-test
probability values were less than 5 percent). The RemediAid™ kit results correlated moderately with the reference method
results for four of the five sampling areas (R2 values ranged from 0.69 to 0.74, and F-test probability values were less than
5 percent). The RemediAid™ kit results correlated weakly with the reference method results for one sampling area (the R2
value was 0.16, and the F-test probability value was 31.83 percent).
The accompanying notice is an integral part of this verification statement.
iv
September 2001
Comparison of the RemediAid™ kit and reference method median relative standard deviations (RSD) showed that the
RemediAid™ kit and the reference method exhibited similar overall precision. Specifically, the median RSD ranges were
3 to 26 percent and 5.5 to 18 percent for the RemediAid™ kit and reference method, respectively. The analytical precision
was the same for the RemediAid™ kit and reference method (a median relative percent difference of 4).
Effect of Interferents: The RemediAid™ kit showed a mean response of less than 5 percent for neat methyl-tert-butyl ether
(MTBE); tetrachloroethene (PCE); Stoddard solvent; and 1,2,4-trichlorobenzene and for soil spiked with humic acid.
However, the device showed a mean response of 62 percent for neat turpentine. The reference method showed varying mean
responses for MTBE (39 percent); PCE (17.5 percent); Stoddard solvent (85 percent); turpentine (52 percent); 1,2,4trichlorobenzene (50 percent); and humic acid (0 percent). For the demonstration, MTBE and Stoddard solvent were included
in the definition of TPH.
Effect of Moisture Content: The RemediAid™ kit showed a statistically significant decrease (8 percent) in TPH results when
the soil moisture content was increased from 9 to 16 percent for weathered gasoline soil PE samples; the reference method
TPH results were unaffected. Both RemediAid™ kit and reference method TPH results were unaffected when the soil
moisture content was increased from less than 1 to 9 percent for diesel soil PE samples.
Measurement Time: From the time of sample receipt, CHEMetrics required 46 hours, 10 minutes, to prepare a draft data
package containing TPH results for 199 samples and 10 extract duplicates compared to 30 days for the reference method,
which was used to analyze 3 additional extract duplicates.
Measurement Costs: The TPH measurement cost for 199 samples and 10 extract duplicates was estimated to be $8,510,
including the capital equipment purchase cost of $800, for the RemediAid™ kit compared to $42,170 for the reference
method.
Key demonstration findings are summarized below for the secondary objectives.
Skill and Training Requirements: The RemediAid™ kit can be operated by one person with basic wet chemistry skills. The
sample analysis procedure for the device can be learned in the field by performing a few practice runs.
Portability: No alternating current power source is required to operate the RemediAid™ kit. The device can be operated
using a direct current power source and can be easily moved between sampling areas in the field, if necessary.
Durability and Availability of the Device: All items in the RemediAid™ kit are available from CHEMetrics. During a 1-year
warranty period, CHEMetrics will supply replacement parts for the device at no cost unless the reason for a part failure
involves misuse of the device. During the demonstration, none of the device’s reusable items malfunctioned or was damaged.
In summary, during the demonstration, the RemediAid™ kit exhibited the following desirable characteristics of a field TPH
measurement device: (1) good accuracy, (2) good precision, (3) lack of sensitivity to interferents that are not petroleum
hydrocarbons (PCE and 1,2,4-trichlorobenzene), (4) high sample throughput, (5) low measurement costs, and (6) ease of use.
Despite some of the limitations observed during the demonstration, the demonstration findings collectively indicated that the
RemediAid™ kit is a reliable field measurement device for TPH in soil.
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 of technology performance under specific, predetermined criteria and
appropriate quality assurance procedures. The EPA makes 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.
v
September 2001
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 knowledge 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 identifying 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 federal government or the private sector. Through
the SITE Program, developers are given the opportunity to conduct a rigorous demonstration of their
technologies under actual field conditions. By completing 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 Sciences Division of NERL in Las Vegas, Nevada.
Gary J. Foley, Ph.D.
Director
National Exposure Research Laboratory
Office of Research and Development
vi
Abstract
The RemediAid™ Total Petroleum Hydrocarbon Starter Kit (RemediAid™ kit) developed by
CHEMetrics, Inc. (CHEMetrics), and AZUR Environmental Ltd 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 performance and cost data for the RemediAid™ kit and six
other field measurement devices for total petroleum 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 throughput, and (5) TPH measurement costs for each
device. The demonstration involved analysis of both performance evaluation samples and
environmental samples collected in five areas contaminated with gasoline, diesel, lubricating oil, 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 demonstration, CHEMetrics required
46 hours, 10 minutes, for TPH measurement of 199 samples and 10 extract duplicates. The TPH
measurement costs for these samples were estimated to be $8,510 for the RemediAid™ kit and
$42,170 for the reference method. The method detection limits were determined to be 60 and
4.79 milligrams per kilogram for the RemediAid™ kit and reference method, respectively. During
the demonstration, the RemediAid™ kit exhibited good accuracy and precision, ease of use, and lack
of sensitivity to interferents that are not petroleum hydrocarbons (neat materials, including
tetrachloroethene and 1,2,4-trichlorobenzene). However, the device showed less than 5 percent
response to neat materials, including methyl-tert-butyl ether and Stoddard solvent, that are petroleum
hydrocarbons. Turpentine and humic acid, which are not petroleum hydrocarbons, caused a
significant measurement bias for the device. In addition, the device exhibited minor sensitivity to
soil moisture content during TPH measurement of weathered gasoline soil samples. Despite some
of the limitations observed during the demonstration, the demonstration findings collectively
indicated that the RemediAid™ kit is a reliable field measurement device for TPH in soil.
vii
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
Description of SITE Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2
Scope of Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3
Components and Definition of TPH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1 Composition of Petroleum and Its Products . . . . . . . . . . . . . . . . . . . . . .
1.3.1.1 Gasoline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.2 Naphthas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.3 Kerosene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.4 Jet Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.5 Fuel Oils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.6 Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1.7 Lubricating Oils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2 Measurement of TPH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2.1 Historical Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2.2 Current Options for TPH Measurement in Soil . . . . . . . . . . . . .
1.3.2.3 Definition of TPH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
Description of Friedel-Crafts Alkylation Reaction, Colorimetry, and the
RemediAid™ Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1
Description of Friedel-Crafts Alkylation Reaction and Colorimetry . . . . . . . . .
2.1.1 Friedel-Crafts Alkylation Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.2 Colorimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
viii
1
1
4
4
4
6
6
6
6
7
7
7
7
7
8
9
11
11
12
12
Contents (Continued)
Chapter
2.2
Page
Description of RemediAid™ Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.1 Device Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.2 Operating Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Developer Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
13
15
16
3
Demonstration Site Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1
Navy Base Ventura County Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.1 Fuel Farm Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.2 Naval Exchange Service Station Area . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.3 Phytoremediation Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2
Kelly Air Force Base Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3
Petroleum Company Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
18
18
19
19
20
20
4
Demonstration Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1
Demonstration Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2
Demonstration Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1 Approach for Addressing Primary Objectives . . . . . . . . . . . . . . . . . . .
4.2.2 Approach for Addressing Secondary Objectives . . . . . . . . . . . . . . . . .
4.3
Sample Preparation and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2 Sample Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
22
22
23
27
31
31
33
5
Confirmatory Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1
Reference Method Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2
Reference Laboratory Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3
Summary of Reference Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
37
39
39
6
Assessment of Reference Method Data Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1
Quality Control Check Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.1 GRO Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.2 EDRO Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2
Selected Performance Evaluation Sample Results . . . . . . . . . . . . . . . . . . . . . . .
6.3
Data Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
48
48
51
57
60
7
Performance of the RemediAid™ Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1
Primary Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.1 Primary Objective P1: Method Detection Limit . . . . . . . . . . . . . . . . . .
7.1.2 Primary Objective P2: Accuracy and Precision . . . . . . . . . . . . . . . . . .
7.1.2.1 Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.2.2 Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.3 Primary Objective P3: Effect of Interferents . . . . . . . . . . . . . . . . . . . .
7.1.3.1 Interferent Sample Results . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.3.2 Effects of Interferents on TPH Results for Soil Samples . . . . .
7.1.4 Primary Objective P4: Effect of Soil Moisture Content . . . . . . . . . . . .
7.1.5 Primary Objective P5: Time Required for TPH Measurement . . . . . . .
61
61
63
64
64
73
75
76
76
87
87
2.3
ix
Contents (Continued)
Chapter
7.2
Page
Secondary Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.1 Skill and Training Requirements for Proper Device Operation . . . . . .
7.2.2 Health and Safety Concerns Associated with Device Operation . . . . .
7.2.3 Portability of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.4 Durability of the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.5 Availability of the Device and Spare Parts . . . . . . . . . . . . . . . . . . . . . .
90
90
90
91
91
91
8
Economic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1
Issues and Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.1 Capital Equipment Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.2 Cost of Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.3 Support Equipment Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.4 Labor Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.5 Investigation-Derived Waste Disposal Cost . . . . . . . . . . . . . . . . . . . . .
8.1.6 Costs Not Included . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2
RemediAid™ Kit Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.1 Capital Equipment Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.2 Cost of Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.3 Support Equipment Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.4 Labor Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.5 Investigation-Derived Waste Disposal Cost . . . . . . . . . . . . . . . . . . . . .
8.2.6 Summary of RemediAid™ Kit Costs . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3
Reference Method Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4
Comparison of Economic Analysis Results . . . . . . . . . . . . . . . . . . . . . . . . . . . .
92
92
92
92
93
93
93
93
94
94
94
95
95
95
95
95
96
9
Summary of Demonstration Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
10
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Appendix
Supplemental Information Provided by the Developer . . . . . . . . . . . . . . . . . . 104
x
Figures
Figure
Page
1-1.
Distribution of various petroleum hydrocarbon types throughout boiling point
range of crude oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5-1.
Reference method selection process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7-1.
Summary of statistical analysis of TPH results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7-2.
Measurement bias for environmental samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
7-3.
Measurement bias for soil performance evaluation samples . . . . . . . . . . . . . . . . . . . . . . 68
7-4.
Linear regression plots for environmental samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
7-5.
Linear regression plots for soil performance evaluation samples . . . . . . . . . . . . . . . . . . 75
xi
Tables
Table
Page
1-1.
Summary of Calibration Information for Infrared Analytical Method . . . . . . . . . . . . . . . 8
1-2.
Current Technologies for TPH Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2-1.
RemediAid™ Kit Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2-2.
Calibration Data for the RemediAid™ Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3-1.
Summary of Site Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4-1.
Action Levels Used to Evaluate Analytical Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4-2.
Demonstration Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4-3.
Environmental Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4-4.
Performance Evaluation Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4-5.
Sample Container, Preservation, and Holding Time Requirements . . . . . . . . . . . . . . . . 36
5-1.
Laboratory Sample Preparation and Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . 39
5-2.
Summary of Project-Specific Procedures for GRO Analysis . . . . . . . . . . . . . . . . . . . . . 41
5-3.
Summary of Project-Specific Procedures for EDRO Analysis . . . . . . . . . . . . . . . . . . . . 45
6-1.
Summary of Quality Control Check Results for GRO Analysis . . . . . . . . . . . . . . . . . . . 52
6-2.
Summary of Quality Control Check Results for EDRO Analysis . . . . . . . . . . . . . . . . . 56
6-3.
Comparison of Soil and Liquid Performance Evaluation Sample Results . . . . . . . . . . . 58
6-4.
Comparison of Environmental Resource Associates Historical Results to Reference
Method Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
7-1.
TPH Results for Low-Concentration-Range Diesel Soil Performance Evaluation
Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
7-2.
RemediAid™ Kit Calibration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
7-3.
Action Level Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
7-4.
Statistical Comparison of RemediAid™ Kit and Reference Method TPH Results for
Environmental Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7-5.
Statistical Comparison of RemediAid™ Kit and Reference Method TPH Results for
Performance Evaluation Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
7-6.
Summary of Linear Regression Analysis Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
xii
Tables (Continued)
Table
Page
7-7.
Summary of RemediAid™ Kit and Reference Method Precision for Field
Triplicates of Environmental Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
7-8.
Summary of RemediAid™ Kit and Reference Method Precision for Extract
Duplicates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
7-9.
Comparison of RemediAid™ Kit and Reference Method Precision for Replicate
Performance Evaluation Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
7-10.
Comparison of RemediAid™ Kit and Reference Method Results for Interferent
Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
7-11.
Comparison of RemediAid™ Kit and Reference Method Results for Soil
Performance Evaluation Samples Containing Interferents . . . . . . . . . . . . . . . . . . . . . . . 81
7-12.
Comparison of Results for Soil Performance Evaluation Samples at Different
Moisture Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
7-13.
Time Required to Complete TPH Measurement Activities Using the
RemediAid™ Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
8-1.
RemediAid™ Kit Cost Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
8-2.
Reference Method Cost Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
9-1.
Summary of RemediAid™ Kit Results for the Primary Objectives . . . . . . . . . . . . . . . . 98
9-2.
Summary of RemediAid™ Kit Results for the Secondary Objectives . . . . . . . . . . . . . 101
xiii
Abbreviations, Acronyms, and Symbols
>
#
±
µg
µm
AC
AEHS
AFB
API
ASTM
bgs
BTEX
BVC
CCV
CFC
CFR
CHEMetrics
DER
DRO
EDRO
EPA
EPH
ERA
FFA
FID
GC
GRO
ICV
IDW
ITVR
kg
L
LCS
LCSD
MCAWW
MDL
Means
mg
min
mL
Greater than
Less than or equal to
Plus or minus
Microgram
Micrometer
Alternating current
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
CHEMetrics, Inc.
Data evaluation report
Diesel range organics
Extended diesel range organics
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
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
Milligram
Minute
Milliliter
xiv
Abbreviations, Acronyms, and Symbols (Continued)
mm
MMT
MS
MSD
MTBE
n-Cx
NERL
NEX
ng
nm
ORD
ORO
OSWER
PC
PCB
PCE
PE
PHC
PPE
PRA
PRO
QA
QC
R2
RemediAid™ kit
RPD
RSD
SFT
SITE
STL Tampa East
SW-846
TPH
UST
VPH
Millimeter
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
Nanometer
Office of Research and Development
Oil range organics
Office of Solid Waste and Emergency Response
Petroleum company
Polychlorinated biphenyl
Tetrachloroethene
Performance evaluation
Petroleum hydrocarbon
Personal protective equipment
Phytoremediation Area
Petroleum range organics
Quality assurance
Quality control
Square of the correlation coefficient
RemediAid™ Total Petroleum Hydrocarbon Starter Kit
Relative percent difference
Relative standard deviation
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 hydrocarbon
xv
Acknowledgments
This report was prepared for the U.S. Environmental 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
Verstuyft of Chevron Research and Technology Company served as the peer reviewers of this report.
This report was prepared for the EPA by Dr. Kirankumar Topudurti and Mr. Tim Denhof of Tetra
Tech EM Inc. Special acknowledgment is given 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 Tetra Tech EM Inc. for their assistance during the preparation of this report.
xvi
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 TPHcontaminated 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.
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 CHEMetrics 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.
This innovative technology verification report (ITVR)
presents demonstration performance results and associated
costs for the RemediAid™ Total Petroleum Hydrocarbon
Starter Kit (RemediAid™ kit). The RemediAid™ kit was
developed by CHEMetrics, Inc. (CHEMetrics), and AZUR
Environmental Ltd in conjunction with Shell Research Ltd.
and manufactured by CHEMetrics. 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
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:
1
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.
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
•
Remediation Technology Program—Conducts
demonstrations of innovative treatment technologies to
provide reliable performance, cost, and applicability
data for site cleanups.
•
Identify performance attributes of innovative
technologies to address field sampling, monitoring,
and characterization problems in a more cost-effective
and efficient manner
•
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.
•
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 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’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 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 costeffective, faster, and safer methods for producing real-time
or near-real-time data than do conventional, laboratorybased technologies. These innovative technologies are
demonstrated under field conditions, and the results are
compiled, evaluated, published, and disseminated by the
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,
2
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
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.
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 learn about the MMT Program.
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 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 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
3
Internet. The ITVRs and additional information on the
SITE Program are available on the EPA ORD web site
(http://www.epa.gov/ORD/SITE).
1.2
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.
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 RemediAid™ kit is based and the field
measurement device itself. Because TPH is a “methoddefined 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.
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).
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.
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).
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.
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.
In preparation for the demonstration, a predemonstration
sampling and analysis investigation was completed at the
4
The hydrocarbon components of crude oil include
paraffinic, naphthenic, and aromatic groups. Paraffins
(alkanes) are saturated, aliphatic hydrocarbons with
straight or branched chains but without any ring structure.
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.
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
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
Source: Speight 1991
Figure 1-1. Distribution of various petroleum hydrocarbon types throughout boiling point range of crude oil.
5
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,
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
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.
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.
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-1, 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-1, 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
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
6
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
1.3.1.7
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.
Fuel Oils
Fuel oils are divided into two classes: distillates and
residuals. No. 1 and 2 fuel oils are distillates and include
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
Lubricating Oils
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.
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.
1.3.2.1
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 methoddefined 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
7
greases along with PHCs. These naturally occurring
materials are typically long-chain fatty acids (for example,
oleic acid, the major component of olive oil).
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.
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
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 (µm), 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.
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.
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
Table 1-1. Summary of Calibration Information for Infrared Analytical Method
Number of Carbon Atoms
Standard
Constituent
Portion of Constituent
in Standard
(percent by volume)
Aliphatic
Aromatic
Portion of Aliphatic CH2 in
Standard Constituent
(percent by weight)
CH2
CH
CH
Hexadecane
Straight-chain aliphatic
37.5
2
14
0
0
91
Isooctane
Branched-chain aliphatic
37.5
5
1
1
0
14
Chlorobenzene
Aromatic
25
0
0
0
5
Constituent Type
CH3
Average
0
35
8
Table 1-2. Current Technologies for TPH Measurement
Technology
What Is Measured
What Is Not Measured
Gravimetry
All analytes removed from the sample by the
extraction solvent that are not volatilized
Volatiles; very polar organics
Infrared
All analytes removed from the sample by the
extraction solvent that contain an aliphatic CH2
stretch
Benzene, naphthalene, and other aromatic
hydrocarbons with no aliphatic group attached;
very polar organics
Gas chromatograph/flame ionization detector All analytes removed from the sample by the
extraction solvent that can be chromatographed
and that respond to the detector
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.
Very polar organics; compounds with high
molecular weights or high boiling points
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.
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-boilingpoint petroleum products. The DRO method uses a
1.3.2.3
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
9
•
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
•
Variations exist among the sample fractionation and
analysis procedures used in different states.
•
Had little inherent bias based on the relative
concentrations of aliphatic and aromatic hydrocarbons
present
•
The repeatability and versatility of sample
fractionation and analysis procedures are not well
documented.
•
Included much of the volatile portion of gasoline,
including all weathered gasoline
•
In some states, TPH-based action levels are still used.
•
The associated analytical costs are high.
•
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
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.
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 abovementioned 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.
10
Chapter 2
Description of Friedel-Crafts Alkylation Reaction,
Colorimetry, and the RemediAid™ Kit
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, infrared and ultraviolet light).
•
The RemediAid™ kit is a field measurement device
capable of providing quantitative TPH measurement
results. Measurements made using the RemediAid™ kit
are based on a combination of the Friedel-Crafts alkylation
reaction and colorimetry, which are described in
Section 2.1. Calibration curves for the RemediAid™ kit
are developed using petroleum products or synthetic
calibration mixtures containing PHCs.
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.
Section 2.1 describes the technology upon which the
RemediAid™ kit is based, Section 2.2 describes the
RemediAid™ kit itself, and Section 2.3 provides
CHEMetrics 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 RemediAid™ kit.
Detailed operating procedures for the device, including soil
extraction, TPH measurement, and TPH concentration
calculation procedures, are available from CHEMetrics.
Supplemental information provided by CHEMetrics is
presented in the appendix.
Field measurement devices may be categorized as
quantitative, semiquantitative, and qualitative. These
categories are explained below.
•
•
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).
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.
2.1
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.
Measurement of TPH in soil using the RemediAid™ kit is
based on a combination of the Friedel-Crafts alkylation
reaction and colorimetry.
Collectively, these two
technologies are suitable for measuring aromatic
hydrocarbons independent of their carbon range. These
technologies are described below.
11
Description of Friedel-Crafts Alkylation
Reaction and Colorimetry
The concentration of the aromatic hydrocarbon in the
reaction mixture is determined by comparing the intensity
of the colored reaction product with photographs of
standards (color charts) or by using a reflectance
spectrophotometer that can measure the concentration of
the colored reaction product in the visible range of the
electromagnetic spectrum. The intensity of the color
produced is directly proportional to the concentration of
the aromatic hydrocarbon present.
2.1.1 Friedel-Crafts Alkylation Reaction
The Friedel-Crafts alkylation reaction involves reaction of
an alkyl halide, such as dichloromethane, with an aromatic
hydrocarbon, such as benzene, in the presence of a solidphase metal halide catalyst, such as anhydrous aluminum
chloride (Fox 1994).
The first step in the reaction is the metal halide, anhydrous
aluminum chloride, reacting with the alkyl halide,
dichloromethane, as shown in Equation 2-1. An alkyl
halide is a molecule that contains at least one carbonchlorine bond. The metal halide polarizes the carbonchlorine bond or bonds of the alkyl halide, causing the
positively charged carbocation (+CH2Cl) and negatively
charged metal halide ions to separate. This separation
results in an intermediate (+CH2Cl), which is a positively
charged ion whose charge resides on the carbon atom.
Dichloromethane (CH2Cl2)
+ aluminum chloride (AlCl3)
X
CH2Cl + AlCl4-
+
The RemediAid™ kit is based on a modified version of the
Friedel-Crafts alkylation reaction. The modified version
has the same reaction steps as the classical Friedel-Crafts
alkylation reaction described above except that the colored
reaction product is not bound to the solid-phase metal
halide but remains in the liquid phase of the reaction
mixture. This effect is achieved by using the alkyl halide
in amounts exceeding the stoichiometry. The total
concentration of PHCs in the reaction mixture is
determined by comparing the intensity of the colored
reaction product with color charts or by using an
absorbance spectrophotometer. Color measurement and
concentration estimation are further discussed in
Section 2.1.2.
(2-1)
In the second step of the reaction, the carbocation attaches
to an aromatic hydrocarbon, such as benzene, producing an
intermediate as shown in Equation 2-2.
2.1.2
Equation 2-2 shows one possible structure of the
intermediate. The positive charge, like the aromatic
double bonds, may be on several of the ring carbon atoms.
In the third step of the reaction, this sharing of the charge
stabilizes the intermediate and gives it time to react with an
AlCl4- ion as shown in Equation 2-3. This reaction
regenerates the catalyst (anhydrous aluminum chloride)
and forms a colored reaction product (a hydrocarbon
derivative) that can absorb light in the visible range of the
electromagnetic spectrum. The colored reaction product
remains bound to the solid-phase metal halide and settles
to the bottom of the reaction mixture.
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. For the classical Friedel-Crafts
alkylation reaction (Equations 2-1 through 2-3), a
Colorimetry
+
+CH
2
Cl
+
CH 2Cl
H
(2-2)
H
+
CH2Cl
+ AlCl 4 -
CH 2Cl + HCl + AlCl 3
H
12
(2-3)
reflectance spectrophotometer is used because the colored
reaction product is bound to a solid-phase metal halide.
The RemediAid™ kit uses an absorbance
spectrophotometer because the colored reaction product is
present in the liquid phase. Therefore, this section
describes colorimetry using an absorbance
spectrophotometer.
where
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 and covered with an opaque light
shield. 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.
2.2
I0
= Intensity of light source
I
= 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 target compounds in the reaction mixture,
or the intensity of the light absorbed by the reaction
mixture is directly proportional to the concentration of
target compounds in the reaction mixture.
2.2.1
b
= Light path length (centimeter)
c
= Concentration of absorbing species (mole
per L)
Description of RemediAid™ Kit
Device Description
As stated in Section 2.1.1, the Friedel-Crafts alkylation
reaction involves reaction of an alkyl halide with an
aromatic compound in the presence of a metal halide. In
the RemediAid™ kit, dichloromethane is used as both the
alkyl halide and extraction solvent, and anhydrous
aluminum chloride is used as the metal halide. When
excessive dichloromethane is used, the colored reaction
product to be measured remains in the liquid phase.
According to CHEMetrics, the presence of stabilizers in
some chlorinated solvents may introduce a positive bias in
According to Beer-Lambert’s law, Equation 2-4 may be
expressed as shown in Equation 2-5.
A =∈bc
= Molar absorptivity (centimeter per mole
per liter [L])
The RemediAid™ kit, a quantitative field measurement
device developed by CHEMetrics and AZUR
Environmental Ltd in conjunction with Shell Research Ltd.
and manufactured by CHEMetrics, is based on a
combination of the Friedel-Crafts alkylation reaction and
colorimetry, which are described in Section 2.1. The
device has been commercially available since 1998. This
section describes the device and summarizes its operating
procedure.
where
= Absorbance
∈
After the absorbance of the reaction mixture is measured,
the TPH concentration is determined by comparing the
absorbance reading for the reaction mixture to absorbance
values for a series of reference standards, which are plotted
on a calibration curve.
(2-4)
A
= Absorbance
Thus, according to Beer-Lambert’s law, the absorbance of
a chemical species is directly proportional to the
concentration of the absorbing chemical species and the
path length of the light passing through the reaction
mixture. In Equation 2-5, the molar absorptivity is a
proportionality constant, which is a characteristic of the
absorbing species and changes as the wavelength changes.
Therefore, Beer-Lambert’s law applies only to
monochromatic light (light of one wavelength).
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 intensity 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 2-4.
A = log (I 0 / I)
A
(2-5)
13
Table 2-1. RemediAid™ Kit Components
the device TPH results. Therefore, CHEMetrics provides
a premeasured volume of stabilizer-free dichloromethane
with the device in a sealed, single-use, double-tipped
ampule. Anhydrous aluminum chloride is used because it
is the most sensitive metal halide and because it provided
the most accurate recoveries for various types of
hydrocarbons during laboratory tests performed by
CHEMetrics. As described in Section 2.1.2, an absorbance
spectrophotometer (referred to by CHEMetrics as a
photometer) is employed to measure sample extract
absorbance using visible light of a 430-nanometer (nm)
wavelength.
Starter kit
• Battery-powered balance (9-volt battery included)
• Battery-powered timer (AAA battery included)
• Battery-powered, portable photometer (9-volt battery included)
• 8 double-tipped ampules containing 20 milliliters each of
dichloromethane
• 8 vacuum-sealed ampules containing anhydrous aluminum chloride
and filtering columns
• Anhydrous sodium sulfate (50 grams)
• 8 extraction cleanup tubes and caps containing Florisil
• 8 reaction tubes and caps containing sodium sulfate
• 8 small, silicone ampule caps
• 8 weighing boats
• Tip-breaking tool
• Light shield
• Ampule rack that holds 36 ampules
• Reaction tube plug/snapper
• Spatula
• Reagent blank ampule
• Test procedure manual
• Material safety data sheets
• Carrying case
According to CHEMetrics, the RemediAid™ kit responds
to all hydrocarbon products as long as they contain
aromatic hydrocarbons. The device can respond to
aromatic hydrocarbons independent of their carbon range.
CHEMetrics states that for optimum performance, the
photometer should be used in a shaded area with a
temperature range of 0 to 50 °C and with a maximum
relative humidity of 95 percent, and it should not be stored
at temperatures greater than 32 °C. The device does not
require any other special storage conditions because its
chemicals are vacuum-sealed and are therefore not
susceptible to degradation.
Replenishment kit
• 16 double-tipped ampules containing 20 milliliters each of
dichloromethane
• 16 vacuum-sealed ampules containing anhydrous aluminum
chloride and filtering columns
• 16 extraction cleanup tubes and caps containing Florisil
• 16 reaction tubes and caps containing sodium sulfate
• 16 weighing boats
The items in the starter kit are packaged in a carrying case
that is 13.75 inches long, 15.5 inches wide, and 4.5 inches
high. The items in the replenishment kit are packaged in
a box that is 9.25 inches long, 10.25 inches wide, and
4.5 inches high. The user needs to provide disposable
gloves, safety glasses, and a disposal pipette or syringe
capable of measuring 5 milliliters (mL). The photometer
operates on one 9-volt battery; weighs 0.43 pound; and is
6.0 inches long, 2.4 inches wide, and 1.25 inches high.
According to CHEMetrics, the method detection limit
(MDL), precision, and accuracy that can be achieved with
the RemediAid™ kit vary depending on the reactivity of
the hydrocarbons being measured. No information is
available from CHEMetrics on the MDL, precision, and
accuracy for soil sample extracts. However, assuming that
a sample extract does not require dilution before analysis,
the following MDL, precision, and accuracy ranges
generally apply to the device: MDLs ranging from
2.0 mg/L for weathered gasoline to 10 mg/L for heavy oil,
precision values ranging from 2.0 mg/L for weathered
gasoline to plus or minus (±) 11.0 mg/L for heavy oil, and
accuracy values (bias) ranging from -4.8 mg/L for
weathered gasoline to +31.3 mg/L for heavy oil.
According to CHEMetrics, one technician can perform
16 analyses in about 1 hour using the RemediAid™ kit.
All reagents are premeasured and provided in vacuumsealed ampules. Only one technician is required to
perform analyses using the device, which is designed to be
used by those with basic wet chemistry skills.
CHEMetrics provides technical support over the telephone
at no additional cost.
Table 2-1 lists the components of the RemediAid™ kit: the
starter kit and replenishment kit.
According to
CHEMetrics, a user of the RemediAid™ kit must first
purchase a starter kit and may then purchase replenishment
kits thereafter. The starter kit includes enough supplies to
perform 8 soil analyses, and the replenishment kit includes
enough supplies to perform 16 more soil analyses.
The device includes a drying agent (anhydrous sodium
sulfate) used to remove moisture from soil samples, thus
allowing efficient extraction of PHCs from wet soil
14
samples. The device also uses Florisil, an activated
magnesium silicate, to eliminate interferences from natural
organic matter in soil. However, as stated in Chapter 1,
this practice results in removal of polar compounds from
sample extracts, including PHC degradation products.
procedure manual. Table 2-2 summarizes the calibration
curve slope and intercept values provided by CHEMetrics
for a variety of petroleum products and PHCs.
During the demonstration, an appropriate amount of
anhydrous sodium sulfate was added to 5 grams of soil
sample in a reaction tube in order to remove sample
moisture. Then 20 mL of solvent (dichloromethane)
supplied in a double-tipped ampule was added to the
reaction tube containing the dried soil sample. The
reaction tube was capped and shaken for 3 minutes. The
soil was allowed to settle to the bottom of the tube, and the
extract supernatant was decanted into a cleanup tube
containing Florisil in order to remove any naturally
occurring polar hydrocarbons as well as background color
from the extract. A filtering column was attached to the tip
of a vacuum-sealed ampule containing anhydrous
aluminum chloride. The ampule was snapped in the
cleanup tube, allowing the hydrocarbons in the sample
extract to react with the aluminum chloride and form a
soluble, yellow to orange-brown product. Finally, color
measurement was completed by inserting the ampule into
the photometer and recording the absorbance at a
wavelength of 430 nm. If the absorbance was less than
0.700, the absorbance value was converted to mg/kg TPH
in the soil sample using the appropriate slope and intercept
values presented in Table 2-2. If the absorbance was equal
to or greater than 0.700, the extract was diluted and the
absorbance of the diluted extract was measured before the
TPH concentration was determined.
According to CHEMetrics, the RemediAid™ kit is
innovative because the colored reaction product remains in
the liquid phase, which allows measurement of color
intensity using the portable absorbance photometer.
According to CHEMetrics, portable versions of reflectance
spectrophotometers are not commercially available,
making assessment of a solid colored reaction product
impossible in the field. All chemicals supplied as parts of
the starter and replenishment kits are vacuum-sealed and
premeasured, which minimizes user contact with reagents
and eliminates the need for pipetting and measuring skills,
thus minimizing the possibility of user error. In addition,
the photometer operates on a 9-volt battery, so an
alternating current (AC) power source is not required in
the field.
2.2.2
Operating Procedure
Measuring TPH in soil using the RemediAid™ kit
involves the following three steps: (1) extraction and
extract cleanup, (2) color development, and (3) color
measurement. The operating procedure is summarized
below. The device does not need to be calibrated in the
field; the user may employ the slope and intercept values
of appropriate calibration curves included in the test
Table 2-2. Calibration Data for the RemediAid™ Kit
Petroleum Product or Hydrocarbon
Slope (milligram per liter)
Intercept (milligram per liter)
Unleaded gasoline
113.5
3.01
Weathered gasoline
108.0
2.4
Diesel
254.6
19.7
Brent crude
223.5
4.3
Lube oil
703.3
25.1
87.5
8.1
197.7
8.4
Benzene, toluene, ethylbenzene, and xylenes
Leaded gasoline
Polynuclear aromatic hydrocarbons
Unknown
17.55
a
195.0
0.162
5.5
Note:
a
When the hydrocarbon or hydrocarbons of interest are unknown, the slope and intercept values for “unknown” hydrocarbons are used for calibration;
these values are the averages of the slope and intercept values for the other hydrocarbons listed.
15
2.3
Developer Contact Information
Additional information about the RemediAid™ kit can be
obtained from the following source:
CHEMetrics, Inc.
Ms. Joanne Carpenter or
Mr. Henry Castaneda
Route 28
Calverton, VA 20138
Telephone: (800) 356-3072
Fax: (540) 788-4856
E-mail: [email protected]
Internet: www.chemetrics.com
16
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 northcentral 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:
•
•
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
characterization of samples was performed in the field by
a geologist during both predemonstration investigation and
demonstration activities.
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.
Some of the predemonstration investigation samples were
also analyzed by the RemediAid™ kit developer,
CHEMetrics, at its facility. CHEMetrics used reference
laboratory and RemediAid™ kit results to gain a
preliminary understanding of the demonstration samples
and to prepare 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.
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.
To ensure that the sampling areas were selected based on
current site characteristics, a predemonstration
17
Table 3-1. Summary of Site Characteristics
Site
Sampling Area
Navy Base Fuel Farm Area
Ventura
County
Petroleum
company
EDRO (weathered diesel with
carbon range from n-C10
through n-C40)
b
Upper layer
b
TPH Concentration
Range (mg/kg)
44.1 to 93.7
Type of Soil
Medium-grained sand
Lower layer
8,090 to 15,000
GRO and EDRO (fairly
weathered gasoline with
carbon range from n-C6
through n-C14)
7 to 8
28.1 to 280
8 to 9
144 to 2,570
9 to 10
617 to 3,030
10 to 11
9.56 to 293
Phytoremediation
Area
EDRO (heavy lubricating oil
with carbon range from n-C14
through n-C40+)
1.5 to 2.5
1,130 to 2,140
Silty sand
B-38 Area
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)
23 to 25
43.8 to 193
25 to 27
41.5 to 69.4
Sandy clay or silty sand and gravel
in upper depth interval and clayey
sand and gravel in deeper depth
interval
GRO and EDRO (combination
of slightly weathered gasoline,
kerosene, JP-5, and diesel
with carbon range from n-C5
through n-C32)
2 to 4
6.16 to 3,300
4 to 6
37.1 to 3,960
6 to 8
43.9 to 1,210
8 to 10
52.4 to 554
Naval Exchange
Service Station
Area
Kelly Air
Force
Base
Contamination Typea
Approximate
Sampling Depth
Interval
(foot bgs)
Slop Fill Tank
Area
Medium-grained sand
Silty clay with traces of sand and
gravel in deeper depth intervals
Notes:
bgs = Below ground surface
mg/kg = Milligram per kilogram
a
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.
b
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
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.
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.
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,
3.1.1 Fuel Farm Area
The FFA is a tank farm in the southwest corner of the
Navy BVC site. The area contains five tanks and was
18
soil in the area was found to generally consist of mediumgrained 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 from 44.1 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.
10-foot bgs depth intervals; and 9.56 to 293 mg/kg in the
10- to 11-foot bgs depth interval.
During the
predemonstration 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.
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-C12 through n-C40 carbon range
with the hydrocarbon hump maximizing at n-C20.
3.1.2
Naval Exchange Service Station Area
3.1.3
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.
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) unvegetated cover, (2) a
grass and legume mix, and (3) a native grass mix. There
are four replicate cells of each cover type.
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, mediumgrained 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
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 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.
19
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-C14 through n-C40+ carbon range
with the hydrocarbon hump maximizing at n-C32.
3.2
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-C6 through n-C25 carbon
range with the hydrocarbon hump maximizing at n-C17;
(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.
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.
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
sampling locations were spaced 15 feet apart to form the
corners 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
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
20
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.
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.
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.
21
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.
P5. Measure the time required for TPH measurement
4.1
The secondary objectives for the demonstration of the
individual field measurement devices were as follows:
P6. Estimate costs associated with TPH measurement
Demonstration Objectives
The primary goal of the SITE MMT Program is to develop
reliable performance and cost data on innovative, fieldready 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.
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
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.
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.
The primary objectives for the demonstration of the
individual field measurement devices were as follows:
P1. Determine the MDL
4.2
P2. Evaluate the accuracy and precision of TPH
measurement for a variety of contaminated soil
samples
P3. Evaluate the
measurement
effect
of
interferents
on
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
TPH
P4. Evaluate the effect of soil moisture content on TPH
measurement
22
from the developers and demonstration site
representatives. The demonstration design is summarized
below.
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 (less than 100 mg/kg), medium (100 to
1,000 mg/kg), or high (greater than 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.
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.
During the demonstration, CHEMetrics field technicians
operated the RemediAid™ kit, 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. CHEMetrics chose to analyze all the
demonstration 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
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.
23
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
gasoline PE samples, the results for these samples could
not be used to address primary objective P2.
Primary Objective P1: 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 Freon 113,
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. CHEMetrics 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 the 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.
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.
Primary Objective P2: Accuracy and Precision
To estimate the accuracy and precision of each field
measurement device, both environmental and PE samples
Table 4-1. Action Levels Used to Evaluate Analytical Accuracy
Typical TPH Concentration Rangea
Action Level (mg/kg)
Fuel Farm Area
Low and high
100
Naval Exchange Service Station Area
Low to high
Phytoremediation Area
High
Site
Navy Base Ventura
County
Area
50
1,500
Kelly Air Force Base
B-38 Area
Low
100
Petroleum company
Slop Fill Tank Area
Medium
500
Performance evaluation samples (GRO analysis)
Medium
200
Performance evaluation samples (EDRO analysis)
Low
High
Medium
High
2,000
15
200
2,000
Notes:
mg/kg = Milligram per kilogram
a
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.
24
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, the ratio of the TPH results of a
given 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.
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 Freon 113 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 collected from a location where
field triplicates were collected. To evaluate a given 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.
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.
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
selection. Specific reasons for the selection of the six
interferents are presented below.
To evaluate whether a statistically significant difference
existed between a given field measurement device and the
reference method results, a two-tailed, paired Student’s ttest was performed. To determine whether a consistent
correlation existed between the TPH results of a given field
measurement device and the reference method, a linear
regression was performed to estimate the square of the
correlation coefficient (R2), the slope, and the intercept of
each regression equation. Separate regression equations
were developed for each demonstration area and for the PE
samples that did not contain interferents. The reliability of
the regression equations was tested using the F-test; the
regression equation probability derived from the F-test was
used to evaluate whether the correlation between the TPH
results of the device and the reference method occurred
merely by chance.
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-concentrationrange PE samples were also used to evaluate analytical
•
25
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-C8 through n-C14 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.
(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.
Primary Objective P4: Effect of Soil Moisture
Content
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.
To evaluate the effect of soil moisture content, highconcentration-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 (less than 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 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.
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 1,2,4trichlorobenzene could not be prepared. Instead, neat
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 two-tailed, two-sample
Student’s t-test was performed to determine whether the
device and reference method results were impacted by
•
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.
26
moisture—that is, to determine whether an increase in
moisture resulted in an increase or decrease in the TPH
concentrations measured.
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.
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-ofcustody 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, the 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.
•
The skills and training required for proper device
operation (secondary objective S1) were evaluated by
observing and noting the skills required to operate the
device and prepare the data package during the
demonstration 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
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
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
(IDW) disposal. Chapter 8 of this ITVR discusses the
costs estimated for the RemediAid™ kit 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.
27
28
8 to 10
6 to 8
4 to 6
2 to 4
P1, P2
Processed garden soil (PE sample) P2
Ottawa sand
(PE sample)
Sample Matrix
SFT
Area
PC
25 to 27
23 to 25
B-38
Area
Kelly
AFB
Silty sand
Fine-grained sand
Soil Characteristics
Silty clay with traces of sand in
deeper depth intervals
Sandy clay or silty sand and
gravel in upper depth interval and
clayey sand and gravel in deeper
depth interval
Diesel
Weathered gasoline
Diesel
Weathered gasolined
Contamination Type
Combination of slightly weathered gasoline,
kerosene, JP-5, and diesel with carbon range
from n-C5 through n-C32
Fresh gasoline and diesel or weathered
gasoline and trace amounts of lubricating oil
with carbon range from n-C6 through n-C40
Heavy lubricating oil with carbon range from
n-C14 through n-C40
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
Medium and GRO and EDRO because weathered
high
gasoline contains significant amounts of
PHCs in both gasoline and diesel
ranges
Low
Typical TPH
Concentration
rangeb
Rationale for Analyses
by Reference Laboratory
GRO and EDRO because samples
contained PHCs in both gasoline and
diesel ranges
Low
Medium
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
Rationale for Analyses
by Reference Laboratory
High
Low
Silty sand
High
Low to
medium
High
Low
10 to 11
Fairly weathered gasoline with carbon range
from n-C6 through n-C14
Weathered diesel with carbon range from
n-C10 through n-C40
Contamination Type
9 to 10
Medium-grained sand
Medium-grained sand
Soil Characteristics
Typical TPH
Concentration
Rangeb
Medium to
high
Objective
Addresseda
P2
Objective
Addresseda
8 to 9
7 to 8
Lower layer
c
Upper layerc
1.5 to 2.5
NEX
Service
Station
Area
FFA
Area
PRA
Navy
BVC
Site
Approximate
Sampling Depth
Interval (foot bgs)
Table 4-2. Demonstration Approach
29
Silty sand
Not applicable (neat liquid PE
sample)
Processed garden soil (PE sample) P3
P2
Not applicable
(Continued)
Sample Matrix
Soil Characteristics
Objective
Addresseda
Table 4-2. Demonstration Approach (Continued)
Only EDRO because 1,2,4trichlorobenzene and humic acid do not
interfere with GRO analysis
Diesel and 1,2,4-trichlorobenzene
(3,350 mg/kg) or humic acid (3,940 mg/kg)
Humic acid (19,500 mg/kg)
Humic acid (3,940 mg/kg)
Diesel and 1,2,4-trichlorobenzene
(16,600 mg/kg) or humic acid (19,500 mg/kg)
The contribution of trace 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.
Only EDRO because humic acid does
not interfere with GRO analysis
GRO and EDRO because (1) Stoddard
solvent contains PHCs in both gasoline
and diesel ranges and (2) turpentine
interferes with both analyses
Diesel and Stoddard solvent (3,650 mg/kg) or
turpentine (3,850 mg/kg)
Diesel and Stoddard solvent (18,200 mg/kg)
or turpentine (19,600 mg/kg)
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
GRO and EDRO because processed
garden soil may contain trace
concentrations 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
Rationale for Analyses
by Reference Laboratory
Diesel
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)
Trace
High
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)
Trace
High
Diesel
Blank soil (control sample)
High
Weathered gasoline
Contamination Type
Typical TPH
Concentration
rangeb
30
Because of problems that arose during preparation of PE samples with low concentrations of weathered gasoline, the results for these samples were not used to evaluate the field measurement
devices.
Performance evaluation
Petroleum hydrocarbon
Phytoremediation Area
Slop Fill Tank
d
=
=
=
=
Because of soil conditions encountered in the FFA during the demonstration, 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. For each sampling location in the area, the sample cores 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.
PE
PHC
PRA
SFT
c
NEX = Naval Exchange
PC
= Petroleum company
PCE = 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.
FFA
= Fuel Farm Area
mg/kg = Milligram per kilogram
MTBE = Methyl-tert-butyl ether
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
Field observations of all sample analyses conducted during the demonstration were used to address primary objectives P5 and P6 and the secondary objectives.
Air Force Base
Below ground surface
Base Ventura County
Diesel (samples prepared at negligible [less
than 1 percent] and 9 percent moisture levels)
Weathered gasoline (samples prepared at
9 and 16 percent moisture levels)
Only EDRO because 1,2,4trichlorobenzene does not interfere with
GRO analysis
GRO and EDRO because turpentine
interferes with both analyses
GRO and EDRO because Stoddard
solvent contains PHCs in both gasoline
and diesel ranges
b
=
=
=
Not
applicable
Turpentine
High
High
Stoddard solvent
1,2,4-Trichlorobenzene
Not
applicable
PCE
Only GRO because MTBE and PCE do
not interfere with EDRO analysis
MTBE
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
High
Rationale for Analyses
by Reference Laboratory
Diesel
Weathered gasoline
Contamination Type
Typical TPH
Concentration
rangeb
a
AFB
bgs
BVC
Notes:
Silty sand
Not applicable (neat liquid PE
sample)
Processed garden soil (PE sample) P4
P3
Not applicable
(Continued)
Sample Matrix
Soil Characteristics
Objective
Addresseda
Table 4-2. Demonstration Approach (Continued)
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.
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.
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
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.
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: (1) the FFA, NEX Service
Station Area, and PRA at the Navy BVC site; (2) the B-38
Area at the Kelly AFB site; and (3) the SFT Area at the PC
site. Samples were collected in all areas except the PRA
using a Geoprobe®; in the PRA, samples were collected
using a Split Core Sampler.
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
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
RemediAid™ kit.
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.
Performance Evaluation Samples
All PE samples for the demonstration were prepared by
ERA and shipped to the sample management trailer at the
Navy BVC 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).
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
31
Table 4-3. Environmental Samples
Site
Area
Navy BVC FFA
Number of
Sampling
Locations
Number of Analyses
by Reference
Laboratoryd
Number of Number of
Number of
Extract
MS/MSDb
TPH Analyses
c
Pairs
Duplicates by CHEMetrics
GRO
EDRO
Upper layer
3
5
1
1
6
0
8
Lower layer
3
5
1
1
5
0
8
NEX
Service
Station
Area
7 to 8
3
5
1
1
5
8
8
PRA
Kelly AFB B-38 Area
PC
Depth
Interval
(foot bgs)
Total Number of
Samples, Including
Field Triplicates, to
CHEMetrics and
Reference
Laboratorya
SFT Area
8 to 9
3
5
1
1
6
8
8
9 to 10
3
5
1
1
6
8
8
10 to 11
3
5
1
1
5
8
8
1.5 to 2.5
6 (4 vegetated
and
2 unvegetated)
8
1
1
9
0
11
23 to 25
3
5
1
1
6
8
8
25 to 27
3
3
1
1
4
6
6
2 to 4
5
7
1
1
8
10
10
4 to 6
5
7
1
1
8
10
10
6 to 8
5
7
1
1
8
10
10
8 to 10
5
Total
7
1
1
8
10
10
74
13
13
84
86
113
Notes:
AFB
bgs
BVC
= Air Force Base
= Below ground surface
= Base Ventura County
FFA
= Fuel Farm Area
MS/MSD = Matrix spike and matrix spike duplicate
NEX
= Naval Exchange
PC
= Petroleum company
PRA = Phytoremediation Area
SFT = Slop Fill Tank
a
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.
b
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 CHEMetrics.
c
Because of site conditions, CHEMetrics did not analyze extract duplicates for the lower layer in the FFA and the 7- to 8- and the 10- to 11-foot bgs
depth intervals in the NEX Service Station Area. Therefore, CHEMetrics analyzed only 10 extract duplicates.
d
All environmental samples were also analyzed for moisture content by the reference laboratory.
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
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 less than 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 Freon 113 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
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.
32
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 RemediAid™ kit.
4.3.2
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 chainof-custody forms and were shipped 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 chainof-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.
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
33
Table 4-4. Performance Evaluation Samples
Sample Type
Typical TPH
Concentration
Rangea
Total
Number of
Samples to
CHEMetrics
and
Reference
Laboratory
Number of
Analyses by Reference
Laboratoryc
Number of
MS/MSDb
Pairs
Number of
Analyses by
CHEMetrics
GRO
EDRO
Soil Samples (Ottawa Sand)
Weathered gasoline
Low
7
0
7
7
7
7
0
7
0
7
Medium
3
0
3
3
3
High
3
1
3
5
5
Medium
3
0
3
0
3
High
3
1
3
0
5
Diesel
Soil Samples (Processed Garden Soil)
Weathered gasoline
Diesel
Blank soil (control sample)
Trace
3
1
3
5
5
MTBE (1,100 mg/kg) and weathered gasoline
High
3
0
3
3
3
MTBE (1,700 mg/kg) and weathered gasoline
3
0
3
3
3
PCE (2,810 mg/kg) and weathered gasoline
3
0
3
3
3
PCE (13,100 mg/kg) and weathered gasoline
3
0
3
3
3
Stoddard solvent (2,900 mg/kg) and weathered
gasoline
3
0
3
3
3
Stoddard solvent (15,400 mg/kg) and weathered
gasoline
3
0
3
3
3
Turpentine (2,730 mg/kg) and weathered gasoline
3
0
3
3
3
Turpentine (12,900 mg/kg) and weathered gasoline
3
0
3
3
3
Stoddard solvent (3,650 mg/kg) and diesel
3
0
3
3
3
Stoddard solvent (18,200 mg/kg) and diesel
3
0
3
3
3
Turpentine (3,850 mg/kg) and diesel
3
0
3
3
3
Turpentine (19,600 mg/kg) and diesel
3
0
3
3
3
1,2,4-Trichlorobenzene (3,350 mg/kg) and diesel
3
0
3
0
3
1,2,4-Trichlorobenzene (16,600 mg/kg) and diesel
3
0
3
0
3
Humic acid (3,940 mg/kg) and diesel
3
0
3
0
3
Humic acid (19,500 mg/kg) and diesel
3
0
3
0
3
Humic acid (3,940 mg/kg)
Trace
3
0
3
0
3
3
0
3
0
3
3
1
3
5
5
3
1
3
0
5
3
1
3
5
5
Diesel
3
0
3
0
3
MTBE
6
0
6
6
0
Humic acid (19,500 mg/kg)
Weathered gasoline at 16 percent moisture
High
Diesel at negligible moisture (less than 1 percent)
Liquid Samples (Neat Material)
Weathered gasoline
High
34
Table 4-4. Performance Evaluation Samples (Continued)
Sample Type
Typical TPH
Concentration
Rangea
Total
Number of
Samples to
CHEMetrics
and
Reference
Laboratory
Number of
Analyses by Reference
Laboratoryc
Number of
MS/MSDb
Pairs
Number of
Analyses by
CHEMetrics
GRO
EDRO
Liquid Samples (Neat Material) (Continued)
PCE
Not applicable
6
0
6
6
0
Stoddard solvent
High
6
0
6
6
6
Turpentine
Not applicable
6
0
6
6
6
6
0
6
0
6
125
6
125
90
125
1,2,4-Trichlorobenzene
Total
Notes:
mg/kg
= Milligram per kilogram
MS/MSD = Matrix spike and matrix spike duplicate
MTBE = Methyl-tert-butyl ether
PCE = Tetrachloroethene
a
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).
b
MS/MSD samples were analyzed only by the reference laboratory.
c
All soil performance evaluation samples were also analyzed for moisture content by the reference laboratory.
35
Table 4-5. Sample Container, Preservation, and Holding Time Requirements
Holding Time (days)
a
Parameter
GRO
Medium
Soil
Container
Two 5-gram EnCores
Preservation
4 ± 2 °C
Extraction
Analysis
2
b
14
b
40
EDRO
Soil
Two 4-ounce, glass jars with Teflon™-lined lids
4 ± 2 °C
14
Percent moisture
Soil
Two 4-ounce, glass jars with Teflon™-lined lids
4 ± 2 °C
Not applicable
TPH
Soil
One 25-gram EnCore
4 ± 2 °C
GRO and EDRO
Liquid
One 2-milliliter ampule for each analysis
Not applicable
7
Performed on sitec
See note d
Notes:
± = Plus or minus
a
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.
c
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.
36
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
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 SW846 Method 4030, were eliminated from further
consideration in the reference method selection process.
Reference Method Selection
•
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.
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, statespecific 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).
The analytical methods considered for the demonstration
and the reference method selected based on the abovelisted criteria are illustrated in a flow diagram in
Figure 5-1. The reference method selection process is
discussed below.
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
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:
37
38
SW-846 Method 8015B provides separate GRO and DRO measurements and, when modified, can also provide EDRO measurements.
Figure 5-1. Reference method selection process.
a
API = American Petroleum Institute, ASTM = American Society for Testing and Materials, DRO = diesel range organics, EPH = extractable petroleum hydrocarbon, GC/FID = gas chromatograph/flame
ionization detector, MCAWW = “Methods for Chemical Analysis of Water and Wastes,” PHC = petroleum hydrocarbon, PRO = petroleum range organics, SW-846 = “Test Methods for Evaluating
Solid Waste,” VPH = volatile petroleum hydrocarbon
Notes:
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.
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 greater than
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
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
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
Table 5-1. Laboratory Sample Preparation and Analytical Methods
Parameter
GRO
EDRO
Percent moisture
Method Reference (Step)
Method Title
Based on SW-846 Method 5035 (extraction)
Closed-System Purge-and-Trap and Extraction for Volatile Organics
in Soil and Waste Samples
Based on SW-846 Method 5030B (purge-and-trap)
Purge-and-Trap for Aqueous Samples
Based on SW-846 Method 8015B (analysis)
Nonhalogenated Volatile Organics by Gas Chromatography
Based on SW-846 Method 3540C (extraction)
Soxhlet Extraction
Based on SW-846 Method 8015B (analysis)
Nonhalogenated Volatile Organics by Gas Chromatography
Based on MCAWW Method 160.3a
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”
a
MCAWW Method 160.3 was modified to include calculation and reporting of percent moisture in soil samples.
39
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 8015B 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 then-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.
40
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.
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 may be collected with or without use of a preservative
solution.
Samples were collected without use of a preservative.
A variety of sample containers, including EnCores, may be used when
high-level samples are collected without use of a preservative.
Samples were containerized in EnCores.
Samples collected in EnCores should be transferred to vials containing
the extraction solvent as soon as possible or analyzed within 48 hours.
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.
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.
Because the reference laboratory obtained acceptable results for
performance evaluation samples extracted with methanol during the
predemonstration investigation, samples were extracted with methanol.
Removal of unrepresentative material from the sample is not discussed. 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.
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.
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.
Nine mL of methanol should be added to a 5-gram (wet weight) soil
sample.
Five mL of methanol was added to the entire soil sample contained in a
5-gram EnCore.
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.
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)
Screening of samples before the purge-and-trap procedure is
recommended using one of the two following techniques:
Samples were screened with an automated headspace sampler (see
SW-846 Method 5021) connected to a GC equipped with a flame
ionization detector.
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 organicfree 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.
According to the reference laboratory, a sample extract concentration
equivalent to 10,000 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.
41
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.
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.
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):
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: 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: 180 °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
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: 115 and 120 °C
8015B (Analysis)
GC Conditions
The following GC conditions are recommended:
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: 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 100 °C at 5 °C/min
Program rate: 100 to 275 °C at 8 °C/min
Hold time: 5 min
Overall time: 38.9 min
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.
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 leastsquares linear regression greater than or equal to 0.990.
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.
Calibration was performed using a commercially available,
10-component GRO standard that contained 35 percent aliphatic
hydrocarbons and 65 percent aromatic hydrocarbons.
42
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
8015B (Analysis) (Continued)
Calibration (Continued)
Initial calibration verification 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 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 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 should be performed using a fuel standard.
CCV was performed using a commercially available, 10-component
GRO standard that contained 35 percent aliphatic hydrocarbons and
65 percent aromatic hydrocarbons.
According to SW-846 Method 8000, CCV should be performed at the
CCV was performed at a concentration equivalent to 2,000 ng
same concentration as the midpoint concentration of the initial
on-column.
calibration curve; however, the concentration of each calibration point is
not specified.
A method sensitivity check is not required.
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-C10. Baseline rise
subtraction was not performed.
Quality Control
Spiking compounds for MS/MSDs and LCSs are not specified.
The spiking compound mixture for MS/MSDs and LCSs was the 10component GRO calibration standard.
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.
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.
43
Table 5-2. Summary of Project-Specific Procedures for GRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
8015B (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 reference laboratory acceptance criteria for MS/MSDs and LCSs
were a relative percent difference less than or equal to 25 with 33 to
115 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 should consist of an aliquot of a clean (control) matrix that is
similar to the sample matrix.
The LCS/LCSD matrix was Ottawa sand.
No LCSD is required.
The spiking compound mixture for LCSDs was the 10-component GRO
calibration standard.
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 surrogate compound was 4-bromofluorobenzene. The reference
laboratory acceptance criterion for surrogates was 39 to 163 percent
recovery.
The method blank matrix is not specified.
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 is not specified.
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
mL
MS
MSD
ng
SW-846
=
=
=
=
=
=
Minute
Milliliter
Matrix spike
Matrix spike duplicate
Nanogram
“Test Methods for Evaluating Solid Waste”
44
Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis
SW-846 Method Reference (Step)
Project-Specific Procedures
3540C (Extraction)
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.
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.
Ten grams of soil sample should be blended with 10 grams of
anhydrous sodium sulfate.
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 should be performed using 300 mL of extraction solvent.
Extraction was performed using 200 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.
Methylene chloride was 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.
Kuderna Danish and nitrogen evaporation were used as the
concentration techniques.
Procedures for addressing contamination carryover are not specified.
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.
8015B (Analysis)
GC Conditions
The following GC conditions are recommended:
An HP 6890 GC was used with the following conditions:
Column:
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
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
45
Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
8015B (Analysis) (Continued)
Calibration
The chromatographic system may be calibrated using either internal or
external standards.
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 leastsquares linear regression greater than or equal to 0.990.
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.
Calibration was performed using a commercially available standard that
contained even-numbered alkanes from C10 through C40.
ICV is not required.
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 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 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 should be performed using a fuel standard.
CCV was performed using a standard that contained only evennumbered alkanes from C10 through C40.
According to SW-846 Method 8000, CCV should be performed at the
CCV was performed at a concentration equivalent to 3,750 ng
same concentration as the midpoint concentration of the initial
on-column.
calibration curve; however, the concentration of each calibration point is
not specified.
A method sensitivity check is not required.
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
C10 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 12-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-C10
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-C10 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-C10 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.
46
Table 5-3. Summary of Project-Specific Procedures for EDRO Analysis (Continued)
SW-846 Method Reference (Step)
Project-Specific Procedures
8015B (Analysis) (Continued)
Quantitation (Continued)
Subtraction of the baseline rise for the method blank resulting from
column bleed is appropriate.
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.
Because phthalate esters contaminate many types of products
commonly found in the laboratory, consistent quality control should be
practiced.
Phthalate peaks were not noted during analysis.
Quality Control
Spiking compounds for MS/MSDs and LCSs are not specified.
The spiking compound for MS/MSDs and LCSs was an EDRO standard
that contained even-numbered alkanes from C10 through C40.
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.
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.
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 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 should consist of an aliquot of a clean (control) matrix that is
similar to the sample matrix.
The LCS/LCSD matrix was Ottawa sand.
No LCSD is required.
The spiking compound for LCSDs was the EDRO standard that
contained even-numbered alkanes from C10 through C40.
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 surrogate compound was o-terphenyl. The reference laboratory
acceptance criterion for surrogates was 45 to 143 percent recovery.
The method blank matrix is not specified.
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 is not specified.
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
Gas chromatograph
Initial calibration verification
Laboratory control sample
Laboratory control sample duplicate
Minute
mL
MS
MSD
n-Cx
ng
SW-846
=
=
=
=
=
=
Milliliter
Matrix spike
Matrix spike duplicate
Alkane with “x” carbon atoms
Nanogram
“Test Methods for Evaluating Solid Waste”
47
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.
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.
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
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 less than or equal to 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 object P4 (effect of soil moisture content).
6.1.1 GRO Analysis
Quality Control Check Results
This section summarizes the results 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.
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
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
48
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.
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.
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 (µg/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 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.
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 greater than 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.
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 µg/L. The acceptance
criteria for MS/MSDs were 33 to 115 percent recovery and
an RPD less than or equal to 25. When the MS/MSD
percent recovery acceptance criterion was not met, instead
49
of attributing the failure to meet the criterion to an
inappropriate spiking 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.
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 outof-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).
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 mediumgrained 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.
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.
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.
Extract Duplicates
For GRO 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
50
aliquots of the GRO extracts for analysis. The acceptance
criterion for extract duplicate precision was an RPD less
than or equal to 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.
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
(± 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.
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 µg/L. The
acceptance criteria for LCS/LCSDs were 33 to 115 percent
recovery and an RPD less than or equal to 25. The
LCS/LCSD acceptance criteria were based on the reference
laboratory’s historical data.
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 results 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.
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.
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.
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.
51
52
Liquid PE
samples
a
91 to 92
87 to 110
77 to 87
88 to 103
0 to 162
81 to 84
87 to 108
43 to 345
Actual
Range
4
20
Not applicable
4
6
15
6
34
40
92
100
83
94
81
83
96
150
Mean
92
100
85
92
80
84
95
136
Median
#25
Acceptance
Criterion
0 to 1
2 to 14
0.5 to 11
1 to 5
4 to 6
1 to 21
Actual
Range
2 pairs
10 pairs
10 pairs
2 pairs
3 pairs
10 pairs
Not applicable
No. of
Measurements
Meeting
Acceptance
Criterion
0.5
6
5
3
5
11
Mean
Precision (Relative Percent Difference)
0.5
6
4
3
5
12
Median
During the demonstration, 12 method blanks (10 for soil samples and 2 for liquid samples) were analyzed. The method blank results met the project-specific acceptance criteria.
#
LCS/LCSD
MS/MSD
PE
QC
33 to 115
33 to 115
39 to 163
Acceptance
Criterion
No. of
Measurements
Meeting
Acceptance
Criterion
Less than or equal to
Laboratory control sample and laboratory control sample duplicate
Matrix spike and matrix spike duplicate
Performance evaluation
Quality control
2 pairs
Soil
environmental
and PE
samples
LCS/LCSD
Notes:
10 pairs
Soil
environmental
samples
=
=
=
=
=
4 (2 pairs)
Liquid PE
samples
10 pairs
6 (3 pairs)
Soil PE
samples
6
Liquid PE
samples
20 (10 pairs)
34
Soil PE
samples
Soil
environmental
samples
56
Soil
environmental
samples
Extract
duplicate
MS/MSD
Surrogate
QC Checka
No. of
Measurements
Matrix
Used to
Associated
Evaluate Data
with QC Check
Quality
Accuracy (Percent Recovery)
Table 6-1. Summary of Quality Control Check Results for GRO Analysis
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.
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.
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 less than or equal to
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.
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.
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 in 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 associated with the analytical
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
53
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).
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 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-ofcontrol 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).
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 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 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 outof-control situations may have been associated with
inadequate spiking levels (0.4 to 0.7 times the unspiked
Two sample pairs collected in the B-38 Area were
designated as MS/MSDs. The sample matrix in this area
54
sample concentrations compared to the minimum
recommended value of 5 times the concentrations).
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 less than or equal
to 45. 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.
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.
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.
Extract Duplicates
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.
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 less than or equal to 45. 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.
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
Laboratory Control Samples and Laboratory
Control Sample Duplicates
For EDRO analysis, LCS/LCSD results were evaluated to
determine the accuracy and precision associated with
55
56
=
=
=
=
=
Soil
environmental
and PE
samples
LCS/LCSD
a
47 to 88
0 to 146
0 to 223
46 to 143
45 to 143
Actual
Range
6
14
185
179
44
Not applicable
Less than or equal to
Laboratory control sample and laboratory control sample duplicate
Matrix spike and matrix spike duplicate
Performance evaluation
Quality control
46 to 124
46 to 124
45 to 143
Acceptance
Criterion
No. of
Measurements
Meeting
Acceptance
Criterion
77
75
67
76
77
Mean
80
78
79
76
77
Median
#45
Acceptance
Criterion
0 to 29
0 to 34
3 to 17
0 to 50
Actual
Range
22 pairs
13 pairs
5 pairs
12 pairs
Not applicable
No. of
Measurements
Meeting
Acceptance
Criterion
6
6
7
17
Mean
Precision (Relative Percent Difference)
5
2
4
16
Median
During the demonstration, 22 method blanks for soil samples and 2 instrument blanks for liquid samples were analyzed. The blank results met the project-specific acceptance criteria.
#
LCS/LCSD
MS/MSD
PE
QC
Notes:
13 pairs
Soil
environmental
samples
Extract
duplicate
44 (22 pairs)
10 (5 pairs)
Soil PE
samples
185
Soil PE
samples
26 (13 pairs)
179
Soil
environmental
samples
Soil
environmental
samples
MS/MSD
Surrogate
QC Checka
No. of
Measurements
Matrix
Used to
Associated
Evaluate Data
with QC Check
Quality
Accuracy (Percent Recovery)
Table 6-2. Summary of Quality Control Check Results for EDRO Analysis
RPDs observed indicated good precision in the EDRO
concentration measurements made during the
demonstration.
6.2
triplicate samples analyzed by ERA using a GC/FID
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.
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 RemediAid™ kit’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 (greater than 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-concentrationrange PE samples, for which seven replicate samples were
analyzed.
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.
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
RemediAid™ kit 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.
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.
For soil samples containing weathered gasoline, the
certified values used for comparison to the reference
method results were based on mean TPH results for
57
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.
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.
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.
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.
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-
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-
Table 6-3. Comparison of Soil and Liquid Performance Evaluation Sample Results
Sample Typea
TPH
Concentration
Range
Performance
Acceptance Limits
(mg/kg)
Certified Value
Reference Method
Mean TPH
Concentration
Reference Method Mean
TPH Concentration/
Certified Value (percent)
Soil Sample (Ottawa Sand)
Diesel
Low
18.1 to 47.4
37.3 mg/kg
14.7 mg/kg
39
Medium
196 to 781
550 mg/kg
344 mg/kg
62
High
1,110 to 4,430
3,120 mg/kg
2,030 mg/kg
65
Weathered gasoline at
16 percent moisture
High
992 to 3,950
2,780 mg/kg
1,920 mg/kg
69
Diesel
Medium
220 to 577
454 mg/kg
281 mg/kg
62
High
1,900 to 4,980
3,920 mg/kg
2,720 mg/kg
69
High
2,100 to 5,490
4,320 mg/kg
2,910 mg/kg
67
Weathered gasoline
High
Not available
814,100 mg/L
648,000 mg/L
80
Diesel
High
Not available
851,900 mg/L
1,090,000 mg/L
128
Soil Samples (Processed Garden Soil)
Weathered gasoline
Diesel at less than 1 percent
moisture
Liquid Samples
Notes:
mg/kg = Milligram per kilogram
mg/L = Milligram per liter
a
Soil samples were prepared at 9 percent moisture unless stated otherwise.
58
containing soil samples ranged from 62 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 18 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 8 percentage points.
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 31 and 8 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 demonstration. 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
32 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
The ratios for diesel-containing soil samples ranged from
39 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.
Table 6-4. Comparison of Environmental Resource Associates Historical Results to Reference Method Results
ERA Historical Results
Sample Type
Mean
Recovery
(percent)
Reference Method Results
Mean Relative
Standard Deviation
(percent)
Mean
Recoverya
(percent)
Reference Method Mean
Recovery/ERA Historical
Mean Recovery (percent)
Mean Relative
Standard Deviationa
(percent)
Weathered gasoline in soil
88.7
26.5
65
74
8
Diesel in soil
87.7
19.6
59
68
7
Weathered gasoline in water
Diesel in water
109
78.5
22.0
80
73
5
22.8
128
163
6
Notes:
ERA = Environmental Resource Associates
a
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.
59
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.
RemediAid™ kit and reference method results for lowand medium-range soil samples containing diesel.
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-concentrationrange 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 lowand medium-range soil samples containing diesel because
the bias exceeded the generally acceptable bias of
±30 percent stated in SW-846 by 31 percentage points for
low-range and 8 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.
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 8 percentage points. For neat gasoline samples,
the bias did not exceed the acceptable bias. For dieselcontaining 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 31, 8, and 2 percentage points, respectively. For
neat diesel samples, the observed positive bias did not
exceed the acceptable bias. The low RSDs (5 to
8 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
60
Chapter 7
Performance of the RemediAid™ Kit
distributed to CHEMetrics 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 P1 through P4 were addressed using statistical
and nonstatistical approaches, as appropriate. The
statistical tests performed to address these objectives 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 RemediAid™ kit results and
reference method results or, when appropriate, their
differences were normally distributed at a significance
level of 5 percent. If the results or their differences 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.
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 RemediAid™ kit 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
RemediAid™ kit based on primary objectives P1 through
P5, which are listed below.
P1. Determine the MDL
P2. Evaluate the accuracy and precision of TPH
measurement for a variety of contaminated soil
samples
P3. Evaluate the
measurement
effect
of
interferents
on
For the RemediAid™ kit, when the TPH concentration in
a given sample was reported as below the reporting limit,
one-half the reporting limit was used as the TPH
concentration for that sample, as is commonly done, so that
necessary calculations could be performed without
rejecting the data. The same approach was used for the
reference method except that 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 limits. Caution was exercised to
ensure that these necessary data manipulations did not alter
the conclusions.
TPH
P4. Evaluate the effect of soil moisture content on TPH
measurement
P5. Measure the time required for TPH measurement
To address primary objectives P1 through P5, samples
were collected from five different sampling areas. In
addition, soil and liquid PE samples were prepared and
61
62
Performed measurement
F-test to determine whether
correlation was merely by
chance
Performed linear regression
to determine whether
consistent correlation existed
between field measurement
device and reference method
TPH results
Performed Wilcoxon signed
rank test (nonparametric) to
determine whether field
measurement device and
reference method TPH
results were statistically
the same
Figure 7-1. Summary of statistical analysis of TPH results.
Was unable to determine
method detection limit
Performed two-tailed, paired
Student's t-test (parametric)
to determine whether field
measurement device and
reference method TPH
results were statistically the
same
Yes
Yes
No
Were
TPH results
normally distributed?
(Wilk-Shapiro
test)
Were
TPH results
normally distributed?
(Wilk-Shapiro
test)
Determined method
detection limit using
approach recommended in
40 Code of Federal
Regulations Part 136,
Appendix B, Revision 1.1.1
Accuracy
(primary objective P2)
Method detection limit
(primary objective P1)
No
No
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
Were
group variances
equal?
(Bartlett's test)
Yes
Were
TPH results
for three sample groups
normally distributed?
(Wilk-Shapiro
test)
Effect of interferents
(primary objective P3)
Yes
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
Calculated relative
percent difference
for extract duplicate
TPH results
Calculated relative
standard deviation
for field triplicate
TPH results
Precision
(primary objective P2)
TPH results
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
Performed two-sample
Student's t-test
(parametric) to determine
whether increase in
moisture content resulted
in increase or decrease in
TPH results
Yes
Were
TPH results
of both sample groups
normally distributed?
(Wilk-Shapiro
test)
Effect of soil moisture content
(primary objective P4)
No
samples and reported the sums of the DRO and ORO
concentrations as the TPH results. The RemediAid™ kit
and reference method results for these samples are
presented in Table 7-1.
The reference method GRO results were adjusted for
solvent dilution associated with the soil sample moisture
content because the reference method required use of
methanol, a water-miscible solvent, for extraction of soil
samples.
In addition, based on discussions with
CHEMetrics, a given TPH result for the RemediAid™ kit
was rounded to the nearest integer when it was less than or
equal to 99 mg/kg or 99 mg/L and to the nearest 10 when
it was greater than 99 mg/kg or 99 mg/L. Similarly, based
on discussions with the reference laboratory, all TPH
results for the reference method were rounded to three
significant figures.
Table 7-1.
RemediAid™ Kit Result (mg/kg)
7.1.1 Primary Objective P1: Method Detection
Limit
To determine the MDLs for the RemediAid™ kit and
reference method, both CHEMetrics and the reference
laboratory analyzed seven low-concentration-range soil PE
samples containing weathered gasoline and seven lowconcentration-range soil PE samples containing diesel. 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.
MDL
16.4
63
16.4
33
13.2
39
16.0
46
14.2
20
14.1
29
12.8
60
4.79
MDL = Method detection limit
mg/kg = Milligram per kilogram
Based on the TPH results for the low-concentration-range
diesel soil PE samples, the MDLs were determined to be
60 and 4.79 mg/kg for the RemediAid™ kit and reference
method, respectively. 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 4.79 mg/kg, which was the same as the
MDL for the reference method based on the EDRO results,
indicating that the ORO concentrations below the reporting
limit did not impact the MDL for the reference method.
The MDL of 60 mg/kg for the RemediAid™ kit was
greater than the MDL of 40 mg/kg estimated by
CHEMetrics based on its MDL for water samples
containing diesel; no soil MDL data for the device were
available prior to the demonstration. The MDL of
4.79 mg/kg for the reference method compared 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.
(7-1)
where
S = Standard deviation of replicate TPH results
t ( n− 1,1− α = 0.99 )
=
Reference Method Result (mg/kg)
74
Notes:
Because the RemediAid™ kit and reference method results
were both 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.
MDL = ( S) t (n −1, 1− α = 0.99 )
TPH Results for Low-Concentration-Range Diesel Soil
Performance Evaluation Samples
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)
For the demonstration, CHEMetrics used three different
sets of slope and intercept values (calibration curves) to
calculate TPH concentrations. For samples containing
only GRO, the TPH results were calculated using
108.0 mg/L for the slope and 2.4 mg/L for the intercept.
For samples that did not contain GRO, the TPH results
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
63
exercised during interpretation of statistical test
conclusions drawn based on a small number of samples.
For example, only three samples were used for each type
of PE sample except the low-range diesel samples; the
small number of samples used increased the probability
that the results being compared would be found to be
statistically the same.
were calculated using 254.6 mg/L for the slope and
19.7 mg/L for the intercept. For samples that contained
both GRO and EDRO, average slope (181.3 mg/L) and
intercept (11.0 mg/L) values were used. Based on this
approach, for the purposes of reporting its demonstration
results, CHEMetrics used 40 mg/kg as the MDL for
samples containing only GRO and 50 mg/kg as the MDL
for samples containing both GRO and EDRO.
As discussed in Section 7.1.1, during the demonstration,
CHEMetrics used one of three different sets of slope and
intercept values to calculate TPH concentrations.
Table 7-2 presents the calibration details relevant to the
demonstration of the RemediAid™ kit. The slope and
intercept values selected by CHEMetrics for the
environmental samples seemed to be generally appropriate
with one exception: although CHEMetrics had established
slope and intercept values for lubricating oil (703.3 and
25.1 mg/L, respectively), during the demonstration,
CHEMetrics used the diesel calibration curve slope and
intercept values for PRA samples that contained primarily
heavy lubricating oil.
7.1.2 Primary Objective P2: Accuracy and
Precision
This section discusses the ability of the RemediAid™ kit
to accurately and precisely measure TPH concentrations in
a variety of contaminated soils. The RemediAid™ kit
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 RemediAid™ kit measurement of TPH
was assessed by determining
•
The following sections discuss how the RemediAid™ kit
results compared with the reference method results by
addressing each of the four factors identified above.
Whether the conclusion reached using the
RemediAid™ kit 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
•
Whether the RemediAid™ kit results were biased high
or low compared to the reference method results
•
Whether the RemediAid™ kit results were different
from the reference method results at a statistical
significance level of 5 percent when a pairwise
comparison was made
•
Whether a significant correlation existed between the
RemediAid™ kit and reference method results
Action Level Conclusions
Table 7-3 compares action level conclusions reached using
the RemediAid™ kit 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. Of the environmental samples, the
percentage of samples for which the conclusions agreed
ranged from 50 to 95. Of the PE samples, the percentage
of samples for which the conclusions agreed ranged from
50 to 100. Overall, the conclusions were the same for
82 percent of the samples.
The least agreement was observed for the PRA
environmental samples, for which the device results were
greater than the reference method results by one order of
magnitude. The high bias observed for the device cannot
be explained. The least agreement observed for the PE
samples, specifically for blank soil samples, appeared to be
associated with the device’s background reading for the
soil used to prepare the PE samples (near 40 mg/kg).
During examination of these four factors, the data quality
of the reference method and RemediAid™ kit 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 lowand 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 RemediAid™ kit
and reference method results, particularly those for lowand medium-range diesel soil samples. Caution was also
When the action level conclusions did not agree, the TPH
results were further interpreted to assess whether the
RemediAid™ kit conclusion was conservative. The device
conclusion was considered to be conservative when the
64
Table 7-2. RemediAid™ Kit Calibration Summary
Sampling Area or Sample Type
Contamination Type
Calibration Curve Used
Slope and Intercept Values Used
(milligram per liter)
Fuel Farm Area
Weathered diesel
Diesel
254.6 and 19.7
Naval Exchange Service Station Area
Weathered gasoline
Weathered gasoline
108.0 and 2.4
Phytoremediation Area
Heavy lubricating oil
Diesel
254.6 and 19.7
B-38 Area
Fresh gasoline and diesel or
weathered gasoline and trace
amounts of lubricating oil
Weathered gasoline and diesel
combined
181.3 and 11.0
Slop Fill Tank Area
Slightly weathered gasoline,
kerosene, JP-5, and diesel
Soil performance evaluation samples
Weathered gasoline
Weathered gasoline
108.0 and 2.4
Diesel
254.6 and 19.7
Blank
Weathered gasoline
108.0 and 2.4
Blank with humic acid
Diesel
254.6 and 19.7
Weathered gasoline and diesel
combined
181.3 and 11.0
Diesel
Diesel
254.6 and 19.7
Methyl-tert-butyl ether
Weathered gasoline
108.0 and 2.4
Weathered gasoline and diesel
combined
181.3 and 11.0
Diesel
254.6 and 19.7
Weathered gasoline with
interferents
Diesel
Diesel with interferents
Liquid performance evaluation samples Weathered gasoline
Tetrachloroethene
Stoddard solvent
Turpentine
1,2,4-Trichlorobenzene
reference method results was observed for samples
collected from the NEX Service Station, B-38, and
SFT Areas; for these samples, 60 to 75 percent of the
RemediAid™ kit results were within 50 percent of the
reference method results. For samples collected from the
FFA, 40 percent of the RemediAid™ kit results were
within 50 percent of the reference method results. For
PRA samples, none of the RemediAid™ kit results were
within 50 percent of the reference method results. These
results generally indicate that the device exhibited less
measurement bias for samples containing lighter PHCs
(NEX Service Station, B-38, and SFT Area samples) than
for samples containing heavier PHCs (FFA and PRA
samples).
device 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. RemediAid™ kit conclusions that
did not agree with reference method conclusions were
conservative for 9 of 15 environmental sample results
(60 percent) and 1 of 3 PE sample results (33 percent).
Measurement Bias
To determine the measurement bias, the ratios of the
RemediAid™ kit TPH results to the reference method TPH
results were calculated. The observed bias values were
grouped to identify the number of RemediAid™ kit results
within the following ranges of the reference method
results: (1) greater than 0 to 30 percent, (2) greater than 30
to 50 percent, and (3) greater than 50 percent.
For the RemediAid™ kit, 26 of 74 environmental sample
results (35 percent) exhibited a high bias of greater than
50 percent compared to the reference method results. As
stated in Chapter 6, the reference method results generally
exhibited a negative bias, but the high bias of greater than
50 percent for the RemediAid™ kit results cannot be
explained based solely on the negative bias associated with
the reference method results.
Figure 7-2 shows the distribution of measurement bias for
environmental samples. Of the five sampling areas,
the best agreement between the RemediAid™ kit and
65
Table 7-3. Action Level Conclusions
Sampling Area or Sample Type
Fuel Farm Area
Naval Exchange Service Station Area
Phytoremediation Area
Action
Level
(mg/kg)
Percentage of Samples for
Total Number Which RemediAid™ Kit and
of Samples
Reference Method
Analyzed
Conclusions Agreed
When Conclusions Did Not Agree,
Were RemediAid™ Kit Conclusions
Conservative or Not Conservative?a
100
10
80
Conservative
50
20
95
Not conservative
1,500
8
50
Conservative
B-38 Area
100
8
88
Slop Fill Tank Area
500
28
75
Not conservative (five of seven
conclusions)
Conservative
PE sample
Blank soil
(9 percent moisture content)
10
3b
50
PE sample
Blank soil and humic acid
(9 percent moisture content)
200
6
100
Soil PE
sample
containing
weathered
gasoline in
Medium-concentration range
(9 percent moisture content)
200
3
100
High-concentration range
(9 percent moisture content)
2,000
3
67
High-concentration range
(16 percent moisture content)
2,000
3
67
Soil PE
sample
containing
diesel in
Low-concentration range
(9 percent moisture content)
15
7c
100
Medium-concentration range
(9 percent moisture content)
200
3
100
High-concentration range
(less than 1 percent moisture
content)
2,000
3
100
High-concentration range
(9 percent moisture content)
2,000
3
100
108
82
Total
Not conservative
Notes:
mg/kg = Milligram per kilogram
PE
= Performance evaluation
a
A conclusion was considered to be conservative when the RemediAid™ kit 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.
b
Action level conclusions could be drawn for only two of three samples. The RemediAid™ kit result for the remaining sample was reported as a
“less than” value (less than 40 mg/kg), which was greater than the action level.
c
Action level conclusions could be drawn for only two of seven samples. The RemediAid™ kit results for the remaining samples were reported as
a “less than” value (less than 60 mg/kg), which was greater than the action level.
medium-, and high-range diesel soil samples exhibited a
high bias of greater than 50 percent compared to the
reference method results. The high bias of greater than
50 percent for the blank and low-range diesel soil samples
appeared to be associated with the background reading or
noise for the RemediAid™ kit when it was measuring TPH
concentrations near or below the device’s MDLs.
Additionally, the high bias observed for the low-range
diesel soil samples may be partially attributed to the
reference method’s significant negative bias in measuring
TPH in low-range diesel soil samples (see Chapter 6).
However, the high bias observed for the medium- and
Figure 7-3 shows the distribution of measurement bias for
selected soil PE samples. Of the five sets of samples
containing PHCs and the one set of blank samples, the best
agreement between the RemediAid™ kit and reference
method results was observed for the high-concentrationrange weathered gasoline soil samples; all RemediAid™
kit results for these samples were within 30 percent of the
reference method results.
Medium-range weathered
gasoline soil sample results also showed good agreement;
two of three RemediAid™ kit results were within
50 percent of the reference method results. The
RemediAid™ kit results for blank soil samples and low-,
66
Figure 7-2. Measurement bias for environmental samples.
67
Diesel in low-concentration range
Total number of samples: 7
3
2
1
0
>0 to 30
>30 to 50
>50
>0 to 30
>30 to 50
>50
Diesel in medium-concentration range
Total number of samples: 3
>0 to 30
>30 to 50
>50
Bias, percent
Weathered gasoline in
high-concentration range
Total number of samples: 6
>0 to 30
>30 to 50
Diesel in high-concentration range
Total number of samples: 6
>50
Bias, percent
Figure 7-3. Measurement bias for soil performance evaluation samples.
68
different. Based on a simple comparison of the results,
these conclusions appeared to be reasonable.
high-range diesel soil samples cannot be explained based
solely on the negative bias associated with the reference
method results. Finally, like the environmental sample
results, the PE sample results indicated that the device’s
measurement bias was less for lighter PHCs (in weathered
gasoline soil samples) than for heavier PHCs (in diesel soil
samples).
High probabilities associated with medium-concentrationrange weathered gasoline soil PE samples (96.14 percent)
and high-concentration-range weathered gasoline soil PE
samples (70.24 percent) with 9 percent moisture content
showed that the RemediAid™ kit demonstrated high
accuracy in measuring TPH concentrations in weathered
gasoline soil samples. The lower probability for highrange weathered gasoline soil PE samples (15.39 percent)
with 16 percent moisture content suggested that the higher
moisture content had a greater impact on TPH
measurement using the RemediAid™ kit than TPH
measurement using the reference method, particularly
because the reference method results remained relatively
unchanged when the sample moisture content was
increased from 9 to 16 percent.
Pairwise Comparison of TPH Results
To evaluate whether a statistically significant difference
existed between the RemediAid™ kit and reference
method TPH results, a parametric test (a two-tailed, paired
Student’s t-test) or a nonparametric test (a Wilcoxon
signed rank test) was selected based on the approach
presented in Figure 7-1. Tables 7-4 and 7-5 present
statistical comparisons of the RemediAid™ kit and
reference method results for environmental and PE
samples, respectively.
The tables present the
RemediAid™ kit and reference method results for each
sampling area or PE sample type, the statistical test
performed and the associated null hypothesis used to
compare the results, whether the results were statistically
the same or different, and the probability that the results
were the same.
As stated above under “Measurement Bias,” the
RemediAid™ kit TPH results for both blank soil and lowconcentration-range diesel soil PE samples appeared to
have been impacted by the device’s background reading or
noise when it measured TPH in samples that contained no
PHCs or trace levels of PHCs. The statistically significant
difference observed for medium-range diesel soil PE
samples may be explained by the significant negative bias
associated with the reference method results (see
Chapter 6).
However, the statistically significant
difference observed for the high-range diesel soil PE
samples cannot be explained based solely on the reference
method’s negative bias.
Table 7-4 shows that the RemediAid™ kit and reference
method results were statistically the same at a significance
level of 5 percent for all sampling areas except the PRA.
Specifically, the probability of the results being the same
was (1) greater than 5 percent for the FFA, NEX Service
Station Area, B-38 Area, and SFT Area and (2) less than
5 percent for the PRA. The statistical test conclusion
appeared to be reasonable based on a simple comparison of
results. The 100 percent probability observed for the NEX
Service Station Area appeared to be associated with the
nonparametric test, which did not take into account the
magnitude of differences between the results. The
90.79 percent probability observed for the SFT Area was
of particular significance because this area contained a
wide range of TPH concentrations and a wide variety of
petroleum product contamination (weathered gasoline,
diesel, JP-5, and kerosene) and because the statistical test
conclusion was based on a relatively large number of
samples.
Contrary to the observations made based on comparisons
of the RemediAid™ kit and reference method TPH results
for soil PE samples, the RemediAid™ kit results were
statistically different from the reference method results for
neat weathered gasoline PE samples but not for neat diesel
PE samples. Specifically, the RemediAid™ kit exhibited
a statistically significant high bias (1) for neat weathered
gasoline PE samples but not for weathered gasoline soil
samples and (2) for diesel soil samples but not for neat
diesel samples.
Of the RemediAid™ kit PE sample results that were
statistically different from the reference method results, on
average the RemediAid™ kit results were biased high by
a factor of two. In addition, the RemediAid™ kit results
for neat materials were biased high when compared to the
materials’ densities. Specifically, the device’s results were
biased high by 65 percent for neat weathered gasoline and
by 39 percent for neat diesel.
Table 7-5 shows that the RemediAid™ kit and reference
method results were statistically the same at a significance
level of 5 percent for blank soil PE samples, medium- and
high-concentration-range weathered gasoline soil PE
samples, and neat diesel liquid PE samples; the TPH
results for all other PE sample types were statistically
69
Table 7-4. Statistical Comparison of RemediAid™ Kit and Reference Method TPH Results for Environmental Samples
TPH Result (mg/kg)
Sampling Area
Fuel Farm Area
RemediAid™
Kit
220
21,840
150
21,770
75
68.2
15,000
90.2
12,000
44.1
26,170
13,900
1,810
1,330
9,840
8,090
66
3,140
Naval Exchange
Service Station
Area
Reference
Method
50
28.8
960
617
270
293
280
1,620
1,870
1,550
1,560
270
1,370
881
1,030
1,120
260
1,180
1,390
5,490
3,030
22,760
1,390
11,030
1,420
2,140
7,450
1,130
10,840
1,530
14,050
1,580
21,400
1,300
58
79.0
Less than 50
41.5
Less than 50
61.4
140
100
Different
0.05
Same
8.02
Null Hypothesis
The median of the differences
between the paired observations
(RemediAid™ kit and reference
method results) is equal to zero.
15.9
1,790
100
Statistical Test
Wilcoxon signed rank test
(nonparametric)
54.5
2,570
Phytoremediation 18,410
Area
28,790
B-38 Area
Same
Null Hypothesis
The mean of the differences
between the paired observations
(RemediAid™ kit and reference
method results) is equal to zero.
15.2
1,400
Less than 40
27.75
14.2
280
41
Same
219
1,080
Less than 40
Probability of Null
Hypothesis Being True
(percent)
9.56
730
Less than 40
Statistical Test
Two-tailed, paired Student’s t-test
(parametric)
Were RemediAid™ Kit and
Reference Method Results
Statistically the Same or Different?
93.7
144
Less than 40
Statistical Test
and Null Hypothesis
12,300
170
570
Statistical Analysis Summary
67.3
193
Less than 50
69.4
Less than 50
43.8
52
51.6
Statistical Test
Two-tailed, paired Student’s t-test
(parametric)
Null Hypothesis
The mean of the differences
between the paired observations
(RemediAid™ kit and reference
method results) is equal to zero.
Statistical Test
Two-tailed, paired Student’s t-test
(parametric)
Null Hypothesis
The mean of the differences
between the paired observations
(RemediAid™ kit and reference
method results) is equal to zero.
70
Table 7-4.
Statistical Comparison of RemediAid™ Kit and Reference Method TPH Results for Environmental Samples (Continued)
TPH Result (mg/kg)
Sampling Area
RemediAid™
Kit
Slop Fill Tank
Area
97
105
1,510
269
440
397
230
339
55
Less than 50
Less than 50
93
Reference
Method
Statistical Test
and Null Hypothesis
Statistical Test
Two-tailed, paired Student’s t-test
(parametric)
Null Hypothesis
The mean of the differences
6.16 between the paired observations
37.1 (RemediAid™ kit and reference
43.9 method results) is equal to zero.
52.4
1,720
3,300
1,750
1,270
350
588
1,050
554
320
834
360
501
340
280
200
185
790
1,090
510
544
180
503
240
146
1,190
938
410
517
280
369
280
253
130
Statistical Analysis Summary
151
3,650
3,960
260
1,210
190
121
Note:
mg/kg = Milligram per kilogram
71
Were RemediAid™ Kit and
Reference Method Results
Statistically the Same or Different?
Probability of Null
Hypothesis Being True
(percent)
Same
90.79
Table 7-5. Statistical Comparison of RemediAid™ Kit and Reference Method TPH Results for Performance Evaluation Samples
TPH Result
Sample Type
RemediAid™
Kit
Statistical Analysis Summary
Statistical Test
and
Null Hypothesis
Reference
Method
Were RemediAid™ Kit
and Reference Method
Results Statistically the
Same or Different?
Probability of Null
Hypothesis Being
True (percent)
Same
10.92
Same
96.14
Same
70.24
Same
15.39
Different
1.56
Different
0.36
Different
0.67
Different
1.82
Different
1.44
Same
18.05
Soil Samples (Processed Garden Soil) (TPH Results in Milligram per Kilogram)
Blank (9 percent moisture content)
40
1,710
5.12 Statistical Test
Two-tailed, paired
Student’s t-test
13.5 (parametric)
350
Null Hypothesis
346
The mean of the
336
differences between the
1,880
paired observations
(RemediAid™ kit and
2,020
reference method results)
2,180
is equal to zero.
1,740
1,670
1,980
1,670
2,050
Less than 40
43
Weathered Medium-concentration range 270
gasoline
(9 percent moisture content) 220
560
High-concentration range
1,980
(9 percent moisture content) 2,010
1,970
High-concentration range
(16 percent moisture
content)
Diesel
Low-concentration range
74
(9 percent moisture content)
64
13.1
16.4
16.4
Less than 60
13.2
Less than 60
16.0
Less than 60
14.2
Less than 60
14.1
Less than 60
12.8
Medium-concentration range 490
(9 percent moisture content) 480
470
276
273
295
High-concentration range
5,170
(9 percent moisture content) 4,910
2,480
2,890
5,150
2,800
High-concentration range
5,930
(less than 1 percent moisture 5,430
content)
5,090
2,950
2,700
3,070
Statistical Test
Wilcoxon signed rank test
(nonparametric)
Null Hypothesis
The median of the
differences between the
paired observations
(RemediAid™ kit and
reference method results)
is equal to zero.
Statistical Test
Two-tailed, paired
Student’s t-test
(parametric)
Null Hypothesis
The mean of the
differences between the
paired observations
(RemediAid™ kit and
reference method results)
is equal to zero.
Liquid Samples (Neat Materials) (TPH Results in Milligram per Liter)
Weathered gasoline
1,322,000
1,465,970
1,243,780
Diesel
1,212,520
1,188,660
1,164,800
656,000 Statistical Test
Two-tailed, paired
611,000 Student’s t-test
(parametric)
677,000
Null Hypothesis
1,090,000 The mean of the
differences between the
1,020,000 paired observations
(RemediAid™ kit and
1,160,000 reference method results)
is equal to zero.
72
Correlation of TPH Results
Environmental Samples
To determine whether a consistent correlation existed
between the RemediAid™ kit and reference method TPH
results, linear regression analysis was performed. A strong
correlation between the RemediAid™ kit and reference
method results would indicate that the device results could
be adjusted using the established correlation and that field
decisions could be made using the adjusted results in
situations where the device results may not be the same as
off-site laboratory results. Figures 7-4 and 7-5 show the
linear regression plots for environmental and soil PE
samples, respectively. Table 7-6 presents the regression
model, square of the correlation coefficient (R2), and
probability that the slope of the regression line is equal to
zero (F-test probability) for each sampling area and soil PE
sample type.
Blind field triplicates were analyzed to evaluate the overall
precision of the sampling, extraction, and analysis steps
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.
Table 7-6 shows that R2 values for (1) environmental
samples except PRA samples ranged from 0.69 to 0.74 and
(2) soil PE samples ranged from 0.86 to 0.98. The R2
value for PRA samples was 0.16. The R2 values for
separate regression models for weathered gasoline
and diesel soil PE samples were higher than the R2 value
for a combined regression model for these PE samples.
The probabilities of the slopes of the regression lines being
equal to zero ranged from 0.00 to 1.01 percent for all
sample groups except the PRA samples, indicating that
there was less than a 5 percent probability that the
RemediAid™ kit and reference method results correlated
only by chance for sample groups other than the PRA
samples. The probability for the PRA samples was
31.83 percent, indicating that there was a high probability
that the RemediAid™ kit and reference method results
correlated by chance. Based on the R2 and probability
values, the RemediAid™ kit and reference method results
were considered to be (1) highly correlated for weathered
gasoline soil PE samples and diesel soil PE samples;
(2) moderately correlated for FFA, NEX Service Station
Area, B-38 Area, and SFT Area samples and for weathered
gasoline and diesel soil PE samples; and (3) weakly
correlated for PRA samples.
Table 7-7 presents the TPH results and RSDs for 12 sets of
field triplicates analyzed using the RemediAid™ kit and
reference method. For the RemediAid™ kit, the RSDs
ranged from 0 to 67 percent with a median of 26 percent.
The RSDs for the reference method ranged from 4 to
39 percent with a median of 18 percent. Comparison of
the RemediAid™ kit and reference method RSDs showed
that the RemediAid™ kit exhibited less overall precision
than the reference method. The RemediAid™ kit and
reference method RSDs did not exhibit consistent trends
based on soil type, PHC contamination type, or TPH
concentration.
7.1.2.2
Tables 7-7 and 7-8 present the RemediAid™ kit and
reference method results for field triplicates and extract
duplicates, respectively. Precision was estimated using
RSDs for field triplicates and RPDs for extract duplicates.
Table 7-8 presents the TPH results and RPDs for 13 sets of
extract duplicates analyzed using the RemediAid™ kit and
reference method. For the RemediAid™ kit, the RPDs
ranged from 0 to 28 with a median of 4 when the
RPD for one extract duplicate set for the FFA, which had
one TPH result above the MDL and one TPH result below
the MDL, was not considered. The RPDs for the reference
method ranged from 0 to 11 with a median of 4. The
RPDs for the RemediAid™ kit and reference method
indicated about the same level of precision. The
RemediAid™ kit and reference method RPDs did not
exhibit consistent trends based on PHC contamination type
or TPH concentration. As expected, the median RPDs for
extract duplicates were less than the median RSDs for field
triplicates for both the RemediAid™ kit and reference
method. These findings 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.
Precision
Both environmental and PE samples were analyzed to
evaluate the precision associated with TPH measurements
using the RemediAid™ kit and reference method. The
results of this evaluation are summarized below.
73
Figure 7-4. Linear regression plots for environmental samples.
74
Performance Evaluation Samples
Comparison of weathered gasoline
performance evaluation sample results
2,500
Table 7-9 presents the RemediAid™ kit and reference
method TPH results and RSDs for eight sets of replicates
for soil PE samples and two sets of triplicates for liquid PE
samples.
2,000
1,500
1,000
For the RemediAid™ kit, of the RSDs for the eight sets of
replicates, the RSD for replicate set 5 was not considered
in evaluating the precision of the device because five of
seven results for the replicate set were below the MDL of
60 mg/kg. The RSDs for the remaining seven replicate
sets ranged from 1 to 52 percent with a median of
3 percent. The RSDs for the two triplicate sets of liquid
samples were 8 and 2 percent with a median of 5 percent.
500
0
0
500
1,000
1,500
2,000
Reference method TPH result (mg/kg)
2,500
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 2 to 10 percent with a median of
7 percent. The RSDs for the two triplicate sets of liquid
samples were 5 and 6 percent with a median of 5.5 percent.
Comparison of the RemediAid™ kit and reference method
RSDs revealed that the device and reference method
exhibited similar precision for both soil and liquid PE
samples. Finally, for the reference method, the median
RSD for the soil PE samples (7 percent) was less than that
for the environmental samples (18 percent), indicating that
greater precision was achieved for the samples prepared
under more controlled conditions (the PE samples).
Similarly, for the RemediAid™ kit, the median RSD for
the soil PE samples (3 percent) was less than that for the
environmental samples (26 percent).
Comparison of diesel
performance evaluation sample results
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
0
1,000
2,000
3,000
4,000
Reference Method TPH result (mg/kg)
Comparison of weathered gasoline
and diesel performance evaluation sample results
6,000
5,000
7.1.3
4,000
3,000
Primary Objective P3: Effect of
Interferents
2,000
The effect of interferents on TPH measurement using the
RemediAid™ kit 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
RemediAid™ kit and the reference method. Liquid
interferent samples were submitted for analysis as blind
1,000
0
0
Figure 7-5.
1,000
2,000
3,000
Reference method TPH result (mg/kg)
4,000
Linear regression plots for soil performance evaluation
samples.
75
Table 7-6. Summary of Linear Regression Analysis Results
Sampling Area or Sample Type
Regression Model
(y = RemediAid™ kit TPH result,
x = reference method TPH result)
Square of Correlation
Coefficient
Probability That Slope of
Regression Line Was Equal to
Zero (percent)
Environmental Samples
Fuel Farm Area
y = 1.40x - 280
0.74
0.15
Naval Exchange Service Station Area
y = 1.13x - 29
0.69
0.00
Phytoremediation Area
y = 9.38x + 2,440
0.16
31.83
B-38 Area
y = 0.73x + 1
0.70
1.01
Slop Fill Tank Area
y = 0.73x + 110
0.73
0.00
Weathered gasoline
y = 0.90x + 55
0.95
0.00
Diesel
y = 1.86x - 52
0.98
0.00
Weathered gasoline and diesel
y = 1.64x - 190
0.86
0.00
Soil Performance Evaluation Samples
demonstration, including MTBE and Stoddard solvent,
which were intended to be measured as TPH (see
Chapter 1).
triplicate samples. CHEMetrics and the reference
laboratory were provided with flame-sealed ampules 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 RemediAid™ kit 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
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 1,2,4trichlorobenzene (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.
Interferent Sample Results
Table 7-10 presents the RemediAid™ kit 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.
7.1.3.2
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.
The mean responses for the RemediAid™ kit ranged from
0 to 2 percent except for turpentine at both low and high
levels. The response observed for turpentine was at least
30 times greater than that for any other interferent.
Although some TPH results for the interferents were quite
variable, the variability did not impact the mean responses
to a significant extent. In summary, the mean responses
showed that, except for turpentine, the RemediAid™ kit
was not sensitive to the interferents used during the
Triplicate sets of control samples and samples containing
interferents were prepared for analysis using the
RemediAid™ kit and reference method. A parametric or
76
Table 7-7. Summary of RemediAid™ Kit and Reference Method Precision for Field Triplicates of Environmental Samples
RemediAid™ Kit
Sampling Area
Field Triplicate
Set
Fuel Farm Area
1
TPH Result
(milligram per kilogram)
Reference Method
Relative Standard
Deviation (percent)
220
49
150
11
46
6
Phytoremediation Area
B-38 Area
7
8
20
881
1,080
1,180
1,550
67
1,120
285
1,390
Less than 40
0
14.2
Less than 40
15.2
18,410
22
2,140
28,790
1,790
22,760
1,390
58
62
79
39
16
23
21
13
61.4
67.3
325
56
834
14
1,090
938
360
18
510
501
4
544
410
517
335
30
180
280
29
503
280
12
9.56
Less than 40
1,190
11
1,560
1,030
790
10
1,870
1,370
100
9
13
219
1,620
Less than 50
Slop Fill Tank Area
280
270
260
5
11
13,900
570
730
4
15,000
12,000
20,170
3
34
44.1
21,840
21,870
Naval Exchange Service
Station Area
68.2
Relative Standard
Deviation (percent)
90.2
75
2
TPH Result
(milligram per kilogram)
369
200
17
185
240
146
280
253
77
28
Table 7-8. Summary of RemediAid™ Kit and Reference Method Precision for Extract Duplicates
Sampling Area
Extract
Duplicate
Set
Fuel Farm Area
1
RemediAid™ Kit
TPH Result
(milligram per kilogram)
120
Relative Percent
Difference
120
Less than 60
2
Naval Exchange Service
Station Area
3
Not calculateda
a
4
1,110
5
280
a
Phytoremediation Area
7
1,190
4
1,420
Not calculateda
a
28,400
55
9
Less than 50
3
370
360
380
13
200
1,710
79.6
0
41.4
4
8
2
78.4
0
41.5
28
829
1
838
0
360
12
15.5
12
280
11
4
1,860
Less than 50
10
2
14.9
62
Slop Fill Tank Area
6
1,360
Less than 40
8
2
1,170
29,180
B-38 Area
226
6
290
Not analyzed
13,700
213
1,050
6
0
14,000
Not calculateda
260
Not analyzed
44.1
Relative Percent
Difference
44.1
26,170
Not analyzed
Reference Method
TPH Result
(milligram per kilogram)
528
11
473
27
271
0
189
290
6
289
200
4
181
Note:
a
Insufficient extract was available to perform an extract duplicate analysis; therefore, a relative percent difference could not be calculated.
sample (neat material) analytical results, MTBE was
expected to have no effect on the TPH results for the
RemediAid™ kit; however, it was expected to bias the
reference method results high.
nonparametric test was selected for statistical evaluation of
the 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 both the RemediAid™ kit and reference method are
presented in Table 7-11. The null hypothesis for the
statistical tests was that mean TPH results for samples with
and without interferents were equal. The statistical results
for each interferent are discussed below.
For the RemediAid™ kit, MTBE biased the TPH results
low; the bias was statistically significant only at the high
interferent level. This observation appeared to contradict
the conclusions drawn from the analytical results for
the neat material (quasi-control) samples. However, the
apparent contradiction was attributable to the fact that
quasi-control sample analyses could predict only a positive
bias (a negative bias is equivalent to a negative
concentration).
Effect of Methyl-Tert-Butyl Ether
The effect of MTBE was evaluated for soil PE samples
containing weathered gasoline. Based on the liquid PE
78
Table 7-9. Comparison of RemediAid™ Kit and Reference Method Precision for Replicate Performance Evaluation Samples
RemediAid™ Kit
Sample Type
Replicate Set
TPH Result
Reference Method
Relative Standard
Deviation (percent)
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
1
Medium-range TPH
concentration
(9 percent moisture
content)
2
High-range TPH
concentration
(9 percent moisture
content)
3
High-range TPH
concentration
(16 percent moisture
content)
4
Low-range TPH
concentration
(9 percent moisture
content)
5
40
36
13.1
43
13.5
270
52
220
1
1
8
2,050
74
47
16.4
63
16.4
Less than 60
13.2
Less than 60
16.0
Less than 60
14.2
Less than 60
14.1
Less than 60
8
1,740
1,980
1,670
High-range TPH
concentration (less
than 1 percent
moisture content)
7
2,180
1,710
1,670
7
1,880
2,020
1,970
High-range TPH
concentration
(9 percent moisture
content)
2
350
1,980
2,010
6
346
45
336
560
Medium-range TPH
concentration
(9 percent moisture
content)
5.12
Less than 40
490
10
12.8
2
480
276
4
273
470
295
5,170
3
2,480
4,910
2,890
5,150
2,800
5,930
8
2,700
5,430
2,950
5,090
3,070
8
6
Liquid Samples (Neat Materials) (TPH Results in Milligram per Liter)
Weathered gasoline
9
1,322,000
8
1,466,000
10
5
611,000
1,244,000
Diesel
656,000
677,000
1,213,000
2
1,090,000
1,189,000
1,020,000
1,165,000
1,160,000
79
6
Table 7-10. Comparison of RemediAid™ Kit and Reference Method Results for Interferent Samples
RemediAid™ Kit
Interferent and Concentrationa
TPH Result
Mean TPH
Result
Reference Method
Mean Responseb
(percent)
TPH Result
Mean TPH
Result
Mean Responseb
(percent)
309,000
284,000
38
299,000
40
272,000
17
295,000
18
598,000
78
708,000
92
468,000
55
408,000
48
688,000
48
754,000
52
Liquid Interferent Samples (TPH Result in Milligram per Liter)
Methyl-tert-butyl ether
(740,000 milligrams per liter)
9,670
9,530
1
8,030
272,000
10,880
5,880
270,000
5,530
1
5,060
313,000
5,660
Tetrachloroethene
(1,621,000 milligrams per liter)
Less than 16,680
282,000
8,340
1
Less than 16,680
277,000
2,005
0
Less than 4,010
21,100
307,000
15,880
2
21,540
606,000
4,380
0
4,480
511,460
713,000
496,650
59
480,090
442,000
542,040
64
549,480
Less than 25,020
349,000
12,510
1
Less than 25,020
711,000
620,000
Less than 25,020
7,920
523,000
353,000
533,720
1,2,4-Trichlorobenzene
(1,439,000 milligrams per liter)
504,000
459,000
498,390
542,910
703,000
Not reported
4,300
Turpentine
(845,600 milligrams per liter)
561,000
628,000
Less than 10,010
4,360
290,000
288,000
Less than 4,010
Stoddard solvent
(771,500 milligrams per liter)
269,000
270,000
Less than 16,680
Less than 4,010
303,000
732,000
4,650
0
754,000
Less than 6,020
756,000
Less than 6,020
752,000
Interferent Samples (Processed Garden Soil) (TPH Result in Milligram per Kilogram)
Humic acid at 3,940 milligrams
per kilogram
Less than 60
42
1
65
9.00
0
8.96
Less than 60
Humic acid at 19,500 milligrams 70
per kilogram
Less than 60
8.99
8.12
43
0
69.3
76.0
0
79.1
Less than 60
78.5
Notes:
a
A given liquid interferent concentration was estimated using its density and purity.
b
The mean response was calculated by dividing the mean TPH result for a triplicate set by the interferent concentration and multiplying by 100.
80
81
PCE
(13,100 mg/kg)
PCE (2,810 mg/kg)
MTBE
(1,700 mg/kg)
Weathered MTBE
gasoline
(1,100 mg/kg)
Soil Samples With Interferents
Diesel
Weathered gasoline
2,540
2,560
2,320
2,150
2,210
1,750
1,900
4,570
4,040
1,960
4,740
2,080
2,200
2,080
6.86
0.80
2,800
2,890
2,480
2,180
2,020
1,880
2,450
Same
Mean with
interferent at
high level
was different
from means
without
interferent
and with
interferent at
low level
Not applicable
Not applicable
2,280
One-way
analysis of
variance
(parametric) and
Tukey (honest,
significant
difference)
pairwise
comparison of
means
(parametric)
Statistical Tests
TPH
Result
(mg/kg)
2,160
2,190
1,580
1,930
5,080
1,990
Mean TPH
Result
(mg/kg)
2,120
2,170
1,570
1,740
1,430
1,810
2,020
1,970
5,150
4,910
5,170
1,970
2,010
1,980
Soil Samples Without Interferents
Sample Matrix and Interferenta
TPH
Result
(mg/kg)
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents Interferents Being
the Same or
the Same
Different?
(percent)
RemediAid™ Kit
4,450
2,380
2,340
1,950
2,720
2,030
Mean TPH
Result
(mg/kg)
Not applicable
Not applicable
Mean with
interferent at
high level
was different
from means
without
interferent
and with
interferent at
low level
One-way analysis of Same
variance
(parametric) and
Tukey (honest,
significant
difference) pairwise
comparison of
means (parametric)
Statistical Tests
0.00
11.21
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents
Interferents
the Same or Being the Same
Different?
(percent)
Reference Method
Table 7-11. Comparison of RemediAid™ Kit and Reference Method Results for Soil Performance Evaluation Samples Containing Interferents
82
Stoddard solvent
(18,200 mg/kg)
Stoddard solvent
(3,650 mg/kg)
Turpentine
(12,900 mg/kg)
Weathered Turpentine
gasoline
(2,730 mg/kg)
Diesel
Stoddard solvent
(15,400 mg/kg)
Weathered Stoddard solvent
gasoline
(2,900 mg/kg)
(Continued)
7,010
10,460
8,230
2,580
2,640
2,430
2,390
2,370
2,450
2,570
2,530
2,500
2,010
2,210
2,540
2,180
2,230
2,250
Soil Samples With Interferents (Continued)
Sample Matrix and Interferenta
TPH
Result
(mg/kg)
8,570
2,550
2,400
2,530
2,250
2,220
Mean TPH
Result
(mg/kg)
Kruskal-Wallis
one-way
analysis of
variance
(nonparametric)
and KruskalWallis pairwise
comparison of
means
(nonparametric)
One-way
analysis of
variance
(parametric) and
Tukey (honest,
significant
difference)
pairwise
comparison of
means
(parametric)
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 without
interferent
was different
from means
with
interferent at
low and high
levels
Kruskal-Wallis
Same
one-way
analysis of
variance
(nonparametric)
and KruskalWallis pairwise
comparison of
means
(nonparametric)
Statistical Tests
0.10
0.00
5.78
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents Interferents Being
the Same or
the Same
Different?
(percent)
RemediAid™ Kit
14,600
11,200
12,800
4,440
3,870
4,410
8,280
6,580
8,770
4,520
4,640
4,390
11,000
14,300
10,300
4,110
4,760
4,350
TPH
Result
(mg/kg)
12,900
4,240
7,880
4,520
11,900
4,410
Mean TPH
Result
(mg/kg)
One-way analysis of
variance
(parametric) and
Tukey (honest,
significant
difference) pairwise
comparison of
means (parametric)
Statistical Tests
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
All three
means (with
and without
interferents)
were
significantly
different from
one another
0.00
0.00
0.00
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents
Interferents
the Same or Being the Same
Different?
(percent)
Reference Method
Table 7-11. Comparison of RemediAid™ Kit and Reference Method Results for Soil Performance Evaluation Samples Containing Interferents (Continued)
83
Diesel
1,2,4-Trichlorobenzene
(16,600 mg/kg)
1,2,4-Trichlorobenzene
(3,350 mg/kg)
Turpentine
(19,600 mg/kg)
Turpentine
(3,850 mg/kg)
4,750
4,810
3,800
4,800
4,360
4,840
7,660
7,070
7,890
4,470
2,740
2,750
Soil Samples With Interferents (Continued)
Sample Matrix and Interferenta
TPH
Result
(mg/kg)
4,450
4,670
7,540
3,320
Mean TPH
Result
(mg/kg)
All three
means (with
and without
interferents)
were
significantly
different from
one another
One-way
Same
analysis of
variance
(parametric) and
Tukey (honest,
significant
difference)
pairwise
comparison of
means
(parametric)
Kruskal-Wallis
one-way
analysis of
variance
(nonparametric)
and KruskalWallis pairwise
comparison of
means
(nonparametric)
Statistical Tests
19.34
2.73
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents Interferents Being
the Same or
the Same
Different?
(percent)
RemediAid™ Kit
6,690
6,560
7,940
3,550
3,750
3,220
13,300
13,300
15,000
5,610
5,810
5,860
TPH
Result
(mg/kg)
7,060
3,510
13,900
5,760
Mean TPH
Result
(mg/kg)
One-way analysis of
variance
(parametric) and
Tukey (honest,
significant
difference) pairwise
comparison of
means (parametric)
Kruskal-Wallis oneway analysis of
variance
(nonparametric) and
Kruskal-Wallis
pairwise
comparison of
means
(nonparametric)
Statistical Tests
Mean with
interferent at
high level
was different
from means
without
interferent
and with
interferent at
low level
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
0.01
2.65
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents
Interferents
the Same or Being the Same
Different?
(percent)
Reference Method
Table 7-11. Comparison of RemediAid™ Kit and Reference Method Results for Soil Performance Evaluation Samples Containing Interferents (Continued)
84
a
Milligram per kilogram
Methyl-tert-butyl ether
Tetrachloroethene
3,020
3,360
3,390
4,430
4,560
4,740
3,260
4,580
Mean TPH
Result
(mg/kg)
One-way
analysis of
variance
(parametric) and
Tukey (honest,
significant
difference)
pairwise
comparison of
means
(parametric)
Statistical Tests
All samples were prepared at a 9 percent moisture level.
mg/kg =
MTBE =
PCE =
Notes:
Humic acid
(19,500 mg/kg)
Diesel
Humic acid
(Continued) (3,940 mg/kg)
Soil Samples With Interferents (Continued)
Sample Matrix and Interferenta
TPH
Result
(mg/kg)
All three
means (with
and without
interferents)
were
significantly
different from
one another
0.00
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents Interferents Being
the Same or
the Same
Different?
(percent)
RemediAid™ Kit
2,270
2,420
2,660
2,360
2,080
2,150
TPH
Result
(mg/kg)
2,450
2,200
Mean TPH
Result
(mg/kg)
One-way analysis of
variance
(parametric) and
Tukey (honest,
significant
difference) pairwise
comparison of
means (parametric)
Statistical Tests
Mean without
interferent
was same as
mean with
interferent at
high level;
mean with
interferent at
low level was
same as
mean with
interferent at
high level
3.87
Were Mean
Probability of
TPH Results
Mean TPH
for Samples
Results for
With and
Samples With
Without
and Without
Interferents
Interferents
the Same or Being the Same
Different?
(percent)
Reference Method
Table 7-11. Comparison of RemediAid™ Kit and Reference Method Results for Soil Performance Evaluation Samples Containing Interferents (Continued)
Effect of Stoddard Solvent
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).
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 have no effect on the
TPH results for the RemediAid™ kit; however, it was
expected to significantly bias the reference method results
high.
Table 7-11 shows that Stoddard solvent did not affect the
RemediAid™ kit TPH results for weathered gasoline soil
PE samples, which confirmed the conclusions drawn from
the results of the neat Stoddard solvent analysis. However,
the mean TPH result without the interferent was
statistically different from the means with the interferent at
low and high levels. Specifically, the TPH results for
diesel soil PE samples were biased low at both low and
high levels of Stoddard solvent.
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 have no effect on the TPH results for the
RemediAid™ kit; however, it was expected to bias the
reference method results high.
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 in 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.
Table 7-11 shows that PCE did not affect the
RemediAid™ kit TPH results for soil PE samples
containing weathered gasoline, which confirmed the
conclusions drawn from the results of the neat PCE
analysis.
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 less than 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 Turpentine
The effect of turpentine was evaluated for weathered
gasoline and diesel soil PE samples. Based on the liquid
PE sample (neat material) analytical results, turpentine was
expected to bias the TPH results high for both the
RemediAid™ kit and reference method.
For the RemediAid™ kit, at the interferent levels used,
turpentine was expected to bias the TPH results high by
84 percent (low level) and 399 percent (high level) for
weathered gasoline soil PE samples and by 47 percent (low
level) and 237 percent (high level) for diesel soil PE
85
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.
samples. The expected bias would be lower (33 and
155 percent, respectively, for weathered gasoline soil PE
samples and 44 and 222 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. As shown in Table 7-11 for
weathered gasoline 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 weathered gasoline 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 25 percent. The anomaly might have been
associated with the nonparametric test used to evaluate the
effect of turpentine on TPH results for weathered gasoline
soil PE samples, as nonparametric tests do not account for
the magnitude of the difference between TPH results. As
shown in Table 7-11 for diesel soil PE samples, the mean
TPH results with and without the interferent were
significantly different. However, a simple comparison of
means indicated that the results were inconclusive
regarding the effect of turpentine because at the low level,
turpentine biased the TPH results low, whereas at the high
level, turpentine biased the TPH results high.
Effect of 1,2,4-Trichlorobenzene
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 have no effect on the TPH results for the
RemediAid™ kit; however, it was expected to bias the
reference method results high.
Table 7-11 shows that 1,2,4-trichlorobenzene did not affect
the RemediAid™ kit TPH results for diesel soil PE
samples, which confirmed the conclusions drawn from the
results of the neat 1,2,4-trichlorobenzene analysis.
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 less than
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
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.
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
86
For the RemediAid™ kit, humic acid biased the TPH
results low; the bias was statistically significant at both low
and high humic acid levels. This observation appeared to
contradict the conclusions drawn from the analytical
results for soil PE samples containing humic acid (quasicontrol samples); however, the apparent contradiction was
attributable to the fact that the quasi-control sample
analyses could predict only a positive bias (a negative bias
is equivalent to a negative concentration).
Table 7-12 shows that RemediAid™ kit TPH results for
diesel soil samples at different moisture levels were
statistically the same at a significance level of 5 percent,
indicating that the increase in sample moisture content
from less than 1 percent to 9 percent did not impact the
results. However, a statistical comparison of the
RemediAid™ kit results for weathered gasoline samples
showed that there was a less than 5 percent probability that
the TPH results were the same at the two moisture levels
(9 and 16 percent), indicating that moisture content had a
statistically significant impact on the device results.
Although the device results at the two moisture levels were
within 9 percent, the statistical test conclusion appeared to
be reasonable when the variabilities associated with the
results at the two moisture levels were considered (RSDs
of 5 and 7 percent at 9 and 16 percent moisture levels,
respectively).
For the reference method, humic acid appeared to have
biased the TPH results low. However, the bias decreased
with an increase in 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.
Table 7-12 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.
7.1.4
7.1.5
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
RemediAid™ kit and reference method.
Primary Objective P4: Effect of Soil
Moisture Content
To measure the effect of soil moisture content on the
ability of the RemediAid™ kit 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 RemediAid™ kit 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. The
RemediAid™ kit and 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 device and reference method results were
impacted by moisture content—that is, to determine
whether an increase in soil moisture content resulted in an
increase or decrease in the TPH concentrations measured.
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 7-12 shows the sample moisture
levels, TPH results, mean TPH results for sets of triplicate
samples, whether the mean TPH results at different
moisture levels were the same, and the probability of the
null hypothesis being true.
Primary Objective P5: Time Required for
TPH Measurement
During the demonstration, the time required for TPH
measurement activities, including RemediAid™ kit setup,
sample extraction and analysis, RemediAid™ kit
disassembly, and data package preparation, was measured.
For the demonstration, two field technicians performed the
TPH measurement activities using the RemediAid™ kit.
Time measurement began at the start of each
demonstration day when the technicians began to set up
the RemediAid™ kit and ended when they disassembled
the RemediAid™ kit. Time not measured included (1) the
time spent by the technicians verifying that they had
received all the demonstration samples indicated on chainof-custody forms, (2) the times when both technicians took
breaks, and (3) the time that the technicians spent away
from the demonstration site. In addition to the total time
required for TPH measurement, the time required to extract
and analyze the first and last analytical batches of soil
samples was measured. The number and type of samples
in a batch were selected by CHEMetrics.
The time required to complete TPH measurement activities
using the RemediAid™ kit is shown in Table 7-13. When
87
88
Sample Type and Moisture Level
Same
82.18
A two-tailed, two-sample Student’s t-test (parametric) was used to evaluate the effect of soil moisture content on TPH results.
The null hypothesis for the t-test was that the two means were equal or that the difference between the two means was equal to zero.
3,100
5,650
2,930
3,000
2,300
2,230
b
2,970
5,410
2,720
3,070
5,590
5,130
5,710
3,180
5,470
2,740
2,440
5,530
1,990
5,980
2,390
2,070
2,010
2,040
2,010
2,070
2,400
0.08
2,220
Different
2,170
2,190
Same
Same
Were Mean TPH
Results at Different
Moisture Levels the
Same or Different?a
Reference Method
TPH Result on
Mean TPH
Probability of
Result
Null Hypothesis Dry Weight Basis
(milligram per
(milligram per
Being Trueb
(percent)
kilogram)
kilogram)
2,210
2,180
Were Mean TPH
Results at Different
Moisture Levels the
Same or Different?a
a
Notes:
Diesel at 9 percent moisture level
Diesel at less than 1 percent
moisture level
Weathered gasoline at 16 percent
moisture level
Weathered gasoline at 9 percent
moisture level
TPH Result on Dry Mean TPH
Weight Basis
Result
(milligram per
(milligram per
kilogram)
kilogram)
RemediAid™ Kit
Table 7-12. Comparison of Results for Soil Performance Evaluation Samples at Different Moisture Levels
71.95
66.52
Probability of
Null Hypothesis
Being Trueb
(percent)
Table 7-13. Time Required to Complete TPH Measurement Activities Using the RemediAid™ Kit
Time Requireda
Measurement Activity
First Sample Batchb
RemediAid™ kit setup
25 minutes
Sample extraction and analysis
2 hours, 5 minutes
RemediAid™ kit disassembly
30 minutes
Last Sample Batchb
c
d
Data package preparation
Not available
Total
3 hours
1 hourc
55 minutes
42 hours, 25 minutes
30 minutes
e
3-Day Demonstration Period
15 minutesc
d
Not available
1 hour, 30 minutesd
e
1 hour, 40 minutes
1 hours, 15 minutese
46 hours, 10 minutes
Notes:
a
The time required for each activity was rounded to the nearest 5 minutes.
b
The first sample batch required 8 soil sample extractions and 18 TPH analyses (8 sample extract analyses, 2 extract duplicate analyses, 7 dilution
analyses, and 1 reanalysis). The last sample batch required 7 soil sample extractions and 7 sample extract analyses.
c
The setup time was measured on days 1 and 3 of the demonstration; the average setup time was used to estimate the total setup time for the 3-day
demonstration period.
d
The disassembly time was measured on days 1 and 2 of the demonstration; the average disassembly time was used to estimate the total
disassembly time for the 3-day demonstration period.
e
The data package preparation time was not separately measured for the first and last batches. At the end of the demonstration period, CHEMetrics
required 1 hour, 15 minutes, to summarize 209 TPH results.
and seven samples, respectively. Extraction and analysis
of the first batch of soil samples required 2 hours,
5 minutes, or an average of 16 minutes per sample.
Extraction and analysis of the last batch of samples results
required 55 minutes, or an average of 8 minutes per
sample. The significant difference appeared to be
associated with the additional number of analyses required
for the first batch. Specifically, extraction and analysis of
the first batch of samples involved eight soil sample
extractions and 18 analyses (eight sample extract analyses,
two extract duplicate analyses, seven dilution analyses, and
one reanalysis), whereas extraction and analysis of the last
batch involved only seven soil sample extractions and
analyses.
a given activity was performed by the two field technicians
simultaneously, the time measurement for the activity was
the total time spent by both technicians. The time required
for each activity was rounded to the nearest 5 minutes.
Overall, CHEMetrics required 46 hours, 10 minutes, for
TPH measurement of 74 soil environmental samples,
89 soil PE samples, 36 liquid PE samples, and 10 extract
duplicates, resulting in an average TPH measurement time
of 13 minutes per sample. Information regarding the time
required for each measurement activity during the entire 3day demonstration and for extraction and analysis of the
first and last batches of soil samples is provided below.
RemediAid™ kit setup required 15 to 25 minutes each
day, totaling 1 hour for the entire demonstration. This
activity included RemediAid™ kit setup and organization
of extraction, dilution, analysis, and decontamination
supplies. The setup time was measured at the beginning of
days 1 and 3 during the 3-day demonstration period.
RemediAid™ kit disassembly required 30 minutes each
day, totaling 1 hour, 30 minutes, for the entire
demonstration. Disassembly included packing up the
RemediAid™ kit and the associated supplies required for
TPH measurement. The disassembly time was measured
at the end of days 1 and 2 of the 3-day demonstration
period.
For the entire demonstration, CHEMetrics required
42 hours, 25 minutes, to report 209 TPH results, indicating
that the average extraction and analysis time was 12
minutes per sample. The time required for extraction and
analysis of the first and last batches of soil samples was
also recorded. CHEMetrics typically designated eight
samples for each analytical batch. The number of samples
was based on the capacity of the RemediAid™ starter kit.
The first and last batches of soil samples consisted of eight
At the end of the demonstration, CHEMetrics required 1
hour, 15 minutes, to summarize 209 TPH results for EPA
review. During the weeks following the demonstration,
CHEMetrics spent additional time making minor revisions
to the data package in order to address EPA comments; the
revisions primarily involved use of appropriate reporting
limits. The amount of additional time that CHEMetrics
89
Each item in the RemediAid™ kit is configured in such a
way as to facilitate TPH measurement and avoid
confusion. For example, dilution ampules containing a
premeasured volume of dichloromethane are doubletipped, whereas the aluminum chloride ampules are singletipped with a flat bottom. The reaction tube and extraction
cleanup tube are readily distinguishable because of their
different sizes and because the cleanup tube has a green
cap. A snapper/plug that fits into the cleanup tube
facilitates snapping of an aluminum chloride ampule. The
sample extract is then drawn though the vacuum-sealed
ampule to react with the aluminum chloride. A silicone
cap is provided to be slipped over the ampule so that the
user’s exposure to the reagents is minimized while the
ampule is shaken. All items necessary for measurement of
TPH in soil are included in the device. The user is
required to provide only personal protective equipment
(PPE), samples for TPH measurement, and pipettes
required to dilute sample extracts containing TPH
concentrations above the device calibration range. The
completeness of the device and its ease of use minimize
the likelihood of user error.
spent finalizing the data package could not be quantified
and was not included as part of the time required for TPH
measurement.
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
RemediAid™ kit in terms of the secondary objectives
stated in Section 4.1. The secondary objectives were
addressed based on (1) observations of the RemediAid™
kit’s performance during the demonstration and
(2) information provided by CHEMetrics.
7.2.1
TPH measurement using the RemediAid™ kit does not
require field calibration of the device. Predetermined slope
and intercept values for a variety of petroleum products
can be used to calculate sample TPH concentrations based
on sample absorbance; these slope and intercept values are
included in the test procedure manual. Field analysis
requires only that the photometer be zeroed using the
reagent blank prior to each measurement, which eliminates
the need for the user to prepare calibration standards and
curves.
Skill and Training Requirements for
Proper Device Operation
Based on observations made during the demonstration, the
RemediAid™ kit is easy to use, requiring one field
technician with basic wet chemistry skills acquired on the
job or in a university. Some experience is also required for
determining (1) whether adequate amounts of anhydrous
sodium sulfate have been used to properly dry moist soil
samples in order to allow efficient PHC extraction and
(2) whether color development is complete and when
sample extract absorbance can be measured. Based on the
observations made during the demonstration, this
experience can be acquired by performing a few practice
runs. For the demonstration, CHEMetrics chose to
conduct sample analyses using two technicians in order to
increase sample throughput. One technician performed
sample extractions while the other performed sample
analyses.
Calculation of a TPH concentration is simple after the
sample absorbance is measured using the RemediAid™
kit. At the end of the demonstration, CHEMetrics reported
209 TPH results after performing the required calculations.
Fewer than 5 percent of the results reported in the field
required correction based on EPA review; the corrections
primarily involved use of inappropriate reporting limits.
7.2.2
In addition to the test procedure manual, during regular
business hours, CHEMetrics provides technical support
over the telephone at no additional cost. Technical
assistance may also be obtained via e-mail by contacting
[email protected] CHEMetrics does not offer a
training video. According to CHEMetrics, the test
procedure manual supplemented by technical support over
the telephone is adequate for a user to learn the TPH
measurement procedure using the RemediAid™ kit.
Health and Safety Concerns Associated
with Device Operation
Sample analysis using the RemediAid™ kit requires
handling small quantities of multiple, potentially
hazardous reagents, including dichloromethane and
aluminum chloride. 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
90
RemediAid™ kit is a durable field measurement device;
none of the device’s reusable items malfunctioned or was
damaged. These items are manufactured or distributed by
scientific equipment suppliers and are provided by
CHEMetrics in a hard-plastic carrying case to prevent
damage to the items during transport. 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,
and the relative humidity ranged from 53 to 88 percent.
During sample analysis, wind speeds up to 20 miles per
hour did not affect device operation.
Laboratory Practices in Laboratories Engaged in Sampling
and Analysis of Water” (ASTM 1998).
During the demonstration, CHEMetrics field technicians
operated the RemediAid™ kit in modified Level D PPE to
prevent eye and skin contact with reagents. The PPE
included safety glasses, disposable gloves, work boots, and
work clothes with 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 chemicals in
the RemediAid™ kit is included in material safety data
sheets available from CHEMetrics. In addition, the user
should exercise caution when handling the dilution
ampules and extraction ampules, which are made of glass.
7.2.5
7.2.3 Portability of the Device
During the demonstration, none of the reusable items in the
RemediAid™ kit 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 CHEMetrics free of charge if the reason for
the original item’s failure does not involve misuse. Spare
parts for reusable items such as the photometer are not
included in the RemediAid™ kit. For items not under
warranty, CHEMetrics recommends that malfunctioning
reusable items be returned to CHEMetrics for service;
according to CHEMetrics, repairs should not be attempted
in the field by the user. The power sources for the
photometer (one 9-volt battery), digital balance (one 9-volt
battery), and digital timer (one AAA battery) can be
purchased from local stores and replaced in the field if
necessary.
The RemediAid™ kit is easily transported between
sampling areas in the field. As shown in Table 2-2, the
starter kit consists of 19 items, including a carrying case
that is 13.75 inches long, 15.5 inches wide, and 4.5 inches
high. Each starter kit weighs 13 pounds and is housed in
the carrying case provided; each replenishment kit weighs
3 pounds. The portable photometer, which is included in
the starter kit, weighs 0.43 pound and is 6.0 inches long,
2.4 inches wide, and 1.25 inches high. The photometer,
digital balance, and digital timer are battery-operated.
Because no AC power source is required, the device can be
easily transported between remote sampling areas.
To operate the RemediAid™ kit, a sample preparation and
analysis area is required. The area must be large enough
to accommodate the items in one starter kit. A staging area
may also be required to store samples, extracts, and the
required number of replenishment kits. During the
demonstration, CHEMetrics performed sample preparation
and analysis under one 8- by 8-foot tent that housed two 8foot-long, folding tables; two folding chairs; one 20-gallon
laboratory pack for flammable waste; and one 55-gallon
drum for general refuse.
7.2.4
Availability of the Device and Spare Parts
All disposable items in the RemediAid™ kit are available
from CHEMetrics. CHEMetrics provides a 2-year
warranty for disposable items and a 1-year warranty for
reusable items, including the photometer, balance, and
timer. The disposable items, such as ampules with
premeasured quantities of chemicals, provided to a given
user on a given occasion all come from the same lot.
Because CHEMetrics 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 source
other than CHEMetrics, CHEMetrics assumes no
responsibility for the quality of the sample analysis results.
According to CHEMetrics, dichloromethane purchased
form another source may contain stabilizers that will affect
the RemediAid™ kit’s performance.
Durability of the Device
The RemediAid™ starter kit contains several reusable
items, including the photometer, ACCULAB® digital
balance, and Fisher Traceable® timer.
Based on
observations made during the demonstration, the
91
Chapter 8
Economic Analysis
As discussed throughout this ITVR, the RemediAid™ kit
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 RemediAid™ kit.
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 RemediAid™ kit unless otherwise
stated.
During the demonstration, the RemediAid™ kit 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 RemediAid™ kit and then compare
this cost to that for the reference method. The cost per
analysis was not estimated for the RemediAid™ kit
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.
8.1.1
Capital Equipment Cost
The capital equipment cost was the cost associated with the
purchase of the RemediAid™ kit used during the
demonstration. This cost was obtained from a standard
price list provided by CHEMetrics. Because the device
must be purchased, no salvage value was included in the
capital equipment cost.
8.1.2
This chapter provides information on the issues and
assumptions involved in the economic analysis
(Section 8.1), discusses the costs associated with using the
RemediAid™ kit (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 RemediAid™ kit and the reference method
(Section 8.4).
Cost of Supplies
The cost of supplies was estimated based on the supplies
required to analyze all demonstration samples using the
RemediAid™ kit that were not included in the capital
equipment cost category. Examples of such supplies
include chemicals (such as solvent for cleaning glassware)
and disposable gloves and pipettes.
During the
demonstration, the types and quantities of all supplies used
by CHEMetrics were noted each day.
92
For supplies provided by CHEMetrics during the
demonstration, CHEMetrics’s costs were used to estimate
the cost of supplies. The costs for supplies not provided by
CHEMetrics were estimated based on price quotes from
independent sources. Because a user cannot typically
return unused supplies, no salvage value for supplies that
were not used during the demonstration was included in
the cost of supplies.
8.1.5
Investigation-Derived Waste Disposal Cost
Because of the large number of samples analyzed during
the demonstration, the EPA provided support equipment,
including a tent, 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.
During the demonstration, CHEMetrics 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, spent
solvent generated from extractions and glassware
decontamination, used EnCores, and unused chemicals that
could not be returned to CHEMetrics or an independent
vendor were disposed of in a laboratory pack. Items such
as used PPE and disposable glassware were disposed of
with municipal garbage in accordance with demonstration
site waste disposal guidelines. CHEMetrics was required
to provide any containers necessary to containerize
individual wastes prior to their placement in a laboratory
pack. The cost for these containers was not included in the
IDW disposal cost estimate.
8.1.4
8.1.6
8.1.3
Support Equipment Cost
Labor Cost
Costs Not Included
The labor cost was estimated based on the time required
for RemediAid™ kit 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
CHEMetrics. The measurement of the time required for
CHEMetrics 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.
Items whose costs were not included in the economic
analysis are identified below along with a rationale for the
exclusion of each.
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 RemediAid™ kit. 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.
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.
Oversight of Sample Analysis Activities. A typical user
of the RemediAid™ kit would not be required to pay for
customer oversight of sample analysis.
EPA
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.
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 projectspecific and were not device- or reference methoddependent.
93
No. TPH001).
CHEMetrics does not rent the
RemediAid™ starter kit. Table 2-1 lists the components of
the RemediAid™ starter kit, which contains the equipment
and supplies required to perform eight TPH measurements.
Supplies required to perform additional measurements are
sold separately in the replenishment kit (Model
No. TPH002). The starter kit can be purchased from
CHEMetrics for $800.
Shipping. Costs for shipping (1) the RemediAid™ kit and
necessary supplies 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 $10.
8.2
8.2.2
Cost of Supplies
Supplies used during the demonstration included the
following: (1) replenishment kit components;
(2) anhydrous sodium sulfate for drying wet soil samples;
(3) dichloromethane for cleaning glassware; (4) disposable,
nitrile gloves; (5) disposable pipettes for performing
necessary sample dilutions; and (6) a microsyringe to
accurately measure and transfer very small quantities of
liquid PE samples.
Of these supplies, only the
replenishment kit components and anhydrous sodium
sulfate are available from CHEMetrics. The other supplies
have to be purchased from a retail vendor of laboratory
supplies. Costs for the supplies are discussed below.
RemediAid™ Kit Costs
This section presents information on the individual costs of
capital equipment, supplies, support equipment, labor, and
IDW disposal for the RemediAid™ kit as well as a
summary of these costs. Additionally, Table 8-1
summarizes the RemediAid™ kit costs.
8.2.1 Capital Equipment Cost
The capital equipment cost was the cost associated with the
purchase of the RemediAid™ starter kit (Model
Table 8-1. RemediAid™ Kit Cost Summary
Item
Quantity
Unit Cost ($)
Itemized Costa ($)
Capital equipment
Purchase of starter kit
1 unit
800
800
Replenishment kit
20 units
240
4,800
Anhydrous sodium sulfate (50-gram container)
22 units
10
220
Supplies
Dichloromethane (1-liter bottle)
1 unit
30.45
30
Disposable, nitrile gloves (100 per pack)
1 unit
18.80
19
Disposable, 5-milliliter, graduated pipettes (500 per pack)
1 unit
29.50
30
5-microliter microsyringe
1 unit
68
68
Tent
1 unit
159
159
Tables and chairs (two each)
1 set for 1 week
39
39
Support equipment
Labor
Field technicians
Investigation-derived waste disposal
6 person-days
332.60
1 20-gallon container
345
b
Total Cost
Itemized costs were rounded to the nearest $1.
b
The total dollar amount was rounded to the nearest $10.
345
$8,510
Notes:
a
1,996
94
During the demonstration, CHEMetrics used bulk supplies
of replenishment kit components. However, a typical user
cannot purchase individual components from CHEMetrics;
a whole kit must be purchased to obtain its components.
Each replenishment kit contains 16 pieces of each
component. Therefore, for each component, the total
quantity used during the demonstration in excess of the
quantity in the starter kit (8) was divided by 16 to calculate
the number of replenishment kits that would have been
required to complete the demonstration analyses. Based on
this approach, an estimated 20 replenishment kits would
have been required at $240 each.
8.2.5
CHEMetrics 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
hazardous waste disposal in a landfill ($307) (Means
2000). The total IDW disposal cost was $345.
8.2.6
8.3
Support Equipment Cost
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 RemediAid™ kit and reference method
costs, the reference method costs were estimated for the
same number of samples as was analyzed by CHEMetrics.
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
CHEMetrics was provided with one 8- by 8-foot tent for
protection from inclement weather during the
demonstration as well as 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
Summary of RemediAid™ Kit Costs
The total cost for performing more than 200 TPH analyses
using the RemediAid™ kit and for preparing a summary
data package was $8,510 (rounded to the nearest $10).
The TPH analyses were performed for 74 soil
environmental samples, 89 soil PE samples, and 36 liquid
PE samples. In addition to these 199 samples, 10 extract
duplicates were analyzed for specified soil environmental
samples.
When CHEMetrics performed multiple
extractions, dilutions, or reanalyses for a sample, these
were not included in the number of samples analyzed.
During the demonstration, the multiple extractions,
dilutions, and reanalyses collectively required about
50 percent more supplies than would otherwise have been
needed. The total cost included $800 for capital
equipment; $5,167 for supplies; $198 for support
equipment; $1,996 for labor; and $345 for IDW disposal.
Of the five costs, the two largest were the cost of supplies
(61 percent of the total cost) and the labor cost (23 percent
of the total cost).
During the demonstration, CHEMetrics also used an
additional 1,080 grams of anhydrous sodium sulfate
because the amounts of this chemical present in reaction
tubes included in the starter and replenishment kits and the
50 grams of this chemical included in the starter kit were
inadequate for drying soil samples. A user can purchase
anhydrous sodium sulfate from CHEMetrics in multiples
of 50 grams. During the demonstration, 22 additional
50-gram containers of anhydrous sodium sulfate
($10 each) would have been required to complete the
analyses. Additional supplies that are not available from
CHEMetrics but were used during the demonstration
included one 1-liter bottle of dichloromethane ($30.45);
one pack of 100 disposable, nitrile gloves ($18.80); one
pack of 500 disposable, 5-mL, graduated pipettes ($29.50);
and one 5-microliter microsyringe ($68). The total cost of
the supplies used by CHEMetrics during the demonstration
was $5,167 (the cost of each item was rounded to the
nearest $1).
8.2.3
Investigation-Derived Waste Disposal Cost
Labor Cost
Two field technicians were required for 3 days each during
the demonstration to complete all sample analyses and
prepare the summary data package. Based on a daily labor
rate of $332.60 per person, the total labor cost for the
RemediAid™ kit was $1,996 (rounded to the nearest $1).
95
8-2, respectively. The total TPH measurement cost for the
RemediAid™ kit was 80 percent less than that for the
reference method. Although the RemediAid™ kit
analytical results did not have the same level of detail (for
example, carbon ranges) as the reference method
analytical results or comparable QA/QC data, the
RemediAid™ kit provided TPH analytical results on site
at significant cost savings. In addition, use of the
RemediAid™ kit 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.
CHEMetrics 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 $42,170. This cost covered preparation of
demonstration samples and their 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 RemediAid™ kit ($8,510) and the
reference method ($42,170) are listed in Tables 8-1 and
Table 8-2. Reference Method Cost Summary
Item
Number of Samples Analyzed
Cost per Analysis ($)
Itemized Cost ($)
Soil environmental samples
GRO
Extract duplicates
EDRO
Extract duplicates
56
8
74
10
111
55.50
142
71
6,216
444
10,508
710
Soil performance evaluation samples
GRO
EDRO
55
89
111
142
6,105
12,638
Liquid performance evaluation samples
GRO
EDRO
27
24
111
106.50
Total Costa
$42,170
Note:
a
2,997
2,556
The total dollar amount was rounded to the nearest $10.
96
Chapter 9
Summary of Demonstration Results
As discussed throughout this ITVR, the RemediAid™ kit
was demonstrated by using it to analyze 74 soil
environmental samples, 89 soil PE samples, and 36 liquid
PE samples. In addition to these 199 samples, 10 extract
duplicates prepared using the environmental samples were
analyzed. The environmental samples were collected from
five 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 RemediAid™ kit.
This chapter compares the performance and cost results for
the RemediAid™ kit 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 RemediAid™ kit
exhibited the following desirable characteristics of a field
TPH measurement device: (1) good accuracy, (2) good
precision, (3) lack of sensitivity to interferents that are not
PHCs (PCE and 1,2,4-trichlorobenzene), (4) high sample
throughput, (5) low measurement costs, and (5) ease of
use.
The RemediAid™ kit 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.
Turpentine biased the RemediAid™ kit TPH results high,
whereas humic acid biased the results low. These findings
indicated that the accuracy of TPH measurement using the
device will likely be impacted by naturally occurring oil
and grease and organic matter present in soil samples. The
device exhibited minor sensitivity to soil moisture content
during TPH measurement of weathered gasoline soil
samples but not diesel soil samples. Specifically, the TPH
results for weathered gasoline soil samples were biased
slightly low (8 percent) when the soil moisture content was
increased from 9 to 16 percent. Despite some of the
limitations observed during the demonstration, the
demonstration findings collectively indicated that the
RemediAid™ kit is a reliable field measurement device for
TPH in soil.
97
98
Determine the method
detection limit
Evaluate the accuracy
and precision of TPH
measurement
P1
P2
Primary Objective
Correlation (as determined by linear regression
analysis) between RemediAid™ kit and reference
method TPH results for (1) soil environmental
samples collected from five areas and (2) soil PE
samples, including weathered gasoline and diesel soil
samples
Pairwise comparison of RemediAid™ kit and
reference method TPH results for (1) soil
environmental samples collected from five areas;
(2) soil PE samples, including blank, weathered
gasoline, and diesel soil samples; and (3) liquid PE
samples consisting of neat weathered gasoline and
diesel
The RemediAid™ kit results correlated weakly with the reference method results for one sampling area
(the R2 value was 0.16, and the F-test probability value was 31.83 percent).
The RemediAid™ kit results correlated moderately with the reference method results for four of the five
sampling areas (R2 values ranged from 0.69 to 0.74, and F-test probability values were less than 5
percent).
The RemediAid™ kit results correlated highly with the reference method results for weathered gasoline
soil PE samples and diesel soil PE samples (R2 values were 0.95 and 0.98, respectively, and F-test
probability values were less than 5 percent).
For liquid PE samples, the RemediAid™ kit results were statistically (1) the same as the reference
method results for diesel samples and (2) different from the reference method results for weathered
gasoline samples.
For soil PE samples, the RemediAid™ kit results were statistically (1) the same as the reference method
results for blank and medium- and high-concentration-range weathered gasoline samples and (2)
different from the reference method results for low-, medium-, and high-concentration-range diesel
samples.
For soil environmental samples, the RemediAid™ kit results were statistically (1) the same as the
reference method results for four of the five sampling areas and (2) different from the reference method
results for one of the five sampling areas.
53 of 102 RemediAid™ kit results (52 percent) were not within 50 percent of the reference method
results; 46 RemediAid™ kit results were biased high, and 7 were biased low.
15 of 102 RemediAid™ kit results (15 percent) were within 30 to 50 percent of the reference method
results; 6 RemediAid™ kit results were biased high, and 9 were biased low.
34 of 102 RemediAid™ kit results (33 percent) were within 30 percent of the reference method results; 11
RemediAid™ kit results were biased high, and 23 were biased low.
Comparison of RemediAid™ kit TPH results with
those of the reference method for 74 soil
environmental and 28 soil PE samples
4.79 mg/kg
Reference Method
Of the 108 RemediAid™ kit results, 6 results were inconclusive. Of the remaining 102 RemediAid™ kit
conclusions, 84 (82 percent) agreed with those of the reference method; 10 RemediAid™ kit conclusions
were false positives, and 8 were false negatives.
RemediAid™ Kit
Performance Results
Comparison of project-specific action level
conclusions of the RemediAid™ kit with those of the
reference method for 74 soil environmental and 34
soil PE samples
Method detection limit based on TPH analysis of
60 mg/kg
seven low-concentration-range diesel soil PE samples
Evaluation Basisa
Table 9-1. Summary of RemediAid™ Kit Results for the Primary Objectives
99
Evaluate the accuracy
and precision of TPH
measurement
(continued)
Evaluate the effect of
interferents on TPH
measurement
P2
P3
Primary Objective
Liquid PE samples (2 triplicates)
RSDs: 5 and 6 percent
Median RSD: 5.5 percent
Liquid PE samples (2 triplicates)
RSDs: 2 and 8 percent
Median RSD: 5 percent
MTBE: 39 percent
PCE: 17.5 percent
Stoddard solvent: 85 percent
Turpentine: 52 percent
1,2,4-Trichlorobenzene: 50 percent
Humic acid: 0 percent
PCE did not cause statistically significant
interference at either of the two levels.
1,2,4-Trichlorobenzene caused statistically significant
interference only at the high level.
Humic acid results were inconclusive.
1,2,4-Trichlorobenzene did not cause
statistically significant interference at either
of the two levels.
Humic acid caused statistically significant
interference at both levels.
Turpentine caused statistically significant interference
(1) at both levels for weathered gasoline samples and
(2) only at the high level for diesel samples.
Stoddard solvent, a petroleum hydrocarbon, caused
statistically significant interference at both levels for
weathered gasoline and diesel samples.
PCE caused statistically significant interference only at
the high level.
MTBE, a petroleum hydrocarbon, caused
MTBE, a petroleum hydrocarbon, did not cause
statistically significant interference only at the statistically significant interference at either of the two
high level.
levels.
62 percent for turpentine and less than
5 percent for the remaining interferents,
including the petroleum hydrocarbons (MTBE
and Stoddard solvent)
Stoddard solvent, a petroleum hydrocarbon,
Interferents for diesel soil PE samples: Stoddard
caused statistically significant interference at
solvent; turpentine; 1,2,4-trichlorobenzene; and humic both levels for diesel samples only.
acid
Turpentine caused statistically significant
interference only at the high level for
weathered gasoline samples; results were
inconclusive for diesel samples.
Interferents for weathered gasoline soil PE samples:
MTBE, PCE, Stoddard solvent, and turpentine
Comparison of TPH results (one-way analysis of
variance) for weathered gasoline and diesel soil PE
samples without and with interferents at two levels
Mean responses for neat materials, including MTBE;
PCE; Stoddard solvent; turpentine; and 1,2,4trichlorobenzene, and for soil spiked with humic acid
(two triplicate sets each)
RPD range: 0 to 11
Median RPD: 4
Soil PE samples (7 replicates)
RSD range: 2 to 10 percent
Median RSD: 7 percent
Soil PE samples (7 replicates)
RSD range: 1 to 52 percent
Median RSD: 3 percent
Reference Method
Soil environmental samples (12 triplicates)
RSD range: 4 to 39 percent
Median RSD: 18 percent
Performance Results
Soil environmental samples (12 triplicates)
RSD range: 0 to 67 percent
Median RSD: 26 percent
RemediAid™ Kit
Analytical precision (RPD) for extract duplicates for
RPD range: 0 to 28
soil environmental samples (9 for the RemediAid™ kit Median RPD: 4
and 13 for the reference method)
Overall precision (RSD) for soil environmental, soil
PE, and liquid PE sample replicates
Evaluation Basis
a
Table 9-1. Summary of RemediAid™ Kit Results for the Primary Objectives (Continued)
100
a
46 hours, 10 minutes, for TPH measurement
of 74 soil environmental samples, 89 soil PE
samples, 36 liquid PE samples, and 10
extract duplicates
Soil moisture content had a statistically
significant impact on weathered gasoline
sample results but not on diesel sample
results.
RemediAid™ Kit
PE
R2
RPD
RSD
=
=
=
=
Performance evaluation
Square of the correlation coefficient
Relative percent difference
Relative standard deviation
Reference Method
$42,170
30 days for TPH measurement of 74 soil environmental
samples, 89 soil PE samples, 36 liquid PE samples, and
13 extract duplicates
Soil moisture content did not have a statistically
significant impact.
Performance Results
Total cost (costs of capital equipment, supplies,
$8,510 (including the capital equipment
support equipment, labor, and IDW disposal) for TPH purchase cost of $800 for the RemediAid™
measurement of 74 soil environmental samples, 89
starter kit)
soil PE samples, 36 liquid PE samples, and 10 extract
duplicates
Total time from sample receipt through preparation of
the draft data package
All statistical comparisons were made at a significance level of 5 percent.
IDW
mg/kg
MTBE
PCE
Evaluation Basis
Comparison of TPH results (two-sample Student’s
t-test) 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
Investigation-derived waste
Milligram per kilogram
Methyl-tert-butyl ether
Tetrachloroethene
Estimate TPH
measurement costs
P6
=
=
=
=
Measure the time
required for TPH
measurement (sample
throughput)
P5
Notes:
Evaluate the effect of
soil moisture content
on TPH measurement
P4
Primary Objective
a
Table 9-1. Summary of RemediAid™ Kit Results for the Primary Objectives (Continued)
Table 9-2. Summary of RemediAid™ Kit Results for the Secondary Objectives
Secondary Objective
S1
Skill and training
requirements for proper
device operation
Performance Results
The device can be operated by one person with basic wet chemistry skills.
The device’s test procedure manual is considered to be adequate training material for proper device
operation. The sample analysis procedure for the device can be learned in the field by performing a few
practice runs.
Calculation of a TPH concentration is simple after a sample extract absorbance is measured using the
device. At the end of the demonstration, CHEMetrics reported 209 TPH results after performing the required
calculations. Fewer than 5 percent of the results reported in the field required corrections, which primarily
involved use of inappropriate reporting limits.
S2
Health and safety concerns
associated with device
operation
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
pants) should be adequate for safe device operation.
S3
Portability of the device
No alternating current power source is required to operate the device. The device can be operated using a
direct current power source and can be easily moved between sampling areas in the field, if necessary.
S4
Durability of the device
The device is provided 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.
S5
Availability of device and
spare parts
All items in the device are available from CHEMetrics. During a 1-year warranty period, CHEMetrics will
supply replacement parts for the device at no cost unless the reason for a part failure involves misuse.
101
Chapter 10
References
AEHS. 1999. “State Soil Standards Survey.” Soil &
Groundwater. December 1999/January 2000.
EPA. 2000. “Field Measurement Technologies for Total
Petroleum Hydrocarbons in Soil—Demonstration
Plan.” ORD. Washington, DC. EPA/600/R-01/060.
June.
API. 1994. “Interlaboratory Study of Three Methods for
Analyzing Petroleum Hydrocarbons in Soils.”
Publication Number 4599. March.
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
API. 1996. “Compilation of Field Analytical Methods for
Assessing Petroleum Product Releases.” Publication
Number 4635. December.
Fox, Marye Anne, and James K. Whitesell. 1994.
Organic Chemistry. Jones and Bartlett Publishers, Inc.
Boston, Massachusetts.
API. 1998. “Selecting Field Analytical Methods: A
Decision-Tree Approach.” Publication Number 4670.
August.
Fritz, James S., and George H. Schenk.
1987.
Quantitative Analytical Chemistry. Allyn and Bacon,
Inc. Boston, Massachusetts. Fifth Edition.
ASTM. 1998. “Standard Guide for Good Laboratory
Practices in Laboratories Engaged in Sampling and
Analysis of Water.” Designation: D 3856-95. Annual
Book of ASTM Standards. Volume 11.01.
Gary, J.H., and G.E. Handwerk. 1993. Petroleum
Refining: Technology and Economics. Marcel Dekker,
Inc. New York, New York.
California Environmental Protection Agency. 1999.
Memorandum Regarding Guidance for Petroleum
Hydrocarbon Analysis. From Bart Simmons, Chief,
Hazardous Materials Laboratory. To Interested
Parties. October 21.
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
Dryoff, George V. Editor. 1993. “Manual of Significance
of Tests for Petroleum Products.” ASTM Manual
Series: MNL 1. 6th Edition.
Means.
2000.
Environmental Remediation Cost
Data-Unit Price. Kingston, Massachusetts.
EPA. 1983. “Methods for Chemical Analysis of Water
and Waste.” Revision. Environmental Monitoring
and Support Laboratory. Cincinnati, Ohio. EPA
600-4-79-020. March.
Provost, Lloyd P., and Robert S. Elder.
1983.
“Interpretation of Percent Recovery Data.” American
Laboratory. December. Pages 57 through 63.
Speight, J.G. 1991. The Chemistry and Technology of
Petroleum. Marcel Dekker, Inc. New York, New
York.
EPA. 1996. “Test Methods for Evaluating Solid Waste.”
Volumes 1A through 1C. SW-846. Third Edition.
Update III. OSWER. Washington, DC. December.
102
Texas Natural Resource Conservation Commission. 2000.
“Waste Updates.” Accessed on April 13. On-Line
Address: www.tnrcc.state.tx.us/permitting/
wastenews.htm#additional
Zilis, Kimberly, Maureen McDevitt, and Jerry Parr. 1988.
“A Reliable Technique for Measuring Petroleum
Hydrocarbons in the Environment.” Paper Presented
at the Conference on Petroleum Hydrocarbons and
Organic Chemicals in Groundwater. National Water
Well Association (Now Known as National Ground
Water Association). Houston, Texas.
103
Appendix
Supplemental Information Provided by the Developer
This appendix contains the following supplemental
information provided by CHEMetrics: comments on the
SITE demonstration, updates on improvements to the
RemediAid™ kit, and a discussion of actual applications
of the device.
site for laboratory analysis and ultimately bringing the
project to closure sooner.
Section 7.1.3 of the ITVR discusses RemediAid™ kit TPH
results for PE samples containing interferents. These
results illustrate the impact of using fuel-specific
calibration data on TPH results for samples containing
compounds that are unknown to the user; the user may
erroneously conclude that some inherent extraction or
analysis problems occurred when the samples contained
interferents that biased the TPH results. However, the
observed bias could be associated with the calibration
slope and intercept values used to calculate the TPH
results.
Therefore, a basic understanding of the
compounds that potentially interfere with the FriedelCrafts reaction is helpful in evaluating sample TPH results.
The following discussion is intended to provide such an
understanding based on the demonstration results for soil
PE samples containing interferents.
Comments on the SITE Demonstration
CHEMetrics sent two people to the demonstration site.
Over a 3-day period, they were able to extract, measure,
and report test results for more than 200 samples.
CHEMetrics had no equipment failures during the
demonstration. CHEMetrics’ personnel divided their tasks
so that one person was dedicated to weighing, drying, and
extracting soil. This person was also responsible for taking
each soil extract through the Florisil cleanup step. The
other person was responsible for pouring the aluminum
chloride ampule into each extract, diluting the extract if
necessary, and measuring and recording final absorbance.
RemediAid™ kit users may find it helpful to work in pairs
and to organize the field work in a similar manner in order
to optimize time spent in the field.
MTBE. Because MTBE is an ether and not an aromatic
hydrocarbon, it is expected not to react with aluminum
chloride; the demonstration results were consistent with
this expectation.
Although the RemediAid™ kit does not utilize highly
sophisticated instrumentation or software, the developer
believes that the device offers an efficient, cost-effective
technique for obtaining valid TPH data to guide soil
remediation surveys. By allowing a more informed
decision-making process in real time during an excavation
and removal project, the device can produce cost savings
by reducing the number of confirmatory samples sent off
PCE. Because PCE is a chlorinated aliphatic hydrocarbon
and not an aromatic hydrocarbon, it is expected not to react
with aluminum chloride; the demonstration results were
consistent with this expectation.
This appendix was written solely by CHEMetrics. The statements presented in this appendix represent the developer’s point of view and
summarize the claims made by the developer regarding the RemediAid™ kit. 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 RemediAid™ kit are
discussed in the body of this ITVR.
104
Stoddard Solvent. Because Stoddard solvent is an
aliphatic naphtha, it is expected not to react with aluminum
chloride. However, the RemediAid™ kit TPH results for
diesel soil PE samples were observed to be biased low at
both low and high levels of Stoddard solvent. This
observation is a direct consequence of CHEMetrics
calculating TPH results (1) for diesel soil PE samples
containing Stoddard solvent using weathered gasoline
calibration slope and intercept values and (2) for diesel soil
PE samples that did not contain Stoddard solvent (control
samples) using diesel calibration slope and intercept
values. The choice of the slope and intercept values used
was based on CHEMetrics’ knowledge that the soil PE
samples containing the interferent were to be analyzed for
both GRO and EDRO under the reference method, as was
appropriately indicated by the sample label based on the
nature of the interferent. Using the diesel calibration slope
and intercept values for both control samples and samples
containing the interferent would have removed the bias.
Therefore, the apparent bias is only a manifestation of a
calculation error and is not attributable to the field
measurement device.
Humic Acid. Humic acid is a mixture of complex
macromolecules having a polymeric phenolic structure.
During the Florisil cleanup of the sample extract, humic
acid is expected to be removed from the extract to some
degree; the demonstration results showed that the
remaining humic acid caused a negative bias in TPH
results.
Updates on Improvements to the RemediAid™
Kit
Revisions to the RemediAid™ kit test procedure have been
implemented since the device’s 1998 introduction to the
market. The developer believes that these revisions
improved the device’s performance and reliability as a
field screening tool. Additional information concerning
detection limits for a variety of fuels in soil is now
included in CHEMetrics’ instruction booklet. The
revisions were made as a result of both customer feedback
and experience gained from the SITE predemonstration
investigation and the actual demonstration. The following
paragraphs summarize these improvements.
Turpentine. Turpentine is a cyclic compound containing
one double bond. Before the demonstration, CHEMetrics
did not know whether turpentine would have the
aromaticity required for the Friedel-Crafts reaction. Based
on the liquid PE sample results for neat turpentine, it
appears that turpentine at high enough levels does
participate in the Friedel-Crafts reaction.
The
demonstration results for soil PE samples were not
consistent with the expectation for diesel soil PE samples
that contained a low level of turpentine, which caused a
negative bias. The negative bias observed at the low
turpentine level is associated with the use of inconsistent
calibration slope and intercept values for control samples
and samples that contained the interferent, as explained
above.
Probably the most significant procedural change to the
RemediAid™ kit test method is inclusion of an extract
cleanup step that utilizes Florisil. CHEMetrics believes
that subjecting a soil extract to a shake-out with Florisil not
only reduces interference from polar hydrocarbons but also
reduces any residual soil moisture that is not removed in
the previous sodium sulfate shake-out step. During the
demonstration, in which more than 200 soil samples were
extracted, CHEMetrics did not experience any occurrence
of a nonsettling, cloudy extract that led to erroneous
readings.
The RemediAid™ kit instruction booklet now includes
additional instructions for measuring samples with high
levels of hydrocarbons by reducing the amount of soil
extracted from 5 grams to 1 gram. In some situations, this
may eliminate the need to perform an extract dilution.
1,2,4-Trichlorobenzene. Because 1,2,4-trichlorobenzene
is a halogenated aromatic compound, it is expected not to
react with aluminum chloride; the demonstration results
were consistent with this expectation.
The instruction booklet now recommends obtaining and
measuring a soil blank sample to help establish
background absorbance readings for a clean sample.
This appendix was written solely by CHEMetrics. The statements presented in this appendix represent the developer’s point of view and
summarize the claims made by the developer regarding the RemediAid™ kit. 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 RemediAid™ kit are
discussed in the body of this ITVR.
105
Additionally, the booklet includes an absorbance threshold
to help users decide whether to subtract background
absorbance from the test soil’s absorbance reading.
Pennsylvania. For example, Insite Group used the device
for in an excavation project involving gasolinecontaminated soil. The device was used to check soil until
a clean profile was obtained. At that point, soil samples
were sent to a laboratory for analysis, and the laboratory
confirmed the device’s results. The excavated surface was
then re-paved.
The calculation necessary to compute final test results has
been clarified. This will aid users who deviate from
the test procedure stated in the instruction booklet and
need to understand how to enter their absorbance readings
in the TPH concentration calculation equation in order to
generate test results correctly.
Another example involves a facility expansion project that
required installation of storm sewers. During the project,
soil contaminated with aged gasoline was inadvertently
combined with uncontaminated soil. The pile of soil was
expansive and was estimated to weigh 1,000 tons. Insite
Group used photoionization detector readings as a
preliminary investigative tool to locate contaminated soil
and then used RemediAid™ kit test results to distinguish
between contaminated and uncontaminated soil. Costs
associated with hauling and disposal of contaminated soil
were minimized based on the timely recommendations that
Insite Group was able to provide to its client.
More descriptive text concerning the range of colors that
users can expect to observe after pouring the aluminum
chloride ampule into a soil extract is now provided in the
instruction booklet. A caution about weighing soil in
windy conditions has been added, as has a caution about
testing soil at temperatures above 27 °C.
Additional changes to the RemediAid™ kit are being
planned that will offer extra consumables necessary to
perform dilutions for high-concentration-range samples.
Alternative means to introduce the aluminum chloride into
a soil extract are also being investigated.
Another environmental consulting firm has used the
RemediAid™ kit to qualitatively track polynuclear
aromatic hydrocarbon contamination in West Virginia.
The device was used as a secondary means of confirming
areas where field personnel believed excavation was near
completion based on visual inspection.
Actual Applications of the RemediAid™ Kit
The RemediAid™ kit has been successfully used by Insite
Group, an engineering consulting firm in Sharpsville,
This appendix was written solely by CHEMetrics. The statements presented in this appendix represent the developer’s point of view and
summarize the claims made by the developer regarding the RemediAid™ kit. 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 RemediAid™ kit are
discussed in the body of this ITVR.
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