United States
Environmental Protection
Agency
Office of
Research and Development
Washington, DC 20460
EPA/600/R-03/147
May 2004
&EPA
Innovative Technology
Verification Report
Field Measurement Technology for
Mercury in Soil and Sediment
Ohio Lumex's RA-915+/RP-91C
Mercury Analyzer
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EPA/600/R-03/147
May 2004
Innovative Technology
Verification Report
Ohio Lumex's RA-915+/RP-91C
Mercury Analyzer
Prepared by
Science Applications International Corporation
Idaho Falls, ID
Contract No. 68-C-00-179
Dr. Stephen Billets
Characterization and Monitoring Branch
Environmental Sciences Division
Las Vegas, Nevada 89193-3478
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
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Notice
The U.S. Environmental Protection Agency through its Office of Research and Development funded
and managed the research described here under contract to Science Applications International
Corporation. It has been subjected to the Agency's peer and administrative review and has been
approved for publication as an EPA document. Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
MEASUREMENT AND MONITORING TECHNOLOGY PROGRAM
VERIFICATION STATEMENT
TECHNOLOGY TYPE: Field Measurement Device
APPLICATION: Measurement for Mercury
TECHNOLOGY NAME: Ohio Lumex Co.'s RA-915+/RP-91C Mercury Analyzer
COMPANY: Ohio Lumex Co.
ADDRESS: 9263 Ravenna Rd., Unit A-3
Twinsburg, OH 44087
WEB SITE: http://www.ohiolumex.com
TELEPHONE: (888) 876-2611
VERIFICATION PROGRAM DESCRIPTION
The U.S. Environmental Protection Agency (EPA) created the Superfund Innovative Technology Evaluation (SITE) and
Measurement and Monitoring Technology (MMT) 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 RA-915+/RP-91C Mercury Analyzer
developed by Ohio Lumex Co.
PROGRAM OPERATION
Under the SITE and MMT 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 Science
Applications International Corporation as the verification organization to assist in field testing five field measurement
devices for mercury in soil and sediment. This demonstration was funded by the SITE Program.
DEMONSTRATION DESCRIPTION
In May 2003, the EPA conducted a field demonstration of the RA-915+/RP-91C and four other field measurement
devices for mercury in soil and sediment. This verification statement focuses on the RA-915+/RP-91C; a similar
statement has been prepared for each of the other four devices. The performance of the RA-915+/RP-91C was
compared to that of an off-site laboratory using the reference method, "Test Methods for Evaluating Solid Waste" (SW-
846) Method 7471 B (modified). To verify a wide range of performance attributes, the demonstration had both primary
and secondary objectives. The primary objectives were:
(1) Determining the instrument sensitivity with respect to the Method Detection Limit (MDL) and Practical
Quantitation Limit (POL);
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(2) Determining the analytical accuracy associated with the field measurement technologies;
(3) Evaluating the precision of the field measurement technologies;
(4) Measuring the amount of time required for mobilization and setup, initial calibration, daily calibration, sample
analysis, and demobilization; and
(5) Estimating the costs associated with mercury measurements for the following four categories: capital, labor,
supplies, and investigation-derived waste (IDW).
Secondary objectives for the demonstration included:
(1) Documenting the ease of use, as well as skills and training required to properly operate the device;
(2) Documenting potential health and safety concerns associated with operating the device;
(3) Documenting the portability of the device;
(4) Evaluating the device durability based on its materials of construction and engineering design; and
(5) Documenting the availability of the device and associated spare parts.
The RA-915+/RP-91C analyzed 56 field soil samples, 26 field sediment samples, 42 spiked field samples, and 73
performance evaluation (PE) standard reference material (SRM) samples in the demonstration. The field samples were
collected in four areas contaminated with mercury, the spiked samples were from these same locations, and the PE
samples were obtained from a commercial provider.
Collectively, the environmental and PE samples provided the different matrix types and the different concentrations of
mercury needed to perform a comprehensive evaluation of the RA-915+/RP-91C. A complete description of the
demonstration and a summary of the results are available in the Innovative Technology Verification Report: "Field
Measurement Technology for Mercury in Soil and Sediment—Ohio Lumex Co.'s RA-915+/RP-91C Mercury Analyzer"
(EPA/600/R-03/147).
TECHNOLOGY DESCRIPTION
The RA-915+ Mercury Analyzer is a portable AA spectrometer with a 10-meter (m) multipath optical cell and Zeeman
background correction. Mercury is detected without preliminary accumulation on a gold trap. Mercury samples are
heated to 750-800°C, causing organic materials to be decomposed and mercury to be vaporized in a carrier gas of
ambient air. The airflow carries the vaporized mercury to be carried to the analytical cell. The RA-915+ includes a built-
in test cell for field performance verification. The operation of the RA-915+ is based on the principle of differential,
Zeeman AA spectrometry combined with high-frequency modulation of polarized light. This combination eliminates
interferences and provides the highest sensitivity. A mercury lamp is placed in a permanent magnetic field in which the
254-nm resonance line is split into three polarized components, two of which are circularly polarized in the opposite
direction. These two components (o- and o+) pass through a polarization modulator, while the third component (n) is
removed. One o component passes through the absorption cell; the other o component passes outside of the
absorption cell and through the test cell. In the absence of mercury vapors, the intensity of the two o com ponents are
equal. When mercury vapor is present in the absorption cell, mercury atoms cause a proportional, concentration-related
difference in the intensity of the o components. This difference in intensity is what is measured by the instrument. The
unit can be used with the optional RP-91C for an ultra-low mercury detection limit in water samples using the "cold
vapor" technique. For direct mercury determination in complex matrices without sample pre treatment, including liquids,
soils and sediments, the instrument will be operated with the optional RP-91 C accessory, as was done during the
demonstration.
During the demonstration, no extraction or sample digestion was required. Individual samples were mixed manually
using a quartz injection spoon. This same spoon was used to transfer the sample directly to the RP-91C sample
injection port after the sample was weighed on a digital balance. The sample weight was manually recorded. The
sample was analyzed, and the device displayed the mercury concentration in parts per million, which is equivalent to
a soil concentration in milligrams per kilogram.
IV
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ACTION LIMITS
Action limits and concentrations of interest vary and are project specific. There are, however, action limits which can
be considered as potential reference points. The EPA Region IX Preliminary Remedial Goals for mercury are 23 mg/kg
in residential soil and 310 mg/kg in industrial soil.
VERIFICATION OF PERFORMANCE
To ensure data usability, data quality indicators for accuracy, precision, representativeness, completeness,
comparability, and sensitivity were assessed for the reference method based on project-specific QA objectives. Key
demonstration findings are summarized below for the primary objectives.
Sensitivity: The two primary sensitivity evaluations performed for this demonstration were the MDL and PQL. Both
will vary dependent upon whether the matrix is a soil, waste, or aqueous solution. Only soils/sediments were tested
during this demonstration, and therefore, MDL calculations and PQL determinations for this evaluation are limited to
those matrices. By definition, values measured below the PQL should not be considered accurate or precise and those
below the MDL are not distinguishable from background noise.
Method Detection Limit - The evaluation of an MDL requires seven different measurements of a low concentration
standard or sample following the procedures established in the 40 Code of Federal Regulations (CFR) Part 136. The
MDL is estimated between 0.0053 and 0.042 mg/kg. The equivalent MDL for the referee laboratory is 0.0026 mg/kg.
Practical Quantitation Limit - The low standard calculations using MDL values suggest that a PQL for the Ohio Lumex
field instrument may be as low as 0.027mg/kg (5 times the lowest calculated MDL). The %D for the average Ohio
Lumex result for a tested sample with a referee laboratory value of 0.06 mg/kg is 0.072 mg/kg, with a %D of 20%. This
was the lowest sample concentration tested during the demonstration that is close to but not below, the calculated PQL
noted above. The referee laboratory PQL confirmed during the demonstration is 0.005 mg/kg with a %D <10%.
Accuracy: The results from the RA-915+/RP-91C were compared to the 95% prediction interval for the SRM materials
and to the referee laboratory results (Method 7471B). The Ohio Lumex data were within SRM 95% prediction intervals
93% of the time, which suggests significant equivalence to certified standards. The comparison between the Ohio
Lumex field data and the referee laboratory results suggest that the two data sets are not the same. When a unified
hypothesis test is performed (which accounts for laboratory bias), this result is confirmed. Ohio Lumex data were found
to be both above and below referee laboratory concentrations, therefore there is no implied or suggested bias. The
number of Ohio Lumex average values less than 30% different from the referee laboratory results or SRM reference
values was significant - 19 of 33 different sample lots. Ohio Lumex results therefore, provide accurate estimates for
field determination. Because the Ohio Lumex data compare favorably to the SRM values, the differences between Ohio
Lumex and the referee laboratory are likely the result of reasons beyond the scope of this study.
Precision: The precision of the Ohio Lumex field instrument is better than the referee laboratory precision. The overall
average RSD, is 22.3% forthe referee laboratory compared to the Ohio Lumex average RSD of 16.1 %. This is primarily
because of the better precision obtained for the SRM analyses by Ohio Lumex. Both the laboratory precision and the
Ohio Lumex precision goals of 25% overall RSD were achieved.
Measurement Time: From the time of sample receipt, Ohio Lumex required approximately 21 hours, 15 minutes, to
prepare a draft data package containing mercury results for 197 samples. One technician performed half of the
equipment setup and demobilization, most of the sample preparation, and all of the analyses. Individual analyses took
1 minute each, but the total time per analysis averaged 8.1 minutes per sample (based upon 1.25 analysts) when all
field activities and data package preparation were included in the calculation because the vendor chose to analyze
replicates of virtually every analysis.
Measurement Costs: The cost peranalyses based upon 197 samples, when renting the RA-915+/RP-91 C, is $23.44
per sample. The cost per analyses for the 197 samples, excluding rental fee, is $15.82 per sample. Based on a 3-day
field demonstration, the total cost for equipment rental and necessary supplies is estimated at $4,617. The cost by
category is: capital costs, 32.5%; supplies, 10.8%; support equipment, 6.0%; labor, 19.5%; and IDW, 31.2%.
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Key demonstration findings are summarized below for the secondary objectives.
Ease of Use: Based on observations made during the demonstration, the RA-915+/RP-91C is reasonably easy to
operate; however, lack of automation somewhat impairs the ease of use. Operation requires one field technician with
a basic knowledge of chemistry acquired on the job or in a university and training on the instrument.
Potential Health and Safety Concerns: No significant health and safety concerns were noted during the
demonstration. The only potential health and safety concerns identified were the generation of mercury vapors and the
potential for burns with careless handling of hot quartz sample boats. The vendor provides a mercury filter as standard
equipment; exercising caution and good laboratory practices can mitigate the potential for burns.
Portability. The RA-915+ airanalyzerwas easily portable, although the device, even when carried in the canvas sling,
was not considered light-weight. The addition ofthe RP-91C and associated pump unit preclude this from being a truly
field portable instrument. The device and attachments can be transported in carrying cases by two people, but must
then be set up in a stationary location. It was easy to set up, but the combined instrument is better characterized as
mobile rather than field portable.
Durability: The RA-915+/RP-91C was well designed and constructed for durability. The outside ofthe RA-915+ is
constructed of sturdy aluminum and the exterior of the RP-91C furnace is stainless steel.
Availability of the Device: The RA-915+/RP-91C is readily available for rental, lease, or purchase. Spare parts and
consumable supplies can be added to the original instrument order, or can be received within 24 to 48 hours of order
placement. Standards are readily available from laboratory supply firms or can be acquired through Ohio Lumex.
PERFORMANCE SUMMARY
In summary, during the demonstration, the RA-915+/RP-91C exhibited the following desirable characteristics of a field
mercury measurement device: (1) good accuracy compared to SRMs, (2) good precision, (3) good sensitivity, (4) high
sample throughput, (5) low measurement costs, and (6) ease of use. During the demonstration the RA-915+/RP-91C
was found to have the following limitations: (1) lack of automation and (2) non-portable due to the instrument size and
weight. The demonstration findings collectively indicated that the RA-915+/RP-91C is a reliable field measurement
device for mercury in soil and sediment.
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.
VI
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the nation's natural resources.
Under the mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a
compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this
mandate, the EPA' s Office of Research and Development provides data and scientific support that can be used to solve
environmental problems, build the scientific 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 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 (RCRA) 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 monitoring and measurement 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, 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 managed by the Office of Research and Development's
Environmental Sciences Division in Las Vegas, NV.
Gary Foley, Ph. D.
Director
National Exposure Research Laboratory
Office of Research and Development
VII
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Abstract
Ohio Lumex's RA915+/91C mercury analyzer was demonstrated under the U.S. Environmental Protection Agency
Superfund Innovative Technology Evaluation Program in May 2003, at the Oak Ridge National Laboratory (ORNL) in Oak
Ridge, TN. The purpose of the demonstration was to collect reliable performance and cost data for the RA915+/91C and
four other field measurement devices for mercury in soil and sediment. The key objectives of the demonstration were:
1) determine sensitivity of each instrument with respect to a vendor-generated method detection limit (MDL) and practical
quantitation limit (POL); 2) determine analytical accuracy associated with vendorfield measurements using field samples
and standard reference materials (SRMs); 3) evaluate the precision of vendor field measurements; 4) measure time
required to perform mercury measurements; and 5) estimate costs associated with mercury measurements for capital,
labor, supplies, and investigation-derived wastes.
The demonstration also involved analysis of SRMs, field samples collected from four sites, and spiked field samples for
mercury. The performance results fora given field measurement device were compared to those of an off-site laboratory
using reference method, "Test Methods for Evaluating Solid Waste" (SW-846) Method 7471 B.
The sensitivity, accuracy, and precision measurements were successfully completed. Results of these measurement
evaluations suggest that the Ohio Lumex field instrument can perform as well as the laboratory analytical method.
Accuracy comparisons to standard reference materials showed statistical equivalence but field sample ana lysis suggested
possible matrix interferences. Field instrument precision was better than laboratory precision as determined by relative
standard deviation calculations. During the demonstration, Ohio Lumex required 21.25 hours (1,275 minutes)foranalysis
of 197 samples. The cost per analysis, based on measurement of 197 samples, when incurring a minimum 1-month rental
fee for the RA-915+/RP-91C, was determined to be $23.44 per sample. Excluding the instrument rental cost, the costfor
analyzing the 197 samples was determined to be $15.82 per sample. Based on the 3-day field demonstration, the total
cost for equipment rental and necessary supplies was estimated at $4,617.
The RA915+/RP-91C exhibited good ease of use and durability, as well as no major health and safety concerns. However,
the device portability is somewhat limited by its size. Additionally, the device is readily available for purchase or lease.
The demonstration findings collectively indicated that the RA91 5+/RP-91 C is a reliable field mobile measurement device
for mercury in soil.
VIM
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Contents
Notice ii
Verification Statement iii
Foreword vii
Abstract viii
Contents ix
Tables xii
Figures xiii
Abbreviations, Acronyms, and Symbols xiv
Acknowledgments xvi
Chapter Page
1 Introduction 1
1.1 Description ofthe SITE Program 1
1.2 Scope of the Demonstration 2
1.2.1 Phase I 2
1.2.2 Phase II 2
1.3 Mercury Chemistry and Analysis 3
1.3.1 Mercury Chemistry 3
1.3.2 Mercury Analysis 4
2 Technology Description 6
2.1 Description of Atomic Absorption Spectroscopy 6
2.2 Description ofthe RA-915+/RP-91C 6
2.3 Developer Contact Information 8
3 Field Sample Collection Locations and Demonstration Site 9
3.1 Carson River 10
3.1.1 Site Description 10
3.1.2 Sample Collection 10
3.2 Y-12 National Security Complex 11
3.2.1 Site Description 11
3.2.2 Sample Collection 11
3.3 Confidential Manufacturing Site 11
3.3.1 Site Description 11
IX
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Contents (Continued)
Chapter
3.3.2 Sample Collection 12
3.4 Puget Sound 12
3.4.1 Site Description 12
3.4.2 Sample Collection 12
3.5 Demonstration Site 13
3.6 SAIC GeoMechanics Laboratory 14
Demonstration Approach 15
4.1 Demonstration Objectives 15
4.2 Demonstration Design 16
4.2.1 Approach for Addressing Primary Objectives 16
4.2.2 Approach for Addressing Secondary Objectives 20
4.3 Sample Preparation and Management 21
4.3.1 Sample Preparation 21
4.3.2 Sample Management 24
4.4 Reference Method Confirmatory Process 25
4.4.1 Reference Method Selection 25
4.4.2 Referee Laboratory Selection 25
4.4.3 Summary of Analytical Methods 27
4.5 Deviations from the Demonstration Plan 28
Assessment of Laboratory Quality Control Measurements 29
5.1 Laboratory QA Summary 29
5.2 Data Quality Indicators for Mercury Analysis 29
5.3 Conclusions and Data Quality Limitations 30
5.4 Audit Findings 32
Performance of the RA-915+/RP-91C 33
6.1 Primary Objectives 33
6.1.1 Sensitivity 33
6.1.2 Accuracy 35
6.1.3 Precision 43
6.1.4 Time Required for Mercury Measurement 46
6.1.5 Cost 48
6.2 Secondary Objectives 48
6.2.1 Ease of Use 48
6.2.2 Health and Safety Concerns 51
6.2.3 Portability of the Device 52
6.2.4 Instrument Durability 53
6.2.5 Availability of Vendor Instruments and Supplies 53
Economic Analysis 54
7.1 Issues and Assumptions 54
7.1.1 Capital Equipment Cost 54
7.1.2 Cost of Supplies 54
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Contents (Continued)
Chapter Page
7.1.3 Support Equipment Cost 55
7.1.4 Labor Cost 55
7.1.5 Investigation-Derived Waste Disposal Cost 55
7.1.6 Costs Not Included 56
7.2 RA-915+/RP-91C Costs 56
7.2.1 Capital Equipment Cost 57
7.2.2 Cost of Supplies 57
7.2.3 Support Equipment Cost 57
7.2.4 Labor Cost 58
7.2.5 Investigation-Derived Waste Disposal Cost 58
7.2.6 Summary of RA-915+/RP-91C Costs 58
7.3 Typical Reference Method Costs 59
8 Summary of Demonstration Results 61
8.1 Primary Objectives 61
8.2 Secondary Objectives 62
9 Bibliography 65
Appendix A - Ohio Lumex Comments 66
Appendix B - Statistical Analysis 67
XI
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Tables
Table Page
1-1 Physical and Chemical Properties of Mercury 4
1-2 Methods for Mercury Analysis in Solids or Aqueous Soil Extracts 5
3-1 Summary of Site Characteristics 10
4-1 Demonstration Objectives 15
4-2 Summary of Secondary Objective Observations Recorded During the Demonstration 20
4-3 Field Samples Collected from the Four Sites 22
4-4 Analytical Methods for Non-Critical Parameters 28
5-1 MS/MSD Summary 30
5-2 LCS Summary 30
5-3 Precision Sum mary 31
5-4 Low Check Standards 31
6-1 Distribution of Samples Prepared for Ohio Lumex and the Referee Laboratory 33
6-2 Ohio Lumex SRM Comparison 37
6-3 ALSI SRM Comparison 37
6-4 Accuracy Evaluation by Hypothesis Testing 38
6-5 Number of Sample Lots Within Each %D Range 40
6-6 Concentration of Non-Target Analytes 40
6-7 Evaluation of Precision 44
6-8 Time Measurements for Ohio Lumex 47
7-1 Capital Cost Summary for the RA-915+/RP-91C 57
7-2 Labor Costs 58
7-3 IDW Costs 58
7-4 Summary of Rental Costs for the RA-915+/RP-91C 59
7-5 RA-915+/RP-91C Costs by Category 59
8-1 Distribution of Samples Prepared for Ohio Lumex and the Referee Laboratory 62
8-2 Summary of RA-915+/RP-91C Results for the Primary Objectives 63
8-3 Summary of RA-915+/RP-91C Results for the Secondary Objectives 64
B-1 Unified Hypothesis Test Summary Information 69
XII
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Figures
2-1 RA-915+ instrument schematic 7
2-2 RA-915+/RP-91C shown setup in a van 7
3-1 Tent and field conditions during the demonstration at Oak Ridge, TN 13
3-2 Demonstration site and Building 5507 13
4-1 Test sample preparation at the SAIC GeoMechanics Laboratory 23
6-1 Data plot for low concentration sample results 41
6-2 Data plot for high concentration sample results 42
6-3 RA-915+/RP-91C peak screen 51
7-1 Capital equipment costs 57
XIII
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Abbreviations, Acronyms, and Symbols
% Percent
%D Percent difference
°C Degrees Celsius
|jg/kg Microgram per kilogram
AAS Atomic absorption spectroscopy
ALSI Analytical Laboratory Services, Inc.
bgs Below ground surface
cm Centimeter
CFR Code of Federal Regulations
Cl Confidence Interval
COC Chain of custody
Dl Deionized (water)
DOE Department of Energy
EPA United States Environmental Protection Agency
g Gram
H&S Health and Safety
Hg Mercury
HgCI2 Mercury (II) chloride
IDL Instrument detection limit
IDW Investigation-derived waste
ITVR Innovative Technology Verification Report
kg Kilogram
L Liter
LCS Laboratory control sample
LEFPC Lower East Fork Poplar Creek
m Meter
MDL Method detection limit
mg Milligram
mg/kg Milligram per kilogram
mL Milliliter
mm Millimeter
MS/MSD Matrix spike/matrix spike duplicate
MMT Monitoring and Measurement Technology
NERL National Exposure Research Laboratory
NiMH Nickel metal halide
ng Nanogram
nm Nanometer
ORD Office of Research and Development
ORNL Oak Ridge National Laboratory
XIV
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Abbreviations, Acronyms, and Symbols (Continued)
ORR Oak Ridge Reservation
OSWER Office of Solid Waste and Emergency Response
PPE Personal protective equipment
ppm Parts per million
POL Practical quantitation limit
QA Quality assurance
QAPP Quality Assurance Project Plan
QC Quality control
RPD Relative percent difference
RSD Relative standard deviation
SAIC Science Applications International Corporation
SITE Superfund Innovative Technology Evaluation
SOP Standard operating procedure
SRM Standard reference material
SW-846 Test Methods for Evaluating Solid Waste; Physical/Chemical Methods
TOC Total Organic Carbon
TOM Task Order Manager
UL Underwriters Laboratory
UEFPC Upper East Fork of Poplar Creek
Y-12 Y-12 Oak Ridge Security Complex, Oak Ridge, TN
xv
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Acknowledgments
The U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation wishes to acknowledge
the support of the following individuals in performing the demonstration and preparing this document: Elizabeth Phillips
of the U.S. Department of EnergyOak Ridge National Laboratory (ORNL); Stephen Chi Ids, Thomas Early, Roger Jenkins,
and Monty Ross of the UT-Battelle ORNL; Dale Rector of the Tennessee Department of Environment and Conservation
(TD EC) Department of Energy Oversight; Sergey Pogarev and Joseph Siperstein of Ohio Lumex; Leroy Lewis of the Idaho
National Engineering and Environmental Laboratory, retired; IshwarMurarkaofthe EPA Science Advisory Board, member;
Danny Reible of Louisiana State University; Mike Bolen, Joseph Evans, Julia Gartseff, Sara Hartwell, Cathleen Hubbard,
Kevin Jago, Andrew Matuson, Allen Motley, John Nicklas, Maurice Owens, Nancy Patti, Fernando Padilla, Mark Pruitt,
James Rawe, Herb Skovronek, and Joseph Tillman of Science Applications International Corporation (SAIC); Scott Jacobs
and Ann Vega of the EPA National Risk Management Research Laboratory's Land Remediation and Pollution Control
Division; and Brian Schumacher of the EPA National Exposure Research Laboratory.
This document was QA reviewed by George Brilis of the EPA National Exposure Research Laboratory.
XVI
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Chapter 1
Introduction
The U.S. Environmental Protection Agency (EPA) under
the Office of Research and Development (ORD), National
Exposure Research Laboratory (NERL), conducted a
demonstration to evaluate the performance of innovative
field measurement devices for their ability to measure
mercury concentrations in soils and sediments. This
Innovative Technology Verification Report (ITVR) presents
demonstration performance results and associated costs
of Ohio Lumex's Mercury Analyzer (RA-915+) with their soil
attachment (RP-91C). The vendor-prepared comments
regarding the demonstration are presented in Appendix A.
The demonstration was conducted as part of the EPA
Superfund Innovative Technology Evaluation (SITE)
Monitoring and Measurement Technology(MMT) Program.
Mercury contaminated soils and sediments, collected from
four sites within the continental U.S., comprised the
majority of samples analyzed during the evaluation. Some
soil and sediment samples were spiked with mercury (II)
chloride (HgCI2) to provide concentrations not occurring in
the field samples. Certified standard reference material
(SRM) samples were also used to provide samples with
certified mercury concentrations and to increase the matrix
variety.
The demonstration was conducted at the Department of
Energy (DOE) Oak Ridge National Laboratory (ORNL) in
Oak Ridge, TN during the week of May 5, 2003. The
purpose of the demonstration was to obtain reliable
performance and cost data for field measurement devices
in order to 1) provide potential users with a better
understanding of the devices' performance and operating
costs underwell-defined field conditions and 2) provide the
instrument vendors with documented results that can assist
them in promoting acceptance and use of their devices.
The results obtained using the five field mercury
measurement devices were compared to the mercury
results obtained for identical sample sets (samples, spiked
samples, and SRMs) analyzed ata referee laboratory. The
referee laboratory, which was selected prior to the
demonstration, used a well-established EPA reference
method.
1.1 Description of the 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 EPA's Officeof 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 meetthree main
objectives: 1) identify and remove obstacles to the
development and commercial use of innovative
technologies; 2) demonstrate promising innovative
technologies and gather reliable performance and cost
information to support site characterization and cleanup
activities; and 3) develop procedures and policies that
encourage the use of innovative technologies at Superfund
sites, as well as at other waste sites or commercial
facilities.
The SITE Program includes the following elements:
The MMT Program evaluates innovative technologies
that sample, detect, monitor, or measure hazardous
and toxic substances in soil, water, and sediment
samples. These technologies are expected to provide
better, faster, or more cost-effective methods for
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producing real-time data during site characterization
and remediation studies than conventional
technologies.
The Remediation Technology Program conducts
demonstrations of innovative treatment technologies to
provide reliable performance, cost, and applicability
data for site cleanups.
The 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 in
the support of the technologies. A significant number
of these activities are performed by EPA's Technology
Innovation Office.
The Field Analysis of Mercury in Soils and Sediments
demonstration was performed under the MMT Program.
The MMT Program 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. The main objectives of the MMT Program are
as follows:
Test and verify the performance of innovative field
sampling and analytical technologies that enhance
sampling, monitoring, and site characterization
capabilities.
Identify performance attributes of innovative
technologies that address field sampling, monitoring,
and characterization problems in a cost-effective and
efficient manner.
Prepare protocols, guidelines, methods, and other
technical publications that enhance acceptance of
these technologies for routine use.
The MMT Program is administered by the Environmental
Sciences Division of the NERL in Las Vegas, NV. 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 technical
support to ensure the effective implementation of
environmental regulations and strategies.
1.2 Scope of the Demonstration
The demonstration project consisted of two separate
phases: Phase I involved obtaining information on
prospective vendors having viable mercury detection
instrumentation. Phase II consisted of field and planning
activities leading up to and including the demonstration
activities. The following subsections provide detail on both
of these project phases.
1.2.1 Phase I
Phase I was initiated by making contact with
knowledgeable sources on the subject of "mercury in soil"
detection devices. Contacts included individuals within
EPA, Science Applications International Corporation
(SAIC), and industry where measurement of mercury in soil
was known to be conducted. Industry contacts included
laboratories and private developers of mercury detection
instrumentation. In addition, the EPA Task Order Manager
(TOM) provided contacts for "industry players" who had
participated in previous MMT demonstrations. SAIC also
investigated university and other research-type contacts for
knowledgeable sources within the subject area.
These contacts led to additional knowledgeable sources on
the subject, which in turn led to various Internet searches.
The Internet searches were very successful in finding
additional companies involved with mercury detection
devices.
All in all, these research activities generated an original list
of approximately 30 companies potentially involved in the
measurement of mercury in soils. The list included both
international and U.S. companies. Each of these
companies was contacted by phone or email to acquire
further information. The contacts resulted in 10 companies
that appeared to have viable technologies.
Due to instrument design (i.e., the instrument's ability to
measure mercury in soils and sediments), business
strategies, and stage of technology development, only 5 of
those 10 vendors participated in the field demonstration
portion of phase II.
1.2.2 Phase II
Phase II of the demonstration project involved strategic
planning, field-related activities for the demonstration, data
analysis, data interpretation, and preparation of the ITVRs.
Phase II included pre-demonstration and demonstration
activities, as described in the following subsections.
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1.2.2.1 Pre-Demonstration Activities
The pre-demonstration activities were completed in the fall
2002. There were six objectives for the pre-demonstration:
Establish concentration ranges for testing vendors'
analytical equipment during the demonstration.
Collect soil and sediment field samples to be used in
the demonstration.
Evaluate sample homogenization procedures.
Determine mercury concentrations in homogenized
soils and sediments.
Selecta reference method and qualify potential referee
laboratories for the demonstration.
Provide soil and sediment samples to the vendors for
self-evaluation of their instruments, as a precursor to
the demonstration.
As an integral part of meeting these objectives, a pre-
demonstration sampling event was conducted in
September 2002 to collect field samples of soils and
sediments containing different levels of mercury. The field
samples were obtained from the following locations:
Carson River Mercury site - near Dayton, NV
Y-12 National Security Complex - Oak Ridge, TN
A confidential manufacturing facility - eastern U.S.
Puget Sound - Bellingham Bay, WA
Immediately after collecting field sample material from the
sites noted above, the general mercury concentrations in
the soils and sediments were confirmed by quick
turnaround laboratory analysis of field-collected
subsamples using method SW-7471B. The field sample
materials were then shipped to a soil preparation laboratory
forhomogenization. Additional pre-demonstration activities
are detailed in Chapter 4.
1.2.2.2 Demonstration Activities
Specific objectives for this SITE demonstration were
developed and defined in a Field Demonstration and
Quality Assurance Project Plan (QAPP) (EPA Report #
EPA/600/R-03/053). The Field Demonstration QAPP is
available through the EPA ORD web site
(http://www.epa.gov/ORD/SITE) or from the EPA Project
Manager. The demonstration objectives were subdivided
into two categories: primary and secondary. Primary
objectives are goals of the demonstration study that need
to be achieved for technology verification. The
measurements used to achieve primary objectives are
referred to as critical. These measurements typically
produce quantitative results that can be verified using
inferential and descriptive statistics.
Secondary objectives are additional goals of the
demonstration study developed for acquiring other
information of interest about the technology that is not
directly related to verifying the primary objectives. The
measurements required forachieving secondary objectives
are considered to be noncritical. Therefore, the analysis of
secondary objectives is typically more qualitative in nature
and often uses observations and sometimes descriptive
statistics.
The field portion of the demonstration involved evaluating
the capabilities of five mercury-analyzing instruments to
measure mercury concentrations in soil and sediment.
During the demonstration, each instrument vendor received
three types of samples 1) homogenized field samples
referred to as "field samples", 2) certified SRMs, and 3)
spiked field samples (spikes).
Spikes were prepared by adding known quantities of HgCI2
to field samples. Together, the field samples, SRMs, and
spikes are referred to as "demonstration samples" for the
purpose of this ITVR. All demonstration samples were
independently analyzed by a carefully selected referee
laboratory. The experimental design for the demonstration
is detailed in Chapter 4.
1.3 Mercury Chemistry and Analysis
1.3.1 Mercury Chemistry
Elemental mercury is the only metal that occurs as a liquid
at ambient temperatures. Mercury naturally occurs,
primarily within the ore, cinnabar, as mercury sulfide (HgS).
Mercury easily forms amalgams with many other metals,
including gold. As a result, mercury has historically been
used to recover gold from ores.
Mercury is ionically stable; however, it is very volatile for a
metal. Table 1-1 lists selected physical and chemical
properties of elemental mercury.
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Table 1-1. Physical and Chemical Properties of Mercury
Properties Data
Appearance
Hardness
Abundance
Density @ 25 "C
Vapor Pressure @ 25 "C
Volatilizes @
Solidifies @
Silver-white, mobile, liquid.
Liquid
0.5% in Earth's crust
13.53g/mL
0.002 mm
356 "C
-39 "C
Source: Merck Index, 1983
Historically, mercury releases to the environment included
a number of industrial processes such as chloralkali
manufacturing, copper and zinc smelting operations, paint
application, waste oil combustion, geothermal energy
plants, municipal waste incineration, ink manufacturing,
chemical manufacturing, paper mills, leather tanning,
pharmaceutical production, and textile manufacturing. In
addition, industrial and domestic mercury-containing
products, such as thermometers, electrical switches, and
batteries, are disposed of as solid wastes in landfills (EPA,
July 1995). Mercury is also an indigenous compound at
many abandoned mining sites and is, of course, found as
a natural ore.
At mercury-contaminated sites, mercury exists in mercuric
form (Hg2+), mercurous form (Hg22+), elemental form (Hg°),
and alkylated form (e.g., methyl or ethyl mercury). Hg22+
and Hg2+ are the more stable forms under oxidizing
conditions. Under mildly reducing conditions, both
organically bound mercury and inorganic mercury may be
degraded to elemental mercury, which can then be
converted readily to methyl or ethyl mercury by biotic and
abiotic processes. Methyl and ethyl mercury are the most
toxic forms of mercury; the alkylated mercury compounds
are volatile and soluble in water.
Mercury (II) forms relatively strong complexes with Cl'and
CO32". Mercury (II) also forms complexes with inorganic
ligands such as fluoride (F~), bromide (Br~), iodide (I"),
sulfate (SO42"), sulfide (S2~), and phosphate (PO43~) and
forms strong complexes with organic ligands, such as
sulfhydryl groups, amino acids, and humic and fulvicacids.
The insoluble HgS is formed under mildly reducing
conditions.
1.3.2 Mercury Analysis
There are several laboratory-based, EPA promulgated
methods for the analysis of mercury in solid and liquid
hazardous waste matrices. In addition, there are several
performance-based methods for the determination of
various mercury species. Table 1-2 summarizes the
commonly used methods for measuring mercury in both
solid and liquid matrices, as identified through a review of
the EPA Test Method Index and SW-846. A discussion of
the choice of reference method is presented in Chapter 4.
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Table 1-2. Methods for Mercury Analysis in Solids or Aqueous Soil Extracts
Method
Analytical
Technology
Type(s) of
Mercury analyzed
Approximate
Concentration Range
Comments
SW-7471B CVAAS
SW-7472 ASV
SW-7473
SW-7474
TD,
amalgamation,
and AAS
AFS
inorganic mercury 10-2,000 ppb
organo-mercury
inorganic mercury 0.1-10,000 ppb
organo-mercury
inorganic mercury 0.2 - 400 ppb
organo-mercury
inorganic mercury 1 ppb - ppm
organo-mercury
Manual cold vapor technique widely
used for total mercury determinations
Newer, less widely accepted method
Allows for total decomposition analysis
Allows for total decomposition analysis;
less widely used/reference
EPA 1631 CVAFS
EPA 245.7 CVAFS
EPA 6200 FPXRF
inorganic mercury 0.5-100ppt
organo-mercury
inorganic mercury
organo-mercury
0.5 - 200 ppt
inorganic mercury >30 mg/kg
Requires "trace" analysis procedures;
written for aqueous matrices; Appendix
A of method written for sediment/soil
samples
Requires "trace" analysis procedures;
written for aqueous matrices; will
require dilutions of high-concentration
mercury samples
Considered a screening protocol
AAS = Atomic Absorption Spectrometry
AAF = Atomic Fluorescence Spectrometry
AFS = Atomic Fluorescence Spectrometry
ASV = Anodic Stripping Voltammetry
CVAAS = Cold Vapor Atomic Absorption Spectrometry
CVAFS = Cold Vapor Atomic Fluorescence Spectrometry
FPXRF = Field Portable X-ray Fluorescence
EPA = U.S. Environmental Protection Agency
mg/kg = milligram per kilogram
ppb = parts per billion
ppm = parts per million
ppt = parts per trillion
SW = solid waste
TD = thermal decomposition
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Chapter 2
Technology Description
This chapter provides a detailed description of the thermal
decomposition method of atomic absorption spectroscopy
(AAS), which is the type of technology on which Ohio
Lumex's instrument is based, and a detailed description of
the RA-915+ Mercury Analyzer with the RP-91C soil
attachment.
2.1 Description of Atomic Absorption
Spectroscopy
The principle of analysis used by the RA-915+and RP-91C
is thermal decomposition followed by AAS, with a 10-meter
(m) multi-path optical cell and Zeeman background
correction. AAS uses the absorption of light to measure
the concentration of gas-phase atoms. Because samples
are liquids or solids, the analyte atoms or ions must be
vaporized in a flame or graphite furnace. The atoms
absorb ultraviolet or visible light and make transitions to
higher electronic energy levels. The analyte concentration
is determined from the amount of absorption.
Concentration measurements are determined from a
working curve after calibrating the instrument with
standards of known concentration.
In reference to AAS, as a general analytical application,
thermal decomposition is followed by atomic absorption;
however, the mechanism of chemical recovery for analysis
may vary. Examples include cold vapor traps,
amalgamation desorption, and direct detection.
A sample of known mass is placed in the drying and
decomposition furnace and heated to between 600-800
Celsius (°C). The liquid or solid sample is dried and
organic materials are decomposed. The amount of light
absorbed by an analyte (the product of decomposition), in
this case mercury vapor, is compared to a standard to
quantify the mass of that analyte present in a sample of
known size. The absorption of light is proportional to the
mass of the analyte present. The wavelength of the light
source is specific to the analyte of interest. For mercury,
the wavelength is 254 nm.
2.2 Description of the RA-915+/RP-91C
The RA-915+ Mercury Analyzer is a portable atomic
absorption (AA) spectrometer with a 10-m multipath optical
cell and Zeeman background correction. Among its
features is the direct detection of mercury without
preliminary accumulation on a gold trap. The RA-915+
includes a built-in testcellforfield performance verification.
The unit can be used with the optional RP-91C for an ultra-
low mercury detection limit in water samples using the
"cold vapor" technique. For direct mercury determination
in complex matrices withoutsample pretreatment, including
liquids, soils and sediments, the instrument is operated
with the RP-91C accessory.
The operation of the RA-915+ is based on the principle of
differential, Zeeman AA spectrometry combined with high-
frequency modulation of polarized light. This combination
eliminates interferences and provides the highest
sensitivity. A mercury lamp is placed in a permanent
magnetic field in which the 254-nm resonance line is split
into three polarized components, twoofwhich are circularly
polarized in the opposite direction. These two components
(o- and o+) pass through a polarization modulator, while
the third component (n) is removed (see Figure 1). One o
component passes through the absorption cell; the other o
component passes outside of the absorption cell. In the
absence of mercury vapors, the intensity of the two o
components are equal. When mercury vapor is present in
the absorption cell, mercury atoms cause a proportional,
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concentration-related difference in the intensity of the o
components. This difference in intensity is what is
measured by the instrument.
71 Zeemdn
mercury triplet
ie envelope
Polarizat
Dry Catal
Multi
Photocfctcclor
Figure 2-1. RA-915+ instrument schematic.
The RP-91C attachment is intended to decompose a
sample and to reduce the mercury using the pyrolysis
technique. The RP-91C attachment is a furnace heated to
800 °C where mercury is converted from a bound state to
the atomic state by thermal decomposition, and reduced in
a two-section furnace. In the first section of the furnace,
the "light" mercury compounds are preheated and burned.
In the second section, a catalytic afterburner decomposes
"heavy" compounds. After the atomizer, the gas flow
enters the analytical cell of the attachment. Ambient air is
used as a carrier gas; no cylinders of compressed gasses
are required. Zeeman correction eliminates interferences,
thus, no gold amalgamation is required. The instrument is
controlled and the data are acquired by software based on
a Microsoft Windows® platform.
Applications and Specifications - The RA-915+ is a
portable spectrometer designed for interference-free
analysis/monitoring of mercury content in ambient air,
water, soil, natural and stack gases from chlor-alkali
manufacturing, spill response, hazardous waste, foodstuff,
and biological materials. The Ohio Lumex system is fully
operational in the field and could be set up in a van, as well
as a helicopter, marine vessel, or hand-carried for
continuous measurements. The RP-91 and RP-91C
attachments are used to convert the instrument into a liquid
or solid sample analyzer, respectively. The instrument is
suitable for field operation using a built-in battery.
According to the RA-91 5+ Analyzer manual, the base unit
has a dimension of 47 cm by 22 cm by 11 cm and weighs
7.57 kg. The palm unit measures 13.5 cm by 8 cm by 2 cm
and weighs 0.32 kg. The power supply can be a built-in, 6-
volt rechargeable battery, a power pack adapter, an
external electric battery, or an optional rechargeable
battery pack. The RP-91 C system includes a pumping unit
that has a dimension of 34 cm by 24 cm by 12 cm and a
power supply unit measuring 14.5 cm by 15 cm by 8.5 cm
(see Figure 2). Site requirements cited in the manual
include a temperature range of 5 to 40 °C, relative humidity
of up to 98%, atmospheric pressures of 84 to 106.7
kilopascals, along with requirements for sinusoidal vibration
and magnetic field tension. Sensitivity of the instrument is
reportedly not affected by up to a 95% background
absorption caused by interfering components (dust,
moisture, organic and inorganic gases).
Figure 2-2. RA-915+/RP-91C shown setup in a van.
Operation - The instrument calibration is performed by use
of liquid or solid, primary National Institute of Standards
and Technology (NIST)-traceable standards. The normal
dynamic analytical range is from 1-100 ug/kg by direct
determination withoutdilution. No sample mineralization is
needed, and the only waste generated is minimal residual
sample residue, excess sample, and any personal
protective equipment that may be used. Sample
throughput is up to 30 samples per hour without an auto
sampler.
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2.3 Developer Contact Information Twmsburg, OH 44087
Toll free: (888) 876-2611
Additional information about the RA-915+and PR-91Ccan Telephone' (3 30) 405-0837
be obtained from the following source: pax. /^Q\ 405-0847
Joseph Siperstein Email: mail@ohiolumex.com
Ohio Lumex Co. Internet: www.ohiolumex.com
9263 Ravenna Rd., Unit A-3
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Chapter 3
Field Sample Collection Locations and Demonstration Site
As previously described in Chapter 1, the demonstration in
part tested the ability of all five vendor instruments to
measure mercury concentrations in demonstration
samples. The demonstration samples consisted of field-
collected samples, spiked field samples, and SRMs. The
field-collected samples comprised the majority of
demonstration samples. This chapter describes the four
sites from which the field samples were collected, the
demonstration site, and the sample homogenization
laboratory. Spiked samples were preparedfrom these field
samples.
Screening of potential mercury-contaminated field sample
sites was conducted during Phase I of the project. Four
sites were selected for acquiring mercury-contaminated
samples thatwere diverse in appearance, consistency, and
mercury concentration. A key criterion was the source of
the contamination. These sites included:
Carson River Mercury site - near Dayton, NV
The Y-12 National Security Complex (Y-12) - Oak
Ridge, TN
A confidential manufacturing facility - eastern U.S.
Puget Sound - Bellingham Bay, WA
Site Diversity - Collectively, the four sites provided
sampling areas with both soil and sediment, having
variable physical consistencies and variable ranges of
mercury contamination. Two of the sites (Carson River
and Oak Ridge) provided both soil and sediment samples.
A third site (a manufacturing facility) provided just soil
samples and a fourth site (Puget Sound) provided only
sediment samples.
Access and Cooperation - Site representatives were
instrumental in providing site access, and in some cases,
guidance on the best areas to collect samples from
relatively high and low mercury concentrations. In addition,
representatives from the host demonstration site (ORNL)
provided a facility for conducting the demonstration.
At three of the sites, the soil and/or sediment sample was
collected, homogenized by hand in the field, and
subsampled for quick turnaround analysis. These
subsamples were sent to analytical laboratories to
determine the general range of mercury concentrations at
each of the sites. (The Puget Sound site did not require
confirmation of mercury contamination due to recently
acquired mercury analytical data from another, ongoing
research project.) The field-collected soil and sediment
samples from all four sites were then shipped to SAIC's
GeoMechanics Laboratory for a more thorough sample
homogenization (see Section 4.3.1) and subsampled for
redistribution to vendors during the pre-demonstration
vendor self-evaluations.
All five of the technology vendors performed a self-
evaluation on selected samples collected and
homogenized during this pre-demonstration phase of the
project. For the self-evaluation, the laboratory results and
SRM values were supplied to the vendor, allowing the
vendor to determine how well it performed the analysis on
the field samples. The results were used to gain a
preliminary understanding of the field samples collected
and to prepare for the demonstration.
Table 3-1 summarizes key characteristics of samples
collected at each of the four sites. Also included are the
sample matrix, sample descriptions, and sample depth
intervals. The analytical results presented in Table 3-1 are
based on referee laboratory mercury results for the
demonstration samples.
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Table 3-1. Summary of Site Characteristics
Site Name
Carson River
Mercury site
Y-12 National
Security Complex
Confidential
manufacturing site
Puget Sound -
Bellingham Bay
Sampling Area
Carson River
Six Mile Canyon
Old Hg Recovery Bldg.
Poplar Creek
Former plant building
Sediment layer
Underlying Native Material
Sample
Matrix
Sediment
Soil
Soil
Sediment
Soil
Sediment
Sediment
Depth
water/sediment
interface
3 - 8 cm bgs
0 - 1 m bgs
0 - 0.5 m bgs
3. 6 -9m bgs
1.5-1.8 m thick
0.3 m thick
Description
Sandy silt, with some
organic debris present
(plant stems and leaves)
Silt with sand to sandy silt
Silty-clay to sandy-gravel
Silt to coarse sandy gravel
Silt to sandy silt
Clayey-sandy silt with
various woody debris
Medium-fine silty sands
Hg Concentration
Range
10 ppb - 50 ppm
10 ppb- 1,000 ppm
0.1 - 100 ppm
0.1 - 100 ppm
5- 1,000 ppm
10 -400 ppm
0.16- 10 ppm
bgs = below ground surface.
3.1 Carson River
3.1.1 Site Description
The Carson River Mercury site begins near Carson City,
NV, and extends downstream to the Lahontan Valley and
the Carson Desert. During the Comstock mining era of the
late 1800s, mercury was imported to the area for
processing gold and silver ore. Ore mined from the
Comstock Lode was transported to mill sites, where it was
crushed and mixed with mercury to amalgamate the
precious metals. The Nevada mills were located in Virginia
City, Silver City, Gold Hill, Dayton, Six Mile Canyon, Gold
Canyon, and adjacent to the Carson River between New
Empire and Dayton. During the mining era, an estimated
7,500 tons of mercury were discharged into the Carson
River drainage, primarily in the form of
mercury-contaminated tailings (EPA Region 9, 1994).
Mercury contamination is present at Carson Riveras either
elemental mercury and/or inorganic mercury sulfides with
less than 1%, if any, methylmercury. Mercury
contamination exists in soils presentat the former gold and
silvermining mill sites; waterways adjacentto the millsites;
and sediment, fish, and wildlife over more than a 50-mile
length of the Carson River. Mercury is also present in the
sediments and adjacent flood plain of the Carson River,
and in the sediments of Lahontan Reservoir, Carson Lake,
Stillwater Wildlife Refuge, and Indian Lakes. In addition,
tailings with elevated mercury levels are still presentat, and
around, the historic mill sites, particularly in Six Mile
Canyon (EPA, 2002a).
3.1.2 Sample Collection
The Carson River Mercury site provided both soil and
sediment samples across the range of contaminant
concentrations desired for the demonstration. Sixteen
near-surface soil samples were collected between 3-8 cm
below ground surface (bgs). Two sediment samples were
collected at the water-to-sediment interface. All 18
samples were collected on September 23-24, 2002 with a
hand shovel. Samples were collected in Six Mile Canyon
and along the Carson River.
The sampling sites were selected based upon historical
data from the site. Specific sampling locations in the Six
Mile Canyon were selected based upon local terrain and
visible soil conditions (e.g., color and particle size). The
specific sites were selected to obtain soil samples with as
much variety in mercury concentration as possible. These
sites included hills, run-off pathways, and dry river bed
areas. Sampling locations along the Carson River were
selected based upon historical mine locations, local terrain,
and river flow.
When collecting the soil samples, approximately 3 cm of
surface soil was scraped to the side. The sample was
then collected with a shovel, screened through a
6.3-millimeter (mm) (0.25-inch) sieve to remove larger
material, and collected in 4-liter (L) scalable bags identified
with a permanent marker. The sediment samples were
also collected with a shovel, screened through a 6.3-mm
sieve to remove larger material, and collected in 4-L
scalable bags identified with a permanent marker. Each of
the 4-L scalable bags was placed into a second 4-L
10
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sealable bag, and the sample label was placed onto the
outside bag. The sediment samples were then placed into
10-L buckets, lidded, and identified with a sample label.
3.2 Y-12 National Security Complex
3.2.1 Site Description
The Y-12 site is located at the DOE ORNL in Oak Ridge,
TN. The Y-12 site is an active manufacturing and
developmental engineering facility that occupies
approximately 800 acres on the northeast corner of the
DOE Oak Ridge Reservation (ORR) adjacent to the city of
Oak Ridge, TN. Built in 1 943 by the U.S. Army Corps of
Engineers as part of the World War II Manhattan Project,
the original mission of the installation was development of
electromagnetic separation of uranium isotopes and
weapon components manufacturing, as partof the national
effort to produce the atomic bomb. Between 1950 and
1963, large quantities of elemental mercury were used at
Y-12 during lithium isotope separation pilot studies and
subsequent production processes in support of
thermonuclear weapons programs.
Soils at the Y-12 facility are contaminated with mercury in
many areas. One of the areas of known high levels of
mercury-contaminated soils is in the vicinity of a former
mercury use facility (the "Old Mercury Recovery Building"
- Building 8110). At this location, mercury-contaminated
material and soil were processed in a Nicols-Herschoff
roasting furnace to recover mercury. Releases of mercury
from this process, and from a building sump used to
secure the mercury-contaminated materials and the
recovered mercury, have contaminated the surrounding
soils (Rothchild, et al., 1984). Mercury contamination also
occurred in the sediments of the East Fork of Poplar Creek
(DOE, 1998). The Upper East Fork of Poplar Creek
(UEFPC) drains the entire Y-12 complex. Releases of
mercury via building drains connected to the storm sewer
system, building basement dewatering sump discharges,
and spills to soils, all contributed to contamination of
UEFPC. Recent investigations showed that bank soils
containing mercury along the UEFPC were eroding and
contributing to mercury loading. Stabilization of the bank
soils along this reach of the creek was recently completed.
3.2.2 Sample Collection
Two matrices were sampled at Y-12 in Oak Ridge, TN,
creek sediment and soil. A total of 10 sediment samples
was collected; one sediment sample was collected from
the Lower East Fork of Poplar Creek (LEFPC) and nine
sediment samples were collected from the UEFPC. A total
of six soil samples was collected from the Building 8110
area. The sampling procedures that were used are
summarized below.
Creek Sediments - Creek sediments were collected on
September 24-25, 2002 from the East Fork of Poplar
Creek. Sediment samples were collected from various
locations in a downstream to upstream sequence (i.e., the
downstream LEFPC sample was collected first and the
most upstream point of the UEFPC was sampled last).
The sediment samples from Poplar Creek were collected
using a commercially available clam-shell sonar dredge
attached to a rope. The dredge was slowly lowered to the
creek bottom surface, where it was pushed by foot into the
sediment. Several drops of the sampler (usually seven or
more) were made to collect enough material for screening.
On some occasions, a shovel was used to remove
overlying "hardpan" gravel to expose finer sediments at
depth. One creek sample consisted of creek bank
sediments, which was collected using a stainless steel
trowel.
The collected sediment was then poured onto a 6.3-mm
sieve to remove oversize sample material. Sieved samples
were then placed in 12-L sealable plastic buckets. The
sediment samples in these buckets were homogenized
with a plastic ladle and subsamples were collected in 20-
milliliter (mL) vials for quick turnaround analyses.
Soil - Soil samples were collected from pre-selected
boring locations September 25, 2002. All samples were
collected in the immediate vicinity of the Building 8110
foundation using a commercially available bucket auger.
Oversize material was hand picked from the excavated soil
because the soil was too wet to be passed through a sieve.
The soil was transferred to an aluminum pan,
homogenized by hand, and subsampled to a 20-mL vial.
The remaining soil was transferred to 4-L plastic
containers.
3.3 Confidential Manufacturing Site
3.3.1 Site Description
A confidential manufacturing site, located in the eastern
U.S., was selected for participation in this demonstration.
The site contains elemental mercury, mercury amalgams,
and mercury oxide in shallow sediments (less than 0.3 m
deep) and deeper soils (3.65 to 9 m bgs). This site
provided soil with concentrations from 5-1,000 mg/kg.
The site is the location of three former processes that
resulted in mercury contamination. The first process
11
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involved amalgamation of zinc with mercury. The second
process involved the manufacturing of zinc oxide. The
third process involved the reclamation of silver and gold
from mercury-bearing materials in a retort furnace.
Operations led to the dispersal of elemental mercury,
mercury compounds such as chlorides and oxides, and
zinc-mercury amalgams. Mercury values have been
measured ranging from 0.05 to over 5,000 mg/kg, with
average values of approximately 100 mg/kg.
3.3.2 Sample Collection
Eleven subsurface soil samples were collected on
September 24, 2002. All samples were collected with a
Geoprobe® unit using plastic sleeves. All samples were
collected at the location of a former facility plant. Drilling
locations were determined based on historical data
provided by the site operator. The intention was to gather
soil samples across a range of concentrations. Because
the surface soils were from relatively clean fill, the sampling
device was pushed to a depth of 3.65 m using a blank rod.
Samples were then collected at pre-selected depths
ranging from 3.65 to 9 m bgs. Individual cores were 1-m
long. The plastic sleeve for each 1-m core was marked
with a permanent marker; the depth interval and the bottom
of each core was marked. The filled plastic tubes were
transferred to a staging table where appropriate depth
intervals were selected for mixing. Selected tubes were cut
into 0.6-m intervals, which were emptied into a plastic
container for premixing soils. When feasible, soils were
initially screened to remove materials larger than 6.3-mm
in diameter. In many cases, soils were too wet and clayey
to allow screening; in these cases, the soil was broken into
pieces by hand and, by using a wooden spatula, oversize
materials were manually removed. These soils (screened
or hand sorted) were then mixed until the soil appeared
visually uniform in color and texture. The mixed soil was
then placed into a 4-L sample container for each chosen
sample interval. A subsample of the mixed soil was
transferred into a 20-mL vial, and it was sent for quick
turnaround mercury analysis. This process was repeated
for each subsequent sample interval.
3.4 Puget Sound
3.4.1 Site Description
The Puget Sound site consists of contaminated offshore
sediments. The particular area of the site used for
collecting demonstration samples is identified as the
Georgia Pacific, Inc. Log Pond. The Log Pond is located
within the Whatcom Waterway in Bellingham Bay, WA, a
well-established heavy industrial land use area with a
maritime shoreline designation. Log Pond sediments
measure approximately 1.5 to 1.8-m thick, and contain
various contaminants including mercury, phenols,
polyaromatic hydrocarbons, polychlorinated biphenyls, and
wood debris. Mercury was used as a preservative in the
logging industry. The area was capped in late 2000 and
early 2001 with an average of 7 feet of clean capping
material, as part of a Model Toxics Control Act interim
cleanup action. The total thickness ranges from
approximately 0.15 m along the site perimeter to 3 m within
the interior of the project area. The restoration project
produced 2.7 acres of shallow sub-tidal and 2.9 acres of
low intertidal habitat, all of which had previously exceeded
the Sediment Management Standards cleanup criteria
(Anchor Environmental, 2001).
Mercury concentrations have been measured ranging from
0.16 to 400 mg/kg (dry wt). The majority (98%) of the
mercury detected in near-shore ground waters and
sediments of the Log Pond is believed to be comprised of
complexed divalent (Hg2+) forms such as mercuric sulfide
(Bothner, et al., 1980 and Anchor Environmental, 2000).
3.4.2 Sample Collection
Science Applications International Corporation (SAIC) is
currently performing a SITE remedialtechnology evaluation
in the Puget Sound (SAIC, 2002). As part of ongoing work
at that site, SAIC collected additional sediment for use
during this MMT project. Sediment samples collected on
August 20-21, 2002 from the Log Pond in Puget Sound
were obtained beneath approximately 3-6 m of water, using
a vibra-coring system capable of capturing cores to 0.3 m
below the proposed dredging prism. The vibra-corer
consisted of a core barrel attached to a power head.
Aluminum core tubes, equipped with a stainless steel
"eggshell" core catcher to retain material, were inserted
into the core barrel. The vibra-core was lowered into
position on the bottom and advanced to the appropriate
sampling depth. Once sampling was completed, the
vibra-core was retrieved and the core liner removed from
the core barrel. The core sample was examined at each
end to verify that sufficient sediment was retained for the
particular sample. The condition and quantity of material
within the core was then inspected to determine
acceptability.
The following criteria were used to verify whether an
acceptable core sample was collected:
Target penetration depth (i.e., into native material) was
achieved.
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Sediment recovery of at least 65% of the penetration
depth was achieved.
Sample appeared undisturbed and intact without any
evidence of obstruction/blocking within the core tube or
catcher.
The percentsediment recovery was determined by dividing
the length of material recovered by the depth of core
penetration below the mud line. If the sample was deemed
acceptable, overlying water was siphoned from the top of
the core tube and each end of the tube capped and sealed
with duct tape. Following core collection, representative
samples were collected from each core section
representing a different vertical horizon. Sediment was
collected from the center of the core that had not been
smeared by, or in contact with, the core tube. The volumes
removed were placed in a decontaminated stainless steel
bowl or pan and mixed until homogenous in texture and
color (approximately 2 minutes).
After all sediment for a vertical horizon composite was
collected and homogenized, representative aliquots were
placed in the appropriate pre-cleaned sample containers.
Samples of both the sediment and the underlying native
materialwere collected in a similarmanner. Distinct layers
of sediment and native material were easily recognizable
within each core.
3.5 Demonstration Site
The demonstration was conducted in a natural
environment, outdoors, in Oak Ridge, TN. The area was
a grass covered hill with some parking areas, all of which
were surrounded by trees. Building 5507, in the center of
the demonstration area, provided facilities for lunch, break,
and sample storage for the project and personnel.
Most of the demonstration was performed during rainfall
events ranging from steady to torrential. Severe puddling
of rain occurred to the extent that boards needed to be
placed under chairs to prevent them from sinking into the
ground. Even when it was not raining, the relative humidity
was high, ranging from 70.6 to 98.3 percent. Between two
and four of the tent sides were used to keep rainfall from
damaging the instruments. The temperature in the
afternoons ranged from 65-70 degrees Fahrenheit, and the
wind speed was less than 10 mph. The latitude is 36°N,
the longitude 35°W, and the elevation 275 m. (Figure 3-1
is a photograph of the site during the demonstration and
Figure 3-2 is a photograph of the location.)
Figure 3-1. Tent and field conditions during the
demonstration at Oak Ridge, TN.
Figure 3-2. Demonstration site and Building 5507.
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3.6 SAIC GeoMechanics Laboratory
Sample homogenization was completed at the SAIC
GeoMechanics Laboratory in Las Vegas, NV. This facility
is an industrial-type building with separate facilities for
personnel offices and material handling. The primary
function of the laboratory is for rock mechanics studies.
The laboratory has rock mechanics equipment, including
sieves, rockcrushers, and sample splitters. The personnel
associated with this laboratory are experienced in the areas
of sample preparation and sample homogenization. In
addition to the sample homogenization equipment, the
laboratory contains several benches, tables, and open
space. Mercury air monitoring equipment was used during
the sample preparation activities for personnel safety.
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Chapter 4
Demonstration Approach
This chapter describes the demonstration approach that
was used for evaluating the field mercury measurement
technologies at ORNL in May 2003. It presents the
objectives, design, sample preparation and management
procedures, and the reference method confirmatory
process used for the demonstration.
4.1 Demonstration Objectives
The primary goal of the SITE MMT Program is to develop
reliable performance and cost data on innovative,
field-ready measurement technologies. A SITE
demonstration must provide detailed and reliable
performance and cost data in order that potential
technology users have adequate information needed to
make sound judgements regarding an innovative
technology's applicability to a specific site and to be able to
compare the technology to conventional technologies.
Table 4-1 summarizes the project objectives for this
demonstration. In accordance with QAPP Requirements
for Applied Research Projects (EPA,1998), the technical
project objectives for the demonstration were categorized
as primary and secondary.
Table 4-1. Demonstration Objectives
Objective
Description
Method of Evaluation
Primary Objectives
Primary Objective # 1
Primary Objective # 2
Primary Objective # 3
Primary Objective # 4
Primary Objective # 5
Determine sensitivity of each instrument with respect to vendor-generated MDL and
PQL.
Determine potential analytical accuracy associated with vendor field measurements.
Evaluate the precision of vendorfield measurements.
Measure time required to perform five functions related to mercury measurements:
1) mobilization and setup, 2) initial calibration, 3) daily calibration, 4) sample
analysis, and 5) demobilization.
Estimate costs associated with mercury measurements for the following four
categories: 1) capital. 2) labor. 3) supplies, and 4) investigation-derived wastes.
Independent laboratory
confirmation of SRMs,
field samples, and
spiked field samples.
Documentation during
demonstration; vendor-
provided information.
Secondary Objectives
Secondary Objective # 1
Secondary Objective # 2
Secondary Objective # 3
Secondary Objective # 4
Secondary Objective # 5
Document ease of use, skills, and training required to operate the device properly.
Document potential H&S concerns associated with operating the device.
Document portability of the device.
Evaluate durability of device based on materials of construction and engineering
design.
Document the availability of the device and its spare parts.
Documentation of
observations during
demonstration; vendor-
provided information.
Post-demonstration
investigation.
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Critical data support primary objectives and noncritical data
support secondary objectives. With the exception of the
cost information, primary objectives required the use of
quantitative results to draw conclusions regarding
technology performance. Secondary objectives pertained
to information that was useful and did not necessarily
require the use of quantitative results to draw conclusions
regarding technology performance.
4.2 Demonstration Design
4.2.1 Approach for Addressing Primary
Objectives
The purpose of this demonstration was to evaluate the
performance of the vendor's instrumentation against a
standard laboratory procedure. In addition, an overall
average relative standard deviation (RSD) was calculated
for all measurements made by the vendor and the referee
laboratory. RSD comparisons used descriptive statistics,
not inferential statistics, between the vendor and laboratory
results. Other statistical comparisons (both inferential and
descriptive) for sensitivity, precision, and accuracy were
used, depending upon actual demonstration results.
The approach for addressing each of the primary
objectives is discussed in the following subsections. A
detailed explanation of the precise statistical determination
used for evaluating primary objectives No. 1 through No. 3
is presented in Chapter 6.
4.2.1.1 Primary Objective #1: Sensitivity
Sensitivity is the ability of a method or instrument to
discriminate between small differences in analyte
concentration (EPA, 2002b). It can be discussed in terms
of an instrument detection limit (IDL), a method detection
limit (MDL), and as a practical quantitation limit (PQL).
MDL is not a measure of sensitivity in the same respect as
an IDL or PQL. It is a measure of precision at a
predetermined, usually low, concentration. The IDL
pertains to the ability of the instrument to determine with
confidence the difference between a sample that contains
the analyte of interest at a low concentration and a sample
that does not contain that analyte. The IDL is generally
considered to be the minimum true concentration of an
analyte producing a non-zero signal that can be
distinguished from the signals generated when no
concentration of the analyte is present and with an
adequate degree of certainty.
The IDL is not rigidly defined in terms of matrix, method,
laboratory, or analyst variability, and it is not usually
associated with a statistical level of confidence. IDLs are,
thus, usually lower than MDLs and rarely serve a purpose
in terms of project objectives (EPA, 2002b). The PQL
defines a specific concentration with an associated level of
accuracy. The MDL defines a lower limit at which a
method measurement can be distinguished from
background noise. The PQL is a more meaningful
estimate of sensitivity. The MDL and PQL were chosen as
the two distinct parameters for evaluating sensitivity. The
approach for addressing each of these indicator
parameters is discussed separately in the following
paragraphs.
MDL
MDL is the estimated measure of sensitivity as defined in
40 Code of Federal Regulations (CFR) Part 136. The
purpose of the MDL measurement is to estimate the
concentration at which an individual field instrument is able
to detect a minimum concentration that is statistically
different from instrument background or noise. Guidance
for the definition of the MDL is provided in EPA G-5i (EPA,
2002b).
The determination of a MDL usually requires seven
different measurements of a low concentration standard or
sample. Following procedures established in 40 CFR Part
136 for water matrices, the demonstration MDL definition
is as follows:
MDL = Vl.O.Q9)S
where: t(n_..
,0.99)
99 percentile of the t-distribution
with n -1 degrees of freedom
number of measurements
standard deviation of replicate
measurements
PQL
The PQL is another important measure of sensitivity. The
PQL is defined in EPA G-5i as the lowest level an
instrument is capable of producing a result that has
significance in terms of precision and bias. (Bias is the
difference between the measured value and the true
value.) It is generally considered the lowest standard on
the instrument calibration curve. It is often 5-10 times
higher than the MDL, depending upon the analyte, the
instrument being used, and the method for analysis;
however, it should not be rigidly defined in this manner.
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During the demonstration, the PQL was to be defined by
the vendor's reported calibration or based upon lower
concentration samples or SRMs. The evaluation of
vendor-reported results for the PQL included a
determination of the percentdifference (%D) between their
calculated value and true value. The true value is
considered the value reported by the referee laboratory for
field samples or spiked field samples, or, in the case of
SRMs, the certified value provided by the supplier. The
equation used for the %D calculation is:
calculated
where: C,,
'true
true concentration as determined
by the referee laboratory or SRM
reference value
calculated test sample
concentration
The PQL and %D were reported for the vendor. The %D
for the referee laboratory, at the same concentration, was
also reported for purposes of comparison. No statistical
comparison was made between these two values; only a
descriptive comparison was made for purposes of this
evaluation. (The %D requirementforthe referee laboratory
was defined as 10% or less. The reference method PQL
was approximately 10 ug/kg.)
4.2.1.2 Primary Objective #2: Accuracy
Accuracy was calculated by comparing the measured value
to a known or true value. For purposes of this
demonstration, three separate standards were used to
evaluate accuracy. These included: 1) SRMs, 2) field
samples collected from four separate mercury-
contaminated sites, and 3)spiked field samples. Foursites
were used for evaluation of the Ohio Lumex field
instrument. Samples representing field samples and
spiked field samples were prepared at the SAIC
GeoMechanics Laboratory. In order to prevent cross
contamination, SRMs were prepared in a separate location.
Each of these standards is discussed separately in the
following paragraphs.
SRMs
The primary standards used to determine accuracy for this
demonstration were SRMs. SRMs provided very tight
statistical comparisons, although they did not provide all
matrices of interest nor all ranges of concentrations. The
SRMs were obtained from reputable suppliers, and had
reported concentrations at associated 95% confidence
intervals (CIs) and 95% prediction intervals. Prediction
intervals were used for comparison because they represent
a statistically infinite number of analyses, and therefore,
would include all possible correct results 95% of the time.
All SRMs were analyzed by the referee laboratory and
selected SRMs were analyzed by the vendor, based upon
instrument capabilities and concentrations of SRMs that
could be obtained. Selected SRMs covered an appropriate
range for each vendor. Replicate SRMs were also
analyzed by the vendor and the laboratory.
The purpose for SRM analysis by the referee laboratory
was to provide a check on laboratory accuracy. During the
pre-demonstration, the referee laboratory was chosen, in
part, based upon the analysis of SRMs. This was done to
ensure a competent laboratory would be used for the
demonstration. Because of the need to provide confidence
in laboratory analysis during the demonstration, the referee
laboratory analyzed SRMs as an ongoing check for
laboratory bias.
Evaluation of vendor and laboratory analysis of SRMs was
performed as follows. Accuracy was reported for
individual sample concentrations of replicate
measurements made at the same concentration.
Two-tailed 95% CIs were computed according to the
following equation:
(n-1,0.975)
-Jn
where: t(n.1?0975) =
97.5th pe re entile of the
t-distribution with n-1 degrees of
freedom
number of measurements
standard deviation of replicate
measurements
The number of vendor-reported SRM results and referee
laboratory-reported SRM results that were within the
associated 95% prediction interval were evaluated.
Prediction intervals were computed in a similar fashion to
the Cl, except that the Student's "t" value use "n" equal to
infinity and, because prediction intervals represented "n"
approaching infinity, the square root of "n" was dropped
from the equation.
A final measure of accuracy determined from SRMs is a
frequency distribution thatshows the percentage of vendor-
reported measurements that are within a specified window
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of the reference value. For example, a distribution within
a 30% window of a reported concentration, within a 50%
window, and outside a 50% window of a reported
concentration. This distribution aspect could be reported
as average concentrations of replicate results from the
vendorfor a particular concentration and matrix, compared
to the same collected sample from the laboratory. These
are descriptive statistics and are used to better describe
comparisons, but they are not intended as inferential tests.
Field Samples
The second accuracystandard used forthis demonstration
was actual field samples collected from four separate
mercury-contaminated sites. This accuracy determination
consisted of a comparison of vendor-reported results for
field samples to the referee laboratory results for the same
field samples. The field samples were used to ensure that
"real-world" samples were tested for each vendor. The
field samples consisted of variable mercury concentrations
within varying soil and sediment matrices. The referee
laboratory results are considered the standard for
comparison to each vendor.
Vendor sample results for a given field sample were
compared to replicates analyzed by the laboratory for the
same field sample. (A hypothesis test was use with alpha
= 0.01 was performed. The null hypothesis was that
sample results were similar. Therefore, if the null
hypothesis is rejected, then the sample sets are considered
different.) Comparisons for a specific matrix or
concentration were made in order to provide additional
information on that specific matrix or concentration.
Comparison of the vendorvalues to laboratory values were
similar to the comparisons noted previously for SRMs,
except that a more definitive or inferential statistical
evaluation was used. Alpha = 0.01 was used to help
mitigate inter-laboratory variability. Additionally, an
aggregate analysis was used to mitigate statistical
anomalies (see Section 6.1.2).
Spiked Field Samples
The third accuracy standard for this demonstration was
spiked field samples. These spiked field samples were
analyzed by the vendors and by the referee laboratory in
replicate, in order to provide additional measurement
comparisons to a known value. Spikes were prepared to
cover additional concentrations not available from SRMs or
the samples collected in the field. They were grouped with
the field sample comparison noted above.
4.2.1.3 Primary Objective #3: Precision
Precision can be defined as the degree of mutual
agreement of independent measurements generated
through repeated application of a process under specified
conditions. Precision is usually thought of as repeatability
of a specific measurement, and it is often reported as RSD.
The RSD is computed from a specified number of
replicates. The more replications of a measurement, the
more confidence is associated with a reported RSD.
Replication of a measurement may be as few as 3
separate measurements to 30 or more measurements of
the same sample, dependent upon the degree of
confidence desired in the specified result. The precision
of an analytical instrument may vary depending upon the
matrix being measured, the concentration of the analyte,
and whether the measurement is made for an SRM or a
field sample.
The experimental design forthis demonstration included a
mechanism to evaluate the precision of the vendors'
technologies. Field samples from the four mercury-
contaminated field sites were evaluated by each vendor's
analytical instrument. During the demonstration,
concentrations were predetermined only as low, medium,
or high. Ranges of test samples (field samples, SRMs,
and spikes) were selected to cover the appropriate
analytical ranges of the vendor's instrumentation. It was
known prior to the demonstration that not all vendors were
capable of measuring similar concentrations (i.e., some
instruments were better at measuring low concentrations
and others were geared toward higher concentration
samples or had other attributes such as cost or ease of use
that defined specific attributes of their technology).
Because of this fact, not all vendors analyzed the same
samples.
During the demonstration, the vendor's instrumentation
was tested with samples from the four different sites,
having different matrices when possible (i.e., depending
upon available concentrations) and having different
concentrations (high, medium, and low) using a variety of
samples. Sample concentrations for an individual
instrument were chosen based upon vendor attributes in
terms of expected low, medium, and high concentrations
that the particular instrument was capable of measuring.
The referee laboratory measured replicates of all samples.
The results were used for precision comparisons to the
individual vendor. The RSD for the vendor and the
laboratory were calculated individually, using the following
equation:
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%RSD = -x1QO
x
where: S = standard deviation of replicate results
x = mean value of replicate results
Using descriptive statistics, differences between vendor
RSD and referee laboratory RSD were determined. This
included RSD comparisons based upon concentration,
SRMs, field samples, and different sites. In addition, an
overall average RSD was calculated for all measurements
made by the vendor and the laboratory. RSD comparisons
were based upon descriptive statistical evaluations
between the vendor and the laboratory, and results were
compared accordingly.
4.2.1.4 Primary Objective #4: Time per Analysis
The amount of time required for performing the analysis
was measured and reported for five categories:
Mobilization and setup
Initial calibration
Daily calibration
Sample analyses
Demobilization
Mobilization and setup included the time needed to unpack
and prepare the instrument for operation. Initial calibration
included the time to perform the vendor recommended
on-site calibrations. Daily calibration included the time to
perform the vendor-recommended calibrations on
subsequent field days. (Note that this could have been the
same as the initial calibration, a reduced calibration, or
none.) Sample analyses included the time to prepare,
measure, and calculate the results for the demonstration
and the necessary quality control (QC) samples performed
by the vendor.
The time per analysis was determined by dividing the total
amount of time required to perform the analyses by the
number of samples analyzed (197). In the numerator,
sample analysis time included preparation, measurement,
and calculation of results for demonstration samples and
necessary QC samples performed by the vendor. In the
denominator, the total number of analyses included only
demonstration samples analyzed by the vendor, not QC
analyses nor reanalyses of samples.
Downtime that was required or that occurred between
sample analyses as a part of operation and handling was
considered a part of the sample analysis time. Downtime
occurring due to instrument breakage or unexpected
maintenance was not counted in the assessment, but it is
noted in this final report as an additional time. Any
downtime caused by instrument saturation or memory
effect was addressed, based upon its frequency and
impact on the analysis.
Unique time measurements are also addressed in this
report (e.g., if soil samples were analyzed directly, and
sedimentsamples required additional time to dry before the
analyses started, then a statement was made noting that
soil samples were analyzed in X amount of hours, and that
sediment samples required drying time before analysis).
Recorded times were rounded to the nearest 15-minute
interval. The number of vendor personnel used was noted
and factored into the time calculations. No comparison on
time per analysis is made between the vendor and the
referee laboratory.
4.2.1.5 Primary Objective #5: Cost
The following four cost categories were considered to
estimate costs associated with mercury measurements:
Capital costs
Labor costs
Supply costs
Investigation-derived waste (IDW) disposal costs
Although both vendor and laboratory costs are presented,
the calculated costs were not compared with the referee
laboratory. A summary of how each cost category was
estimated for the measurement device is provided below.
The capital cost was estimated based on published
price lists for purchasing, renting, or leasing each field
measurement device. If the device was purchased,
the capital cost estimate did not include salvage value
for the device after work was completed.
The labor cost was based on the number of people
required to analyze samples during the demonstration.
The labor rate was based on a standard hourly rate for
a technician or other appropriate operator. During the
demonstration, the skill level required was confirmed
based on vendor input regarding the operation of the
device to produce mercury concentration results and
observations made in the field. The labor costs were
based on: 1) the actual number of hours required to
complete all analyses, quality assurance (QA), and
reporting; and 2) the assumption thata technician who
worked for a portion of a day was paid for an entire
8-hour day.
The supply costs were based on any supplies required
to analyze the field and SRM samples during the
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demonstration. Supplies consisted of items not
included in the capital category, such as extraction
solvent, glassware, pipettes, spatulas, agitators, and
similar materials. The type and quantity of all supplies
broughtto the field and used during the demonstration
were noted and documented.
Any maintenance and repair costs during the
demonstration were documented or provided by the
vendor. Equipment costs were estimated based on
this information and standard cost analysis guidelines
used in the SITE Program.
The IDW disposal costs included decontamination
fluids and equipment, mercury-contaminated soil and
sediment samples, and used sample residues.
Contaminated personal protective equipment (PPE)
normally used in the laboratory was placed into a
separate container. The disposal costs for the IDW
were included in the overall analytical costs for each
vendor.
After all of the cost categories were estimated, the cost per
analysis was calculated. This costvalue was based on the
number of analyses performed. As the numberof samples
analyzed increased, the initial capital costs and certain
other costs were distributed across a greater number of
samples. Therefore, the per unit cost decreased. For this
reason, two costs were reported: 1) the initial capital costs
and 2) the operating costs per analysis. No comparison to
the referee laboratory's method cost was made; however,
a generic cost comparison was made. Additionally, when
determining laboratory costs, the associated cost for
laboratory audits and data validation should be considered.
4.2.2 Approach for Addressing Secondary
Objectives
Secondary objectives were evaluated based on
observations made during the demonstration. Because of
the number of vendors involved, technology observers
were required to make simultaneous observations of two
vendors each during the demonstration. Four procedures
were implemented to ensure that these subjective
observations made by the observers were as consistent as
possible.
First, forms were developed for each of the five secondary
objectives. These forms assisted in standardizing the
observations. Second, the observers met each day before
the evaluations began, at significant break periods, and
after each day of work to discuss and compare
observations regarding each device. Third, an additional
observerwas assigned to independently evaluate onlythe
secondary objectives in order to ensure that a consistent
approach was applied in evaluating these objectives.
Finally, the SAIC TOM circulated among the evaluation
staff during the demonstration to ensure that a consistent
approach was being followed by all personnel. Table 4-2
summarizes the aspects observed during the
demonstration for each secondary objective. The
individual approaches to each of these objectives are
detailed further in the following subsections.
Table 4-2. Summary of Secondary Objective Observations Recorded During the Demonstration
SECONDARY OBJECTIVE
General
Information
- Vendor Name
- Observer Name
- Instrument Type
- Instrument Name
- Model No.
- Serial No.
Secondary Objective # 1
Ease of Use
- No. of Operators
- Operator Names/Titles
- Operator Training
- Training References
- Instrument Setup Time
- Instrument Calibration Time
- Sample Preparation Time
- Sample Measurement Time
Secondary Objective # 2
H&S Concerns
- Instrument Certifications
- Electrical Hazards
- Chemicals Used
- Radiological Sources
- Hg Exposure Pathways
- Hg Vapor Monitoring
- PPE Requirements
- Mechanical Hazard
- Waste Handling Issues
Secondary Objective # 3
Instrument Portability
- Instrument Weight
- Instrument Dimensions
- Power Sources
- Packaging
- Shipping & Handling
Secondary Objective # 4
Instrument Durability
- Materials of Construction
- Quality of Construction
- Max. Operating Temp.
- Max. Operating Humidity
- Downtime
- Maintenance Activities
- Repairs Conducted
H&S = Health and Safety
PPE = Personal Protective Equipment
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4.2.2.1 Secondary Objective #1: Ease of Use
The skills and training required for proper device operation
were noted; these included any degrees or specialized
training required by the operators. This information was
gathered by interviews (i.e., questioning) of the operators.
The number of operators required was also noted. This
objective was also evaluated by subjective observations
regarding the easeof equipment useand major peripherals
required to measure mercury concentrations in soils and
sediments. The operating manual was evaluated to
determine if it is easily useable and understandable.
4.2.2.2 Secondary Objective #2: Health and Safety
Concerns
Health and safety (H&S) concerns associated with device
operation were noted during the demonstration. Criteria
included hazardous materials used, the frequency and
likelihood of potential exposures, and any direct exposures
observed during the demonstration. In addition, any
potential for exposure to mercury during sample digestion
and analysis was evaluated, based upon equipment
design. Other H&S concerns, such as basic electrical and
mechanical hazards, were also noted. Equipment
certifications, such as Underwriters Laboratory (UL), were
documented.
4.2.2.3 Secondary Objective #3: Portability of the
Device
The portability of the device was evaluated by observing
transport, measuring setup and tear down time,
determining the size and weightof the unit and peripherals,
and assessing the ease with which the instrument was
repackaged for movement to another location. The use of
battery power or the need for an AC outlet was also noted.
4.2.2.4 Secondary Objective #4: Instrument Durability
The durability of each device and major peripherals was
assessed by noting the quality of materials and
construction. All device failures, routine maintenance,
repairs, and downtime were documented during the
demonstration. No specific tests were performed to
evaluate durability; rather, subjective observations were
made using a field form as guidance.
4.2.2.5 Secondary Objective #5: Availability of Vendor
Instruments and Supplies
The availability of each device was evaluated by
determining whether additional units and spare parts are
readily available from the vendor or retail stores. The
vendor's office (or a web page) and/or a retail store was
contacted to identify and determine the availability of
supplies of the tested measurement device and spare
parts. This portion of the evaluation was performed after
the field demonstration, in conjunction with the cost
estimate.
4.3 Sample Preparation and Management
4.3.1 Sample Prepara tion
4.3.1.1 Field Samples
Field samples were collected during the pre-demonstration
portion of the project, with the ultimate goal of producing a
set of consistent test soils and sediments to be distributed
among all participating vendors and the referee laboratory
for analysis during the demonstration. Samples were
collected from the following four sites:
Carson River Mercury site (near Dayton, NV)
Y-12 National Security Complex (Oak Ridge, TN)
Manufacturing facility (eastern U.S.)
Puget Sound (Bellingham, WA)
The field samples collected during the pre-demonstration
sampling events comprised a variety of matrices, ranging
from material having a high clay content, to material
composed mostly of gravelly, coarse sand. The field
samples also differed with respect to moisture content;
several were collected as wet sediments. Table 4-3 shows
the number of distinct field samples that were collected
from each of the four field sites.
Prior to the start of the demonstration, the field samples
selected for analysis during the demonstration were
processed at the SAIC GeoMechanics Laboratory in Las
Vegas, NV. The specific sample homogenization
procedure used by this laboratory largely depended on the
moisture content and physical consistency of the sample.
Two specific sample homogenization procedures were
developed and tested by SAIC at the GeoMechanics
Laboratory during the pre-demonstration portion of the
project. The methods included a non-slurry sample
procedure and a slurry sample procedure.
A standard operating procedure (SOP) was developed
detailing both methods. The procedure was found to be
satisfactory, based upon the results of replicate samples
during the pre-demonstration. This SOP is included as
Appendix A of the Field Demonstration Quality Assurance
Project Plan (SAIC, August 2003, EPA/600/R-03/053).
Figure 4-1 summarizes the homogenization steps of the
SOP, beginning with sample mixing. This procedure was
21
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used for preparing both pre-demonstration and
demonstration samples. Prior to the mixing process (i.e.,
Step 1 in Figure 4-1), all field samples being processed
were visually inspected to ensure that oversized materials
were removed, and that there were no clumps that would
hinderhomogenization. Non-slurry samples were air-dried
in accordance with the SOP, so that they could be passed
multiple times through a riffle splitter. Due to the high
moisture content of many of the samples, they were not
easily air-dried and could not be passed through a riffle
splitter while wet. Samples with very high moisture
contents, termed "slurries," were not air-dried, and
bypassed the riffle splitting step. The homogenization
steps for each type of matrix are briefly summarized, as
follows.
Table 4-3. Field Samples Collected from the Four Sites
No. of Samples / Matrices
Field Site Collected Areas For Collecting Sample Material
Volume Required
Carson River
Y-12
Manufacturing Site
Puget Sound
12 Soil
6 Sediment
10 Sediment
6 Soil
12 Soil
4 Sediment
Tailings Piles (Six Mile Canyon)
River Bank Sediments
Poplar Creek Sediments
Old Mercury Recovery Bldg. Soils
Subsurface Soils
High-Level Mercury (below cap)
Low-Level Mercury (native material)
4 L each for soil
12 L each for sediment
12 L each for sediment
4 L each for soil
4 L each
1 2 L each
Preparing Slurry Matrices
For slurries (i.e., wet sediments), the mixing steps were
sufficiently thorough that the sample containers could be
filled directly from the mixing vessel. There were two
separate mixing steps for the slurry-type samples. Each
slurry was initially mixed mechanically within the sample
container (i.e., bucket) in which the sample was shipped to
the SAIC GeoMechanics Laboratory. A subsample of this
premixed sample was transferred to a second mixing
vessel. A mechanical drill equipped with a paint mixing
attachment was used to mix the subsample. As shown in
Figure 4-1, slurry samples bypassed the sample riffle
splitting step. To ensure all sample bottles contained the
same material, the entire set of containers to be filled was
submerged into the slurryas a group. The filled vials were
allowed to settle for a minimum of two days, and the
standing water was removed using a Pasteur pipette. The
removal of the standing waterfrom the slurry samples was
the only change to the homogenization procedure between
the pre-demonstration and the demonstration.
Preparing "Non-Slurry" Matrices
Soils and sediments having no excess moisture were
initially mixed (Step 1) and then homogenized in the
sample riffle splitter (Step 2). Prior to these steps, the
material was air-dried and subsampled to reduce the
volume of material to a size that was easier to handle.
As shown in Figure 4-1 (Step 1) the non-slurry subsample
was manually stirred with a spoon or similar equipment
until the material was visually uniform. Immediately
following manual mixing, the subsample was mixed and
split six times for more complete homogenization (Step 2).
After the sixth and final split, the sample material was
leveled to form a flattened, elongated rectangle and cut into
transverse sections to fill the containers (Steps 3 and 4).
After homogenization, 20-mL sample vials were filled and
prepared for shipment (Step 5).
For the demonstration, the vendor analyzed 197 samples,
which included replicates of up to 7 samples per sample
lot. The majority of the samples distributed had
concentrations within the range of the vendor's tech no logy.
Some samples had expected concentrations at or below
the estimated level of detection for each of the vendor
instruments. These samples were designed to evaluate
the reported MDL and PQL and also to assess the
prevalence of false positives. Field samples distributed to
the vendor included sediments and soils collected from all
four sites and prepared by both the slurry and dry
homogenization procedures. The field samples were
segregated into broad sample sets: low, medium, and high
mercury concentrations. This gave the vendor the same
general understanding of the sample to be analyzed as
they would typically have for field application of their
instrument.
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Test material mixed until
visually uniform
For non-slurries
Mix manually
a) Mix mechanically the entire
sample volume
b) Subsample slurry, transfer to
mixing vessel, and mix
mechanically
r
Slurries transferred
directly to 20 ml_ vials
(vials submerged into slurry)
Non-slurries to
riffle splitter
Combined splits
are reintroduced
into splitter (6 X)
\ /
Transfer cut
sections to
20 ml_ vials
zn
TEFLON SURFACE
Elongated
rectangular pile
(from6 ** split)
Sample aliquots made
by transverse cuts
across sample piles
1
Samples shipped @ 4 °C to
referee lab and Oak Ridge
(Container numbers will vary)
Figure 4-1. Test sample preparation at the SAIC GeoMecharries Laboratory.
23
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In addition, selected field samples were spiked with
mercury (II) chloride to generate samples with additional
concentrations and test the ability of the vendor's
instrumentation to measure the additional species of
mercury. Specific information regarding the vendor's
sample distribution is included in Chapter 6.
4.3.1.2 Standard Reference Materials
Certified SRMs were analyzed by both the vendors and the
referee laboratory. These samples were homogenized
matrices which had a known concentration of mercury.
Concentrations were certified values, as provided by the
supplier, based on independent confirmation via multiple
analyses of multiple lots and/or multiple analyses by
different laboratories (i.e., round robin testing). These
analytical results were then used to determine "true"
values, as well as a statistically derived intervals (a 95%
prediction interval) that provided a range within which the
true values were expected to fall.
The SRMs selected were designed to encompass the
same contaminant ranges indicated previously: low-,
medium-, and high-level mercury concentrations. In
addition, SRMs of varying matrices were included in the
demonstration to challenge the vendor technology as well
as the referee laboratory. The referee laboratory analyzed
all SRMs. SRM samples were intermingled with site field
samples and labeled in the same manner as field samples.
4.3.1.3 Spiked Field Samples
Spiked field samples were prepared by the SAIC
GeoMechanics Laboratory using mercury (II) chloride.
Spikes were prepared using field samples from the
selected sites. Additional information was gained by
preparing spikes at concentrations not previously
obtainable. The SAIC GeoMechanics Laboratory's ability
to prepare spikes was tested prior to the demonstration
and evaluated in order to determine expected variability
and accuracyof the spiked sample. The spiking procedure
was evaluated by preparing several different spikes using
two different spiking procedures (dry and wet). Based
upon replicate analyses results, it was determined that the
wet, or slurry, procedure was the only effective method of
obtaining a homogeneous spiked sample.
4.3.2 Sample Management
4.3.2.1 Sample Volumes, Containers,and Preservation
A subset from the pre-demonstration field samples was
selected for use in the demonstration based on the
sample's mercury concentration range and sample type
(i.e., sediment versus soil). The SAIC GeoMechanics
Laboratory prepared individual batches of field sample
material to fill sample containers for each vendor. Once all
containers from a field sample were filled, each container
was labeled and cooled to 4 °C. Because mercury
analyses were to be performed both by the vendors in the
field and by the referee laboratory, adequate sample size
was taken into account. Minimum sample size
requirements for the vendors varied from 0.1 g or less to
8-10 g. Only the referee laboratory analyzed separate
sample aliquots for parameters otherthan mercury. These
additional parameters included arsenic, barium, cadmium,
chromium, lead, selenium, silver, copper, zinc, oil and
grease, and total organic carbon (TOC). Since the mercury
method (SW-846 7471B) being used by the referee
laboratory requires 1 g for analysis, the sample size sent to
all participants was a 20-mL vial (approximately 10 g),
which ensured a sufficient volume and mass for analysis
by all vendors.
4.3.2.2 Sample Labeling
The sample labeling used for the 20-mL vials consisted of
an internal code developed by SAIC. This "blind" code was
used throughout the entire demonstration. The only
individuals who knew the key to the coding of the
homogenized samples to the specific field samples were
the SAIC TOM, the SAIC GeoMechanics Laboratory
Manager, and the SAIC QA Manager.
4.3.2.3 Sample Record Keeping, Archiving, and
Custody
Samples were shipped to the laboratory and the
demonstration site the week prior to the demonstration. A
third set of vials was archived at the SAIC GeoMechanics
Laboratory as reserve samples.
The sample shipment to Oak Ridge was retained at all
times in the custody of SAIC at their Oak Ridge office until
arrival of the demonstration field crew. Samples were
shipped under chain-of-custody (COC) and with custody
seals on both the coolers and the inner plastic bags. Once
the demonstration crew arrived, the coolers were retrieved
from the SAIC office. The custody seals on the plastic
bags inside the cooler were broken by the vendor upon
transfer.
Upon arrival at the ORNL site, the vendor set up the
instrumentation at the direction and oversight of SAIC. At
the start of sample testing, the vendor was provided with a
sample set representing field samples collected from a
particular field site, intermingled with SRM and spiked
samples. Due to variability of vendor instrument
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measurement ranges for mercury detection, not all vendors
received samples from the same field material. All
samples were stored in an ice cooler prior to demonstration
startup and were stored in an on-site sample refrigerator
during the demonstration. Each sample set was identified
and distributed as a set, with respect to the site from which
it was collected. This was done because, in any field
application, the location and general type of the samples
would be known.
The vendor was responsible for analyzing all samples
provided, performing any dilutions or reanalyses as
needed, calibrating the instrument if applicable, performing
any necessary maintenance, and reporting all results. Any
samples that were not analyzed during the day were
returned to the vendor for analysis at the beginning of the
next day. Once analysis of the samples from the first
location were completed by the vendor, SAIC provided a
set of samples from the second location. Samples were
provided at the time that they were requested by the
vendor. Once again, the transfer of samples was
documented using a chain-of-custody (COC) form.
This process was repeated forsamples from each location.
SAIC maintained custody of all remaining sample sets until
they were transferred to the vendor. SAIC maintained
custody of samples that already had been analyzed and
followed the waste handling procedures in Section 4.2.2 of
the Field Demonstration QAPP to dispose of these wastes.
4.4
Reference
Process
Method Confirmatory
The referee laboratory analyzed all samples that were
analyzed by the vendor technologies in the field. The
following subsections provide information on the selection
of the reference method, selection of the referee
laboratory, and details regarding the performance of the
reference method in accordance with EPA protocols.
Other parameters that were analyzed by the referee
laboratory are also discussed briefly.
4.4.1 Reference Method Selection
The selection of SW-846 Method 7471B as the reference
method was based on several factors, predicated on
information obtained from the technology vendors, as well
as the expected contaminant types and soil/sediment
mercury concentrations expected in the test matrices.
There are several laboratory-based, promulgated methods
for the analysis of total mercury. In addition, there are
several performance-based methods for the determination
of various mercury species. Based on the vendor
technologies, it was determined that a reference method
for total mercury would be needed (Table 1-2 summarizes
the methods evaluated, as identified through a review of
the EPA Test Method Index and SW-846).
In selecting which of the potential methods would be
suitable as a reference method, consideration was given to
the following questions:
Was the method widely used and accepted? Was the
method an EPA-recommended, or similar regulatory
method? The selected reference method should be
sufficiently used so that it could be cited as an
acceptable method for monitoring and/or permit
compliance among regulatory authorities.
Did the selected reference method provide QA/QC
criteria that demonstrate acceptable performance
characteristics over time?
Was the method suitable for the species of mercury
that were expected to be encountered? The reference
method must be capable of determining, as total
mercury, all forms of the contaminant known or likely
to be present in the matrices.
Would the method achieve the necessary detection
limits to evaluate the sensitivity of each vendor
technology adequately?
Was the method suitable for the concentration range
that was expected in the test matrices?
Based on the above considerations, itwas determined that
SW-846 Method 7471B (analysis of mercury in solid
samples by cold-vapor AAS) would be the best reference
method. SW-846 method 7474, (an atomic fluorescence
spectrometry method using Method 3052 for microwave
digestion of the solid) had also been considered a likely
technical candidate; however, because this method was
not as widely used or referenced, Method 7471B was
considered the better choice.
4.4.2 Referee Laboratory Selection
During the planning of the pre-demonstration phase of this
project, nine laboratories were sent a statement of work
(SOW) for the analysis of mercury to be performed as part
of the pre-demonstration. Seven of the nine laboratories
responded to the SOW with appropriate bids. Three of the
seven laboratories were selected as candidate laboratories
based upon technical merit, experience, and pricing.
These laboratories received and analyzed blind samples
and SRMs during pre-demonstration activities. The referee
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laboratory to be used for the demonstration was selected
from these three candidate laboratories. Final selection of
the referee laboratory was based upon: 1) the laboratory's
interest in continuing in the demonstration, 2) the
laboratory-reported SRM results, 3) the laboratory MDL for
the reference method selected, 4) the precision of the
laboratory calibration curve, 5) the laboratory's ability to
support the demonstration (scheduling conflicts, backup
instrumentation, etc.), and 6) cost.
One of the three candidate laboratories was eliminated
from selection based on a technical consideration. It was
determined that this laboratory would not be able to meet
demonstration quantitation limit requirements. (Its lower
calibration standard was approximately 50 ug/kg, and the
vendor comparison requirements were well below this
value.) Two candidates thus remained, including the
eventual demonstration laboratory, Analytical Laboratory
Services, Inc. (ALSI):
Analytical Laboratory Services, Inc.
Ray Martrano, Laboratory Manager
34 Dogwood Lane
Middletown, PA 17057
(717)944-5541
In order to make a final decision on selecting a referee
laboratory, a preliminary audit was performed by the SAIC
QA Manager at the remaining two candidate laboratories.
Results of the SRM samples were compared for the two
laboratories. Each laboratory analyzed each sample (there
were two SRMs) in triplicate. Both laboratories were within
the 95% prediction interval foreach SRM. In addition, the
average result from the two SRMs was compared to the
95% Cl for the SRM.
Calibration curves from each laboratory were reviewed
carefully. This included calibration curves generated from
previously performed analyses and those generated for
other laboratory clients. There were two QC requirements
regarding calibration curves; the correlation coefficient had
to be 0.995 or greater and the lowest point on the
calibration curve had to be within 10% of the predicted
value. Both laboratories were able to achieve these two
requirements for all curves reviewed and for a lower
standard of 10 ug/kg, which was the lower standard
required for the demonstration, based upon information
received from each of the vendors. In addition, an analysis
of seven standards was reviewed for MDLs. Both
laboratories were able to achieve an MDL that was below
1 ug/kg.
It should be noted that vendor sensitivity claims impacted
how low this lower quantitation standard should be. These
claims were somewhat vague, and the actual quantitation
limit each vendor could achieve was uncertain prior to the
demonstration (i.e., some vendors claimed a sensitivity as
low as 1 ug/kg, but it was uncertain at the time if this limit
was actually a PQLora detection limit). Therefore, it was
determined that, if necessary, the laboratory actually
should be able to achieve even alowerPQL than 10 ug/kg.
For both laboratories, SOPs based upon SW-846 Method
7471B were reviewed. Each SOP followed this reference
method. In addition, interferences were discussed
because there was some concern that organic
interferences may have been present in the samples
previously analyzed by the laboratories. Because these
same matrices were expected to be part of the
demonstration, there was some concern associated with
how these interferences would be eliminated. This is
discussed at the end of this subsection.
Sample throughput was somewhat important because the
selected laboratory was to receive all demonstration
samples at the same time (i.e., the samples were to be
analyzed at the same time in order to eliminate any
question of variability associated with loss of contaminant
due to holding time). This meant that the laboratory would
receive approximately 400 samples for analysis over the
period of a few days. It was also desirable for the
laboratory to produce a data report within a 21-day
turnaround time for purposes of the demonstration. Both
laboratories indicated that this was achievable.
Instrumentation was reviewed and examined at both
laboratories. Each laboratory used a Leeman mercury
analyzer for analysis. One of the two laboratories had
backup instrumentation in case of problems. Each
laboratory indicated that its Leeman mercury analyzer was
relatively new and had not been a problem in the past.
Previous SITE program experience was another factor
considered as partof these pre-audits. This is because the
SITE program generally requires a very high level of QC,
such that most laboratories are not familiar with the QC
required unless they have previously participated in the
program. A second aspect of the SITE program is that it
generally requires analysis of relatively "dirty" samples and
many laboratories are not use to analyzing such "dirty"
samples. Both laboratories have been longtime
participants in this program.
Other QC-related issues examined during the audits
included: 1) analyses of other SRM samples not previously
examined, 2) laboratory control charts, and 3) precision
26
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and accuracy results. Each of these issues was closely
examined. Also, because of the desire to increase the
representativeness of the samples for the demonstration,
each laboratory was asked if sample aliquot sizes could be
increased to 1 g (the method requirement noted 0.2 g).
Based upon previous results, both laboratories routinely
increased sample size to 0.5 g, and each laboratory
indicated that increasing the sample size would not be a
problem. Besides these QC issues, other less tangible QA
elements were examined. This included analyst
experience, management involvement in the
demonstration, and internal laboratory QA management.
These elements were also factored into the final decision.
Selection Summary
There were very few factors that separated the quality of
these two laboratories. Both were exemplary in performing
mercury analyses. There were, however, some minor
differences based upon this evaluation that were noted by
the auditor. These were as follows:
ALSI had backup instrumentation available. Even
though neither laboratory reported any problems with
its primary instrument (the Leeman mercury analyzer),
ALSI did have a backup instrument in case there were
problems with the primary instrument, or in the event
that the laboratory needed to perform other mercury
analyses during the demonstration time.
As noted, the low standard requirement for the
calibration curve was one of the QC requirements
specified for this demonstration in order to ensure that
a lower quantitation could be achieved. This low
standard was 10 ug/kg for both laboratories. ALSI,
however, was able to show experience in being able to
calibrate much lower than this, using a second
calibration curve. In the event that the vendor was
able to analyze at concentrations as low as 1 ug/kg
with precise and accurate determinations, ALSI was
able to perform analyses at lower concentrations as
part of the demonstration. ALSI used a second, lower
calibration curve for any analyses required below 0.05
mg/kg. Very few vendors were able to analyze
samples at concentrations at this low a level.
Management practices and analyst experience were
similar at both laboratories. ALSI had participated in a
few more SITE demonstrations than the other
laboratory, but this difference was not significant
because both laboratories had proven themselves
capable of handling the additional QC requirements for
the SITE program. In addition, both laboratories had
internal QA management procedures to provide the
confidence needed to achieve SITE requirements.
Interferences for the samples previously analyzed were
discussed and data were reviewed. ALSI performed
two separate analyses for each sample. This included
analyses with and without stannous chloride.
(Stannous chloride is the reagent used to release
mercury into the vapor phase for analysis. Sometimes
organics can cause interferences in the vapor phase.
Therefore, an analysis with no stannous chloride would
provide information on organic interferences.) The
other laboratory did not routinely perform this analysis.
Some samples were thought to contain organic
interferences, based on previous sample results. The
pre-demonstration results reviewed indicated that no
organic interferences were present. Therefore, while
this was thought to be a possible discriminator
between the two laboratories in terms of analytical
method performance, it became moot for the samples
included in this demonstration.
The factors above were considered in the final evaluation.
Because there were only minor differences in the technical
factors, cost of analysis was used as the discriminating
factor. (If there had been significant differences in
laboratory quality, cost would not have been a factor.)
ALSI was significantly lower in cost than the other
laboratory. Therefore, ALSI was chosen as the referee
laboratory for the demonstration.
4.4.3 Summary of Analytical Methods
4.4.3.1 Summary of Reference Method
The critical measurement forthis study was the analysis of
mercury in soil and sediment samples. Samples analyzed
by the laboratory included field samples, spiked field
samples, and SRM samples. Detailed laboratory
procedures for subsampling, extraction, and analysis were
provided in the SOPs included as Appendix B of the Field
Demonstration QAPP. These are briefly summarized
below.
Samples were analyzed for mercury using Method 7471 B,
a cold-vapor atomic absorption method, based on the
absorption of light at the 253.7-nm wavelength by mercury
vapor. The mercury is reduced to the elemental state and
stripped/volatilized from solution in a closed system. The
mercury vapor passes through a cell positioned in the light
path of the AA spectrophotometer. Absorbance (peak
height) is measured as a function of mercury
concentration. Potassium permanganate is added to
eliminate possible interference from sulfide. As per the
27
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method, concentrations as high as 20 mg/kg of sulfide, as
sodium sulfide, do not interfere with the recovery of added
inorganic mercury in reagent water. Copper has also been
reported to interfere; however, the method states that
copper concentrations as high as 10 mg/kg had no effect
on recovery of mercury from spiked samples. Samples
high in chlorides require additional permanganate (as much
as 25 ml_) because, during the oxidation step, chlorides are
converted to free chlorine, which also absorbs radiation of
254 nm. Free chlorine is removed by using an excess (25
ml_) of hydroxylamine sulfate reagent. Certain volatile
organic materials that absorb at this wavelength may also
cause interference. A preliminary analysis without
reagents can determine if this type of interference is
present.
Prior to analysis, the contents of the sample container are
stirred, and the sample mixed prior to removing an aliquot
for the mercury analysis. An aliquot of soil/sediment (1 g)
is placed in the bottom of a biochemical oxygen demand
bottle, with reagent water and aqua regia added. The
mixture is heated in a water bath at 95 °C for 2 minutes.
The solution is cooled and reagent water and potassium
permanganate solution are added to the sample bottle.
The bottle contents are thoroughly mixed, and the bottle is
placed in the water bath for 30 minutes at 95 °C. After
cooling, sodium chloride-hydroxylamine sulfate is added to
reduce the excess permanganate. Stannous chloride is
then added and the bottle attached to the analyzer; the
sample is aerated and the absorbance recorded. An
analysis without stannous chloride is also included as an
interference check when organic contamination is
suspected. In the event of positive results of the non-
stannous chloride analysis, the laboratory was to report
those results to SAIC so that a determination of organic
interferences could be made.
4.4.3.2 Summary of Methods for Non-Critical
Measurements.
A selected set of non-critical parameters was also
measured during the demonstration. These parameters
were measured to provide a better insightinto the chemical
constituency of the field samples, including the presence of
potential interferents. The results of the tests for potential
interferents were reviewed to determine if a trend was
apparent in the event that inaccuracy or low precision was
observed. Table 4-4 presents the analytical method
reference and method type for these non-critical
parameters.
Table 4-4. Analytical Methods for Non-Critical Parameters
Parameter
Method Reference Method Type
Arsenic, barium,
cadmium,
chromium, lead,
selenium, silver,
copper, and zinc
SW-846 3050/6010 Acid digestion, ICP
Oil and Grease
TOC
Total Solids
EPA 1664
SW-846 9060
EPA 2540G
n-Hexane
extraction,
Gravimetric
analysis
Carbonaceous
analyzer
Gravimetric
4.5 Deviations from
Plan
the Demonstration
There was one deviation to the demonstration plan. The
samples were distributed to Ohio Lumex by site (Carson
River, Oak Ridge, etc.) as planned; however, due to the
potential for memory effects, Ohio Lumex analyzed the
high concentration samples from all sites prior to analyzing
the low concentration samples for any of the sites.
Additionally, Ohio Lumex was able to complete allanalyses
during the demonstration; however, they were unable to
locate the results for one data point, and therefore,
provided data for 196 samples prior to leaving the
demonstration site.
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Chapter 5
Assessment of Laboratory Quality Control Measurements
5.1 Laboratory QA Summary
QA may be defined as a system of activities, the purpose
of which is to provide assurance that defined standards of
quality are met with a stated level of confidence. A QA
program is a means of integrating the quality planning,
quality assessment, QC, and quality improvement efforts
to meet user requirements. The objective of the QA
program is to reduce measurement errors to agreed-upon
limits, and to produce results of acceptable and known
quality. The QAPP specified the necessary guidelines to
ensure that the measurement system for laboratory
analysis was in control, and provided detailed information
on the analytical approach to ensure that data of high
quality could be obtained to achieve project objectives.
The laboratory analyses were critical to project success, as
the laboratory results were used as a standard for
comparison to the field method results. The field methods
are of unknown quality, and therefore, for comparison
purposes the laboratory analysis needed to be a known
quantity. The following sections provide information on the
use of data quality indicators, and a detailed summary of
the QC analyses associated with project objectives.
5.2 Data Quality Indicators for Mercury
Analysis
To assess the quality of the data generated by the referee
laboratory, two important data quality indicators of primary
concern are precision and accuracy. Precision can be
defined as the degree of mutual agreement of independent
measurements generated through repeated application of
the process under specified conditions. Accuracy is the
degree of agreement of a measured value with the true or
expected value. Both accuracy and precision were
measured by the analysis of matrix spike/matrix spike
duplicates (MS/MSDs). The precision of the spiked
duplicates is evaluated by expressing, as a percentage, the
difference between results of the sample and sample
duplicate results. The relative percent difference (RPD) is
calculated as:
(Maximum Value - Minimum Value)
(Maximum Value -(-Minimum Value)/2
To determine and evaluate accuracy, known quantities of
the target analytes were spiked into selected field samples.
All spikes were post-digestion spikes because of the high
sample concentrations encountered during the
demonstration. Pre-digestion spikes, on high-
concentration samples would either have been diluted or
would have required additional studies to determine the
effect of spiking more analyte and subsequent recovery
values. To determine matrix spike recovery, and hence
measure accuracy, the following equation was applied:
%R=
C
x100
where,
Css = Analyte concentration in spiked
sample
Cus = Analyte concentration in unspiked
sample
Csa = Analyte concentration added to
sample
Laboratory control samples (LCSs) were used as an
additional measure of accuracy in the event of significant
29
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matrix interference. To determine the percent recovery of
LCS analyses, the equation below was used:
„,,_. Measured Concentration .__
%R = xi 00
Theoretical Concentration
While several precautions were taken to generate data of
known quality through control of the measurement system,
the data must also be representative of true conditions and
comparable to separate sample aliquots.
Representativeness refers to the degree with which
analytical results accurately and precisely reflect actual
conditions present at the locations chosen for sample
collection. Representativeness was evaluated as part of
the pre-demonstration and combined with the precision
measurement in relation to sample aliquots. Sample
aliquoting by the SAIC GeoMechanics Laboratory tested
the ability of the procedure to produce homogeneous,
representative, and comparable samples. All samples
were carefully homogenized in order to ensure
comparability between the laboratory and the vendor.
Therefore, the RSD measurement objective of 25% or less
for replicate sample lotanalysis was intended to assess not
only precision but representativeness and comparability.
Sensitivity was another critical factor assessed for the
laboratory method of analysis. This was measured as a
practical quantitation limit and was determined by the low
standard on the calibration curve. Two separate calibration
curves were run by the laboratory when necessary. The
higher calibration curve was used for the majority of the
samples and had a lower calibration limit of 25 ug/kg. The
lower calibration curve was used when samples were
below this lowercalibration standard. The lowercalibration
curve had a lower limit standard of 5 ug/kg. The lower limit
standard of the calibration curve was run with each sample
batch as a check standard and was required to be within
10% of the true value (QAPP QC requirement). This
additional check on analytical sensitivity was performed to
ensure that this lower limit standard was truly
representative of the instrument and method practical
quantitation limit.
5.3 Conclusions and Data Quality
Limitations
Critical sample data and associated QC analyses were
reviewed to determine whether the data collected were of
adequate quality to provide proper evaluation of the
project's technical objectives. The results of this review
are summarized below.
Accuracy objectives for mercury analysis by Method 7471B
were assessed by the evaluation of 23 spiked duplicate
pairs, analyzed in accordance with standard procedures in
the same manner as the samples. Recovery values for the
critical compounds were well within objectives specified in
the QAPP, except for two spiked samples summarized in
Table 5-1. The results of these samples, however, were
only slightly outside specified limits, and given the number
of total samples (46 or 23 pairs), this is an insignificant
number of results that did not fa II within specifications. The
MS/MSD results therefore, are supportive of the overall
accuracy objectives.
Table 5-1. MS/MSD Summary
Parameter Value
QC Limits
Recovery Range
Number of Duplicate Pairs
Average Percent Recovery
No. of Spikes Outside QC
Specifications
80%- 120%
85.2%- 126%
23
108%
An additional measure of accuracywas LCSs. These were
analyzed with every sample batch (1 in 20 samples) and
results are presented in Table 5-2. All results were within
specifications, thereby supporting the conclusion that QC
assessment met project accuracy objectives.
Table 5-2. LCS Summary
Parameter
QC Limits
Recovery Range
Number of LCSs
Average Percent Recovery
No. of LCSs Outside QC
Specifications
Value
90%- 110%
90% -100%
24
95.5%
0
Precision was assessed through the analysis of 23
duplicate spike pairs for mercury. Precision specifications
were established prior to the demonstration as a RPD less
30
-------
than 20%. All but two sample pairs were within
specifications, as noted in Table 5-3. The results of these
samples, however, were only slightly outside specified
limits, and given the number of total samples (23 pairs),
this is an insignificant number of results that did not fall
within specifications. Therefore, laboratory analyses met
precision specifications.
Table 5-3. Precision Summary
Parameter Value
QC Limits
MS/MS D RPD Range
Number of Duplicate Pairs
Average MS/MSD RPD
No. of Pairs Outside QC
Specifications
RPD<
0.0%
23
5.7%
2
20%
to 25%
Sensitivity results were within specified project objectives.
The sensitivity objective was evaluated as the PQL, as
assessed by the low standard on the calibration curve. For
the majority of samples, a calibration curve of 25-500 ug/kg
was used. This is because the majority of samples fell
within this calibration range (samples often required
dilution). There were, however, some samples below this
range and a second curve was used. The calibration range
for this lower curve was 5-50 ug/kg. In order to ensure that
the lower concentration on the calibration curve was a true
PQL, the laboratory ran a low check standard (lowest
concentration on the calibration curve) with every batch of
samples. This standard was required to be within 10% of
the specified value. The results of this low check standard
are summarized in Table 5-4.
Table 5-4. Low Check Standards
Parameter Value
QC Limits
Recovery Range
Number of Check Standards
Analyzed
Average Recovery
Recovery 90% - 110%
88.6%-111%
23
96%
There were a few occasions where this standard did not
meet specifications. The results of these samples,
however, were only slightly outside specified limits, and
given the number of total samples (23), this is an
insignificant number of results that did not fall within
specifications. In addition, the laboratory reanalyzed the
standard when specifications were not achieved, and the
second determination always fell within the required limits.
Therefore laboratory objectives for sensitivity were
achieved according to QAPP specifications.
As noted previously, comparabilityand representativeness
were assessed through the analysis of replicate samples.
Results of these replicates are presented in the discussion
on primary project objectives for precision. These results
show that data were within project and QA objectives.
Completeness objectives were achieved for the project. All
samples were analyzed and data were provided for 100%
of the samples received by the laboratory. No sample
bottles were lost or broken.
Other measures of data quality included method blanks,
calibration checks, evaluation of linearity of the calibration
curve, holding time specifications, and an independent
standard verification included with each sample batch.
These results were reviewed for every sample batch run by
ALSI, and were within specifications. In addition, 10% of
the reported results were checked against the raw data.
Raw data were reviewed to ensure that sample results
were within the calibration range of the instrument, as
defined by the calibration curve. A 6-point calibration curve
was generated at the start of each sample batch of 20. A
few data points were found to be incorrectly reported.
Recalculations were performed for these data, and any
additional data points that were suspected outliers were
checked to ensure correct results were reported. Veryfew
calculation or dilution errors were found. All errors were
corrected so that the appropriate data were reported.
Another measure of compliance were the non-stannous
chloride runs performed by the laboratory for every sample
analyzed. This was done to check for organic interference.
There were no samples that were found to have any
organic interference by this method. Therefore, these
results met expected QC specifications and data were not
qualified in any fashion.
Total solids data were also reviewed to ensure that
calculations were performed appropriatelyand dry weights
reported when required. All of these QC checks met
31
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QAPP specifications. In summary, all data quality
indicators and QC specifications were reviewed and found
to be well within project specifications. Therefore, the data
are considered suitable for purposes of this evaluation.
5.4 Audit Findings
The SAIC SITE QA Manager conducted audits of both field
activities and of the subcontracted laboratory as part of the
QA measures for this project. The results of these
technical system reviews are discussed below.
The field audit resulted in no findings or non-
conformances. The audit performed at the subcontract
laboratory was con ducted during the time of project sample
analysis. One non-conformance was identified and
corrective action was initiated. It was discovered that the
laboratory PQL was not meeting specifications due to a
reporting error. The analyst was generating the calibration
curves as specified above; however, the lower limit on the
calibration curve was not being reported. This was
immediately rectified and no other findings or non-
conformances were identified.
32
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Chapter 6
Performance of the RA-915+/RP-91C
Ohio Lumex analyzed 197 samples from May 5-8, 2003 in
Oak Ridge, TN. Results for these samples were reported
by Ohio Lumex, and a statisticalevaluation was performed.
Additionally, the observations made during the
demonstration were reviewed, and the remaining primary
and secondary objectives were completed. The results of
the primary and secondary objectives, identified in Chapter
1, are discussed in Sections 6.1 and 6.2, respectively.
The distribution of the samples prepared for Ohio Lumex
and the referee laboratory is presented in Table 6-1. From
the four sites, Ohio Lumex received samples at 36 different
concentrations for a total of 197 samples. These 197
samples consisted of 22 concentrations in replicates of 7,
1 concentration in replicate of 4, and 1 3 concentrations in
replicates of 3.
Table 6-1. Distribution of Samples Prepared for Ohio Lumex and the Referee Laboratory
Site
Concentration Range
Soil
Sediment
Sample Type
Spiked Soil
SRM
Carson River
(Subtotal = 62)
Puget Sound
(Subtotal = 67)
Oak Ridge
(Subtotal = 51)
Manufacturing
(Subtotal = 17)
Subtotal
(Total = 197)
Low(1-500ppb)
Mid (0.5-50 ppm)
High (50->1, 000 ppm)
Low (1 ppb - 10 ppm)
High (10-500 ppm)
Low (0.1 -10 ppm)
High (10-800 ppm)
General (5-1,000 ppm)
3
0
0
30
0
10
3
10
56
10
0
0
0
3
7
6
0
26
7
7
0
14
7
7
0
0
42
7
28
0
13
0
14
4
7
73
6.1 Primary Objectives
6.1.1 Sensitivity
Sensitivity objectives are explained in Chapter 4. The two
primary sensitivity evaluations performed for this
demonstration were the MDL and POL. Determinations of
these two measurements are explained in the paragraphs
below, along with a comparison to the referee laboratory.
These determinations set the standard for the evaluation of
accuracy and precision for the Ohio Lumex field
instrument. Any sample analyzed by Ohio Lumex and
subsequently reported as below their level ofdetection was
not used as part of any additional evaluations. This was
done because of the expectation that values below the
lower limit of instrument sensitivity would not reflect the true
instrument accuracy and precision.
The sensitivity measurements of MDL and POL are both
dependent upon the matrix and method. Hence, the MDL
and POL will vary, depending upon whether the matrix is a
soil, waste, or water. Only soils and sediments were tested
during this demonstration and therefore, MDL calculations
for this evaluation reflect soil and sediment matrices. POL
determinations are not independent calculations, but are
dependent upon results provided by the vendor for the
samples tested.
33
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Comparison of the MDLand PQLto laboratory sensitivity
required that a standard evaluation be performed for all
instruments tested during this demonstration. PQL, as
previously noted, is defined in EPA G-5i as the lowest level
of method and instrument performance with a specified
accuracy and precision. This is often defined by the lowest
point on the calibration curve. Our approach was to let the
vendorprovide thelowerlimitofquantitation asdetermined
by their particular standard operating procedure, and then
test this limit by comparing results of samples analyzed at
this low concentration to the referee laboratory results, or
comparing the results to a standard reference material, if
available. Comparison of these data are, therefore,
presented for the lowest concentration sample results, as
provided bythe vendor. If the vendor provided "non-detect"
results, then no formal evaluation of that sample was
presented. In addition, the sample(s) was not used in the
evaluation of precision and accuracy.
Method Detection Limit - The standard procedure for
determining MDLs is to analyze a low standard or
reference material seven times, calculate the standard
deviation and multiply the standard deviation by the "t"
value for seven measurements at the 99th percentile
(alpha = 0.01). (This value is 3.143 as determined from a
standard statistics table.) This procedure for determination
of an MDL is defined in 40 CFR Part 136, and while
determinations for MDLs may be defined differently for
other instruments, this method was previously noted in the
demonstration QAPP and is intended to provide a
comparison to other similar MDL evaluations. The purpose
is to provide a lower level of detection with a statistical
confidence at which the instrument will detectthe presence
of a substance above its noise level. There is no
associated accuracy or precision provided or implied.
Several blind standards and field samples were provided to
Ohio Lumex at their estimated lower limit of sensitivity.
The Ohio Lumex lower limit of sensitivity was previously
estimated at 0.005 mg/kg. Because there are several
different SRMs and field samples at concentrations close
to the MDL, evaluation of the MDL was performed using
more than a single concentration. Samples chosen for
calculation were based upon: 1) concentration and how
close it was to the estimated MDL, 2) number of analyses
performed for the same sample (e.g., more than 4), and 3)
if non-detects were reported by Ohio Lumex for a sample
used to calculate the MDL. Then the next highest
concentration sample was selected based upon the
premise that a non-detect result reported for one of several
samples indicates the selected sample is on the "edge" of
the instruments detection capability.
Seven replicates were analyzed by Ohio Lumex for a
sample that had a reported average concentration by the
referee laboratory of 0.06 mg/kg. (Sample lot 02 from the
Puget Sound site.) The average concentration reported by
Ohio Lumex for this sample was 0.072 mg/kg and the
standard deviation was 0.0135 mg/kg. An SRM with a
reference value of 0.017 mg/kg (sample lot 35) was
analyzed seven times by Ohio Lumex with a reported
average concentration of 0.0067 mg/kg and a standard
deviation of 0.0017 mg/kg. Calculations of the respective
MDLs based upon each of these standards are 0.042 and
0.0053 mg/kg.
As a further check of the MDL, sample lot 37 (SRM) had a
reference value of 0.1 58 mg/kg. Seven samples analyzed
by Ohio Lumex for this sample lot had a reported average
concentration of 0.196 mg/kg and a standard deviation of
0.0098 mg/kg. This results in a calculated MDL of 0.031
mg/kg, which falls between the values noted above.
Based upon these results it appears that the M DL for this
instrument is somewhere between 0.0053 and 0.042
mg/kg. The lowest standard analyzed by Ohio Lumex was
the SRM noted above (sample lot 35) with a reference
value of 0.017 mg/kg (which is close to the average MDL)
with a reported average concentration by Ohio Lumex of
0.0067 mg/kg. While the average result for this sample
has a percent difference (%D) of-63.5%, the sample was
easily detected by the Ohio Lumex field instrument, and is,
therefore, by definition within the range of the MDL.
Consequently, the estimated sensitivity provided by Ohio
Lumex of 0.005 mg/kg is a reasonable estimation of the
MDL for aqueous samples, assuming that some samples
will likely have matrix interferences and may result in a
slightly higher MDL. The calculated MDL for soils and
sediments is somewhere between 0.0053 and 0.042
mg/kg. The equivalent MDL for the referee laboratory is
0.0026 mg/kg. The calculated result is only intended as a
statistical estimation and not a true test of instrument
sensitivity.
Practical Quantitation Limit - This value is usually
calculated by determining a low standard on the instrument
calibration curve, and it is estimated as the lowest standard
at which the instrument will accurately and precisely
determine a given concentration within specified QC limits.
The PQL is often around 5-10 times the MDL. This PQL
estimation, however, is method- and matrix-dependent. In
order to determine the PQL, several low standards were
provided to Ohio Lumex, and subsequent %Ds were
calculated.
34
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The lower limit of sensitivity previously provided by the
vendor(0.005 mg/kg) appears to be close to their MDL, but
this would likely result in a higher instrument and method
PQL. The PQL should have a precision and accuracy that
matches the instrument capabilities within a certain
operating range of analysis. The relationship between
sensitivity and precision is such that the lower the
concentration, the higher the variation in reported sample
results. Five times the estimated MDL (estimated PQL)
would result in a value of 0.027 to 0.21 mg/kg. Therefore,
values in this range were chosen for estimating the PQL
and associated %D between the Ohio Lumex reported
average and the reference value if it is an SRM, or the
average value reported by the referee laboratory. Also
compared are the 95% CIs for additional descriptive
information.
The Ohio Lumex average result for the 0.017 mg/kg SRM
noted above (sample lot 35) was 0.0067 mg/kg. The
standard deviation was 0.0017 mg/kg and the 95% Cl is
0.0051 to 0.0083 mg/kg. The %D for this sample is-63.5%
and therefore this is clearly below the instrument PQL.
The Ohio Lumex average result for the 0.158 mg/kg SRM
(sample lot 37) was 0.196 mg/kg. The standard deviation
was 0.0098 mg/kg and the 95% Cl is 0.187 - 0.205 mg/kg.
The %D for this sample is 24.1%. This is a reasonable %D
for most analytical instrumentation and therefore within the
instrument's PQL.
The average result reported by the referee laboratory for
sample lot 02 was 0.06 mg/kg. The result reported by Ohio
Lumex for this same sample was 0.072 mg/kg. The
standard deviation was 0.0135 mg/kg. The %D for this
sample is 20%.
Sensitivity Summary
The low standard calculations using MDL values suggest
that a PQL for the Ohio Lumex field instrument may be as
low as 0.027 mg/kg. The referee laboratory PQL
confirmed during the demonstration is 0.005 mg/kg with a
%D of <10%. The %D for the average Ohio Lumex result
for the average referee laboratory value of 0.06 mg/kg is
0.072 mg/kg, with a %D of 20%. This was the lowest
sample concentration tested during the demonstration that
is close to the calculated PQL noted above.
The range for the calculated MDL is between 0.0053 and
0.042 mg/kg, based on the results of seven replicate
analyses for low standards. The equivalent MDL for the
referee laboratory is 0.0026 mg/kg. The MDL
determination, however, is only a statistical calculation that
has been used in the past by EPA, and is currently not
considered a "true" MDL by SW-846 methodology.
SW-846 is suggesting thatperformance-based methods be
used, and that PQLs be determined using low standard
calculations.
6.1.2 Accuracy
Accuracy is the instrument measurement compared to a
standard, or "true" value. For this demonstration, three
separate standards were used for determining accuracy.
The primary standard is SRMs. The SRMs are traceable
to national systems. These were obtained from reputable
suppliers with reported concentration and an associated
95% Cl and 95% prediction interval. The Cl from the
reference material is used as a measure of comparison
with Cl calculated from replicate analyses for the same
sample analyzed by the laboratory or vendor. Results are
considered comparable if CIs of the SRM overlap with the
CIs computed from the replicate analyses by the vendor.
While this is not a definitive measure of comparison, it
provides some assurance that the two values are
equivalent.
Prediction intervals are intended as a measure of
comparison for a single laboratory or vendor result with the
SRM. When computing a prediction interval, the equation
assumes an infinite number of analyses, and it is used to
compare individual sample results. A 95% prediction
interval would, therefore, predict the correct result from a
single analysis 95% of the time for an infinite number of
samples, if the result is comparable to that of the SRM. It
should be noted that the corollary to this statement is that
5% of the time a resultwill beoutside the prediction interval
if determined for an infinite number of samples. If several
samples are analyzed, the percentage of results within the
prediction interval will be slightly above or below 95%. The
more samples analyzed, the more likely the percentage of
correct results will be close to 95% if the result for the
method being tested is comparable to the SRM.
All SRMs were analyzed in replicates of three, four, or
seven by both the vendor and the referee laboratory. In
some instances, analyses performed by the vendor were
determined to be invalid measurements and were,
therefore, not included with the reported results. There
were nine different SRMs analyzed by both the vendor and
the laboratory, for a total of 57 data points by the vendor
and 62 data points by the laboratory. One specially
prepared SRM (sample lot 55) was not included, because
analyses performed by the vendor and the laboratory
suggested that the SRM value was in question. Because
this was a specially prepared SRM, and had somewhat
35
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less documentation in regards to the reference value, and
because both the referee laboratory and vendor results,
while statistically equivalent were statistically different from
the SRM value, this SRM was not included in the
evaluation.
The second accuracy determination used a comparison of
vendor results of field samples and SRMs to the referee
laboratory results for these same samples. Field samples
were used to ensure that "real-world" samples were tested
by the vendor. The referee laboratory result is considered
as the standard for comparison to the vendor result. This
comparison is in the form of a hypothesis test with alpha =
0.01. (Detailed equations along with additional information
aboutthis statisticalcomparison is included in Appendix B.)
It should be noted that there is evidence of a laboratory
bias. This bias was determined by comparing average
laboratory values to SRM reference values, and is
discussed below. The laboratory bias is low in comparison
to the reference value. A bias correction was not made
when comparing individual samples (replicate analyses)
between the laboratory and vendor; however, setting alpha
= 0.01 helps mitigate for this possible bias by widening the
range of acceptable results between the two data sets.
An aggregate analysis, or unified hypothesis test, was also
performed for all 33 sample lots. (A detailed discussion of
this statistical comparison is included in Appendix B.) This
analysis provides additional statistical evidence in relation
to the accuracy evaluation. A bias term is included in this
calculation in order to account for any data bias.
The third measure of accuracy is obtained by the analysis
of spiked field samples. These were analyzed by the
vendor and the laboratory in replicate in order to provide
additional measurement comparisons and are treated the
same as the other field samples. Spikes were prepared to
cover additional concentrations not available from SRMs or
field samples. There is no comparison to the spiked
concentration, only a comparison between the vendor and
the laboratory reported value.
The purpose for SRM analyses by the referee laboratory is
to provide a check on laboratory accuracy. During the
pre-demonstration, the referee laboratory was chosen, in
part, based upon the analysis of SRMs. This was done to
ensure that a competent laboratory would be used for the
demonstration. The pre-demonstration laboratory
qualification showed that the laboratory was within
prediction intervals for all SRMs analyzed. Because of the
need to provide confidence in laboratory analysis during the
demonstration, the referee laboratory also analyzed SRMs
as an ongoing check of laboratory bias. As noted in Table
6-3, not all laboratory results were within the prediction
interval. This is discussed in more detail below. All
laboratory QC checks, however, were found to be within
compliance (see Chapter 5).
Evaluation of vendor and laboratory analysis of SRMs is
performed in the following manner. Accuracy was
determined by comparing the 95% Cl of the sample
analyzed by the vendor and laboratory to the 95% Cl for
the SRM. (95% CIs around the true value are provided by
the SRM supplier.) This information is provided in Tables
6-2 and 6-3, with notations when the CIs overlap,
suggesting com parable results. In addition, the number of
SRM results forthe vendor's analytical instrumentation and
the referee laboratory that are within the associated 95%
prediction interval are reported. This is a more definitive
evaluation of laboratory and vendor accuracy. The
percentage of total results within the prediction interval for
the vendor and laboratory are reported in Tables 6-2 and
6-3, respectively.
The single most importantnumberfrom these tables is the
percentage of samples within the 95% prediction interval.
As noted for the Ohio Lumex data, this percentage is 93%,
with n = 57. This suggests that the Ohio Lumex data are
within expected accuracy accounting for statistical
variation. For five of the nine determinations, Ohio Lumex
average results are above the reference value. This would
suggest that there is no bias associated with the Ohio
Lumex data. Six of the nine sample groups overlap with
the 95% CIs calculated from the Ohio Lumex data,
compared to values provided by the supplier of the SRM.
This number is also suggestive of a reasonable
comparison to the SRM value, accounting for statistical
variation.
The percentage of samples within the 95% prediction
interval for the laboratory data is 87%. For 7 of the 9
determinations, ALSI average results are below the
reference value. This suggests that the ALSI data are
potentially biased low. Because of this bias, the
percentage of samples outside the prediction interval is
slightly below the anticipated number of results, given that
the number of samples analyzed (62) is relatively high.
Nonetheless, the referee laboratory data should be
considered accurate and not significantly different from the
SRM value. Because there is no bias correction term in
the individual hypothesis tests (Table 6-4), alpha is set at
0.01 to help mitigate for laboratory bias. This in effect
widens the scope of vendor data that would fall within an
acceptable range of the referee laboratory. Six of the nine
36
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sample groups overlap with the 95% CIs calculated from
the ALSI data, compared to values provided by the supplier
of the SRM. This number is also suggestive of a
Table 6-2. Ohio Lumex SRM Comparison
reasonable comparison to the SRM value accounting for
statistical variation.
Sample SRM Value/ 95% Cl
Lot No.
a
b
37
44
35
36
38
39
41
43
45
0.158/0.132-0.184
4.7/4.3-5.1
0.017/0.010-0.024
0.082/0.073-0.091
0.62/0.61 -0.63s
1.09/1. 06 -1.126
2.42/2.16-2.46
3.80/3.50-4.11
6.45 / 6.06 - 6.84
Total Samples
% of samples w/in
prediction interval
Ohio Lumex Avg./ 95% Cl
0.196/0.187-0.205
4.88 / 4. 72 -5. 03
0.0067/0.0051 -0.0083
0.071 / 0.062 -0.080
0.627 / 0.607- 0.647
1.07/ 1.01-1.13
2.01 / 1.68 -2. 37
3.64/3.33-3.95
8.14/8.02-8.26
Cl is estimated based upon n=30. A 95% prediction interval
Prediction interval is estimated
based upon n=30. A 95% Cl
Cl
Overlap
(ves/no)
no
yes
no
yes
yes
yes
yes
yes
no
was provided
was provided
No. of 95% Prediction Ohio Lumex No.
Samples Interval w/in Prediction
Analyzed
7
6
7
3
7
6
7
7
7
57
by the SRM
by the SRM
0-
3.0-
0-
0.035 -
0.545 -
0.94-
1.3-
2.41 -
4.83-
supplier but no Cl
0.357
6.4
0.0358 b
0.13 b
0.695
1.24
3.3
5.20
8.06
was given.
Interval
7
6
7
3
7
5
7
7
4
53
93%
supplier but no prediction interval was given.
Table 6-3. ALSI SRM Comparison
Sample SRM Value/ 95% Cl
Lot No.
37
44
35
36
38
39
41
43
45
a
b
0.158/0.132-0.184
4.7/4.3-5.1
0.017/0.010-0.024
0.082/0.073-0.091
0.62/0.61 -0.63"
1.09/ 1.06- 1.12"
2.42/2.16-2.46
3.80/3.50-4.11
6.45 / 6.06 - 6.84
Total Samples
% of samples w/in
prediction interval
Cl is estimated based upon n=30.
ALSI Avg./ 95% Cl
0.139/0.093-0.185
2.33 / 1.05-3.61
0.0087/0.0078-0.0096
0.073/0.068-0.078
0.628 / 0.606 - 0.650
1 .24 / 0.634 - 1 .85
1.79/1.29-2.29
2.76/2.51 -3.01
5.44/4.10-6.78
A 95% prediction interval
Prediction interval is estimated based upon n=30. A 95% Cl
Cl
Overlap
(ves/no)
yes
no
no
yes
yes
yes
yes
no
ves
was provided
was provided
No. of 95% Prediction ALSI No. w/in
Samples Interval Prediction
Analyzed
7
7
7
7
7
7
7
7
6
62
by the SRM
by the SRM
0-
3.0-
0-
0.035 -
0.545 -
0.94-
1.3-
2.41 -
4.83-
supplier but no Cl
0.357
6.4
0.0358 b
0.13 b
0.695
1.24
3.3
5.20
8.06
was given.
Interval
7
2
7
7
7
6
6
7
5
54
87%
supplier but no prediction interval was given.
Hypothesis Testing
Sample results from field and spiked field samples for the
vendor com pared to sim ilar tests by the referee laboratory
are used as another accuracy check. Spiked samples
were used to cover concentrations not found in the field
samples, and they are considered the same as the field
samples for purposes of comparison. Because of the
limited data available for determining the accuracy of the
spiked value, these were not considered the same as
reference standards. Therefore, these samples were
evaluated in the same fashion as field samples, but they
were not compared to individual spiked concentrations.
Using a hypothesis test with alpha = 0.01, vendor results
for all samples were compared to laboratory results to
determine if sample populations are the same or
significantly different. This was performed for each sample
lot separately. Because this test does not separate
precision from bias, if Ohio Lumex's or ALSI's computed
standard deviation was large due to a highly variable result
(indication of poor precision), the two CIs could overlap.
Therefore, the fact that there was no significant difference
between the two results could be due to high sample
variability. Accordingly, associated RSDs have also been
reported in Table 6-4 along with results of the hypothesis
testing for each sample lot.
37
-------
Table 6-4. Accuracy Evaluation by Hypothesis Testing
Sample Lot No./ Site
03/ Oak Ridge
Ohio Lumex
ALSI
09/ Oak Ridge
Ohio Lumex
ALSI
14/ Oak Ridge
Ohio Lumex
ALSI
21/ Oak Ridge
Ohio Lumex
ALSI
241 Oak Ridge
Ohio Lumex
ALSI
261 Oak Ridge
Ohio Lumex
ALSI
371 Oak Ridge
Ohio Lumex
ALSI
441 Oak Ridge
Ohio Lumex
ALSI
60/ Oak Ridge
Ohio Lumex
ALSI
021 Puget Sound
Ohio Lumex
ALSI
05/ Puget Sound
Ohio Lumex
ALSI
08/ Puget Sound
Ohio Lumex
ALSI
10/ Puget Sound
Ohio Lumex
ALSI
11/ Puget Sound
Ohio Lumex
ALSI
12/ Puget Sound
Ohio Lumex
ALSI
251 Puget Sound
Ohio Lumex
ALSI
34/ Puget Sound
Ohio Lumex
ALSI
36/ Puget Sound
Ohio Lumex
ALSI
571 Puget Sound
Ohio Lumex
ALSI
Avg. Cone.
mg/kg
0.317
0.260
0.497
0.466
7.86
4.75
17.3
11.2
197
221
97.7
77.0
0.196
0.139
4.88
2.33
149
165
0.062
0.06
0.267
0.21
0.52
0.36
1.76
0.55
1.31
0.81
1.4
1.08
41.3
16.6
117
11.3
0.071
0.07
1.03
0.73
RSD or CV
4.8%
3.8%
23.2%
34.2%
32.0%
27.5%
23.3%
23.8%
28.0%
44.8%
2.6%
13.2%
5.0%
36.4%
3.0%
59.4%
23.8%
30.9%
43.9%
23.6%
9.4%
33.3 %
14.2%
13.4%
120%
20.5%
14.2%
32.7%
7.2%
2.8%
12.4%
12.3%
24.7%
23.4%
4.9%
6.7%
1 1 .2%
16.2%
Number of
Measurements
3
3
7
7
7
7
3
3
3
7
3
7
7
7
6
7
7
7
7
4
3
3
7
7
3
3
7
7
3
3
3
3
3
7
3
7
7
7
Significantly Different at
Alpha = 0.01
yes
no
yes
no
no
yes
no
no
no
no
no
yes
no
yes
no
yes
no
no
yes
Relative Percent
Difference (Ohio
Lumex to ALSI)
19.8%
6.4%
49.3%
42.8%
-1 1 .5%
23.7%
34.0%
70.7%
-10.2%
3.3 %
23.9%
36.4%
105%
47.2%
25.8%
85.3%
165%
1 .4%
34.1%
38
-------
Sample Lot No./ Site
61/ Puget Sound
Ohio Lumex
ALSI
621 Puget Sound
Ohio Lumex
ALSI
01 / Carson River
Ohio Lumex
ALSI
041 Carson River
Ohio Lumex
ALSI
06/ Carson River
Ohio Lumex
ALSI
38/ Carson River
Ohio Lumex
ALSI
39/ Carson River
Ohio Lumex
ALSI
41 / Carson River
Ohio Lumex
ALSI
431 Carson River
Ohio Lumex
ALSI
56/ Carson River
Ohio Lumex
ALSI
59/ Carson River
Ohio Lumex
ALSI
13/ Manufacturing Site
Ohio Lumex
ALSI
Ml Manufacturing Site
Ohio Lumex
ALSI
451 Manufacturing Site
Ohio Lumex
ALSI
Avg. Cone.
mg/kg
154
200
23.7
14.6
0.29
0.24
0.13
0.11
0.29
0.26
0.63
0.63
1.07
1.24
2.01
1.79
3.64
2.76
0.22
0.23
1.91
1.71
10.2
5.91
15.7
10.5
8.14
5.44
RSD or CV
47.0%
10.9%
13.0%
28.3%
30.5%
37.8%
18.9%
9.1%
7.3%
15.7%
3.5%
3.8%
6.5%
52.9%
17.5%
30.5%
9.1%
9.6%
8.0%
12.6%
10.2%
7.9%
51.9%
15.4%
24.2%
14.6%
1.6%
23.4%
Number of
Measurements
7
7
7
7
7
7
3
7
3
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
3
7
7
6
Significantly Different at
Alpha = 0.01
no
yes
no
no
no
no
no
no
yes
no
no
no
no
no
Relative Percent
Difference (Ohio
Lumex to ALSI)
-26.0%
47.5%
21 .5%
18.9%
10.3%
-0.2%
-14.7%
1 1 .6%
27.5%
5.2%
11.1%
53.3%
39.7%
39.8%
CV = Coefficient of variance
Of the 33 sample lots, 9 results are significantly different
based upon the hypothesis test noted above. Most of the
relative percent differences are positive, which indicates
that the Ohio Lumex result is generally higher than the
laboratory result. This is indicative of the previously noted
low bias associated with the laboratory data. There are
some Ohio Lumex results that are less than the laboratory
result, therefore, no overall Ohio Lumex high or low bias
is apparent. It appears that Ohio Lumex data are subject
to more random variability.
In determining the number of results significantly above or
below the value reported by the referee laboratory, 19 of 33
Ohio Lumex average results were found to have RPDs less
than 30% for sample concentrations above the estimated
POL. Only two of 33 Ohio Lumex average results have
RPDs greater than 100% for this same group of samples
(see Table 6-5). Interferences may be a problem but,
because of the random variability associated with the data,
no interferences are specifically apparent from the data
collected. Table 6-6 shows the results of additional data
collected for these same samples.
39
-------
Table 6-5. Number of Sample Lots Within Each %D Range
<30% >30%, <50%
>50%, <100%
>100%
Total
Positive %D 14
Negative %D 5
Total 19
Only those sample lots with the average
9
0
9
3
0
3
2
0
2
28
5
33
result greater than the PQL are tabulated.
Table 6-6. Concentration (in mg/kg) of Non-Target Analytes
Lot* Site TOC O&G Ad As Ba
1 Carson River 870
2 Puget Sound 3500
3 Oak Ridge 2300
4 Carson River 2400
5 Puget Sound 3500
6 Carson River 7200
8 Puget Sound 8100
9 Oak Ridge 3300
10 Puget Sound 4200
11 Puget Sound 3800
12 Puget Sound 3500
13 Manufacturing Site 3200
14 Oak Ridge 7800
17 Manufacturing Site 2400
21 Manufacturing Site 7800
24 Oak Ridge 6600
25 Puget Sound 46000
26 Oak Ridge 88000
34 SRM CRM-204 (web) NR
35 SRM Can met SO-3 NR
36 SRM Can met SO-2 NR
37 SRMCRM-016 NR
38 SRM NWRI TH-2 NR
39 SRM NWRI WQB-1 NR
41 SRMCRM026 NR
43 SRM CRM 027 NR
44 SRM CRM 021 NR
45 SRM CRM 033 NR
46 SRM CRM 032 NR
55 SRM RTC spec. NR
56 Spiked Lot 1 870
57 Spiked PS- X1.X4 3500
59 Spiked CR-SO-14 870
60 Spiked Lot 7 5100
61 Spiked Lot 10 4200
62 Spiked Lot 5 3500
CRM = Canadian Reference Material
190
290
530
200
210
200
200
150
130
130
290
100
180
90
320
250
1200
340
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
190
290
190
150
130
210
<0.5
<0.5
1.8
<0.5
<0.5
<0.5
<0.5
1.9
<0.5
<0.5
<0.5
<0.5
0.32
<0.5
1.9
<0.5
<0.5
9.1
<0.5
NR
NR
0.7
5.8
1
0.57
6
6.5
0.78
81
NR
<0.5
<0.5
<0.5
1.1
<0.5
<0.5
9
3
4
8
3
4
3
5
3
4
3
2
2
<2
4
5
2
10
0.82
NR
NR
7.8
8.7
23
5.4
12
25
130
370
NR
9
3
9
5
3
3
210
23
150
240
28
32
27
160
24
20
23
110
41
180
150
89
46
140
0.04
300
970
79
570
600
210
170
590
220
120
NR
210
23
210
120
24
28
Cd
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
1.0
0.5
<0.5
<0.5
0.8
<0.5
0.4
<0.5
2.8
<0.5
0.7
1.9
14
NR
NR
0.47
5.2
2
12
12
1.2
89
130
NR
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
Cr
19
16
46
17
18
16
17
70
18
18
16
42
16
48
22
6.3
35
47
4.5
26
16
14
120
89
27
27
11
100
15
NR
19
16
19
50
18
18
Cu
13
10
20
32
11
9
23
49
8
8
7
51
9
20
40
7
33
73
NR
17
7
16
120
80
19
9.9
4800
96
590
NR
13
10
13
28
8
11
Pb
3
1
15
12
3
1
99
24
1
1
2
7
11
15
23
10
31
82
11
14
21
14
190
84
26
52
6500
61
4600
NR
3
1
3
15
1
3
Se
<2
<2
<2
<2
<2
<2
2
<2
<2
<2
<2
<2
<2
<2
<2
<2
<2
<2
NR
NR
NR
1
0.83
1
1.9
14
NR
89
170
NR
<2
<2
<2
<2
<2
<2
Sn
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<4
<5
<4
<5
6
5
NR
NR
NR
NR
NR
3.9
NR
NR
300
390
1300
NR
<5
<5
<5
<5
<5
<5
Zn
60
24
55
66
28
24
37
100
24
24
23
61
74
120
340
31
98
250
NR
52
120
70
900
275
140
51
550
230
2600
NR
60
24
60
61
24
28
Ha
0.19
0.04
0.31
0.10
0.16
0.23
0.37
0.66
0.62
0.63
1.1
5.5
78
10
14
220
35
100
0.002
0.02
0.08
0.16
0.62
1.09
2.4
3.8
4.7
6.4
21
0.01
0.19
0.61
1.6
72
220
23
RTC = Resource Technology Corporation
NR = Not Reported by Standard Supplier
40
-------
Discussion of Interferences
The RSDs for Ohio Lumex are small, suggesting that
precision is good and is not simply random variation
causing the differences noted above. (This will be
discussed in more detail in Section 6.1.3) As noted
previously, it would appear that interference is the cause of
the inaccurate analyses, but it is not readily apparent as to
the interferent causing the problem. Specifically, there is
no apparentsignificant difference between reported values
and associated sites from which the samples were
collected. There are possible exceptions, however, noted
for the Puget Sound samples but only descriptive
observations. For example, discounting SRMs, for the
Puget Sound site, only 6 of the 11 results reported by Ohio
Lumex are considered the same as those from the referee
laboratory. Therefore, there may be a significant
interference in the Puget Sound samples not presentin the
other samples. Upon examination of additional data
collected for these samples (see Table 6-6), no apparent
differences were noted. For example, a high organic
content may cause interference, but not all the Puget
Sound samples necessarily have a higher organic content
than othersamples tested. In addition, the Method 7471 B
mercury analysis requires that a non-stannous chloride
analysis be conducted with each sample analyzed, in order
to test for organic interferences. Upon examination of the
referee laboratory data for the sample sets mentioned
above, there was no apparent interference noted in the
non-stannous chloride analyses.
Puget Sound samples also had a higher percentage of
moisture for some of the samples analyzed which may help
explain these differences. But this does not explain all
differences or all similarities. There are not enough
samples to suggest that this difference is statistically
significant. Other interferences caused by additional
elements were also not found to be significant. Of course,
there could be interferences that were not tested, and
therefore, while it may be an interference (or likely a
combination of interferences) particular to a sample lot, the
exact cause remains unknown. The reason(s) for these
similarities and differences and the reason(s) for the
difference between the Ohio Lumex and referee laboratory
results is only speculative. In addition to the statistical
summary presented above, data plots (Figures 6-1 and 6-
2) are included in order to present a visual interpretation of
the accuracy.
Figure 6-1. Data plot for low concentration sample results.
41
-------
400
350
300
j? 250
I
g
li 200
I
o 150
100
50
Figure 6-2. Data plot for high concentration sample results.
Two separate plots have been included for the Ohio Lumex
data. These two plots are divided based upon sample
concentration in order to provide a more detailed
presentation. Concentrations ofsamples analyzed by Ohio
Lumex ranged approximately from 0.01 to over 200 mg/kg.
The previous statisticalsummaryeliminated some of these
data based upon whether concentrations were interpreted
to be in the analytical range of the Ohio Lumex field
instrument. This graphical presentation presents all data
points. It shows Ohio Lumex data com pared to ALSI data
plotted against concentration. Sample groups are shown
by connecting lines. Breaks between groups indicate a
different set of samples at a different concentration.
Sample groups were arranged from lowest to highest
concentration.
As can be seen by this presentation, samples analyzed by
Ohio Lumex appear to match well with the ALSI results,
with some notable exceptions. This is only a visual
interpretation and does not provide statistical significance.
It does however, provide a visual interpretation that
supports the previous statistical results for accuracy, as
presented above.
Unified Hypothesis Test
SAIC performed a unified hypothesis test analysis to
assess the comparability of analytical results provided by
Ohio Lumex and those provided by ALSI. (See Appendix
B for a detailed description of this test.) Ohio Lumex and
ALSI both supplied multiple assays on replicates derived
from a total of 33 different sample lots, whether field
materials or reference materials. The Ohio Lumex and
ALSI data from these assays formed the basis of this
assessment.
Results from this analysis suggest that the two data sets
are not the same. The null hypothesis tested was that, on
average, Ohio Lumex and ALSI produce the same results
within a given sample lot. The null hypothesis is rejected
in part because Ohio Lumex results tended to exceed
those from ALSI for the same sample lot. Even when a
bias term is used to correct this discrepancy, the null
42
-------
hypothesis is still rejected. Additional information about
this statistical evaluation is included in Appendix B.
Accuracy Summary
In summary, Ohio Lumex data were within SRM 95%
prediction intervals 93% of the time, which is statistically
equivalent. ALSI data also compared favorably to SRM
values and were within the 95% prediction interval 87% of
the time indicating statistical parity found to be biased low.
The comparison between the Ohio Lumex field data and
the ALSI results suggest that the two data sets are not the
same. When a unified hypothesis test is performed, this
result is confirmed. Ohio Lumex data were found to be
both above and below referee laboratory concentrations.
The number of Ohio Lumex average values less than 30%
different from the referee laboratory results or SRM
reference values was 19 of 33 different sample lots. Ohio
Lumex results therefore, provide accurate estimates for
field determination, and may be affected by interferences
not identified by this demonstration. Because the Ohio
Lumex data compare favorably to the SRM values, the
differences between Ohio Lumex and the referee
laboratory are likely the result of matrix interferences.
6.1.3 Precision
Precision is usually thought of as repeatability of a specific
measurement, and it is often reported as RSD. The RSD
is computed from a specified number of replicates. The
more replications of a measurement, the higher confidence
associated with a reported RSD. Replication of a
measurement may be as few as 3 separate
measurements, to 30 or more measurements of the same
sample, depending upon the degree of confidence desired
in the specified result. Most samples were analyzed seven
times by both Ohio Lumex and the referee laboratory. In
some cases, samples may have been analyzed as few as
three times. This was often the situation when it was
believed that the chosen sample, or SRM, was likely to be
below the vendor quantitation limit. The precision goal for
the referee laboratory, based upon pre-demonstration
results, is an RSD of 25% or less. A descriptive evaluation
for differences between Ohio Lumex RSDs and the referee
laboratory RSDs was determined. In Table 6-7, the RSD
for each separate sample lot is shown for Ohio Lumex
compared to the referee laboratory. The average RSD was
then computed for all measurements made by Ohio
Lumex, and this value was compared to the average RSD
for the laboratory.
In addition, the precision of an analytical instrument may
vary depending upon the matrix being measured, the
concentration of the analyte, and whether the
measurement is made for an SRM or a field sample. To
evaluate precision for clearly different matrices, an overall
average RSD for the SRMs is calculated and compared to
the average RSD for the field samples. This comparison
is also included in Table 6-7 and shown for both Ohio
Lumex and the referee laboratory.
The purpose of this evaluation is to determine the field
instrument's capability to precisely measure analyte
concentrations under real-life conditions. Instrument
repeatability was measured using samples from each of
four different sites. Within each site, there may be two
separate matrices, soil and sediment. Not all sites have
both soil and sediment matrices, nor are there necessarily
high, medium, and low concentrations for each sample
site. Therefore, spiked samples were included to cover
additional ranges.
Table 6-7 shows results from Oak Ridge, Puget Sound,
Carson River, and the manufacturing site. It was thought
that because these four different field sites represented
different matrices, measures of precision may vary from
site to site. The average RSD for each site is shown in
Table 6-7 and compared between Ohio Lumex and the
referee laboratory. SRM RSDs are not included in this
comparison because SRMs, while grouped with different
sites for purposes of ensuring that the samples remained
blind during the demonstration, were not actually samples
from that site, and were, therefore, compared separately.
The RSDs of various concentrations are compared by
noting the RSD of the individual sample lots. The ranges
of test samples (field, SRMs, and spikes) were selected to
cover the appropriate analytical ranges of Ohio Lumex's
instrumentation. Average referee laboratory values for
sample concentrations are included in the table, along with
SRM values, when appropriate. These are discussed in
detail in Section 6.1.2, describing the accuracy evaluation
and are included here for purposes of precision
comparison. Sample concentrations were separated into
approximate ranges: low, medium, and high, as noted in
Table 6-7 and Table 6-1. Samples reported by Ohio
Lumex as below their approximated POL were not included
in Table 6-7. There appears to be no correlation between
concentration (low, medium, or high) and RSD; therefore,
no other formal evaluations of this comparison were
performed.
43
-------
Table 6-7. Evaluation of Precision
Sample Lot No. Ohio Lumex
and Lab
Avg. Cone, or Reference
SRM Value
RSD
Number of
Samples
w/in 25% RSD Goal?
OAK RIDGE
Lot no. 03
Ohio Lumex
ALSI
Lot no. 09
Ohio Lumex
ALSI
Lot no. 14
Ohio Lumex
ALSI
Lot no. 21
Ohio Lumex
ALSI
Lot no. 24
Ohio Lumex
ALSI
Lot no. 26
Ohio Lumex
ALSI
Lot no. 37
Ohio Lumex
ALSI
Lot no. 44
Ohio Lumex
ALSI
Lot no. 60
Ohio Lumex
ALSI
Oak Ridge Avg. RSD
Ohio Lumex
ALSI
0.26 (low)
0.47 (low)
4.75 (medium)
1 1 .2 (medium)
221 (high)
77.0 (high)
0.14 (low)
2.33 (medium)
165 (high)
4.8%
3.8%
23.2%
34.2%
32.0%
27.5%
23.3%
23.8%
28.0%
44.8%
2.6%
13.2%
5.0%
36.4%
3.0%
59.4%
23.8%
30.9%
19.7%
25.5%
3
3
7
7
7
7
3
3
3
7
3
7
7
7
7
7
7
7
yes
yes
yes
no
no
no
yes
yes
no
no
yes
yes
yes
no
yes
no
yes
no
yes
no
PUGET SOUND
Lot no. 02
Ohio Lumex
ALSI
Lot no. 05
Ohio Lumex
ALSI
Lot no. 08
Ohio Lumex
ALSI
Lot no. 10
Ohio Lumex
ALSI
Lot no. 1 1
Ohio Lumex
ALSI
Lot no. 12
Ohio Lumex
ALSI
Lot no. 25
Ohio Lumex
ALSI
Lot no. 34
Ohio Lumex
ALSI
0.06 (low)
0.21 (low)
0.36 (low)
0.55 (low)
0.81 (low)
1.08 (medium)
16.6 (high)
11.3 (medium)
43.9%
23.6%
9.4%
33.3%
14.2%
13.4%
120%
20.5%
14.2%
32.7%
7.1%
2.8%
12.4%
12.3%
24.7%
22.4%
7
7
3
3
7
7
3
3
7
7
3
3
3
3
3
7
no
yes
yes
no
yes
yes
no
yes
yes
no
yes
yes
yes
yes
yes
yes
44
-------
Table 6-7. Continued
Sample Lot No. Ohio Lumex
and Lab
Lot no. 36
Ohio Lumex
ALSI
Lot no. 57
Ohio Lumex
ALSI
Lot no. 61
Ohio Lumex
ALSI
Lot no. 62
Ohio Lumex
ALSI
Puget Sound/ Avg. RSD
Ohio Lumex
ALSI
Avg. Cone, or Reference
SRM Value
0.073 (low)
0.73 (low)
154 (high)
14.6 (high)
RSD
4.9%
6.7%
1 1 .2%
16.2%
47.0%
10.9%
13.0%
28.3%
28.8%
19.7%
Number of
Samples
3
7
7
7
7
7
7
7
w/in 25% RSD Goal?
yes
yes
yes
yes
no
yes
yes
no
no
yes
CARSON RIVER
Lot no. 01
Ohio Lumex
ALSI
Lot no. 04
Ohio Lumex
ALSI
Lot no. 06
Ohio Lumex
ALSI
Lot no. 38
Ohio Lumex
ALSI
Lot no. 39
Ohio Lumex
ALSI
Lot no. 41
Ohio Lumex
ALSI
Lot no. 43
Ohio Lumex
ALSI
Lot no. 56
Ohio Lumex
ALSI
Lot no. 59
Ohio Lumex
ALSI
Carson River/ Avg. RSD
Ohio Lumex
ALSI
0.24 (low)
0.11 (low)
0.26 (low)
0.63 (low)
1.24 (medium)
1 .79 (medium)
2.76 (medium)
0.23 (low)
1.71 (medium)
30.5%
37.7%
18.9%
9.1%
7.3%
15.7%
3.5%
3.8%
6.5%
52.9%
17.5%
30.5%
9.1%
9.6%
8.0%
12.6%
10.2%
7.9%
15.0%
16.6%
7
7
3
7
3
7
7
7
7
7
7
7
7
7
7
7
7
7
no
no
yes
yes
yes
yes
yes
yes
yes
no
yes
no
yes
yes
yes
yes
yes
yes
yes
yes
MANUFACTURING SITE
Lot no. 13
Ohio Lumex
ALSI
Lot no. 17
Ohio Lumex
ALSI
Lot no. 45
Ohio Lumex
ALSI
5.91 (medium)
10.5 (high)
5.44 (medium)
51.9%
15.4%
24.2%
14.6%
1.6%
23.4%
7
7
3
7
7
6
no
yes
yes
yes
yes
ves
45
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Table 6-7. Continued
Sample Lot No. Ohio Lumex
and Lab
Avg. Cone, or Reference
SRM Value
RSD
Number of
Samples
w/in 25% RSD Goal?
Manufacturing Site/Avg. RSD
Ohio Lumex
ALSI
38.0 %
15.0%
no
yes
SUMMARY STATISTICS
Overall Avg. RSD
Ohio Lumex
ALSI
16.1%
22.3%
yes
yes
Field Samples/Avg. RSD
Ohio Lumex
ALSI
24.3%
20.3%
yes
yes
SRMs/Avg. RSD
Ohio Lumex
ALSI
8.0%
24.3%
yes
yes
The referee laboratory analyzed replicates of all samples
analyzed by Ohio Lumex. This was used for purposes of
precision comparison to Ohio Lumex. RSD for the vendor
and the laboratory were calculated individually and shown
in Table 6-7.
As noted from Table 6-7, Ohio Lumex precision is similar
to that of the referee laboratory. The single most important
measure of precision provided in Table 6-7, overall
average RSD, is 22.3% for the referee laboratory
compared to the Ohio Lumex average RSD of 16.1%. The
laboratory and Ohio Lumex RSD are both within the 25%
RSD objective for precision expected from both analytical
and sampling variance.
In addition, field sample precision compared to SRM
precision shows that there may be some difference
between these two sample lots; field sample RSD is 20.3%
for ALSI and 24.3% for Ohio Lumex; SRM RSD is 24.3%
for ALSI and 8.0% for Ohio Lumex. This is similar to the
results for the accuracy comparison. Ohio Lumex appears
to have better precision for the SRM analyses than for the
field sample analyses. For purposes of this analysis,
spiked samples are considered the same as field samples
because these were similar field matrices and the resulting
variance was expected to be equal to that of field samples.
The replicate sample RSDs also confirm the pre-
demonstration results, showing that sample
homogenization procedures met their originally stated
objectives.
There appears to be no significant site variation between
Oak Ridge, Puget Sound, and the manufacturing site
samples. (See Table 6-7 showing average RSDs for each
of these sample lots. These average RSDs are computed
using only the results of the field samples and not the
SRMs.) The Carson River site had a lower average RSD
for both the vendor and the laboratory, but this difference
may not be significant because this same result was not
evident in the data comparisons performed for other data
sets.
Precision Summary
The precision of the Ohio Lumex field instrument is better
than the referee laboratory precision. The overall average
RSD is 22.3% for the referee laboratory, compared to the
Ohio Lumex average RSD of 16.1%. This is primarily
because of the better precision obtained for the SRM
analyses by Ohio Lumex. Both the laboratory precision
and the Ohio Lumex precision goals of 25% overall RSD
were achieved.
6.1.4 Time Required
Measurement
for Mercury
During the demonstration, the time required for mercury
measurement activities was measured. Specific activities
that were timed included: instrument setup, sample
analysis, and instrument disassembly. One field technician
performed all operations during the demonstration, with the
exception of instrument setup and tear down, plus a small
46
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amount of sample preparation activities.
operator assisted with these items.
A second
Setup and disassemble times were measured one time.
Analytical time was measured each day, beginning when
the first blank was started, and continuing until the last
blank was completed at the end of the day. Any downtime
was noted and then subtracted from the total daily
operational time. The total of the operational time from all
four days was divided by the total number of analyses
performed. For this calculation, analyses of blanks and
calibration standards, and reanalyses of samples were not
included in the total number of samples.
Setup time for the RA-915+/RA-91C consisted of removing
the instrument from the shipping container, placement on
a level working surface, establishment of all electrical and
gas tubing connections, and instrument warm-up. The
time required to remove the RA-915+/RA-91C from the
shipping container could not be measured precisely
because the device was removed from the shipping
container before the evaluation team could time these
activities; however, the vendor did replicate the majority of
this process at the request of the evaluator, so that a time
estimate could be made. Based on these observations, it
is estimated that one person could remove the device from
the shipping container in 15 minutes. Setup time for other
peripheral devices, such as the computer/monitor and
analytical balance, was accomplished during the
instrument warm-up time. Leveling of the balance,
depending on field conditions, took between 5 and 10
minutes. Setup of the computer/monitor took less than 5
minutes.
After all devices were set in place, remaining electrical and
gas flow connections had to be made. The
RA-915+/RP-91C was connected to a powersource and to
the com puter/monitor. The balance was also connected to
the power source, but not to the computer/monitor. Gas
connections had to be made from the auxiliary pump,
through a flip-up flow gauge, and then to the instrument.
A mercury trap came pre-assembled and already inserted
in the vent line which was attached to the instrument.
Overall, the electrical and gas flow connections required 10
minutes.
After initial setup of the RA-915+/RP-91 C was complete,
the instrument required approximately 45 to 60 minutes to
warm to 800 °C. It is worth noting that setup of the balance
and computer/monitor were performed during this time
period.
Overall, the time required to remove the instrument from its
shipping container, setup the device, allow the instrument
to reach operating temperature, and setup peripheral
devices during instrument warm-up is estimated at
approximately 60 to 75 minutes.
Individual sample analysis times were not measured for the
duration of the demonstration. Analysis time was
estimated by recording start and stop times each day, and
accounting for any instrument downtime due to operator
breaks or device failure and maintenance activities.
Therefore, the total time for analyses included blanks,
calibration standards, and any sample reanalyses;
however, the total number of analyses performed includes
only demonstration samples (samples, spikes, and SRMs),
not vendor blanks, calibration standards, or reanalyses.
Table 6-8 presents the time measurements recorded for
each of the four days of operation of the RA-915+/RP-91C.
It should be noted thatthe second technician was required
approximately 25% of the time in order to achieve the
sample throughput observed during the demonstration, and
that the times in Table 6-8 are lapse times not labortimes.
Table 6-8. Time Measurements for Ohio Lumex
Day Day Day Day Day 4-Day
1234 Total
Run Time
(minutes)
195 540 540
1,275
Analysis Time Summary
In total, Ohio Lumex analyzed 197 samples during the
demonstration. The turnaround time on individual sample
analyses was 1 minute; however, the vendor chose to
analyze replicates of virtually every sample. Using the total
analytical time reported in Table 6-8 and factoring in the
second analyst (1275 minutes x 1.25analysts), 8.1 minutes
per analysis is a better approximation of real world
operating conditions (assuming that replicate analyses are
performed). The vendor claims that 25 samples can be
processed in an hour over an 8-hour day, an average of 2.4
minutes per sample, if replicates are not performed. Field
observations support this claim.
The number of blanks, standards, and reanalysis of
samples outside of the calibration range will vary from site
to site, depending on project goals (e.g., are "greater than"
results acceptable or must all samples be quantified) and
site conditions (e.g., high concentration samples or very
heterogeneous samples). If project goals require all
47
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samples to be quantified, the number of reanalyses and
blanks required could be higherand, therefore, the time per
analysis could be greater. If on the other hand, sample
results can be reported as "greater than" values (as was
gene rally doneduring the demonstration), then 6.5 minutes
per analysis is a reasonable average time.
Instrument disassembly was measured from the time that
the lastsample or blank analysis ended until the instrument
was disassembled and placed in the original shipping
container. Disassembly involved turning off power,
disconnecting the powersource and interface cables to the
computer/monitor, and removal of the auxiliary pump unit.
Packaging involved placing these components in wheeled
shipping cases. It is estimated that this complete process
would take one person approximately 30 minutes to
complete.
6.1.5 Cost
Background information, assumptions used in the cost
analysis, demonstration results, and a cost estimate are
provided in Chapter 7.
6.2 Secondary Objectives
This section discusses the performance results for the
RA-915+, along with the RP-91C attachment for soils, in
terms of the secondaryobjectives described in Section 4.1.
These secondary objectives were addressed based on
observations of the RA-915+ and RP-91C combination and
information provided by Ohio Lumex.
6.2.1 Ease of Use
Documents the ease of use, as well as the skills and
training required to properly operate the device.
Based on observations made during the
demonstration, the RA-915+/RP-91C is
reasonably easy to operate; lack of automation
somewhat impairs the ease of use. Operation
requires one field technician with a basic
knowledge of chemistry acquired on the job or in
a university and training on the instrument.
Six major elements were addressed in evaluating the ease
of use:
Usefulness of Standard Operating Practices (SOPs)
Operator training and experience required
Ease of equipment setup
Ease of calibration
Ease of sample preparation
Ease of measurement
Each of these is described, in sequence, in the following
paragraphs. Five of the six elements were given a
subjective rating -excellent, good, fair, and poor- based on
observations made by the instrument evaluator. Operator
training and experience in merely discussed.
The vendor provided two SOPs, one entitled "RA-915+
Mercury Analyzer" and the other entitled "RP-91 C
Attachment." These procedures were evaluated during the
demonstration.
The RA-915+ procedure provides the following information:
Comprehensive safety guidelines
Equipment list with corresponding images
Equipment application, including applicable media,
detection limits, sample parameters, and detection
technique
Technical specifications and operating conditions
Design and operation of the analyzer, including a
schematic
Description of the appearance and functions of the
equipment from all angles
Pre-operational procedures such as setup and
selection of operational mode
Operational procedures for the display unit and for
connection to a personal computer
Detailed equipment test and maintenance procedures
Troubleshooting guide
The SOP was well-organized, covered major information
requirements, and was easy to understand. The safety
precautions were thorough and well-documented. The
parts and equipment list covered all required parts for use
of the RA-915+. The table clearly presented various
applications and related data, including the need for
ancillaryequipmentforwaterand soil analyses. Equipment
specifications matched those documented during the
demonstration. The schematics and discussion of system
design and operational principles were well written. They
provided a thorough description of the operational principle
for the technology, easily understood by someone
unfamiliar with the technology. The description of
48
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appearance and functional controls was also useful for
novices with the equipment. Similarly, the detailed pre-
operational procedures were generally clear and
comprehensive, allowing an operator with training on the
basics of the equipment to setup and operate the RA-915+.
A step-by-step evaluation of the procedure could not be
performed without impacting the evaluation of analytical
throughput(see Section 6.1.4). Finally, the troubleshooting
table was easy to follow; however, there was no opportunity
to evaluate the table, for accuracy or completeness, during
the demonstration.
The SOP for the RP-91C was written in a manner similar
to the SOP for the RA-915+. The RP-91C SOP was
equally clearand thorough. Adequate detail was provided
to assist an inexperienced operator in equipment setup,
calibration, operation, troubleshooting, and maintenance.
The only maintenance activity that was performed during
the demonstration was replacement of the optical lense.
The procedure provides adequate information for a
technician to perform this maintenance activity.
There were two crucial operational elements encountered
during the demonstration that were not adequately
addressed in the RP-91C SOP. The first was the selection
of sample size such that the results remain within the
calibration range. The SOP instructs the user to use a
sample mass such that the mass of mercury is less than
1 ug; however, selection of sample size requires an
estimate of the expected mercury concentration. This
problem is not unique to the RA-915+/RP-91C; any AA
instrument requires an estimate of sam pie concentration to
obtain sample results within a specified calibration range.
Second, no information was provided on how to handle
samples that were outside of the calibration range.
Procedures implemented during the demonstration
included analyzing a blank sample after a sample was
above the calibration range (to purge the system of
mercury) and reducing sample size on subsequent
reanalyses (if quantitative results are reported). These
procedures were not described in the SOP; however, the
software provided the following prompt: "OUT OF RANGE".
It is not known whether the analyst is trained to analyze a
clean-out blankfollowing this prompt. The specific content
of the training course is not known.
Ohio Lumex provides a 1-day training course for an
additional cost of $600 to anyone who purchases, rents, or
leases the RA-915+/RP-91C. The vendor asserts thatthis
is a 6-hour, comprehensive course covering software and
hardware installation, and operationaltraining on use of the
instrument for soil analysis. The training course was not
evaluated during the demonstration. It may supplement
the SOPs. Overall, the SOPs were good, but could use
additionaldetail related to sample size selection and results
outside of the calibration curve.
Ohio Lumex chose to operate the RA-915+/RP-91C with
one chemist during the demonstration. The chemist held
a Ph.D. in chemistry. Ohio Lumex claims that a laboratory
or field technician with a high school diploma and basic
computer knowledge can operate the equipment after a
1-daytraining course on the instrument. Field observations
support this claim. Most operations required either use of
a keyboard or mouse with a Microsoft Windows-based
system. The prompts were clear and easy to understand.
The operator performed equipment setup with ease. The
RP-91C connected rapidly and easily to the RA-915 + . The
unit plugged into a power supply and an interface with the
PC. The external air pump and flow meter (used with the
RP-91 C) were encased in a metal box with a hinged lid.
The lid was opened, the flow meter (rotometer) was hinged
upward into a vertical position, and the pump was
connected to the rotometer with plastic tubing that comes
with the unit. The self-standing balance was easily setup
and leveled.
It was difficult to determine exactly how much time was
required for setup because a second vendor representative
helped with setup to expedite the process. Typically, the
two vendor representatives setup the equipment in 5
minutes (the instrument was already unpacked from its
shipping case). Field observations indicate that one
person could setup all required equipment, starting with
shipping containers, in approximately 30 minutes, perhaps
less in some cases. It should be noted that once
instrument setup is complete, furnace warm-up requires
45-60 minutes to reach the operating temperature of 800
°C. There was no display indicating actual furnace
temperature; the operator merely observed theinnerlining
of the furnace. When it achieved a red glow, the furnace
was deemed hot enough for operation. Overall, the ease
of setup was good, with the only drawback being the
extended warm-up time for the instrument.
Calibration was performed by the operator alone. A blank
was analyzed and a 2-point calibration performed in less
than five minutes. The RP-91C SOP (p13) recommended
three to four calibration points. Calibration consisted of
weighing the standard(s)and analyzing them according to
the steps in the SOP. A calibration curve was plotted and,
if acceptable, the calibration coefficients were accepted.
Overall, the ease of calibration was good.
49
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The operator was able to perform sample preparation and
analysis on a continuous basis. Sample preparation took
less than one minute per sample, on average, although
some minorassistance was performed by a second vendor
representative. In general, sample preparation was
unwieldy, increasing the potential for lost sample or
weighing errors.
Sample preparation consisted of preparing small pieces of
aluminum foil (approximately 5-8 cm squares) for weighing
soil samples. Several times during the demonstration, a
second vendor representative assisted with this task. The
samples were initially mixed in the original container, using
a clean quartz weigh boat. Approximately one half of the
sample was transferred to the aluminum foil, which was
then placed on the digital balance. The balance was
zeroed with the sample and foil, which were then removed
from the balance. A small amount of sample was then
transferred to a clean, quartz weigh boat. Sample transfer
was completed by dipping the quartz cup of the weigh boat
into the soil and scooping a small quantity into the bowl.
Each weigh boat was equipped with an insulated plastic
handle to allow safe handling of the weigh boat
immediately after heating.
The balance was placed at ground level, inside a
cardboard box (a standard file storage box with dimensions
of 30 cm wide by 40 cm long by 30 cm deep) to shield the
balance from wind effects. The balance had a hinged top
cover with a 5-cm, transparent portal for convenient
viewing of the sample; however, each time a sample was
inserted or removed, the lid had to be opened and then
closed. The operator sat in a chair almost continuously
during the demonstration so as to be able to reach the
balance and the sample injection port in alternating steps.
The location of the balance on the ground was required
because of the top-opening mechanism on the balance.
Inserting and removing samples through the hinged top
and the box opening required great care. Each time the
operator took a short break, it was clear that he was stiff
from working in a sitting position on a continuous basis.
An aluminum foil square with soil sample was placed on
the balance (the balance is not part of the system, but can
be provided), the balance was zeroed (tare weight), the
aluminum foil with sample was removed from the balance,
and a small amount of the sample was placed in the weigh
boat. The aluminum foil and residual sample were placed
on the balance again (gross weight). The difference
between the tare weight (zero) and the gross weight (a
negative number) was the net weight used for the analysis.
This weight was manually calculated and recorded in the
instrument data entry panel using the keyboard. This
operation was relatively easy to understand and could be
performed by a trained technician. However, there were
opportunities for spilling residual sample after weighing or
improperly calculating or entering netweightdata. Sample
weights can be determined by recording a tare weight for
the weigh boat, adding sample, and recording a gross
weight (the difference being the net weight). In this way,
use of aluminum foil can be eliminated. The same issues
remain with manual calculations and data recording.
Sample analysis took less than 1 minute per sample.
Because of the lack of automation in the process, the
operator was constantly busy weighing samples, recording
and entering weights, inserting and removing weigh boats
from the RP-91C, or recording analytical results. It should
be noted that the operator always analyzed duplicate
samples and, oftentimes, analyzed triplicates to ensure
good analytical precision.
As samples were analyzed, vendor-proprietary software
screens allowed the user to track the sample adsorption
curve on the screen and know when the analysis was
completed (see Figure 6-3). The software is compatible
with Windows 95, 98, or 2000, and can export data to
Microsoft Excel. Sample analysis consisted of inserting the
pre-weighed sample boat in the small opening in the
furnace, watching the adsorption curve to show the
analysis was completed, and removing the sample weigh
boat. Sample analysis was easy to understand and could
be performed by a trained technician.
During the demonstration, samples with concentrations
outside of the equipment calibration range were
encountered. These samples would result in a peak that
was above the top end of the calibration range. The
operator was required to analyze a blank to demonstrate
that excess mercury had been purged from the system; an
"OUT OF RANGE" screen prompt advised the operator
that the sample was not in the calibration range.
The digital balance was the major peripheral item. The
vendorwill supply a balance, or the usercan supply his/her
own balance. Though the balance is not part of the
required vendor equipment, a balance is a necessary
peripheral. Therefore, the balance was evaluated during
the demonstration. The reader should note that other
brands and models of balances may be used and these
may not perform in the same manner as the balance used
during the demonstration. The balance itself was easy to
use, but the lack of an automatic interface with the
monitor/software made the overall system more difficult to
operate and increased the potential for error.
50
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FVogtom
Vogtom
EM^B ? j
,1111 • .
! 4 - - * • -I- --I \- - * *-
I .
, .--*,_ I, _ -.1 i_ 4 t
.k , i i i i i i
JL-i. -_ -J.--L--I 1. . i u
0 20 AC< SO 60 1QO 120 HO 16O 13O 2CO 22O 2*0 260 260 300 320 3+0 330 350 ICO 420 4-iO <6O -*3O SOO S2C S*O 560 560 600
Figure 6-3. RA-91 5+/RP-91 C peak screen.
6.2.2 Health and Safety Concerns
Documents potential health and safety concerns
associated with operating the device.
No significant health and safety concerns were
noted during the demonstration. The only
potential health and safety concerns identified
were the generation of mercury vapors and the
potentialforburns with careless handling of hot
quartz sample boats. The vendor provides a
mercury filter as standard equipment; exercising
caution and good laboratory practices can
mitigate the potential for burns.
Health and safety concerns, including chemical hazards,
radiation sources, electrical shock, explosion, and
mechanical hazards were evaluated.
No chemicals were used in the preparation or processing
of samples, except for analytical standards. During this
demonstration, the analyticalstandards were soil SRMsfor
mercury. These were handled with gloves, and the
operator wore safety glasses at all times. Such standard
laboratory precautions mitigate the potential for dermal
exposure. Similar procedures were also used for soil
samples which contained mercury. Because the RP-91C
attachment is designed to thermally convert mercury
compounds to mercury vapors as part of the analytical
process, and no fume hood was present to exhaust
mercury vapors after analysis, inhalation of mercury was a
concern. The vendor installs a proprietary mercury trap in
the exhaust line from the RP-91C attachment.
Measurements were taken with a Jerome 431-x gold film
mercury vapor analyzer manufactured by Arizona
Instruments Corporation. The instrument has a range of
0.000 to 0.999 mg/m3. In all cases, readings were 0.000
mg/m in the breathing zone of the operator.
In looking at electrical shock potential, two factors were
evaluated: 1) obvious areas where electrical wires are
51
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exposed and 2) safety certifications. No obviouslyexposed
wires were noted during the demonstration. All
connections between equipment were made using
standard electrical power cords, modem interface lines,
and 8-pin cords. Power cords were grounded and a surge
protector (provided by EPA) was utilized. The RA-915 +
line voltage (110 volts AC) was stepped down to 12 volts
(DC) at 2.5 amps using a power transformer. The
RA-915+ was U L, SA, and CE certified, among other
certifications marked on the transformer. The balance
utilized during the demonstration was a KND 1-microgram,
digital balance, model FX-320. It operated on a 12-volt DC
(at 0.Samps) power source that was stepped down from
110 volts and 7.5 amps. This device had no visible
certifications. A standard laptop computer was used
(Hewlett Packard Pavilion, model HP F145A). This
computer had UL, CE, and numerous other certifications.
No obvious explosion hazards were noted. The use of
ambient air as a carrier gas eliminates the possibility of
explosion associated with the use of oxygen as a carrier
gas in the presence of ignition sources.
No serious mechanical hazards were noted during the
demonstration. All equipment edges were smooth,
minimizing any chance of cuts or scrapes. The hinged lid
on the RP-91C pump/rotometer housing presents the
possibility of a pinch hazard, as would any hinged device;
however, the lid is very light weight, remained opened
throughout the demonstration, and is designed to remain
securely in place when the lid is open.
6.2.3 Portability of the Device
Documents the portability of the device.
The RA-915+ air analyzer was easily portable,
although the device, even when carried in the
canvas sling, was not considered light-weight.
The addition of the RP-91C and associated
pump unit preclude this from being a truly field
portable instrument. The device and
attachments can be transported in carrying
cases by two people, but must then be setup in
a stationary location. It was easy to setup, but
the combined instrument is better characterized
as mobile rather than field portable.
The RA-915+ measured 46 cm (L) by 11 cm (W) by 21 cm
(H). The weight was reported as 7.5 kg. The RP-91C
attachment measures 32 cm by 24 cm by 12 cm and
weighs 5.5 kg. Also included as a standard feature with
the RP-91 C were a monitor, keyboard and mouse; and the
pump/rotometer case. All were light weight and easily
portable, with the pump and rotometer enclosed in a metal
carry case with a handle. Remote locations also require
the use of a generator or 12-volt battery.
The RA-915+/RP-91C was not easily portable from the
standpoint of being a handheld instrument. Movement and
setup of the equipment gene rally took two people about 10
minutes, with the equipment already unpacked. It is
estimated that one person would require approximately 30
minute to unpack the instrument from the carrying case
and complete setup. The RA-915+ air analyzer was easily
portable, although the device, even when carried in the
canvas sling, was notlightweight. The addition ofthe RPD-
91, pump unit, and battery preclude this from being a truly
field portable instrument. The device and attachments can
be transported by carrying two containers with handles,
plus the RP-91 C attachment, the monitor/mouse, power
cords/transformers, and data cables (plus an analytical
balance). Even when placed in wheeled shipping
containers, the device is only portable in the sense that it
can be managed in a manner similar to wheeled luggage.
Transport in paved areas is easy; transport up a rocky
incline would be difficult. The device is, however, easily
transportable in any size vehicle, and can be moved to any
location where a vehicle can go. Therefore, it would be
practical for many field applications. It should not be
characterized as a handheld instrument. During the
demonstration, the complete soil analytical unit, including
the monitor and air pump, easily fit on a table measuring 30
inches wide by 72 inches long, with adequate space for
sample staging and preparation.
The balance required a flat, stable surface. Because the
balance was top loaded, the vendor chose to place the
balance on the ground near the chair in which the operator
sat. The balance was placed inside of a cardboard box to
eliminate the effects of wind on the enclosed balance. This
setup required the operator to repeatedly bend over to tare
the sample (on aluminum foil) and again after the analytical
sample was removed in the sample boat.
The RA-915+/RP-91Cwasoperated using a 12-volt battery
during the Visitors' Day. The unit appeared to operate well,
although no samples were being processed for evaluation
and no evaluation was made of the amount of time the
battery lasted. The vendor reports a battery life of
approximately 3.5 hours. Alternatively, a standard
electrical source of 11 0 volts can be utilized. Power can be
supplied by any standard 2,000 watt generator.
52
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For the demonstration, the vendor was supplied with a
folding table, two chairs, and a tent to provide shelter from
inclement weather. In addition, one 1-gallon container
each was provided for waste soil and decontamination
water utilized to clean weigh boats. A 2-gallon zip-lock bag
was furnished for disposal of used gloves, wipes, and other
wastes which were contaminated during the demonstration.
Finally, a large trash bag was supplied for disposal on non-
contaminated wastes.
6.2.4 Instrument Durability
Evaluates the durability of the device based on its
materials of construction and engineering design.
The RA-915+/RP-91C was well designed and
constructed for durability.
The outside of the RA-915+ is constructed of sturdy
aluminum (2 mm thickness) that was painted to prevent
corrosion. The exterior of the RP-91C furnace is stainless
steel; the interior is quartz. The furnace is covered by a
painted metal guard to prevent burns. The auxiliary air
pump and rotometer were housed in a sturdy, painted
aluminum box (2 mm thickness). The lid of this container
was secured with hinges, and was opened when the
rotometer was setup for operation. No environmental (e.g.,
corrosion) or mechanical (e.g., shear stress or impact)
tests were performed; however, the outer shell of the
instrument was well-designed and constructed, indicating
that the device would likely be durable under field
conditions.
No evaluation could be made regarding the long-term
durability of the furnace, analytical cell, or circuitry.
External visual inspection did not indicate that any
problems were likely, although many parts were obscured
from view. The vendor offers a standard 1-year warranty,
and will provide a 1-year extended warranty and
maintenance plan at the owner's cost. This warranty cost
$2,400, and covers all parts and labor except consumable
items (lamp, rechargeable battery for the RA-915 + , and
filters). The only mechanical part with the potential to fail
overtime is the air pump. Long term operation could result
in the need for repairer replacement of the air pump. The
heating element of the furnace is the other part with some
potential for long term failure, although it worked properly
during the demonstration. Plastic tubing for the rotometer
may also be subject to long term failure due to the effects
of sun and temperature or mechanical failure. Overall,
however, the design and construction of the instrument
support the vendor claim that this instrument is durable.
The vendor asserts that life expectancy of the furnace and
air pump is 3-5 years with heavy use.
Finally, most of the demonstration was performed during
rainfall events ranging from steady to torrential. The
instrument was located under a tent with side flaps to
protect it from rainfall. Even when it was not raining, the
relative humidity was high. The high humidity and rainfall
had no apparent impact on the reliability of the instrument
operation.
6.2.5 Availability of Vendor Instruments
and Supplies
Documents the availability of the device and spare
parts.
The RA-915+/RP-91C is readily available for
rental, lease, or purchase. Spare parts and
consumable supplies can be added to the
original instrument order or can be received
within 24-48 hours of order placement.
Standards are readily available from laboratory
supply firms or can be acquired through Ohio
Lumex.
EPA representatives contacted Ohio Lumex regarding the
availability of the RA-915+/RP-91C and supplies.
According to Ohio Lumex, such systems are available
within a few weeks of order placement, but can be
expedited. The RA-915+/RP-91C also is available for
rental or leasing and lead time is subject to availability.
The instrument comes standard with four quartz-sample
injectors; no other parts or consumable supplies are
provided standard with the equipment. Spare parts, such
as the furnace, furnace lenses, the air pump, or additional
sample injectors, can be ordered individually. These and
any other parts are available within 24-48 hours.
Standards can be provided by Ohio Lumex or can be
purchased from a laboratory supply firm.
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Chapter 7
Economic Analysis
The purpose of the economic analysis was to estimate the
total cost of mercury measurement at a hypothetical site.
The cost per analysis was estimated; however, because
the cost per analysis would decrease as the number of
samples analyzed increased, the totalcapital costwas also
estimated and reported. Because unit analytical costs are
dependent upon the total number of analyses, no attempt
was made to compare the cost of field analyses with the
RA-915+/RP-91C to the costs associated with the referee
laboratory. "Typical" unit cost results gathered from
analytical laboratories were reported to provide a context
in which to review the RA-915+/RP-91C costs. No attempt
was made to make a direct comparison between these
costs because of differences in sample throughput,
overhead factors, total equipment utilization factors, and
other issues that make a head-to-head comparison
impractical.
This chapter describes the issues and assumptions
involved in the economic analysis, presents the costs
associated with field use of the RA-915+/RP-91C, and
presents a cost summary for a "typical" laboratory
performing sample analyses using the reference method.
7.1 Issues and Assumptions
Several factors can affect mercury 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. Ohio Lumex offers three options for potential
RA-915+/RP-91C users: 1) purchase of the instrument, 2)
weekly rental, and 3) equipment leasing with an option to
purchase. Because site and user requirements vary
significantly, all three of these options are discussed to
provide each user with the information to make a case-by-
case decision.
A more detailed cost analysis was performed on the
equipment rental option because this case represents the
most frequently encountered field scenario. The results of
that cost analysis are provided in Section 7.2
7.1.1 Capital Equipment Cost
The RA-915+/RP-91C comes complete with the analytical
instrument (RA-915+), furnace attachment and auxiliary air
pump/flow meter (RP-91C), a set of 4 quartz injection
spoons with ceramic handles, and software, regardless of
whetherthe instrument is purchased, rented, or leased. An
optional digital balance is available for purchase, rental, or
lease from Ohio Lumex, but not included in the base cost
of any of these three options because the usermay provide
his/herown balance. Because there is no outputsignallink
between the balance and the system, any balance can be
used. A laptop computer with display screen can be
purchased, rented, or leased from Ohio Lumex or can be
provided by the user. A user-supplied printer can also be
attached to the system using a standard printer cable; no
purchase, lease, or rental option is available forthe printer.
The cost quoted by Ohio Lumex does not include
packaging orfreightcosts to ship the instrument to the user
location. No deposit is required for rental and lease
agreements. A user manual is provided at no cost. A
6-hour training session is available for an additional fee.
7.1.2 Cost of Supplies
The cost of supplies was estimated based on the supplies
required to analyze demonstration samples and
discussions with Ohio Lumex. Requirements vary
depending on whether solid or liquid samples are being
54
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analyzed. For purposes of this costestimate, only supplies
required to analyze solid samples are factored into the cost
estimate because only solid samples were analyzed during
the demonstration. Supplies required for liquid samples
are not noted because a different analytical attachment is
used. Supplies consisted of consumable items (e.g.,
calibration standards, mercury trap) and non-consumables
that could not be returned because they were contaminated
or the remainder of a set (e.g., quartz injection spoons).
The purchase prices and supply sources were obtained
from Ohio Lumex, and confirmed by contacting those
sources. Because the user cannot return unused or
remaining portions of supplies, no salvage value was
included in the cost of supplies. PPE supplies were
assumed to be part of the overall site investigation or
remediation costs; therefore, no PPE costs were included
as supplies.
7.1.3 Support Equipment Cost
During the demonstration, the RA-915+/RP-91C, air pump,
laptop computer, and balance were operated using AC
power. The costs associated with providing the power
supply and electrical energy were not included in the
economic analysis; the demonstration site provided AC
power at no cost. During Visitors' Day, all of the items
mentioned were operated using a 12-volt DC battery.
Because of the large number of samples expected to be
analyzed during the demonstration, EPA provided support
equipment, including tables and chairs for the two field
technician's comfort. In addition, EPA provided a tent to
ensure that there were no delays in the project due to
inclement weather. These costs may not be incurred in all
cases. However, such equipment is frequently needed in
field situations, so these costs were included in the overall
cost analysis.
7.1.4 Labor Cost
The labor cost was estimated based on the time required
for RA-915+/RP-91C setup, sample preparation, sample
analysis, summary data preparation, and instrument
packaging at the end of the day. Setup time covered the
time required to take the instrument out of its packaging,
set up all components, and ready the device for operation.
However, the RA-915+/RP-91Cwas already removed from
the original shipping container. Therefore, this time was
estimated rather than measured. Sample preparation
involved mixing samples with the injection spoon. Sample
preparation was generally completed while previous
samples were being analyzed. Sample analysis comprised
the time required to analyze all sam pies and submit a data
summary. The data summary was strictly a tabulation of
results in whatever form the vendor chose to provide. In
this case, the vendortranscribed results from the electronic
database to the field COC forms (no printer was available
in the field). The time required to perform all tasks was
rounded to the nearest hour. However, 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-
hourday. Based on this assumption, a daily rate for a field
technician was used in the analysis.
During the demonstration, EPA representatives evaluated
the skill level required for the field technician to analyze
and report results for mercury samples. Based on these
field observations, a field technician with basic chemistry
skills acquired on the job or in a university setting, and a
1-day training course specific to the RA-915+/RP-91C, was
considered qualified to operate the instrument. For the
economic analysis, an hourly rate of $15 was used for a
field technician. A multiplication factor of 2.5 was applied
to laborcosts to account for overhead costs. Based on this
hourly rate and multiplication factor, and an 8-hour day, a
daily rate of $300 was used for the economic analysis.
Monthly labor rates are based on the assumption of an
average of 21 work days per month. This assumes 365
days per year, and non work days totaling 113 days per
year (104 weekend days and 9 holidays; vacation days are
discounted assuming vacations will be scheduled around
short-term work or staff will be rotated during long
projects). Therefore, 252 total annual work days are
assumed.
7.1.5 Investigation-Derived Waste Disposal
Cost
Ohio Lumex was instructed to segregate its waste into
three categories during the demonstration: 1) general
trash; 2) lightly contaminated PPE and wipes; and
3) contaminated soil (both analyzed and unanalyzed) and
other highly contaminated wastes. General trash was not
included as IDW and is not discussed in this document. A
separate container was provided for each waste category.
Lightly contaminated wastes consisted primarily of used
surgical gloves, wipes, and aluminum foil. The surgical
gloves were discarded for one of three reasons: 1) they
posed a risk of cross contamination (noticeably soiled),
2) they posed a potential health and safety risk (holes or
tears), or 3) the operator needed to perform other tasks or
take a break. The rate of waste generation was in excess
of what would be expected in a typical application of this
instrument. In addition, the EPA evaluators occasionally
55
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contributed used gloves to this waste accumulation point.
Wipes were used primarily to clean injection spoons (after
cooling) between samples. In cases where cross
contamination is not a major concern (e.g., field screening
orall samples are in the same concentration range), lesser
amounts of waste would likely be generated. Aluminum foil
contained the soil while it was being weighed. In the case
of soils, the foil contained virtually no residual soil, and was
discarded in this container. Foil used to weigh wet
sediments was considered highly contaminated, and was
discarded with the soil.
Contaminated soils consisted primarily of soil placed in the
injection spoon and then removed because the weightwas
above the target weight. Soil that was analyzed was also
placed in this waste container as a precaution, even though
it is expected that such soils would be free of mercury after
being heated to high temperatures in the analytical
instrument. In some cases, these sample residuals may
not need to be handled as hazardous waste.
The contaminated soil, excess sample material, and lightly
contaminated gloves and wipes were considered
hazardous wastes for purposes of this cost analysis.
7.1.6 Costs Not Included
Items for which costs were not included in the economic
analysis are discussed in the following subsections, along
with the rationale for exclusion of each.
Oversight of Sample Analysis Activities. A typical user
of the RA-915+/RP-91C would not be required to pay for
customer oversight of sample analysis. EPA
representatives observed and documented all activities
associated with sample analysis during the demonstration.
Costs for this oversight were not included in the economic
analysis because they were project specific. For the same
reason, costs for EPA oversight of the referee laboratory
were also not included in the analysis.
Travel and Per Diem for Field Technician. Field
technicians may be available locally. Because the
availability of field technicians is primarily a function of the
location of the project site, travel and per diem costs for
field technicians were not included in the economic
analysis.
Sample Collection and Management. Costs for sample
collection and management activities, including sample
homogenization and labeling, are site specific and,
therefore, not included in the economic analysis.
Furthermore, these activities were not dependent upon the
selected reference method or field analytical tool.
Likewise, sample shipping, COC activities, preservation of
samples, and distribution of samples were specific
requirements of this project that applied to all vendor
technologies and may vary from site to site. None of these
costs was included in the economic analysis.
Items Costing Less than $10. The costs of inexpensive
items, such as paper towels, was not included in the
economic analysis.
Documentation Supplies. The costs for digital cameras
used to document field activities were not included in
project costs. These were considered project-specific
costs that would not be needed in all cases. In addition,
these items can be used for multiple projects. Similarly,
the cost of supplies (logbooks, copies, etc.) used to
document field activities was not included in the analysis
because such supplies are project specific.
Health and Safety Equipment. Costs for rental of the
mercury vapor analyzer and the purchase of PPE were
considered site specific and, therefore, not included as
costs in the economic analysis. Safety glasses and
disposable gloves were required for sample handlers and
would likely be required in most cases. However, these
costs are not specific to any one vendor or technology. As
a result, these costs were not included in the economic
analysis.
Mobilization and Demobilization. Costs for mobilization
and demobilization were considered site specific, and not
factored into the economic analysis. Mobilization and
demobilization costs actually impact laboratory analysis
more than field analysis. When a field economic analysis
is performed, it may be possible to perform a single
mobilization and demobilization. During cleanup or
remediation activities, several mobilizations,
demobilizations, and associated downtime costs may be
necessary when an off-site laboratory is used because of
the wait for analytical results.
7.2 RA-915+/RP-91C Costs
This section presents information on the individual costs of
capital equipment, supplies, support equipment, labor, and
IDW disposal for the RA-915+/RP-91C. Table 7-1
summarizes the RA-915+/RP-91C costs.
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Table 7-1. Capital Cost Summary for the RA-915+/RP-91C
Item Quantity Unit Cost
($)
Purchase RA-915+/RP-91C 1
Monthly Rental of RA-915+/RP-91C 1
Monthly Lease of RA-91 5+/RP-91C 1
Purchase Balance (Optional) " 1
Purchase Printer (Optional) " 1
$29,000
$3,500
$3,500
$600
$150
1 -Month
$29,000
$3,500
$3,500
$600
$150
Total Cost for Selected Project Duration
3-Month 6-Month 12-Month
$29,000
$10,500
$10,500
$600
$150
$29,000
$21,000
$21,000
$600
$150
$29,000
$42,000
$42,000
$600
$150
24-Month
$29,000
$84,000
$84,000
$600
$150
A balance is required, but may be provided by the user. A printer is optional; it may also be provided by the user.
7.2.1 Capital Equipment Cost
During the demonstration, the RA-915+/RP-91C was
operated for approximately two and one-half days and was
used to analyze 197 samples.
Figure 7-1 summarizes the RA-915+/RP-91C capital costs
for the three procurement options: rental, lease, and
purchase. These costs reflect the basic RA-915+/RP-91C
system, with the optional computer. No other options (e.g.,
balance or printer) and no supply or shipping costs are
included. As would be expected, this chart clearly shows
thateither rental or leasing is the most cost-effective option
forshort-term projects (less than 8 months). When project
duration (or use on multiple projects) exceeds eight
months, the purchase option is the most cost-effective.
These scenarios cover only capital cost, not the cost of
supplies, support equipment, labor, and IDW disposal.
Purchase
Rental
Lease
Munths
Figure 7-1. Capital equipment costs.
The RA-915+/RP-91C, including the auxiliary air pump and
flow meter, and related electrical connections, sells for
$29,000. Also included are four quartz injection spoons,
plastic tubing for air connections, and an instruction
manual. The portable computer/monitor is not included in
the cost, but the software is included. A balance is also
required and can be purchased from Ohio Lumexfor $600,
or rented or leased for $150 per week. However, the user
can supply any existing balance. The costs presented in
Figure 7-1 do not include the cost of the balance.
7.2.2 Cost of Supplies
Supplies used during the demonstration included solid
SRMs and a mercury trap. NIST soil SRMs sell for $250
each; typically both a high and a low standard will be
required for many applications, for a total cost of $500. If
sediments are analyzed, a NIST sediment SRM may be
obtained for $150. No costs for a sediment SRM are
included in this analysis. These standards have a life-
expectancy of one to three years (one year is assumed for
this cost analysis). A mercury trap was also required
during the demonstration and would likely be needed for
most field applications. The proprietary trap costs $250
and comes pre-assembled. The trap is good for
approximately 1,000 samples. Based on the sample
throughput achieved during the demonstration, the trap
should last three weeks if running one shift per day and
one week if running three shifts per day.
7.2.3 Support Equipment Cost
Ohio Lumex was provided with a 10x10 foot tent for
protection from inclement weather during the
demonstration. Itwas also provided with one table and two
chairs for use during sample preparation and analytical
activities. The rental costfor the tent (including detachable
sides, ropes, poles, and pegs) was $270 per week. The
rental costfor the table and two chairs for one week totaled
57
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$6. Total support equipment costs were $276 per weekfor
rental.
For longer projects, purchase of support equipment should
be considered. Two folding chairs would cost
approximately $40. A 1 0x10 foot tent would cost between
$260 and $1,000, depending on the construction materials
and the need for sidewalls and other accessories (e.g.,
sand stakes, counterweights, storage bag, etc.). A cost of
$800 was used forthis cost analysis. A folding table would
cost between $80 and $250, depending on the supplier.
For purposes of this cost analysis, $160 was used. Total
purchase costs for support equipment are estimated at
$1,000.
The RA-915+/RP-91C requires an electrical source: either
110/220 volts 50/60 Hz AC at 1.2 amps or 12 volts DC at
18 amps. No cost was calculated for the DC electrical
source used during the demonstration because any
instrument will require a power source. The Ohio Lumex
instrument reportedly can be operated on a rechargeable
12-volt battery for 3.5 hours. (Ohio Lumex, 2003) The
battery can be purchased for less than $1 00. Alternatively,
a standard 2,000 watt generator can be used to power the
instrument. The estimated cost for a locally-supplied
generator is $500; Ohio Lumex will also rent a generator
for $200 per week, or one can be rented from a local tool
rental firm.
7.2.4 Labor Cost
One field technician was required for 3 days during the
demonstration to complete sample analyses and prepare
a data summary. Based on a labor rate of $300 per day,
total labor cost for application of the RA-915+/RP-91C was
$900 for the 2.5-day period (assumes the technician was
payed for a complete day on the third day). Labor costs
assume qualified technicians are available locally, and that
no hotel or per diem costs are applicable. Table 7-2
summarizes labor costs for various operational periods.
The costs presented do not include supervision and quality
assurance because these would be associated with the
use of any analytical instrument and are a portion of the
overhead multiplier built into the labor rate.
7.2.5 Investigation-Derived Waste Disposal
Cost
Ohio Lumex generated waste personal protective
equipment, contaminated wipes and aluminum foil, and
excess soil waste. The PPE waste was charged to the
overall project due to project constraints. The minimum
waste volume is a 5-gallon container. Mobilization and
container drop-off fees were $1,040; disposal of a 5-gallon
soil waste containerwas $400. (This cost was based on a
listed waste stream with a hazardous waste numberU151.)
The total IDW disposal cost was $1,440. These costs may
vary significantly from site to site, depending on whether
the waste is classified as hazardous or nonhazardous and
whether excess sample material requiring disposal is
generated. Table 7-3 presents IDW costs for various
operational periods, assuming that waste generation rates
were similar to those encountered during the
demonstration.
Table 7-2. Labor Costs
Item
1
Months
6
12
24
Technician $6,300 $18,900 $37,800 $75,600 $151,200
Supervisor NA NA NA NA NA
Quality NA NA NA NA NA
Control
Total
$6,300 $18,900 $37,800 $75,600 $151,200
Table 7-3. IDW Costs
Item
Drop Fee
Disposal
Total
1
$1,040
$400
$1
,440
$3
$1
$4
3
,120
,200
,320
Months
6
$6,240
$2,400
$8,640
$12
$4
12
,480
,800
$17,280
$24
$9
$34
24
,960
,600
,560
7.2.6 Summary of RA-915+/RP-91C Costs
The total cost for performing mercury analysis is
summarized in Table 7-4. This table reflects costs for
projects ranging from 1 -24 months. The rental option was
used for estimating the equipment cost. Table 7-5
summarizes total costs and the percentage of total costs
for the actual demonstration.
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Table 7-4. Summary of Rental Costs for the RA-915+/RP-91C
Item
Quantity Unit
Unit
Cost
($)
Months
3 6
12
24
Capital Equipment
Monthly Rental 1
Supplies
Quartz Injectors a 1
Solid SRM b 2
Mercury Trap (all components) 1
Total Supply Cost
Support Equipment0
Table (optional) - weekly 1
Chairs (optional) - weekly 2
Tent (for in clement weather only) 1
- weekly
Total Support Equipment Cost
Labor
Field Technician (person day) 1
IDW
Drop Fee NA
Disposal NA
Total IDW Costs
Total Cost
NA
$3,500 $3,500 $10,500 $21,000 $42,000 $84,000
each $150
each $250
each NA
each
each
each
$5
$1
$270
hour
week
$1,040
$400
$0
$500
$65
$565
$20
$10
$800
$830
$0
$500
$250
$750
$150
$500
$500
$1,150
$300
$1,000
$1,000
$2,300
$600
$1,500
$2,000
$4,100
$60
$25
$800
$885
$120
$40
$800
$960
$160
$40
$800
$160
$40
$800
$1,000 $1,000
$38 $6,300 $18,900 $37,800 $75,600 $151,200
$1,040 $3,120 $6,240 $12,480 $24,960
$400 $1,200 $2,400 $4,800 $9,600
$1,440 $4,320 $8,640 $17,280 $34,560
$18,935 $32,645 $69,715 $138,630 $274,930
a For solid samples and SRMs; a set of 4 comes standard and is assumed to last 2 years, with breakage of one per 6 months
b Only for use with solid samples; assumes two SRMs are required (a low and a high standard) with a life expectancy of 1 year (some standards
will have longer shelf lives).
c Rental costs were used through the 3-month period for chairs and the 6-month period forthe table. Purchase costs were used for longer periods.
Purchase costs for the tent were used for all periods.
d Other than unit costs, all costs are rounded to the nearest $5.
e The instrument is available for weekly rentals at $1,500 per week.
Table 7-5. RA-915+/RP-91C Costs by Category
Category
Instrument
Supplies
Support Equipment
Labor
IDW Disposal
Category Cost
w
$1,500
$500
$277
$900
$1,440
Percentage of
Total Costs
32.5%
10.8%
6.0%
19.5%
31.2%
Total
$4,617
100.0%
The cost per analysis based upon 197 samples, when
renting the RA-915+/RP-91 C, is $23.44 per sample. The
cost per ana lysis for the 197 samples, excluding instrument
cost, is $15.82 per sample.
7.3 Typical Reference Method Costs
This section presents costs associated with the reference
method used to analyze the demonstration samples for
mercury. Costs for other project analyses are not covered.
The referee laboratory utilized SW-846 Method 7471B for
all soil and sediment samples. The referee laboratory
performed 421 analyses over a 21-day time period.
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A typical mercury analysis cost, along with percent laboratory can be reduced to 14, 7, oreven fewer calendar
moisture for dry-weight calculation, is approximately $35. days, with a cost multiplier of from 125% to 300%,
This cost covers sample management and preparation, depending on project needs and laboratory availability.
analysis, quality assurance, and preparation of a data This results in a cost range from $6,895 to $20,685. The
package. The total cost for 197 samples at $35 would be laboratory cost does not include sample packaging,
$6,895. This is based on a standard turnaround time of shipping, or downtime caused to the project while awaiting
21-calendar days. The sample turnaround time from the sample results.
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Chapter 8
Summary of Demonstration Results
As discussed previously in this ITVR, the Ohio Lumex
RA-915+/RP-91C was evaluated by having the vendor
analyze 197 soil and sediment samples. These 197
samples consisted of high-, medium-, and low-
concentration field samples from four sites, SRMs, and
spiked field samples. Table 8-1 provides a breakdown of
the numbers of these samples for each sample type, and
concentration range orsource. Collectively, these samples
provided the different matrices, concentrations, and types
of mercury needed to perform a comprehensive evaluation
of the RA-915+/RP-91C.
8.1 Primary Objectives
The primary objectives of the demonstration were centered
on evaluation of the field instrument and performance in
relation to sensitivity, accuracy, precision, time foranalysis,
and cost. Each of these objectives was discussed in detail
in previous chapters and is summarized in the following
paragraphs. The overall demonstration results suggest
that the experimental design was successful for evaluation
of the Ohio Lumex RA-915+/RP-91C. Quantitative results
were reviewed. The results from this field instrument were
found to be comparable to standard analyses performed by
the laboratory in terms of precision, and accuracy in
comparison to SRMs. Field sample analyses were not
found to be comparable, however, to referee laboratory
results. The collected data provide evidence to support
these statements.
The two primary sensitivity evaluations performed for this
demonstration were the MDL and POL. Following
procedures established in 40 CFR Part 136, the MDL is
between 0.0053 and 0.042 mg/kg based on the results of
seven replicate analyses for low standards. The equivalent
MDL for the referee laboratory is 0.0026 mg/kg. The
calculated MDL is only intended as a statical estimation
and not a true test of instrument sensitivity.
The low standard calculations using MDL values suggest
that a POL for the Ohio Lumex field instrument may be as
low as 0.027mg/kg (5 times the lowest calculated MDL).
The referee laboratory POL confirmed during the
demonstration is 0.005 mg/kg with a %D of <10%. The
%D for the average Ohio Lumex result for a tested sample
with a referee laboratory value of 0.06 mg/kg is 0.072
mg/kg, with a %D of 20%. This was the lowest sample
concentration tested during the demonstration that is close
to, but not below, the calculated POL noted above. Both
the MDL and POL were determined for soils and
sediments.
Accuracy was evaluated by comparison to SRMs and
comparison to the referee laboratory analysis for field
samples. This included spiked field samples for evaluation
of additional concentrations not otherwise available. In
summary, Ohio Lumex data were within SRM 95%
prediction intervals 93% of the time, which suggests
significant equivalence to certified standards. The
comparison between the Ohio Lumex field data and the
ALSI results, however, suggest that the two data sets are
notthe same. When a unified hypothesis testis performed
(which accounts for laboratory bias), this result is
confirmed. Ohio Lumex data were found to be both above
and below referee laboratory concentrations, therefore
there is no implied or suggested bias. The number of Ohio
Lumex average values less than 30% different from the
referee laboratory results or SRM reference values;
however, was 19 of 33 different sample lots. Ohio Lumex
results, therefore, can often provide a reasonable estimate
of accuracy for field determination, and may be affected by
interferences notidentified bythis demonstration. Because
the Ohio Lumex data compare favorably to the SRM
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values, the differences between Ohio Lumex and the
referee laboratory are likely the result of matrix
interferences.
The precision was determined by analysis of replicate
samples. The precision of the Ohio Lumex field instrument
is better than the referee laboratory precision. The overall
average RSD, is 22.3% for the referee laboratory
compared to the Ohio Lumex average RSD of 16.1%. This
is primarily because of the better precision obtained for the
SRM analyses by Ohio Lumex. Both the laboratory
precision and the Ohio Lumex precision goals of 25%
overall RSD were achieved.
Time measurements were based on the length of time the
operator spent performing all phases of the analysis,
including setup, calibration, and sample analyses (including
all reanalysis). Ohio Lumex analyzed 197 samples in
1,275 minutes times 1.25 analysts over three days, which
averaged to 8.1 minutes per sample result. Based on this,
an operator could be expected to analyze 59 samples (8
hours x 60 minutes •*• 8.1 minutes/sample) in a 8-hourday.
Cost of the Ohio Lumex sample analyses included capital,
supplies, labor, support equipment, and waste disposal.
The cost per sample was calculated both with and without
the cost of the instrument included. This was performed
because the first sample requires that the instrument is
either purchased or rented, and as the sample number
increases, the cost per sample would decrease. A
comparison of the field Ohio Lumex cost to off-site
laboratory cost was not made. To compare the field and
laboratory costs correctly, it would be necessary to include
the expense incurred to the project due to waiting for
analysis results to return from the laboratory (potentially
several mobilizations and demobilizations, stand-by fees,
and other aspects associated with field activities).
Table 8-2 summarizes the results of the primary
objectives.
8.2 Secondary Objectives
Table 8-3 summarizes the results of the secondary
objectives.
Table 8-1. Distribution of Samples Prepared for Ohio Lumex and the Referee Laboratory
Site
(Subtotal = 17)
Subtotal
Concentration Range
Soil
Sediment
Sample Type
Spiked Soil
SRM
Carson River
(Subtotal = 62)
Puget Sound
(Subtotal = 67)
Oak Ridge
(Subtotal = 51)
Manufacturing
Low(1-500ppb)
Mid (0.5-50 ppm)
High (50->1,000 ppm)
Low (1 ppb - 10 ppm)
High (10-500 ppm)
Low (0.1 -10 ppm)
High (10-800 ppm)
General (5-1,000 ppm)
3
0
0
30
0
10
3
10
10
0
0
0
3
7
6
0
7
7
0
14
7
7
0
0
7
28
0
13
0
14
4
7
56
26
42
73
62
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Table 8-2. Summary of RA-915+/RP-91C Results for the Primary Objectives
Demonstration
Objective
Instrument
Sensitivity
Evaluation Basis Performance Results
RA-915+/RP-91C
MDL. Method from 40 CFR Part 1 36. Between 0.0053 and 0.042
mg/kg
Reference Method
0.0026 mg/kg
Accuracy
Precision
Time per Analysis
Cost
PQL. Low concentration SRMs or
samples.
Comparison to SRMs, field, and spiked
samples covering the entire range of the
instrument calibration.
Determined by analysis of replicate samples
at several concentrations.
Timed daily operations for 2.5 days and
divided the total time by the total number of
analyses.
Costs were provided by Ohio Lumex and
independent suppliers of support equipment
and supplies. Labor costs were estimated
based on a salary survey. IDW costs were
estimated from the actual costs encountered
at the Oak Ridge demonstration.
< 0.06 mg/kg
0.005mg/kg
Ohio Lumex data were within SRM 95% prediction
intervals 93% of the time. 19 of 33 different sample lots
within 30% of referee laboratory value.
Ohio Lumex overall average RSD; 16.1%
One technician performed half of the equipment setup
and demobilization, most sample preparation, and all
calibration checks and analyses. Individual analyses
took 1 minute each, but the total time per analysis
averaged approximately 8.1 minutes per sample.
The cost per analyses based upon 197 samples, when
renting the RA-915+/RP-91C, is $23.44 per sample. The
cost per analyses for the 197 samples, excluding capital
cost, is $15.82 per sample. The total cost for equipment
rental and necessary supplies during the demonstration
is estimated at $4,617. The cost breakout by category is:
capital costs, 32.5%; supplies, 10.8%; support
equipment, 6.0%; labor, 19.5%; and IDW, 31.2%.
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Table 8-3. Summary of RA-915+/RP-91C Results for the Secondary Objectives
Demonstration
Objective
Evaluation Basis
Performance Results
Ease of Use
Field observations during the demonstration.
Health and Safety Observation of equipment, operating
Concerns procedures, and equipment certifications
during the demonstration.
Portability of the
Device
Review of device specifications,
measurement of key components, and
observation of equipment setup and tear
down before, during, and after the
demonstration.
Instrument
Durability
Availability of
Vendor
Instruments and
Supplies
Observation of equipment design and
construction, and evaluation of any
necessary repairs or instrument downtime
during the demonstration.
Review of vendor website and telephone
calls to the vendor after the demonstration.
The RA-915+/RP-91C combination is reasonably easy to
operate; lack of automation somewhat impairs the ease
of use. Operation requires one field technician with a
basic knowledge of chemistry acquired on the job or in a
university, and training on the instrument.
No significant health and safety concerns were noted
during the demonstration. The only potential health and
safety concerns identified were the generation of mercury
vapors and the potential for bums with careless handling
of hot quartz sample boats. The vendor provides a
mercury filter as standard equipment; exercising caution
and good laboratory practices can mitigate the potential
for burns.
The RA-915+ air analyzer was easily portable, although
the device, even when carried in the canvas sling, was
not considered light-weight. The addition of the RP-91C
and associated pump unit preclude this from being a truly
field portable instrument. The device and attachments
can be transported in carrying cases by two people, but
must then be set up in a stationary location. It was easy
to set up, but the combined instrument is better
characterized as mobile rather than field portable.
The RA-915+/RP-91C combination was well designed
and constructed for durability.
The RA-915+/RP-91C combination is readily available
for rental, lease, or purchase. Spare parts and
consumable supplies can be added to the original
instrument order or can be received within 24-48 hours of
order placement. Standards are readily available from
laboratory supply firms or can be acquired through Ohio
Lumex.
64
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Section 9
Bibliography
Anchor Environmental. 2000. Engineering Design
Report, Interim Remedial Action Log Pond Cleanup/
Habitat Restoration Whatcom Waterway Site,
Bellingham, WA. Prepared for Georgia Pacific West,
Inc. by AnchorEnvironmental, L.L.C., Seattle, WA. July
31, 2000.
Confidential Manufacturing Site. 2002. Soil Boring Data
from a Remedial Investigation Conducted in 2000.
Ohio Lumex, 2001. Portable Zeeman Mercury Anlyzer:
RA-915+ Analyzer; RP-91 and RP-91C Attachments.
2001.
Rothchild, E.R., R.R. Turner, S.H. Stow, M.A. Bogle, L.K.
Hyder, O.M. Sealand, H.J. Wyrick. 1984. Investigation
of Subsurface Mercury at the Oak Ridge Y-12 Plant.
Oak Ridge National Laboratory, TN. ORNL/TM-9092.
U.S. Environmental Protection Agency. 1994. Region 9.
Human Health Risk Assessment and Remedial
Investigation Report - Carson River Mercury Site
(Revised Draft). December 1 994.
U.S. Environmental Protection Agency. 1995.
Contaminants and Remedial Options at Selected
Metal-Contaminated Sites. July 1995. Washington
D.C. EPA/540/R-95/512.
U.S. Environmental Protection Agency. 1996. Test
Methods for Evaluating Solid Waste,
Physical/Chemical Methods, SW-846 CD ROM, which
contains updates for 1986, 1992, 1994, and 1996.
Washington DC.
U.S. Department of Energy. 1998. Report on the
Remedial Investigation of the Upper East Fork of
Poplar Creek Characterization Area at the Oak Ridge
Y-12 Plant, Oak Ridge, TN. DOE/OR/01-1641&D2.
U.S. Environmental Protection Agency. 1998.
Unpublished. Quality Assurance Project Plan
Requirements for Applied Research Projects, August
1998.
U.S. Environmental Protection Agency. 2002a. Region
9 Internet Web Site, www.epa.gov/region9/index. html.
U.S. Environmental Protection Agency. 2002b.
Guidance on Data Quality Indicators. EPA G-5i,
Washington D.C., July 2002.
U.S. Environmental Protection Agency. 2003. Field
Demonstration Quality Assurance Project Plan - Field
Analysis of Mercury in Soil and Sediment. August
2003. Washington D.C., EPA/600/R-03/053.
Wilcox, J.W., Chairman. 1983. Mercury at Y-12: A
Summary of the 1983 UCC-ND Task Force Study.
Report Y/EX-23, November 1983.
www.OhioLumex.com, 2003.
65
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Appendix A
Ohio Lumex Comments
Accuracy and Precision
The accuracy of the instrument was tested in field
conditions and this may have caused a loss of one sample
result data. Also, one sample was entered in the data
sheet as 0.16 ug/kg instead of 160 ug/kg. Nevertheless,
the demonstrated accuracy (95% for SRM) and precision
(average RSD for reference laboratory was 22.3%, the
average RSD for Ohio Lumex was 16.1% or 7.6 % for
SRM) of the Ohio Lumex instrument was better than
results obtained by a reference laboratory.
Method Detection and Practical Quantitation Limits
The method detection limits (MDLs) and practical
quantitation limits (PQLs) determined by the results of
testing were obtained for conditions specifically set for the
instrument to expand the upper (high concentration) range
to 200 mg/kg. A simple change of instrument parameters
will enable the operator to change the MDL and POL to
0.001 mg/kg and 0.005mg/kg respectively. A specifically
developed Pyro 915 attachment for ultra low direct mercury
measurements enables one to achieve MDL/PQL
0.0001mg/kg and 0.0005 mg/kg.
Automation
Since the time of the testing, Ohio Lumex has developed
a balance interface to automatically enter sample size into
a computer spread sheet.
Auto Sampler- The turnaround time to analyze an
individual sample is 1 minute. 25+ samples can be
manually processed in an hour over an 8-hour day, an
average of 2.4 minutes per sample. The time required only
to load an auto sampler will be up to 10 minutes per
sample. Also, addition of the auto sampler will affect the
reliability and portability of the system.
Portability
The instrument consist of two modules and can be easily
packed in one rolling pelican case with total weight of the
system not exceeding 60 pounds. No compressed gases
are required. Set-up time from unpacking to operation is
within 1 hour. We also have many customers using these
settings in the field in remote locations while using portable
power generators.
This appendix was written solely by Ohio Lumex. The statements presented in this appendix represent the developer's point of view and
summarize the claims made by the developer regarding the RA-915+/RP-91C. Publication of this material does not represent EPA's approval
or endorsement of the statements made in this appendix; performance assessment and economic analysis results for the RA-915+/RP-91C are
discussed in the body of the ITVR.
66
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Appendix B
Statistical Analysis
Two separate hypothesis tests were used to compare the
referee laboratory samples to the vendor tested samples.
This appendix details the equations and information for
both of these statistical analyses. For purposes of this
appendix, we have chosen to call the test comparing
sample populations using a separate calculation for each
sample lot the "hypothesis test," and the statistical
comparison of the entire sample set (all 33 separate
sample lots) analyzed by the vendor and the laboratory the
"unified hypothesis test," also known as an "aggregate
analysis" for all of the sample lots.
Hypothesis Test
A hypothesis test is used to determine if two sample
populations are significantly different. The analysis is
performed based on standard statistical calculations for
hypothesis testing. This incorporates a comparison
between the two sample populations assuming a specified
level of significance. For establishing the hypothesis test,
it was assumed that both sample sets are equal.
Therefore, if the null hypothesis is rejected, then the
sample sets are not considered equal. This test was
performed on all sample lots analyzed by both Ohio Lumex
and the referee laboratory. H0 and Ha, null and alternative
hypothesis respectively, were tested with a 0.01 level of
significance (LOS). The concern related to this test is that,
if two sample populations have highly variable data (poor
precision), then the null hypothesis may be accepted
because of the test's inability to exclude poor precision as
a mitigating factor. Highly variable data results in wider
acceptance windows, and therefore, allows for acceptance
of the null hypothesis. Conclusions regarding this analysis
are presented in the main body of the report.
To determine if the two sample sets are significantly
different, the absolute value of the difference between the
laboratory average XL and the vendor average xv is
compared to a calculated u. When the absolute value of
the difference is greater than u, then the alternate
hypothesis is accepted, and the two sets (laboratory and
vendor) are concluded to be different.
To calculate u, the variances for the laboratory data set
and the vendor data set are calculated by dividing their
standard deviations by the number of samples in their data
set. The effective number of degrees of freedom is then
calculated.
Where:
f
V,
Vv
= effective number of degrees of freedom
= variance for the laboratory results
= number of samples for the laboratory
data set
= variance for the vendor results
= number of samples for the vendor data
set.
The degrees of freedom (f) is used to determine the
appropriate "t" value and used to calculate u at the 0.01
level of significance using the following:
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Unified Hypothesis Test
For a specified vendor, let Y,j be the measured Hg
concentration for the f replicate of the ith sample for
/=1,2,...,l and)= 1,2,...,Ji. LetX^= log(Y^), where log is the
logarithm to the base 10. Define x,log to be the average
over all log replicates for the Ith sample given by:
Where x M is approximately a chi-square random variable
with (1-1) degrees of freedom:
5 = 7
-'
tog
z'log
ilog
-J
'
log
and
Denote the estimate of the variance of the log replicates for
the Ith sample to be:
-1
Now for the reference laboratory, let Y',y be the measured
Hg concentration for the/1 replicate of the ith sample for
/ =1,2,...,!' and j = 1,2,. ...J',. Denote the reference
laboratory quantities X',j, x/, and s'2 defined in a manner
similar to the corresponding quantities for the vendor.
Assumptions: Assume that the vendormeasurements, Y,y,
are independent and identically distributed according to a
lognormal distribution with parameters u,and o2. That is,
X,y= log(Y,y) is distributed according to a normal distribution
with expected value u,and variance o2. Further, assume
that the reference laboratory measurements, Y',j, are
independent and identically distributed according to a
lognormal distribution with parameters u',and o'2.
The null hypothesis to be tested is:
HQ : /jj = fj'j + 5, for some S and i = I,..., I
against the alternative hypothesis that the equality does not
hold for at least one value of /.
The null hypothesis H0 is rejected for large values of:
Zi-i =
i-1
i-i
1 pool
Critical values for the hypothesis test are the upper
percentile of the chi-square distribution with (1-1) degrees
of freedom obtained from a chi-square table.
Results of Unified Hypothesis Test for Ohio Lumex
SAIC performed a unified hypothesis test analysis to
assess the comparability of analytical results provided by
Ohio Lumex and those provided by ALSI. Ohio Lumex
and ALSI both supplied multiple assays on replicates
derived from a total of 33 different sample lots, be they
field materials or reference materials with sample lots 35
and 55 excluded because these were below the
instrument POL. The Ohio Lumex and ALSI data from
these assays formed the basis of this assessment.
The statistical analysis is based on log-transformed
(logarithm base 10) data and uses a chi-square test for
equality of Ohio Lumex and ALSI population means for
given sample lot. Equality of variances is assumed.
Initially, the null hypothesis tested was that, on average,
Ohio Lumex and ALSI would produce the same results
within a given sample lot. This hypothesis is stated as
H10: (Ohio Lumex Lot log mean) = (ALSI Lot log mean)
H10 was rejected in that the chi-square statistic was
130.26, which exceeds the upper 99th percentile of the
chi-square distribution with 33 degrees of freedom
having a value of 54.78.
The null hypothesis was rejected in part because Ohio
Lumex results tended to exceed those from ALSI for the
same sample lot. To explore this effect, the null
68
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hypothesis was revised to included a bias term in the
form of
H20: (Ohio Lumex Lot log mean) = (ALSI Lot log mean)
+(delta),
where delta is a single value that does not change from
one sample lot to another, unlike the lot log means. H20
was rejected strongly in that the chi-square statistic was
101.46, which exceeded the upper 99th percentile of the
chi-square distribution with 32 degrees of freedom with a
value of 53.49. In this analysis, delta was estimated to
be 0.133 in logarithmic (base 10) space, which indicates
an average upward bias for Ohio Lumex of 100121=1.358
or about 36%.
For both hypotheses, the large values of the chi-square
test statistics summarize the disagreement between the
Ohio Lumex and ALSI analytical results. Furthermore, a
review of the statistical analysis details indicates that the
overall discordance between Ohio Lumex and ALSI
analytical results cannot be traced to the disagreement in
results for one or two sample lots.
Summary information on these analyses is provided in
Table B-1. The p-value can be considered as a
significance level. This is a calculated value and usually
when one sets a p-value (e.g., 95% confidence level
which translates to a p-value of 0.05), this value is used
to test the level of significance for comparison. As noted
in Table B-1 the p-value is calculated from the test
statistics and therefore it can be seen that because the
p-value is so small (< 0.000000) the two sample
populations are considered to be non-equivalent and
hence the large chi-square value.
Table B-1. Unified Hypothesis Test Summary Information
Hypothesis
HIO
H™
1 Ulcll OeUlljJII
Lots
33
33
" Excluded Lot
35, 55
35,55
DF
33
32
S pool
0.03967
0.03967
Delta
0.0000
0.1329
Chi-square
130.26
101.46
P-value
0.000000
0.000000
69
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