&EPA
United States
Environmental Protection
Agency
Office of
Research and Development
Washington, DC 20460
EPA/600/R-03/148
May 2004
Innovative Technology
Verification Report
Field Measurement Technology for
Mercury in Soil and Sediment
NITON'S XLi/XLt 700 Series
X-Ray Fluorescence Analyzers
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EPA/600/R-03/148
May 2004
Innovative Technology
Verification Report
NITON'S XLi/XLt 700 Series
X-Ray Fluorescence Analyzers
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
hot 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: NITON'sฎ XLi/XLt 700 Series Environmental Analyzers
COMPANY: NITON LLC
ADDRESS: 900 Middlesex Turnpike, Building 8
Billerica, Massachusetts 01821
WEB SITE: www.niton.com
TELEPHONE: (978) 670-7460
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 the demonstrations of two XLi/XLt 700 Series X-ray Fluorescence
Analyzers developed by NITON Inc.
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 measurem enttechnologies, 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 XLi/XLt 700 Series Analyzers XLi 702 (isotope) and XLt
792 (X-ray tube) and four other field measurement devices for mercury in soil and sediment. This verification statement
focuses on these two analyzers; a similar statement has been prepared for each of the other four devices. The
performance of each of these two X-ray fluorescence analyzers was compared to that of an off-site laboratory using
the reference method, "Test Methods for Evaluating Solid Waste" (SW-846) Method 7471B (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 (PQL);
(2) Determining the analytical accuracy associated with the field measurement technologies;
(3) Evaluating the precision of the field measurement technologies;
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(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 the skills and training required to properly operate the devices;
(2) Documenting potential health and safety concerns associated with operating the devices;
(3). Documenting the portability of the devices;
(4) Evaluating the devices durability based on their materials of construction and engineering design; and
(5) Documenting the availability of the devices and associated spare parts.
The XLi/XLt 700 Series Analyzers analyzed 62 field soil samples, 23 field sediment samples, 42 spiked field samples,
and 70 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 field and PE samples provided the different matrix types and the different concentrations of mercury
needed to perform a comprehensive evaluation of the XLi/XLt 700 Series Analyzers. 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 SedimentNITON's XLi/XLt 700 Series X-Ray Fluorescence
Analyzers" (EPA/600/R-03/148).
TECHNOLOGY DESCRIPTION
The NITON XL 700 series analyzer is an energy dispersive X-ray fluorescence (EDXRF) spectrometer that uses either
a Cd-109 radioactive isotope (XLi mod el) or a low powered miniature X-ray tube with a silver target (XLt model) to excite
characteristic X-rays of a test sample's constituent elements. These characteristic X-rays are continuously detected,
identified, and quantified by the spectrometer during sample analysis. The energy of each X-ray detected identifies a
particular element present in the sample, and the rate at which X-rays of a given energy are counted provides a
determination of the quantity of that element that is present in the sample.
Detection ofthe characteristic mercury X-rays is achieved using a highly-efficient, therm o-electrically cooled,solid-state
detector. Signals from this detector are amplified, digitized, and then quantified via integral multichannel analysis and
data processing units. Results are displayed in ppm (mg/kg) of total elemental mercury.
The NITON XLt 700 Series Analyzer with X-ray tube excitation provides the user with the speed and efficiency of X-ray
tube excitation, while reducing the regulatory demands typically encountered with isotope-based systems. In most
cases, the X-ray tube equipped XLt 700 analyzer can be shipped between most states and countries with minimal
paperwork and expense. The XLi and XLt 700 Series Analyzers offer testing modes for soil and other bulk samples;
filters, wipes and other thin samples; and lead-based paint. Testing applications include management of remediation
projects, site assessments, and compliance testing. They provide simultaneous analysis of up to 25 elements, including
all eight of the characteristic metals underthe Resource Conservation and Recovery Act (RCRA). XRF analysis is non-
destructive, so screened samples can be sent to an accredited laboratory for confirmation of results obtained on-site.
NITON's software corrects automatically for variations in soil matrix and density, making it applicable for both in-situ
and intrusive testing.
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 (PRGs) for mercury are
23 mg/kg in residential soil and 310 mg/kg in industrial soil.
IV
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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
range of the MDL for the NITON X-ray tube instrument is between 13.9 and 69.8 mg/kg. It is likely that the MDL is
closer to the lower end of this range based upon the results for sample lot 62 (referee laboratory value = 14.6 mg/kg)
and sample lot 47 (SRM value = 32.4 mg/kg) which both had one of the seven results reported as below the NITON
detection level indicating that these values are on the edge of the instruments detection capability. The lowest
calculated MDL for the NITON Isotope instrument is 39.3 mg/kg. Based, upon results presented in the report, the MDL
for the NITON Isotope field instrument is close to 32 mg/kg. The equivalent calculated MDL for the referee laboratory
is 0.0026 mg/kg.
Practical Quantitation Limit- The NITON X-ray PQL is somewhere between 62.9 mg/kg and 99. 8 mg/kg. The %D for
the 99.8 mg/kg SRM is 8.2%. The NITON Isotope PQL is also between 62.9 mg/kg and 99.8 mg/kg. The %D for the
99.8 mg/kg SRM is 9.2%. The referee laboratory PQL confirmed during the demonstration is 0.005mg/kg, with a %D
Accuracy: The results from the XLi/XLt 700 Series Analyzers were compared to the 95% prediction interval for the SRM
materials and to the referee laboratory results (Method 7471.B). NITON X-ray data were within SRM 95% prediction
interva Is 93% of thetime, which suggests significantequivalence to certified standards. NITON Isotope data were within
SRM 95% prediction intervals 91% of the time, which also suggest significant equivalence to certified standards.
The statistical comparison between the NITON X-ray field data and the referee laboratory results suggest that the two
data sets are not the same. The statistical comparison between the NITON Isotope fie Id data and the referee laboratory
results also suggest that these two data sets are not the same. Because the NITON data compare favorably to the
SRM values, the differences between NITON and the referee laboratory are likely the result of matrix interferences for
field sample analysis. The number of NITON X-ray average values less than 30% different from the referee laboratory
results or SRM reference values; however, was 14 of 26 different sample lots. Only 1 of 26 NITON average results
have relative percent differences greater than 100% for this same group of samples. The number of NITON Isotope
average values less than 30% different from the referee laboratory results or SRM reference values was 14 of 24
different sample lots. Zero of 24 NITON Isotope average results have relative percent differences greater than 100%
for this same group of samples. Both NITON X-ray and NITON Isotope results; therefore, can provide a reasonable
estimate of accuracy for field determination.
Precision: The precision of the NITON X-ray and NITON Isotope field instruments is betterthen the referee laboratory
precision. The overall average RSD is 20.0% for the referee laboratory, compared to the NITON X-ray overall average
RSD of 13.1% and the NITON Isotope overall average RSD of 14.4%. Both the laboratory and NITON precision goals
are within the predicted 25% RSD objective for precision expected from both analytical and sampling variance.
Measurement Time: From the time of sample receipt, NITON required 17.5 hours (35 man hours) to prepare a draft
data package of mercury results for 197 samples for both devices. Two technicians performed all setup, sample
preparation and analysis, and equipment demobilization. Individual measurements took approximately 120 seconds
each (after sample preparation), but the total time per analysis averaged 5.3 minutes when all field activities and data
package preparation were included and only one technician per device .is included in the calculation.
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Measurement Costs: The cost per analysis based upon 197 samples, wherr renting the XLi 702, is $39.52 per sample.
The cost per analysis for the 197 samples, excluding rental fee, is $13.18 per sample. Based on the 3-day field
demonstration, the total cost for equipment rental and necessary supplies is estimated at $7,786. The cost breakout
by category is: capital costs, 66.7%; supplies, 3.6%; support equipment, 3.5%; labor, 7.7%; and IDW, 18.5%.
The cost peranalysis based upon 197 samples, when renting the XLt 792, is $47.69 persample. The cost per analysis
for the 197 samples, excluding rental fee, is $13.18 persample. Based on the 3-day field demonstration, the total cost
for equipment rental and necessary supplies is estimated at $9,396. The cost breakout by category is: capital costs,
72.4%; supplies, 3.0%; support equipment, 2.9%; labor, 6.4%; and IDW, 15.3%.
Key demonstration findings are summarized below for the secondary objectives.
Ease of Use: Based on observations made during the demonstration, the XLi/XLt 700 Series Analyzers are very easy
to operate, requiring one field technician with a high school education. A free 8-hour training course on instrument
operation and radiation safety is mandatory prior to operating the instruments. The analyzers contain an integrated
touch-screen display with an advanced and intuitive user interface.
Potential Health and Safety Concerns: No significant health and safety concerns were noted during the
demonstration. Potential exposure to radiation from the excitation sources (Cd-109, Am-241, Fe-55 and X-ray tube)
was the only health and safety concern during the demonstration. The analyzers should never be pointed at anyone
while the sources are exposed. No solvents or acids are used for sample preparation. According to NITON, the
sources are designed to remain secure even under extreme conditions, so that even if the instrument is broken, crushed
or burned there should be no leakage of radioactive material.
Portability: The XLi/XLt 700 Series Analyzers are handheld portable single piece units weigh only 0.8 kg (XLi 702) and
1.4 kg (XLt 792). There are no cables and no separate processing units. The analyzers have an attractive ergonomic
form. During the demonstration, the analyzers each operated on 1 battery pack that lasted for 4-8 hours.
Durability: Based on observations during the demonstration, the analyzers were-well constructed, field-rugged and
durable. They are constructed of high-strength injection molded plastic. During the three days in which the instrument
was observed, there was no downtime, maintenance or repairs. The equipment apparently was not affected by the
almost continuous rain.
Availability of the Devices: The XLi/XLt 700 Series Analyzers are readily available for lease or purchase. During
most of the year, NITON is typically able to rent an analyzer to a customer in 10-14 days (10 isotope rentals and 3 X-ray
tube rentals). There are also radiation licensing requirements forthese devices. NITON offers over 100 user/radiation
training classes to help expedite the process. Supplies not provided by NITON are readily available from supply firms.
PERFORMANCE SUMMARY
In summary, during the demonstration, the XLi 702 and XLt 792 exhibited the following desirable characteristics of a
field mercury measurement device: (1) good accuracy compared to standard reference materials, (2) good precision,
(3) high sample throughput, (4) low measurement costs, and (5) ease of use. During the demonstration the XLi 702
and XLt 792 were found to have the following limitations: (1) a PQL that exceeds the residential soil PRG action limit.
The XLi/XLt 700 Series Analyzers are handheld devices for rapid field measurements of 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 ata 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
NITON's XLi/XLt 700 Series X-ray fluorescence analyzers were demonstrated under the U.S. Environmental Protection
Agency Superfund Innovative Technology Evaluation Program in May 2003 atthe Oak Ridge National Laboratory (ORNL)
in Oak Ridge, TN. The purpose of the demonstration was to collect reliable performance and cost data for the XLi 702
and XLt 792 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 (PQL); 2) determine analytical accuracy associated with vendor field 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 involved analysis of SRMs, field samples collected from four sites, and spiked field samples for
mercury. The performance results for a 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 7471B.
The sensitivity, accuracy, and precision measurements were successfully completed for both instruments. Results with
the XLi 702 were found to be very precise and accurate when compared to standard reference materials. During the
demonstration, NITON required 17.5 hours (assumes one technician) for analysis of 197 samples. The measurement
costs were estimated to be $7,786 for NITON's XLi 702 rental option, or $39.52 per sample; $13.18 per sample excluding
rental costs.
Results for the XLt 792 was found to be very precise and accurate when compared to standard reference materials. During
the demonstration, NITON required 17.5 hours (assumes one technician) for analysis of 197 samples. The measurement
costs were estimated to be $9,396 for NITON's XLi 792 rental option, or $47.69 per sample; $13.18 per sample excluding
rental costs.
The XLi/XLt 700 Series Analyzers exhibited good ease of use and durability, as well as no major health and safety
concerns. The analyzers are hand-held single units and extremely portable. The demonstration findings collectively
indicated that the XLi/XLt 700 Series Analyzers are rapid, lightweight, hand-held portable field measurement devices for
mercury in soil.
viii
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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
Acknowledgm ents xvi
Chapter Page
1 Introduction 1
1.1 Description of the 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 Chem istry 3
1.3.2 Mercury Analysis 4
2 Technology Description 6
2.1 Description of X-Ray Fluorescence 6
2.1.1 Theory of E DXRF Analysis 6
2.1.2 System Components 7
2.2 NITON XLi/XLt 700 Series Technology Description 7
2.3 Developer Contact Information 8
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
IX
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Contents (Continued)
Chapter Page
3.3 Confidential Manufacturing Site 11
3.3.1 Site Description 11
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
4 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
5 Assessment of Laboratory Quality Control Measurements 29
5.1 Laboratory QA Sum mary 29
5.2 Data Quality Indicators for Mercury Analysis 29
5.3 Conclusions and Data Quality Limitations 30
5.4 Audit Findings 32
6 Performance of the XLi/XLt 700 Series Analyzers 33
6.1 Primary Objectives 33
6.1.1 Sensitivity 33
6.1.2 Accuracy 37
6.1.3 Precision 48
6.1.4 Time Required for Mercury Measurement 53
6.1.5 Cost .54
6.2 Secondary Objectives 54
6.2.1 Ease of Use 54
6.2.2 Health and Safety Concerns : 56
6.2.3 Portability of the Device 57
6.2.4 Instrument Durability 57
6.2.5 Availability of Vendor Instruments and Supplies 58
7 Econom ic Analysis 59
7.1 Issues and Assumptions 59
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Contents (Continued)
Chapter Page
7.1.1 Capital Equipment Cost 59
7.1.2 Cost of Supplies '. 60
7.1.3 Support Equipment Cost 60
7.1.4 Labor Cost 60
7.1.5 Investigation-Derived Waste Disposal Cost 60
7.1.6 Costs Not Included 61
7.2 XLi/XLt 700 Series Analyzers Costs 61
7.2.1 Capital Equipment Cost 61
7.2.2 Cost of Supplies 63
7.2.3 Support Equipment Cost 63
7.2.4 Labor Cost 63
7.2.5 Investigation-Derived Waste Disposal Cost 63
7.2.6 Summary of XLi/XLt 700 Series Costs 63
7.3 Typical Reference Method Costs . .. . . 65
8 Summary of Demonstration Results 66
8.1 Primary Objectives 66
8.2 Secondary Objectives 67
9 Bibliography 70
Appendix A - NITON Comments : - 71
Appendix B - Statistical Analysis 74
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 Summary 31
5-4 Low Check Standards 31
6-1 Distribution of Samples Prepared for NITON and the Referee Laboratory 33
6-2 NITON SRM Comparison (XLt) 38
6-3 NITON SRM Comparison (XLi) 38
6-4 ALSI SRM Com parison 38
6-5 Accuracy Evaluation by Hypothesis Testing (XLt) 40
6-6 Accuracy Evaluation by Hypothesis Testing (XLi) 41
6-7 Number of Sample Lots Within Each%D Range (XLt) 43
6-8 Number of Sample Lots Within Each %D Range (XLi) 45
6-9 Concentration of Non-Target Analytes 47
6-10 Evaluation of Precision (XLt) .- 49
6-11 Evaluation of Precision (XLi) 51
6-12 Mercury Measurement Tjmes 54
7-1 Capital Cost Summary for the XLi/XLt 700 Series Analyzers 62
7-2 Labor Costs 63
7-3 IDW Costs 63
7-4 Summary of Rental Costs for the XLi 702 (Isotope) 64
7-5 Summary of Rental Costs for the XLt (X-Ray Tube) 64
7-6 XLi 702 (Isotope) Costs by Category 65
7-7 XLt (X-Ray Tube) Costs by Category 65
8-1 Distribution of Sam pies Prepared for NITON and the Referee Laboratory 67
8-2 Summary of NITON XLi/XLT 700 Series Analyzers Results for the Primary Objectives 68
8-3 Summary of NITON XLi/XLt 700 Series Analyzers Results for the Secondary Objectives 69
B-1 Unified Hypothesis Test Summary Information for the NITON XLi Instrument 76
B-2 Unified Hypothesis Test Summary Information for the NITON XLt Instrument 77
xii
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Figures
Figure Page
2-1 Basic x-ray fluorescence process , 6
2-2 Photograph of the NITON XLi/XLt 700 Series instruments during the field demonstration 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 the NITON XLt low concentration sample results 43
6-2 Data plot for the NITON XLt high concentration sample results 44
6-3 Data plot for the NITON XLi low concentration sample results 45
6-4 Data plot for the NITON XLi high concentration sample results 46
6-5 Main menu screen shot 55
6-6 Screen shot of sample spectra 55
6-7 Multi-element data report 56
7-1 Capital equipment costs for the XLi (isotope) 62
7-2 Capital equipment costs for the XLt (X-ray tube) 62
A-1 . Comparison of precision, all samples, laboratory and model XLt 73
XIII
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Abbreviations, Acronyms, and Symbols
% Percent
%D Percent difference
ฐC Degrees Celsius
ug/kg Microgram per kilogram
g/L Gram per liter
AAS Atomic absorption spectrometry
ALSI Analytical Laboratory Services, Inc.
bgs Below ground surface
cm Centimeter
CFR Code of Federal Regulations
Cl Confidence Interval
COC Chain of Custody
DOE Department of Energy
EDXRF Energy Dispersive X-ray Fluorescence
EPA United States Environmental Protection Agency
FPXRF Field Portable X-ray Fluorescence
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
MMT Monitoring and Measurement Technology
MS/MSD Matrix Spike/Matrix Spike Duplicate
NERL National Exposure Research Laboratory
ng Nanogram
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
PQL 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) Supeffund 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 Energy Oak Ridge National Laboratory (ORNL); Stephen Childs, Thomas Early, Roger Jenkins,
and Monty Ross of the UT-Battelle ORNL; Dale Rector of the Tennessee Department of Environment and Conservation
(TDEC) Department of Energy Oversight; VolkerThomsen, Debbie Schatzlein, and David Mercuro of NITON, lnc;Leroy
Lewis of the Idaho National Engineering and Environmental Laboratory, retired; Ishwar Murarka of the 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 NITON'S XLi/XLt 700 Series X-ray fluorescence
instruments, designated as XLi 702 and XLt 792. 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) Prog ram.
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 under well-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 Office of Solid Waste and Emergency
Response (OSWER) and ORD under the Superfund
Amendments and Reauthorization Act of 1986.
The overall goal of the SITE Program is to conduct
performance verification studies and to promote the
acceptance of innovative technologies that may be used to
achieve long-term protection of human health and the
environment. The program is designed tomeetthree 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
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better, faster, or more cost-effective methods for
producing real-time data during site characterization
and remediation studies than conventional
technologies.
The Remediation Technology Program conducts
dem onstrations 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), arid 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 10companies
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 dem onstration, data
analysis, data interpretation, and preparation of the ITVRs.
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Phase II included pre-demonstration and demonstration
activities, as described in the following subsections.
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.
Select a 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
for homogenization. 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 for achieving 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 byadding 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 ฐC
-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+), elementalform (Hgฐ),
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 biot'c 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 CI" and
CO32". Mercury (II) also forms complexes with inorganic
ligands such as fluoride (F~), bromide (Br~), iodide (I"),
sulfate (SO42-), sulfide (S2'), and phosphate (PO,,3") and
forms strong complexes with organic ligands, such as
sulfhydryl groups, amino acids, and humic and fulvic acids.
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 Type(s)of Approximate
Technology Mercury analyzed Concentration Range
Comments
SW-7471B CVAAS
SW-7472 ASV .
SW-7473
TD,
amalgamation,
and AAS
SW-7474 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 -100 ppt
organo-mercury
inorganic mercury 0.5 - 200 ppt
organo-mercury
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 chaptercontainsgeneral information on field portable
X-ray fluorescence (FPXRF) analyzers, including the theory
of operation, system components, radioisotope sources,.
and mode of operation. The chapter also provides a
detailed description of the NITON XLi/XLt 700 Series
Analyzers.
2.1 Description of X-Ray Fluorescence
Energy dispersive X-ray fluorescence (EDXRF) is a
method of detecting metals and non-metallic elements in
soil and sediment. Some of the elements that EDXRF can
identify are arsenic, barium, cadmium, chrom ium, copper,
lead, mercury, selenium, silver and zinc. Field-portable
X-ray fluorescence units thatoperate on battery power and
use a radioactive source were first developed for use in
analysis of lead-based, paint. FPXRF analyzers are being
used in the field to identify and characterize metal-
contaminated sites, and to guide remedial work.
2.1.1 Theory of EDXRF Analysis
EDXRF analysis detects and measures many elements
simultaneously. Generally, EDXRF units can detect and
quantify elements from atomic number 19 (potassium)
through 94 (plutonium). There are two types of EDXRF
units. They can use either an X-ray tube or a radioisotope
as a source of X-rays. Both types of EDXRF analyzers
were evaluated during the demonstration.
In XRF analysis, a process known as photoelectric effect
is used in analyzing samples. Fluorescent X-rays are
produced by exposing a sample to an X-ray source that
has an excitation energy similar to, but greater than, the
binding energy of the inner-shell electrons of the elements
in the sample. Some of the source X-rays will be scattered,
but a portion will be absorbed by the elements in the
sample. Because of their higher energy level, they will
cause ejection of the inner shell electrons. The electron
vacancies, that result will be filled by electrons cascading in
from outer shells. However, since electrons in the outer
shells have higher energy states than the inner-shell
electrons they are replacing, the outer shell electrons must
give off energy as they cascade down. The energy is given
off in the form of X-rays, and the phenomenon is referred
to as X-ray fluorescence (Figure 2-1). Because every
element has a different electron shell configuration, each
element emits a unique X-ray at a set energy level or
wavelength that is characteristic of that element. The
elements present in a sample can be identified by
observing the energy level of the characteristic X-rays,
while the intensity of the X-rays is proportional to the
concentration and can be used to perform quantitative
analysis.
Sj*rajr emtasd
Figure 2-1. Basic X-ray fluorescence process.
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2.1.2 System Components
A FPXRF system has two basic components: the
radioisotope source and the detector. The source irradiates
the sample to produce characteristic X-rays. The detector
measures both the energy and the characteristic X-rays
that are emitted and their intensity to identify and quantify
the elements present in the sample.
The radioisotope sources currently being used are Fe-55,
Cd-109,and Am-241. FPXRF units have been developed
that use more than one source, which allows them to
analyze a greater number and range of elements. Typical
arrangements of such multi-source instruments include
Cd-109 and Am-241 or Fe-55, Cd-109, and Am-241.
FPXRF units use either gas-filled or solid-state detectors.
Solid state detectors include Si(Li), Hgl2, and silicon-PIN
diode. The Si(Li) is capable of the highest resolution, but is
quite temperature sensitive. The Si(Li) has a resolution of
170 electron volts (eV) if cooled to at least -90 ฐC, either
with liquid nitrogen or by thermoelectric cooling that uses
the Peltier effect. The Hgl2 detector can operate at a
moderately subambient temperature, is cooled by use of
the Peltier effect, and has a resolution of 270 to 300 eV.
The silicon-PIN diode detector is cooled only slightly by the
Peltier effect, and has a resolution of 250 eV.
2.2 NITON XLi/XLt 700 Series Technology
Description
The NITON XLi/XLt 700 Series sample analyzers are
energy dispersive X-ray fluorescence (EDXRF)
spectrometers that use either a radioactive isotope (XLi
model 702) or a low powered miniature X-ray tube with a
silvertarget (XLt model 792) to excite characteristic X-rays
of a test sample's constituent elements (Figure 2-2).
These characteristic X-rays are continuously detected,
identified, and quantified by the spectrometer during
sample analysis. The energy of each X-ray detected
identifies a particular element present in the sample, and
the rate at which X-rays of a given energy are counted
provides a determination of the quantity of that element
that is present in the sample.
Detection of the characteristic mercury X-rays is achieved
using a highly-efficient, thermo-electrically cooled, solid-
state detector. Signals from this detector are amplified,
digitized, and then quantified via integral multichannel
analysis and data processing units. Sample test results
are displayed in parts per million (milligrams per kilogram)
of total elemental mercury.
The NITON XLt 700 Series Analyzer with X-ray tube
excitation provides the user with the speed and efficiency
of X-ray tube excitation, while reducing the regulatory
demands typically encountered with isotope-based
systems. In most cases, the X-ray tube can be shipped
from state to state and country to country with minimal
paperwork and expense.
Figure 2-2. Photograph of the NITON XLi/XLt 700 Series
instruments during the field demonstration.
Applications and Specifications - The XLi and XLt 700
Series analyzers offer testing modes forsoil and other bulk
samples; filters, wipes and other thin samples; and lead-
based paint. Testing applications include management of
remediation projects, site assessments, and compliance
testing. They provide simultaneous analysis of up to 25
elements, including all eight of the characteristic metals
listed under the Resource Conservation and Recovery Act
(RCRA). XRF analysis is non-destructive, so screened
samples can be sent to an accredited laboratory for
confirmation of results obtained on-site.
NITON's software corrects automatically for variations in
soil matrix and density, making it applicable for both in-situ
and intrusive testing.
Operation - For in-situ analysis, the analyzer is placed
directly on the ground oron bagged soil samples. Because
contamination patterns tend to be heterogeneous, a large
number of data points can be produced using in-situ testing
to delineate contamination patterns. In-situ testing with
either the XLi 702 or XLt 792 is in full compliance with U.S.
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EPA Method 6200. In-situ testing allows for testing many
locations in a short time, and is ideal for rapid site-profiling,
locating sources of contamination, and monitoring and fine-
tuning remediation efforts on-the-spot. In-situ analysis is
not appropriate for wet sediment samples. In that case,
sediments must be dried, and can then be measured either
bagged or in sample cups.
For intrusive testing, the XLi/XLt 700 Series can test
prepared (dried, ground, sifted, homogenized),
representative soil samples for laboratory grade analysis
whenever analytical-grade data quality is required. Both
the XLi and XLt 700 Series Soil Analyzers come with
sample-preparation protocols. During the demonstration,
all samples were tested intrusively.
The NITON instruments are factory-calibrated. NITON's
Compton normalization software automatically corrects for
any differences in sample density and matrix, so site-
specific calibration standards are never required. The units
also analyze for zinc, arsenic, and lead since these
elem ents may cause interference at certain concentrations.
The vendor states that total analysis time usually does not
exceed 120 seconds (after sample preparation).
Depending on the data quality needed for a project, longer
counttimes can be employed. As count times increase, the
detector collects a larger number of X-rays from the
sample, including more X-rays from interfering elements
that are present at comparable lower concentrations. The
longer the count time, the lower the detection limit.
Sample preparation, for those samples not analyzed
directly in-situ, may include grinding and/or sieving dried
samples, using either mortar and pestle or electric grinder.
Wet sam pies, at a minimum are filtered to remove standing
water, then dried. Although EPA Method 6200 specifies
that mercury samples should not be oven-dried due to the
potential volatilization loss of mercury, NITON has oven-
dried sample material without negative impact. During the
demonstration, some samples which contained free-
standing water were dried in a toaster oven for about 2
hours.
2.3 Developer Contact Information
Additional information about NITON'S XLi/XLt 700 Series
Analyzers can be obtained from the following source:
NITON Corporation
Jonathan J. Shein
900 Middlesex Turnpike Building 8
Billerica, MA. 01821
Telephone:(800)875-1578
Fax:(978)670-7430
Email: sales@niton.com
Internet: www.niton.com
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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 prepared from 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 -9 m bgs
1.5 -1.8m 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
10ppb-50ppm
10ppb-1,000ppm
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 preseat at the former gold and
silver mining mill sites; waterways adjacentto the mill sites;
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 present at, 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, localterrain,
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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scalable 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) adjacentto the city of
Oak Ridge, TN. Built in 1943 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, aspartof 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 scalable 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
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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
Geoprobeฎ 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 m ixing. 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 0.15m along the site perimeterto 3m 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 percent sediment 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
material were collected in a similar manner. 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 36ฐN,
the longitude 35ฐW, 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, so that potential technology
users have adequate information to make sound
judgements regarding an innovative technology's
applicability to a specific site, and 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 vendor field 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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Criticaldata 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 Chapters.
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 (IOL), a method detection
limit (MDL), and as a practical quantitation limit (PQL).
MDL is not a measure of sensitivity in the same respectas
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 atwhich 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 an 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:
where: t(n_1i0.M) =
n =
s =
99th percen tile 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. .
During the demonstration, the PQL was to be defined by
the vendor's reported calibration or based upon lower
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concentration samples or SRMs. The evaluation of
vendor-reported results for the PQL included a
determination of the percent difference (%D) betweentheir
calculated value and the 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:
%D
; F
true calculated
'true
x100
where: Ct,
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 requirement forthe 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 bycomparing 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 NITON field instruments.
Samples representing field samples and spiked field
samples were prepared at the SAIC GeoMechanics
Laboratory. Inordertopreventcrosscontamination,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 thedemonstration, the referee
laboratory analyzed SRMs as an on-going 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)
s/^/n
where: t(r_1f 0.975)=
97.5th percentile 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
of the reference value. For example, a distribution within
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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
vendor for a particular concentration and matrix compared
to the same 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 accuracy standard 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 testwas used with alpha
= 0.01. The null hypothesis was that sample results were
similar. Therefore, if the null hypothesis is rejected, then
the sample sets are considered different.) Comparisons
fora specific matrix or concentration were made in orderto
provide additional information on that specific matrix or
concentration. Comparison of the vendor values 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 asRSD.
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 for this 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, 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 laboratorymeasured 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:
%RSD = -x100
I
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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
sediment samples 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 list's for purchasing, renting, or leasing each field
measurement device. If the device was purchased,
the capital cost estimate did riot 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 orother 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 that a 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
demonstration. Supplies consisted of items not
included in the capital category, such as extraction
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solvent, glassware, pipettes, spatulas, agitators, and
'similar materials. The type and quantity of all supplies
brought to 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 cost value was based on the
number of analyses performed. As the numberof samples
analyzed increases, the initial capital costs and certain
other costs were distributed across a greater number of
samples. Therefore, the per unit cost decreased. Forthis
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 dem onstration. 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 m et 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
observer was assigned to independently evaluate only the
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
- Instalment 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
20
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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 weight of 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 Preparation
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
Prq/ecfP/an(SAIC,August2003, EPA/600/R-053). Figure
4-1 summarizes the homogenization steps of the SOP,
beginning with sample mixing. This procedure was used
21
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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 hinder
homogenization. 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
Table 4-3. Field Samples Collected from the Four Sites
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.
Field Site
No. of Samples / Matrices
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
1 2 L each for sediment
12 L each for sediment
4 L each for soil
4 L each
12 Leach
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. Asubsample 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 slurry as 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 water from 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.
22
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Test material mixed until
visually uniform
For non-slurries
Mix manually
For slurries
a) Mix mechanically the entire
sample volume
b) Subsample slurry, transfer to
mixing vessel, and mix
mechanically
Slurries transferred
directly to 20 mL vials
(vials submerged into slurry)
Non-slurries to
riffle splitter
Combined splits
are reintroduced
into splitter (6 X)
1 J
^ ^
L : ^^
\
4T , , . A 1 1 1 1 1 1 II
Transfer cut i
sections to
20 mL vials 3 ฃ
4
/ RIFFLE \\ I
SPLITTER VI I
v . $i
J^vvX.
/Elongated
rectangular pile
(from 6" split)
.
iiiiiir\^iiiiiMiiiiiMiii\
TEFLON SURFACE 1
Sample aliquots made
by transverse cuts
across sample piles
Samples shiped @ 4 ฐC to
referee lab and Oak Ridge
(Container numbers will vary)
Figure 4-1. Test sample preparation at the SAIC GeoMechanics 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 Chapters.
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 known concentrations 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 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 m anner 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 accuracy of the spiked sample. The spiking procedure
was evaluated by preparing several different spikes using
two different spiking procedures (dry and wet). Based
upon results of replicate analyses, 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 ฐC. 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 aliquotsfor 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 foranalysis, the sample size sent to
all participants was a 20-rnL 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, arid
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
24
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measurem ent ranges for mercury detection, not all vendors
received samples from the same field material. All
samples were stored in an ice coolerpriorto 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
if 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 COC form.
This process was repeated for samples 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 these considerations, it was determined that
SW-846 Method 7471B [analysis of mercury in solid
samples by coldwapor atomic absorption spectrometry
(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.
25
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These laboratories received and analyzed blind samples
andSRMs during pre-demonstration activities. The referee
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 theSAIC
QA Manager at the remaining two candidate laboratories.
Results of the SRM samples were compared for the two
laboratories. Each laboratory analyzed each sam pie (there
were two SRMs) in triplicate. Both laboratories were within
the 95% prediction interval for each SRM. In addition, the
average result from the two SRMs was compared to the
95% CI 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 pg/kg, but it was uncertain at the time if this limit
was actually a PQL or a detection limit). Therefore, it was
determined that, if necessary, the laboratory actually
should be able to achieve even a lower PQL than 10 M9/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 part of 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.
26
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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
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 aliquotsizes 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 pg/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 for this 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 7471B,
a cold-vapor atomic absorption method, based on the
absorption of radiation 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
27
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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
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 have 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 at
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 ฐC 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 ฐC. 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
Measurements.
for Non-Critical
A selected set of non-critical parameters was also
measured during the demonstration. These parameters
were measured to provide a better insight into the chemical
constituencyof 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
EPA2540G
n-Hexane
extraction,
Gravimetric
Carbonaceous
analyzer
Gravimetric
4.5 Deviations from the Demonstration
Plan
There were no deviations to the demonstration plan. -
28
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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:
RPD
(Maximum Value - Minimum Value)
(Maximum Value + Minimum Value)/2
x100
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=Cgs, C"sx100
' C.
where,
GSS = Analyte concentration in spiked
sample
Cus = Analyte concentration in unspiked
sample
Cja = 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= -=r, : : x1DO
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
aliqupting 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 lot analysis 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
Limitations
and Data Quality
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 fall with in specifications. The
MS/MSP 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 accuracy was 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
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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/MSD RPD Range
Number of Duplicate Pairs
Average MS/MSD RPD
No. of Pairs Outside QC
Specifications
RPD< 20%
0.0% to 25%
23
5.7%
2
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, comparability and 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 wereachieved 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. Very few
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 forevery 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 appropriately and 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
TheSAIC 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 conducted 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 XLi/XLt 700 Series Analyzers
NITON analyzed 197 samples from May 5-7, 2003 in Oak
Ridge, TN. Results for these samples were reported by
NITON, and a statistical evaluation was performed by
SAIC. Since X-ray is non-destructive for soil samples,
NITON prepared each sample once and analyzed the.
sample on both the XLt and XLi instruments. Additionally,
the observations made during the demonstration were
reviewed, and the remaining primary and secondary
objectives were completed. The results of the studies for
the primary and secondary objectives, identified in Chapter
1, are discussed in Sections 6.1 and 6.2, respectively.
Samples with high amounts of water (based upon visual
examination) were dried in a toaster oven. Those samples
identified as "dried" by NITON were compared to the
laboratory "dry weight" result. All other samples were
compared to the laboratory "as received" result.
The distribution of the samples prepared for NITON and
the referee laboratory is presented in Table 6-1. From the
four sites, NITON received samples at 35 different
concentrations for a total of 197 samples. These 197
samples consisted of 23 concentrations in replicates of 7
and 12 concentrations of 3.
Table 6-1. Distribution of Samples Prepared for NITON and the Referee Laboratory
Site
Concentration Range
Soil
Sample Type
Sediment Spiked Soil
SRM
Carson River
(Subtotal = 31)
Puget Sound
(Subtotal = 34)
Oak Ridge
(Subtotal = 54)
Manufacturing
(Subtotal = 78)
Subtotal
(Total = 197)
Low (1-500 ppb)
Mid (0.5-50 ppm)
Hiah(50->1.000 com)
Low(1 ppb- 10 ppm)
Hiah (1 0-500 oom)
Low (0.1-10 ppm)
Hiah H 0-800 pom)
General (5-1,000 ppm)
0
7
3
3
0
0
13
36
62
0
0
0
0
10
3
10
0
23
0
0
7
0
7
0
14
14
42
0
0
14
0
14
0
14
28
70
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 PQL. Determinations of
these two measurem ents 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 both of NITON'S field
instruments (XLi 702 and XLt 792). Any sample analyzed
by NITON and subsequently reported as below their level
of detection, was not used as part of any additional
evaluations. This was done because the expectation that
values below the lower limit of instrument sensitivity would
not reflect the true instrument accuracy and precision.
33
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The sensitivity measurements of MDL and PQL are both
dependent upon the matrix and method. Hence, the MDL
and PQL 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. PQL
determinations are not independent calculations, but are
dependent upon results provided by the vendor for the
samples tested.
Comparison of the MDL and PQL to 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. Because the NITON field
instruments do not use a calibration curve for the analysis
of samples, but instead depend upon instrument counts
and an associated standard deviation to determine the
lower level of quantitation, our approach was to let the
vendor provide the lower limits of quantitation as
determined by their particular standard operating
procedure, and then test these limits by comparing the
results to referee laboratory results, or comparing the
results to results for a standard reference material, if
available. Comparison of these .data are, therefore,
presented for the lowest level sample results, as provided
by the vendor. If the vendor provided "non-detect" results,
then no formal evaluation of that sample was presented.
In addition, that sample (or samples) 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 detect the 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
NITON at their estimated lower limit of sensitivity. The
NITON lower limit of sensitivity for both instruments was
previously estimated at 20 mg/kg. Because there are
several d if fe re ntSRMs and fie Id 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 NITON 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.
NITON XLt (X-ray) Evaluation
Afield sample with an average concentration of 14.6 mg/kg
as reported by the referee laboratory (sample lot 62 from
the Puget Sound site) was run by NITON 7 times. One
result was reported as below their detection limit and the
other 6 results had a reported average concentration of
27.4 mg/kg and a standard deviation of 4.14 mg/kg.
Calculation of the respective MDL is 13.9 mg/kg. Because
Niton reported a result below their detection limit additional
samples were selected for calculating the MDL.
Seven replicates were run by NITON for an SRM with a
reference value of 32.6 mg/kg (sample lot 47). The
average concentration reported by NITON for this sample
was 78 mg/kg and the standard deviation was 6.4 mg/kg.
This particular sample lot was not used in the general
calculations because of problems noted with reported
results from allthe vendors who analyzed this SRM and the
laboratory reported result. Specifically this sample lot was
thrown out because all vendor results and the referee
laboratory results were outside acceptable SRM reported
values. It was therefore determined that there was likely a
problem with this SRM. Nonetheless this was considered
an accuracy problem and because MDL calculations are
determined using precision results (standard deviation
calculations) and because this SRM has a reported
concentration of 32.6 it would likely still be an acceptable
value for determining an MDL. There are only six valid
results reported by NITON as one result was reported as
below their detection limit. The MDL calculation using this
sample is 21.5 mg/kg.
It should be noted that if the SRM value of 32.6 mg/kg were
correct (there is evidence to suggest that this may be
incorrect for the sample lot received but it is likely close to
this value) then this concentration would likely be close to
34
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the NITON M DL, as they reported one of the seven tested
samples below their limit of detection.
Seven replicates were run by NITON for an SRM that had
a reference value of 99.8 mg/kg (sample lot 49). The
average concentration reported by NITON for this sample
was 108 mg/kg and the standard deviation was 22.2
mg/kg. Calculation of the MDL for this sample is 69.8
mg/kg.
The average of all three of these values (if an average
were used) is 35.1 mg/kg. It is probably more accurate,
however, to report that the range of the MDL, as
determined statistically by 40 CFR part 136 is between
13.9 and 69.8 mg/kg. It is likely that the MDL is closer to
the lower end of this range based upon the results for
sample lot 62 (referee laboratory value = 14.6 mg/kg) and
sample lot 47 (SRM value = 32.4 mg/kg) which both had 1
of the 7 results reported as below the NITON detection
level indicating that these values are on the edge of the
instruments detection capability. It is also more likely to
conclude that the MDL is closer to the lower end of this
range because MDLs calculated for the lower-
concentration samples are also at the lower end of the
calculated range of results.
As a further check of the MDL, sample lot 18 had a
reported average concentration bythereferee laboratoryof
10.1 mg/kg. This was consistently reported by NITON as
below their MDL thereby confirming that the calculated
MDL, noted previously was above this value.
Based upon the results presented above, the three
different MDL calculations for this instrument have reported
values of 13.9, 21.5, and 69.8 mg/kg. It appears that the
MDL for this instrument is close to the lower end of this
range. The equivalent MDL for the referee laboratory
based upon analysis of a low standard analyzed 7 times 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.
For the NITON field instruments, there is no calibration
curve, and therefore the low standard from a calibration
curve is not a valid estimation of the PQL. 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 NITON and subsequent %Ds were calculated.
The lower limit of sensitivity previously provided by the
vendor (20 mg/kg) appears to be below their calculated.
MDL and below the vendor 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 69.5 to 349
mg/kg. The average calculated PQL would be 209 mg/kg;
however, based upon sample results, this is clearly above
the PQL noted during the demonstration. Therefore,
values closerto 69.5 mg/kg were chosen for estimating the
PQL and associated %D between the NITON .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.
Sample lot 65 had a reported average value by the referee
laboratory of 62.9 mg/kg. The average value reported by
NITON for this sample was 84.6 mg/kg with a standard
deviation of 35.0 mg/kg. The 95% Cl for this sample is
52.2 to 117 mg/kg. The %D for this sample is 34.5%.
The result for the 32.6 mg/kg SRM noted above (sample lot
47) had a reported average concentration of 77.5 mg/kg.
The standard deviation was 6^44 mg/kg and the 95% Cl is
71.5 to 83.5 mg/kg. The %D for this sample is 137%, and
therefore, this concentration appears to be below the
instrument PQL.
The result for the 99.8 mg/kg SRM (sample lot 49) had a
reported average concentration of 108 mg/kg. The
standard deviation was 22.2 mg/kg and the 95% Cl is 79.3
to 120 mg/kg. The %D for this sample is 8.2%.
It could be inferred that the NITON XLt field instrument
PQL may be somewhere between 62.9 and 99.8 mg/kg.-
The SRM with a reference value of 32.6 mg/kg had a
reported %D of 137% and therefore was lower than the
PQL.
NITON XLi (Isotope) Evaluation
Seven replicates were analyzed by NITON for an SRM that
had a reference value of 99.8 mg/kg (sample lot 49). The
average concentration reported by NITON for this sample
was 109 mg/kg and the standard deviation was 35.6
mg/kg. Another SRM that had a reference value of 32.6
mg/kg (sam pie lot 47) had an average concentration from
35
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seven separate replicates reported by NITON as 92.7
mg/kg and a standard deviation of 12.5 mg/kg. A field
sample with an average concentration of 14.6 mg/kg as
reported by the referee laboratory (sample lot 62 from the
Puget Sound site) was analyzed by NITON seven times.
All but one result was reported as below their detection
limit. This suggests that this sample is below the NITON
XLi MDL. Calculations of the respective MDLs, based
upon 2 of the 3 samples/standards noted above, are 112
and 39.3 mg/kg. The average of these two values is 75.6
mg/kg.
As a further check of the MDL, sample lot 18 (Carson
River) had a reported average concentration by the referee
laboratory of 10.1 mg/kg. This was consistently reported
by NITON as below their MDL, thereby confirming that the
calculated MDL noted previously was above this value.
Sample lot 47 (SRM) had a reference value of 32.6 mg/kg
(noted previously) and the average result reported by
NITON was 92.7 mg/kg. The %D for this sample is 184%.
This would suggest that NITON'S MDL is below the
average calculated above.
Based upon these results, the MDL for this instrument is
close to 32 mg/kg, however, this, is not the average of the
MDL calculations, but close to the lowercalculated value of
39.3 mg/kg. The estimated sensitivity provided by NITON
of 20 mg/kg is probably close to the observed MDL value.
In fact, sam pie lot 46 (SRM with a reference value of 21.4
mg/kg) was analyzed 7 times and reported an average
value of 121 mg/kg for 5 of 7 analyses. The other two
analyses were reported as non-detect, suggesting that this
is close to or below the instrument's capability. The
equivalent calculated 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 POL
estimation, however, is method- and matrix- dependent.
In orderto determine the PQL, several low standards were
provided to NITON and %Ds were calculated from the
results.
The lower limit of sensitivity previously provided by the
vendor (20 mg/kg) appears to be close to their MDL and
below the vendor 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 values of 196.5 and .560
mg/kg. The average calculated PQL would be 378 mg/kg,
however, based upon sample results this is clearly far
above the PQL noted during the demonstration. Therefore,
values closer to 32 mg/kg were chosen for estimating the
PQL and associated %D between the NITON reported
average and the reference value if it is an SRM, or the
average value reported bythe referee laboratory. The 95%
CIs are also compared for additional descriptive
information.
Sample lot 65 had a reported average value by the referee
laboratory of 62.9 mg/kg. The average value reported by
NITON for this sample was 80.3 mg/kg with a standard
deviation of 26.9 mg/kg. The 95% Cl for this sample is
55.4 to 105 mg/kg. The %D forthis sample is 27.7%.
The result for the 32.6 mg/kg SRM noted above (sample lot
47) had a reported average concentration of 92.7 mg/kg.
The standard deviation is 12.5 mg/kg and the 95% Cl is
81.1 to 104 mg/kg. The %D forthis sample is 184% and
therefore, this concentration appears to be below the
instrument PQL.
The result for the 99.8 mg/kg SRM (sample lot 49) had a
reported average concentration of 109 mg/kg. The
standard deviation is 35.6 mg/kg and the 95% Cl is 76.1 to
132 mg/kg. The %D for this sample is 9.2%.
It can be inferred that the NITON XLi field instrument PQL
is between 62.9 and 99.8 mg/kg. The SRM with a
reference value of 32.6 mg/kg had a reported %Dof 184%
and therefore, was lower than the PQL.
Sensitivity Summary
The low standard calculations suggest that the MDL for the
NITON XLt field instrument is 42 mg/kg (average of MDL
calculations). Based upon the results presented above, the
MDL for the NITON XLi field instrument is close to 32
mg/kg. The lowest calculated MDL, however, is 39.3
mg/kg. The equivalent calculated MDL for the referee
laboratory is 0.0026 mg/kg. The MDL determination,
however, is onlya statistical calculation thathas been used
in the past by EPA, and is currently not considered a "true"
MDL by SW-846 methodology. SW-846 fs suggesting that
performance-based methods be used, and that PQLs be
determined using low standard calculations.
36
-------
The referee laboratory PQL confirmed during the
demonstration is 0.005 mg/kg. The %D is <10%. The
NITON XLt field instrument PQL is between 62.9 and 99.8
mg/kg. The %D for the 99.8 mg/kg SRM is 8.2%. The
NITON XLi field instrument PQL is between 62.9 and 99.8
mg/kg. The %D for the 99.8 mg/kg SRM is 9.2%.
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 concentrations and an associated
95% Cl and 95% prediction interval. The Cl from the
reference material is used as a measure of.comparison
with the 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 result will be outside 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 or seven by
both the vendor and by 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 9 differentSRMs 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 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 statistical comparison 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 24 sample lots for the NITON XLi field
instrument and on 26 sample lots for the NITON XLt field
instrument. (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 the laboratory data bias
previously noted.
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
coveradditionalconcentrations 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 in
orderto ensure that a competent laboratory would be used
for the demonstration. The pre-demonstration laboratory
37
-------
qualification showed that the laboratory was within
prediction intervals for all SRMs analyzed. The percentage
of total results within the prediction interval for the vendor
are reported in Tables 6-2 and 6-3, and the laboratory in
Table 6-4. 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).
Table 6-2. NITON SRM Comparison (XLt)
Sample Lot
No.
51
48
50
53
54
49
52
SRM Value/ 95% Cl
405/365-445-
77.78/71.53-84.03
203/183-223-
910/821-999-
1120/ 1010-1230-
99.8/81.9-118
608/ 490 - 726
Total Samples
% of samples w/in
prediction interval
NITON Avg./ 95% Cl
312/301-323
128/89.4-167
195/183-207
712/664-760
896/ 863 - 929
108/87.5-128
496/475-517
Cl Overlap
(yes/no)
no
no
yes
no
no
yes
ves
No. of
Samples
Analyzed
7
4
7
7
7
7
7
46
95% Prediction
Interval
194-615
45.58 - 109.97
97.4 - 308
437 - 1380
582 - 1701
31.3-168
292 - 924
NITON No. w/in
Prediction
Interval
7
1
7
7
7
7
7
43
93%
Cl is estimated based upon n=30. A 95% prediction interval was provided by the SRM supplier but no Cl was given.
Table 6-3. NITON SRM Comparison (XLi)
Sample Lot
No.
51
48
50
53
54
49
52
SRM Value/ 95% Cl
405/ 365 - 445-
77.78/71.53-84.03
203/183-223'
910/821-999-
1120/1010-1230-
99.8/81.9-118
608/ 490 - 726
Total Samples
% of samples w/in
prediction interval
a Cl is estimated based upon n=30.
Table 6-4. ALSI
Sample Lot
No.
51
48
50
53
54
49
52
SRM Comparison
SRM Value/ 95% Cl
405/365-445-
77.78/71.53-84.03
203/183-223'
910/821 -999-
1120/1010-1230 '
99.8/81.9-118
608/ 490 - 726 '
Total Samples
% of samples w/in
prediction interval
NITON Avg./ 95% Cl
305/ 269 - 343
171/100-242
217/164-270
720/673-767
917/837-997
109/76.1-142
504/465-543
Cl Overlap
(yes/no)
no
no
yes
no
no
yes
ves
A 95% prediction interval was provided
ALSI Avg./ 95% Cl
291/ 254 - 328
87.1/60.6-114
167/ 140-194
484/ 325 - 643
71 1/ 573 - 849
84.2/74.5-93.9
424/338-510
Cl Overlap
(yes/no)
no
yes
yes
no
no
yes
yes
No. of
Samples
Analyzed
7
4
7
7
7
7
7
46
95% Prediction
Interval
194-615
45.58 - 109.97
97.4 - 308
437 - 1380
582 - 1701
31.3-168
292 - 924
NITON No. w/in
Prediction
Interval
7
0
. 7
7
7
7
7
42
91%
by the SRM supplier but no Cl was given.
No. of
Samples
Analyzed
7
7
7
7
7
7
7
49
95% Prediction
Interval
194-615
45.58-109.97
97.4 - 308
437 - 1380
582 - 1701
31.3-168
292 - 924
ALSI No. w/in
Prediction
Interval
7
6
7
4
5
7
7
43
88%
Cl is estimated based upon n=30. A 95% prediction interval was provided by the .SRM supplier but no Cl was given.
38
-------
Evaluation of vendor and laboratory analysis of SRMs was
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 comparable 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.
SRM Analysis for NITON XLt (X-ray)
The single most important number from these tables is the
percentage of samples within the 95% prediction interval.
As noted for the NITON XLt data, this percentage is 93%
with n = 46. This suggests that the NITON data are within
expected accuracy, accounting for statistical variation. For
5 of the 7 determinations, NITON average results are
below the reference value. This would suggest that there
is a possible bias associated with the NITON data;
however, this is not necessarily significant based upon the
minimum number of sample lots evaluated. There were
fewer SRMs than expected because NITON's detection
limit was much lower than predicted (see Section 6.1.1).
This resulted in three SRM results that could not be used.
The percentage of samples within the 95% prediction
interval for the laboratory data is 88%. For 6 of the 7
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 (49) 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 6-5), 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.
SRM Analysis for NITON XLi (Isotope)
The single most important number from these tables is the
percentage of samples within the 95% prediction interval.
As noted forthe NITON XLi data, this percentage is 91%,
with n = 46. This suggests that the NITON data are within
expected accuracy, accounting for statistics I variation. For
5 of the 7 determinations, NITON average results are
below the reference value. This would suggest that there
is a possible bias associated with the NITON data,
however, as noted above this is not necessarily significant
based upon the minimum number of sample lots evaluated.
There were fewer SRMs than expected because NITON's
detection limit was much lower than predicted (see Section
6.1.1). This resulted in three SRM results thatcould not be
used.
The percentage of samples within the 95% prediction
interval for the laboratory data is 88%. For 6 of the 7
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 (49) is relatively high.
Nonetheless, the referee laboratory data should be
considered accurate and not significantly differentfrom the
SRM value. Because there is no bias correction term in
the individual hypothesis tests (Table 6-6), 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.
Hypothesis Testing
Sample results from field and spiked field samples for the
vendor compared to similar 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 (per instrument) 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 NITON's or ALSI's
computed standard deviation was large due to a highly
variable result (indication of poor precision), the two CIs
could overlap. Conversely, if the variance is small then
relatively small differences between the two sample means
could be significant. The fact that there was no significant
difference between the two results could be due to high
sample variability or could be a result of the small variance
(i.e. high precision) for that particular sample lot.
39
-------
Accordingly, associated RSDs have also been reported in
Tables 6-5 and 6-6 along with results of the hypothesis
testing for each sample lot. Results of these analyses
should therefore be considered accordingly; based upon
the minimum number of samples tested for each different
sample lot for each instrument.
Table 6-5. Accuracy Evaluation by Hypothesis Testing (NITON XLt)
Sample Lot No 7 Site
221 Oak Ridge
NITON
ALSI
247 Oak Ridge
NITON
ALSI
267 Oak Ridge
NITON
ALSI
31/ Oak Ridge
NITON
ALSI
517 Oak Ridge
NITON
ALSI
65/ Oak Ridge
NITON
ALSI
671 Oak Ridge
NITON
ALSI
251 Puget Sound
NITON
ALSI
271 Puget Sound
NITON
ALSI
487 Puget Sound
NITON
ALSI
50/ Puget Sound
NITON
ALSI
237 Carson River
NITON
ALSI
537 Carson River
NITON
ALSI
547 Carson River
NITON
ALSI
637 Carson River
NITON
ALSI
197 Manufacturing Site
NITON
ALSI
207 Manufacturing Site
NITON
ALSI
Avg. Cone.
mg/kg
116
81.6
417
. 207
156
123
1360
947
312
291
84.6
62.9
1330
835
43.7
39.1
126
136
128
87.1
195
167
. 174
117
712
484
896
711
202 .
169
45.5
28.7
54.3
63.9
RSD or CV
7.9%
9.4%
9.6%
48.4%
12.4%
13.5%
3.3%
13.2%
3.9%
13.4%
35.0%
8.5%
4.5%
14.8%
11.5%
10.7%
13.3%
16.9%
18.9%
32.9%
6.6%
17.2 %
22.2%
5.7%
7.3%
35.5%
4.0%
21.0%
9.2%
6.5%
19.5%
32.2%
19.2%
25.4%
Number of
Measurements
3
3
7
7
7
7
3
3
7
7
7
7
7
7
3
3
7
7
4
6
7
7
3
3
7
7
7
7
7
7
4 .
7
3
7
Significantly Different at
Alpha = 0.01
yes
yes
yes
no
no
no
yes
no
no
no
no
no
no
no
yes
no
no
Relative Percent
Difference (NITON
to ALSO
34.8%
67.3%
23.7%
35.8%
7.0%
28.7%
45.7%
4.6%
-7.6%
38.0 %
15.5%
39.2%
38.1%
23.0%
17.8%
45.3%
-16.2%
40
-------
Table 6-5. Continued
Sample Lot NoJ Site
281 Manufacturing Site
NITON .
ALSI
291 Manufacturing Site
NITON
ALSI
30/ Manufacturing Site
NITON
ALSI
321 Manufacturing Site
NITON
ALSI
33/ Manufacturing Site
NITON
ALSI
491 Manufacturing Site
NITON
ALSI
521 Manufacturing Site
NITON
ALSI
641 Manufacturing Site
NITON
ALSI
66/ Manufacturing Site
NITON
ALSI
CV = Coefficient of variance
Avg. Cone.
mg/kg
318
251
335
374
376
451
300
592
379
1204
108
84.2
496
424
404
285
985 .
892
Table 6-6. Accuracy Evaluation by Hypothesis
Sample Lot No7 Site
221 Oak Ridge
NITON
ALSI
24/ Oak Ridge
NITON
ALSI
26/ Oak Ridge
NITON
ALSI
31/ Oak Ridge
NITON
ALSI
517 Oak Ridge
NITON
ALSI
65/ Oak Ridge .
NITON
ALSI
67/ Oak Ridge
NITON
ALSI
Avg. Cone.
mg/kg
141
81.6
438
207
157
123
1279
947
305
291
80.3
62.9
1296
835
RSD or CV
8.2%
15.6%
27.8%
17.4%
13.8%
11.4%
7.8%
12.7%
10.8%
13.3%
20.5%
12.5%
4.7%
21.9%
8.7%
8.9%
3.8%
11.2%
Number of
Measurements
3
3
3
7
3
3
7
7
6
7
7
7
7
7
7
7
7
7
Significantly Different at
Alpha = 0.01
no
no
no
yes
yes
no
. no
yes
no
Relative Percent
Difference (NITON
to ALSI)
23.6%
-11.0%
-18.1%
-65.5%
-104%
24.8%
15.7%
34.5%
34.5%
Testing (NITON XL! )
RSD or CV
15.8%
9.4%
23.7%
48.4%
15.8%
13.5% '
6.4%
13.2%
13.1%
13.4%
33.5%
62.9%
5.0%
14.8%
Number of
Measurements
3
3
7
7
7
7
3
3
7
7
7
7
7
7
Significantly Different at
Alpha = 0.01
no
yes
no
no
no
no
no
Relative Percent
Difference (NITON
to ALSI)
53.4%
71.6%
23.7%
29.8%
4.7%
24.3%
43.3%
41
-------
Table 6-6. Continued
Sample Lot NoV Site
277 Puget Sound
NITON
ALSI
481 Puget Sound
NITON
ALSI
50/ Puget Sound
NITON
ALSI
231 Carson River
NITON
ALSI
53/ Carson River
NITON
ALSI
541 Carson River
NITON
ALSI
63/ Carson River
NITON
ALSI
201 Manufacturing Site
NITON
ALSI
281 Manufacturing Site
NITON
ALSI
291 Manufacturing Site .
NITON
ALSI
307 Manufacturing Site
NITON
ALSI
321 Manufacturing Site
NITON
ALSI
33/ Manufacturing Site
NITON
ALSI
49/ Manufacturing Site
NITON
ALSI
521 Manufacturing Site
NITON
ALSI
641 Manufacturing Site
NITON
ALSI
66/ Manufacturing Site
NITON
ALSI
Avg. Cone.
mg/kg
97.0
136
171
87.1
217
167
153
117
720
484
917
711
223
169
73.4
63.9
370
251
319
374
362
451
309
592
416
1204
109
84.2
504
424
400
285
974
892
RSD or CV
21.1%
16.9%
25.9%
32.9%
10.0%
17.2 %
11.7%
5.7%
7.0%
35.5%
9.4%
21.0%
11.2%
6.5%
18.3%
25.4%
8.6%
15.6%
16.2%
17.4%
17.5%
11.4%
3.9%
1Z7%
9.5%
13.3%
32.8%
12.5%
8.3%
21.9%
7.1%
8.9%
3.6%
11.2%
Number of
Measurements
7
7
4
6
7
7
3
3
7
7
7
7
7
7
3
7
3
3
3
7
3
3
7
7
6
7
7
7
7
7
7
7
6
7
Significantly Different at
Alpha = 0.01
yes
no
yes
no
no
no
yes
no
yes
no
no
yes
yes
no
no
yes
no
Relative Percent
Difference (NITON
to ALSI)
33.5%
65.0%
26.0%
26.7%
39.2%
25.3%
27.6%
13.8%
38.3%
-15.9%
-21.9%
-62.8%
-97.3%
25.7%
17.2%
33.6%
8.8%
CV = Coefficient of variance
NITON XLt (X-ray) Evaluation
Of the 26 sample lots, 8 results are significantly different,
based upon the hypothesis test noted above. Most of the
relative percent differences are positive which indicates
that the NITON result is generally higher than the
laboratory result. This is indicative of the previously noted
low bias associated with the laboratory data. There are
42
-------
some NITON results that are less than the laboratory
result, therefore, no overall NITON high or low bias is
apparent. It appears that NITON data are subject to more
random variability.
In determining the number of results significantly above or
below thevalue reported bythe referee laboratory, 14 of26
NITON average results were found to have relative percent
differences less than 30% for sample concentrations above
the estimated PQL. Only 1 of 26 NITON average results
have relative percentdifferences greater than 100% forthis
same group of samples (see Table 6-7). Interferences
may be a problem but, because of the random variability
associated with the data, no interferences are specifically
apparent.
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. Two
separate plots have been included for the NITON X-ray
data. These two plots are divided based upon sample
concentration in order to provide a more detailed
presentation.
Table 6-7. Number of Sample Lots Within Each %D Range (NITON XLt)
<30% >30%. <50% >50%. <100%
>100%
Total
Positive %D
Negative %D
Total
10
4
14
20
6
26
Only those sample lots with the average result greater than the PQL are tabulated.
-1. Data plot for the NITON XLt low concentration sample results
43
-------
16DD
14HD
1ZID
. 1UJO
8 em
Figure 6-2. Data plot for the NITON XLt high concentration sample results.
Concentrations of samples analyzed by NITON ranged
approximately from 10 to over 1,200 mg/kg. The previous
statistical summary eliminated some of these data based
upon whether concentrations were interpreted to be in the
analytical range of the NITON X-ray field instrument. This
graphical presentation presents all data points. It shows
NITON X-ray data compared 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. Sam pie groups were
arranged from lowest to highest concentration.
As can be seen by this presentation, samples analyzed by
NITON below about 100 mg/kg did not match well with the
ALSI results with some exceptions. For higher
concentrations, sample results were much closer to ALSI
with some deviations present. 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.
NITON XLi (Isotope) Evaluation
Of the 24 sample lots, 8 results are significantly different
based upon the hypothesis test noted above. Most of the
relative percent differences are positive which indicates
that the NITON XLi 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 NITON results that are less than the laboratory
result; therefore, no overall NITON high or low bias is
apparent. It appears that NITON data are subject to more
random variability.
In determining the number of results significantly above or
below the value reported by the referee laboratory, 14 of 24
NITON average results were found to have relative percent
differences less than 30% for sample concentrations above
the estimated PQL. Zero of 24 NITON average results
have relative percentdifferencesgreaterthan 100% for this
same group of samples (see Table 6-8). Interferences
may be a problem but, because of the random variability
associated with the data, no interferences are specifically
apparent.
44
-------
Table 6-8. Number of Sample Lots Within Each %D Range (NITON XLi)
Positive %D
Negative %D
Total
<30%
12
2
14
>30%. <50%
5
0
5
>50%. <100%
3
2
5
>100%
0
0
0
Total
20
4
24
Only those sample lots with the average result greater than the PQL are tabulated.
In addition to the statistical summary presented above,
data plots (Figures 6-3 and 6-4) are included in order to
present a visual interpretation of the accuracy. Two
separate plots have been included for the NITON Isotope
data. These two plots are divided based upon sample
concentration in order to provide a more detailed
presentation. Concentrations of samples analyzed by
NITON ranged approximately from 1 to over 1,200 mg/kg.
The previous statistical summary eliminated some of these
data based upon whether concentrations were interpreted
to be in the analytical range of the NITON Isotope field
instrument. This graphical presentation presents all data
points. It shows NITON Isotope data compared 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
NITON below about 100 mg/kg did not match well with the
ALSI results with some exceptions. For higher
concentrations, sample results were much closer to ALSI
with some deviations present. 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.
250
Figure 6-3. Data plot for the NITON XLi low concentration sample results.
45
-------
1600
1400
Figure 6-4. Data plot for the NITON XLi high concentration sample results.
Discussion of Interferences
RSDs for the'NITON XLt and XLi instruments are small,
suggesting that precision is good. (This will be discussed
in more detail in Section 6.1.3) As noted previously, it
would therefore, appear that interferences may be the
cause of the inaccurate analyses for field samples, but it is
.not apparent as to the specific interferent causing the
problem. There is no apparent significant difference
between reported values and associated sites from which
the samples were collected. Table 6-9 shows additional,
non-target analyses for each of the collected samples and
associated sampling sites.
Unified Hypothesis Test
SAIC performed a unified hypothesis test analysis to
assess the comparability of analytical results provided by
NITON and those provided by ALSI. (See appendix B for
a detailed description of this test.) NITON and ALSI both
supplied multiple assays on replicates derived from a total
of 24 different sample lots for the NITON XLi field
instrument and 26 different sample lots for the NITON XLt
field instrument, be they field materials or reference
materials. The NITON 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 for both the NITON XLi and XLt
instruments. The null hypothesis tested was that, on
average, NITON and ALSI produce the same results within
a given sample lot. The null hypothesis is rejected in part
because NITON results tended to exceed those from ALSI.
forthe same sample lot. Even when a bias term is used to
correct this discrepancy, the null hypoth esis is still rejected.
Additional information about this statistical evaluation is
included in Appendix B.
46
-------
Table 6-9. Concentration (in mg/kg) of Non-Target Analytes
iota
Site
TOC O&G
Aq
As
Ba
Cd
Cr
Cu
Pb
Se
Sn
Zn
Hg
1 1 Puget Sound
14 Oak Ridge
17 Manufacturing Site
18 Carson River
19 Manufacturing Site
20 Manufacturing Site
21 Manufacturing Site
22 Oak Ridge
23 Carson River
24 Oak Ridge
25 Puget Sound
26 Oak Ridge
27 Puget Sound
28 Manufacturing Site
29 Manufacturing Site
30 Manufacturing. Site
31 Oak Ridge
32 Manufacturing Site
33 Manufacturing Site
45 SRM CRM 033
46 SRM CRM 032
47 SRM NIST 2710
48 SRM CRM 023
49 SRM CRM 025
50 SRM RTC spec.
51 SRM RTC spec.
52 SRM RTC spec.
53 SRM RTC spec.
54 SRM RTC spec.
62 Spiked Lot 5
63 Spiked Lot 23
64 Spiked Lot 19
65 Spiked Lot 14
66 Spiked MS-SO-08
67 SoikedLot26
3800
7800
2400
1900
630
2000
7800
6600
5700
6600
46000
88000
37000
2000
900
1400
5000
4700
<470
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
3500
5700
630
7800
NA .
88000
130
180
90
70
60
<50
320
190
100
250
1200
340
1100
50
110
70
80
120
120
NR
NR
NR
NR
.NR
NR
NR
NR
NR
NR
210
100
60
180
NA
340
<0.5 4
0.32 2
<0.5 <2
26 17
<0.5 <2
O.5 <2
1.9 4
1.7 5
37 11
<0.5 5
<0.5 2
9.1 10
<0.5 3
0.86 <2
<0.5 <2
<0.5 <2
0.59 4
<0.5 2
<0.5 <2
0.78 130
81 370
35 630
NR 380 .
130 340
NR NR
NR NR
NR NR
NR NR
NR NR
<0.5 3
37 11
<0.5 <2
0.32 2
NA NA
9.1 10
20
41
180
. 46
410
150
150
120
280
89
46
140
33
160
210
230
120
160
340
220
120
700
76
1800
NR
NR
NR
NR
NR
28
280
410
41
NA
145
<0.5
0.4
<0.5
2
<0.5
<0.5
2.8
<0.5
0.9
<0.5
0.7
1.9
0.7
<0.5
<0.4
<0.5
<0.5
<0.5
<0.5
89
130
22
0.92
370
NR
NR
NR
NR
NR
<0.5
0.9
-------
or SRM reference values was 14 of 26 different sample
lots. The number of NITON XLi average values less than
30% different from the referee laboratory results or SRM
reference values was also 14 of 24 different sample lots.
Both NITON XLt and XLi results; therefore, often provide a
reasonable estimate of accuracy for field determination,
and may be affected by interferences not identified by this
demonstration. Because the NITON data compare
favorably to the SRM values, the differences between
NITON and the referee laboratory are likely the result of
.matrix interferences for field sample analysis.
Initially, there were more sample lots tested for both
instruments, however, several of the samples were below
the estimated detection limit. Many samples were not used
because they were reported as non-detect by NITON. The
previously estimated detection limit was found to be too low
for several of the analyses performed. More information on
detection limits is provided in Section 6.1.1.
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 measurem ents
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 NITON and the referee laboratory. In some cases,
samples may have been analyzed as few as three times
and some NITON results were judged invalid and were not
used. This was often the situation when it was believed
thatthe chosen sample, or SRM, was likely to be below the
vendorquantitatiqn 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- NITON RSDs and the referee
laboratory RSDs was determined. In Tables 6-9 and 6-10,
the RSD for each separate sample lot is shown for NITON
compared to the referee laboratory. The average RSD was
computed for all measurements made by NITON, and this
value was compared to the average RSDforthe 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 Tables 6-10 and 6-11 and shown for
both NITON instruments 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.
Originally, it was anticipated that NITON detection limits
would be lower, based upon information supplied by the
developer. During the demonstration it was discovered
that several lower concentration samples analyzed by
NITON were reported as non-detect because the NITON
detection limit was higher than expected. Therefore, there
are fewer sample lots than originally anticipated for the
evaluation because these non-detect samples could not be
included.
Tables 6-10 and 6-11 show 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 Tables 6-10 and 6-11 and'compared between
NITON 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 NITON'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, and are included here for purposes
of precision comparison. Sample concentrations were
separated into approximate ranges: medium and high, as
noted in Tables 6-10, 6-11, and 6-1. Sample results
reported by NITON as below their approximated PQLwere
not included in Tables 6-10 and 6-11. There appears to be
no correlation between concentration (medium or high) and
RSD; therefore, no other formal evaluations of this
comparison were performed.
48
-------
The referee laboratory analyzed replicates of all samples
analyzed by NITON. This was used for purposes of
precision comparison to NITON. RSD for the vendor and
Table 6-10. Evaluation of Precision (NITON XLt)
the laboratory were calculated individually and shown in
Tables 6-10 and 6-11.
Sample Lot No. NITON and
Lab
Avg. Cone, or Reference
SRM Value
RSD
Number of
Samples
w/in 25% RSD Goal?
OAK RIDGE
Lot no. 22
NITON
ALSI
Lot no. 24
NITON
ALSI
Lot no. 26
NITON
ALSI
Lot no. 31
NITON
ALSI
Lot no. 51
NITON
ALSI
Lot no. 65
NITON
ALSI
Lot no. 67
NITON
ALSI
Oak Ridge Avg. RSD
NITON
ALSI
81.6 (medium)
207 (high)
123 (high)
947 (high)
405 (high)
62.9 (medium)
835 (high)
7.9%
. 9.4%
9.5%
48.4%
12.4%
13.5%
3.3%
13.2%
3.9%
13.4%
41.3%
13.5%
4.5%
14.8%
19.6%
20.4%
3
3
7
7
7
7
3
3
7
7
7
7
7
7
yes
yes
yes
no
yes
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
yes
PUGET SOUND
Lot no. 25
NITON
ALSI
Lot no. 27
NITON
ALSI
Lot no. 48
NITON
ALSI
Lot no. 50
NITON
ALSI
Puget Sound/ Avg. RSD
NITON
ALSI
39.1 (medium)
136 (high)
77.8 (medium)
203 (high)
11.5%
10.7%
13.3%
16.9%
18.9%
32.9%
6.6%
17.7%
13.3%
22.1%
3
3
7
7
4
6
7
7
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
CARSON RIVER
Lot no. 23
NITON
ALSI
Lot no. 53
NITON
ALSI
. Lot no. 54
NITON
ALSI
117 (medium)
910 (high)
1120 (high)
22.2%
5.7%
,\
\
7.3%
35.5%
4.0%
21.0%
3
3
7
7
7
7
yes
yes
yes
no
yes
yes
49
-------
Table 6-10. Continued
Sample Lot No. NITON and
Lab
Lot no. 63
NITON
ALSI
Carson River/ Avg. RSD
NITON
ALSI
Avg. Cone, or Reference ' RSD
SRM Value
169 (high)
9.2%
6.5%
15.7%
6.7%
Number of
Samples
7
7
w/in 25% RSD Goal?
yes
yes
yes .
yes
MANUFACTURING SITE
Lot no. 19
NITON
ALSI
Lot no. 20
NITON
ALSI
Lot no. 28
NITON
ALSI
Lot no. 29
NITON
ALSI
Lot no. 30
NITON
ALSI
Lot no. 32
NITON
ALSI
Lot no. 33
NITON
ALSI
Lot no. 49
NITON
ALSI
Lot no. 52
NITON
ALSI
Lot no. 64
NITON
ALSI .
Lot no. 66
NITON
ALSI
Manufacturing Site/ Avg. RSD
NITON
ALSI
Overall Avg. RSD
NITON
ALSI
Field Samples/ Avg. RSD
NITON
ALSI
SRMs/Avg. RSD
NITON
ALSI
28.7 (medium)
63.9 (medium)
251 (high)
374 (high)
451 (high)
592 (high)
379 (high)
99.8 (medium)
608 (high)
285 (high)
985 (high)
19.5%
32.2%
19.2%
25.4%
8.2%
15.6%
27.8%
17.4%
13.8%
11.4%
7.8%
12.7%
10.8%
13.3%
20.5%
12.5%
4.7%
21.9%
8.7%
8.9%
3.8%
11.2%
3.8%
11.2%
SUMMARY STATISTICS
13.1%
20.0%
16.9%
17.5%
9.3%
22.5%
4
7
3
7
3
3
3
7
3
3
7
7
6
7
7
7
7
7
7
7
7
7
yes
no
yes
yes
. yes
yes
no
yes
no
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
" yes
yes
yes
ves
50
-------
Table 6-11. Evaluation of Precision (NITON XLi)
Sample Lot No. NITON and
Lab
Avg. Cone, or Reference
SRM Value
RSD
Number of
Samoles
w/in 25% RSD Goal?
OAK RIDGE
Lot no. 22
NITON
ALSI
Lot no. 24
NITON
ALSI
Lot no. 26
NITON
ALSI
Lot no. 31
NITON
ALSI
Lot no. 51
NITON
ALSI
Lot no. 65
NITON
ALSI
Lot no. 67
NITON
ALSI
Oak Ridge Avg. RSD
NITON
ALSI
81.6 (medium)
207 (high)
123 (high)
947 (high)
405 (high)
62.9 (medium)
835 (high)
15.8%
9.4%
23.7%
48.4%
15.8%
13.5%
6.4%
13.2%
13.1%
13.4%
33.5%
13.5%
5.0%
14.8%
16.7%
20.4% .
3
3
7
7
7
7
3
3
7
7
7
7
6
7
yes
yes
yes
no
yes
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
yes
PUGET SOUND
Lot no. 27
NITON
ALSI
Lot no. 48
NITON
ALSI
Lot no. 50
NITON
ALSI
Puget Sound/ Avg. RSD
NITON
ALSI
Lot no. 23
NITON
ALSI
Lot no. 53
NITON
ALSI
Lot no. 54
NITON
ALSI
Lot no. 63
NITON
ALSI
Carson River/ Avg. RSD
NITON
ALSI
136 (high)
77.8 (medium)
203 (high)
117 (medium)
910 (high)
11 20 (high)
169 (high)
21.1%
16.9%
25.9%
32.9%
10.0%
17.7%
21.1%
22:1%
CARSON RIVER
11.7%
5.7%
7.0%
35.5%
9.4%
21.0%
11.2%
6.5%
11.4%
6.7%
7
7
4
6
7
7
3
3
7
7
7
7
7
7
yes
yes
no
no
yes
yes
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
yes
yes
51
-------
Table 6-11. 'Continued
Sample Lot No. NITON and
Lab
Avg. Cone, or Reference RSD
SRM Value
Number of
Samples
w/in 25% RSD Goal?
MANUFACTURING SITE
Lot no. 20
NITON
ALSI
Lot no. 28
NITON
ALSI
Lot no. 29
NITON
ALSI
Lot no. 30
NITON
ALSI
Lot no. 32
NITON
ALSI
Lot no. 33
NITON
ALSI
Lot no. 49
NITON
ALSI
Lot no. 52
NITON
ALSI
Lot no. 64
NITON
ALSI
Lot no. 66
NITON
ALSI
Manufacturing Site/ Avg. RSD
NITON
ALSI
63.9 (medium)
251 (high)
374 (high)
451 (high)
592 (high)
379 (high)
99.8 (medium)
608 (high)
285 (high)
985 (high)
18.3%
25.0%
8.6%
15.6%
16.2%
17.4%
17.5%
11.4%
3.9%
12.7%
9.5%
13.3%
32.8%
12.5%
8.3%
21.9%
7.1%
8.9%
3.6%
11.2%
11.6%
16.3%
3
7
3
3
3
7
3
3
'7
7
6
7
7
7
7
7
7
7
6
7
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
Overall Avg. RSD
NITON
ALSI
SUMMARY STATISTICS
14.4%
20.0%
yes
yes
Field Samples/ Avg. RSD
NITON
ALSI
SRMs/ Avg. RSD
NITON
ALSI
13.8%
17.5%
15.0%
22.5%
yes
yes
yes
ves
NITON XLt (X-ray) Evaluation
As noted from Table 6-10, the NITON XLt precision is
better than that of the referee laboratory. The single most
important measure of precision provided in Table 6-10,
overall average RSD, is 20.0% for the referee laboratory,
compared to the NITON XLt average RSD of 16.1%. The
laboratory and NITON RSD are both within the predicted
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 17.5%
for ALSI and 16.9% for NITON; SRM RSD is 22.5% for
ALSI and 9.3% for NITON. This is similar to the results for
52
-------
the accuracy comparison. NITON appears to have better
precision for the SRM analyses compared to the field
samples. NITON'S comparison for SRMs was statistically
significant, and for the precision evaluation NITON had a
narrower range for the RSD. Forpurposes ofthis analysis,
spiked samples are considered the same as field samples
because these were similarfield matrices and the resulting
variance was expected to be equal to 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 in
precision between Oak Ridge, Puget Sound, Carson River,
and the manufacturing site samples. (See Table 6-10
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
Manufacturing site had a lower average RSD for both the
vendor and the laboratory but this difference was not
significant in results from the other NITON instrument or
other data sets and, therefore, may not be significant.
NITON XLi (Isotope) Evaluation
As noted from Table 6-11, the NITON XLi precision is
better than that of the referee laboratory. The single most
important measure of precision provided in Table 6-11,
overall average RSD, is 20.0% for the referee laboratory,
compared to the NITON XLi average RSD of 14.4%. The
laboratory and NITON RSD are both within the predicted
25% RSD objective for precision expected from both
analytical and sampling variance. Field sample precision
compared to SRM precision shows no significantdifference
between these two sample lots; field sample RSD is 17.5%
for ALSI and 13.8% for NITON; SRM RSD is 22.5% for
ALSI and 15.0% for NITON.
There appears to be no significant site variation between
Oak Ridge, Puget Sound, Carson River, and the
manufacturing site samples. (See Table 6-11 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 was not significant in results
from the other NITON instrument or other data sets and,
therefore, may not be significant.
Precision Summary
The precision of the NITON XLt and XLi field instruments
is better than the referee laboratory precision. The overall
average RSD is 20.0% for the referee laboratory,
compared to the NITON XLt average RSD of 13.1% and
the NITON XLi average RSD of 14.4%. Both the laboratory
and NITON precision goals of 25% overall RSD were
achieved.
6.1.4 Time Required for Mercury
Measurement
The 700 Series Analyzers were evaluated over a 3-day
period. The amount of time that was needed to setup,
prepare and analyze 197 samples using 2 instruments,
calibrate the analyzers, as well as the time necessary to
demobilize was determined.
Two technicians performed all activities including sample
preparation and analysis for four batches of mercury-
contaminated soil. Setup involved taking the analyzers,
test stands, battery packs and battery charger out of the
carrying case, installing a battery pack and connecting the
computers and keyboard (optional equipment) to the
electric power source. This took approximately 2 minutes.
Afterturningon the instruments, they were allowedto warm
up for 10 minutes before the instruments were calibrated.
The technician selected the Calibrate Detector icon to
recalibrate either instrument. The instrument calibration
screen was displayed until the calibration was complete.
After the calibration finished, the calibration results were
displayed. During the demonstration, calibration check
samples were analyzed prior to analysis, in the middle of
the day, and towards the end operation for the day. The
check samples were analyzed for 240 seconds, the same
time used when analyzing samples for the demonstration.
Total setup time including warm-up was about 20 minutes
on the first day of the demonstration. The XL Series
Analyzers were calibrated with a 230 mg/kg standard. The
instruments recorded concentrations very close to the
standard throughout the demonstration.
The time required for mercury measurements started with
sample setup and ended when NITON disconnected the
devices and placed them back into the padded carrying
cases. After setup, sample preparation was carried out.
Soil samples were provided to NITON in 20 mL amber
VOA vials. Priorto filling the XRFsample cups,the NITON
technicians prepared for the samples by placing a circle of
Mylar film on top of the sample cup, and securing the film
with a collar. The film was smooth and taut. NITON
performed this step, which took 3 seconds per sample,
ahead of time. (The observer watched the Mylar film
placed on several sample cups during the demonstration.)
Dry soil was transferred from the VOA vial to the sample
cup using a metal spatula. A metal spatula was used to
53
-------
lightly tamp the sample in the cup. A filter paper disc was
then placed on the sample. The rest of the sample cup
was stuffed with polyester filling to prevent the sample from
moving during measurement. Finally a cap and sample
label were placed on the cup. Sample preparation took
about two minutes persample. The cup was now ready for
measurement. Sample analysis was done in
approximately the top 2-5 mm of the sample.
Some sample batches had free standing water. One batch
was moist and appeared tar-like. Some of these samples
were placed in a toaster oven at 200 ฐFfor 2-3 hours prior
to analysis. Sample preparation and analysis continued
while the moist samples were drying in the toaster oven.
Measurements taken with the 700 Series Analyzers
required placing the test platform on a flat level surface.
The technician then placed the nose cone adapter with the
analyzer's window againstthe test stand's analysis window
and the LCD screen towards the technician. The prepared
sample was placed in the pocket on the test stand. The
technician depressed the test platform lever and pushed
the sample test drawer fully closed. The technician then
selected the desired test procedure. There are four
different methods of operation for taking sample
measurements. During the demonstration, the trigger-and
proximity-sensor method was used. With this method, the
measurement window was placed against the sample to be
analyzed to engage the proximity sensor on the frontof the
instrument and the trigger for sample analysis was then
activated.
Measurement times from 30-600 seconds can be
employed, depending on the data quality needs of the
project. As the measurement time increases, the detector
collects a larger number of X-rays from the sample. Based
on years of experience and sound engineering practice,
NITON determined the measurement times used during
the demonstration. The measurement time selected was
120 seconds per sample. The measurement time shown
on the screen was the total time that had elapsed. In some
cases sample measurement times exceeded 120 seconds.
Sample results we're transcribed from the computerscreen
to the Chain-of-Custody form and given to the EPA
representative prior to leaving the site on day one. On days
two and three, the results were given to the EPA
representative shortly after returning to the hotel. Results
were available on-site, however NITON wanted some
additional time to look over the data.
Analysis Time Summary
NITON required a total of 17.5 hours (35 man hours) for
mercury measurements of 197 soil samples analyzed using
2 instruments during their 3-day demonstration. It should
be noted that one technician performed sample preparation
while the other technician simultaneously operated both
analyzers. Table 6-12 indicates the time required to
complete mercury measurements using the 700 Series
Analyzers.
Table 6-12. Mercury Measurement Times
Measurement Activity Time Required
System Setup
Battery Pack Installation
Battery Pack Charge
Analyzer Warm Up
Analyzer Calibration
Sample Preparation
Count Times
Demobilization
2 minutes
1 minute
120 minutes
10 minutes
5 minutes
2 minutes per sample
2 minutes per sample
2 minutes
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
XL-700 Series Analyzers in terms of secondary objectives
described in Section 4.1. These secondary objectives
were addressed based on observations of the XLi 702 and
XLt 792 and information provided by NITON.
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 700 Series Analyzers are very
easy to operate, requiring one field technician
with a high school education. NITON requires
any user to attend a free-of-charge, 8-hour
training course priorto operating their analyzers.
The instruments come equipped with
customizable, PC-based reporting software that
automatically corrects for variations in soil-
sample chemistry and density. Internet-based
diagnostics and troubleshooting are available.
54
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During the demonstration, one technician prepared most of
the soil samples while the other technician performed
sample analysis. However, both technicians did perform
sample preparation and analysis during the three days in
thefield. One technician could easily perform both sample
preparation and analysis for one instrument. Two
technicians were used during the demonstration in order to
increase sample throughput during the limited time on-site.
Based on observations and conversations during the field
demonstration, the instrument could be easily operated by
a high school graduate, after attending NITON's 8-hour
training course.
After the analyzer, test stand, computer, keyboard, and
battery charger were unpacked from the carrying case, the
technicians prepared the analyzers for use. The NITON
devices are hand-held portable X-ray fluorescence
analyzers. The on/off/escape button on the control panel
was pressed for about 3 seconds to turn the instrument on.
On start-up, the screen display was replaced by the re-start
screen which counts down from 29 to 0, in increments of 1
second. When the restart was complete, it was replaced
by the logon screen. The technician selected a 4-digit
security code, followed by the enter key. After the
technician completed the log-on procedure, the word
"success" appeared on the screen. The technician
checked the date/time on the screen. The NITON 700
Series main menu system allows the technician to take
readings, view and move data with a minimum number of
steps. Menus were presented as small pictures (Figure
6-5) which allowed the technician to do several things:
1. Toggle between two different functions or views,
such as turning backlighting on or off.
2. Present a sub-menu which allowed access to
more choices.
3. Present a screen which allowed the technician to
view data, edit data or control the instrument.
The standard soil testing mode was available from the bulk
mode menu. The standard soil testing menu allowed the
technician to perform tests on soil without adjusting for a
particular matrix. The standard soil testing mode uses
Compton Normalization to automatically adjust for the
effects of the matrix. Sample spectra are viewed on the
screen (Figure 6-6).
The results were displayed throughout the duration of the
reading, and updated every 3 seconds. When the reading
was complete, a final screen on the analyzer displayed the
final measurements which have just been completed.
XL-700 Series downloads include precision data and X-ray
spectra, name of data collector, test location, sample-
identification, and sample results (Figure 6-7).
Figure 6-5. Main menu screen shot.
x| a a ปlซ!ปi tfiai*! mai aitr
E:11.82KeV HgtLH 11.82
R:O.77 Br iKa 11.91
Tl iLb 12.21
Figure 6-6. Screen shot of sample spectra.
55
-------
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Figure6-7. Multi-element data report
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 XLi 702
contains radioisotope sources, and should never
be pointed at any person when the shutter is
open. With the safety shutter(s) open while
testing samples, the exposure to the user's hand
is <.05 mR/hr. During setup and operation, both
analyzers are password protected.
Health and safety concerns, including chemical hazards,
radiation sources, electrical shock, explosion, and
mechanical hazards were evaluated.
Potential exposu re to radiation from the excitation sources
(Cd-109, Am-241, Fe-55 and. the X-ray tube) was the
primary health and safety concern during the
demonstration. The XLi 702 used during the demonstration
contained a three radioactive source configuration of a 10
millicurie (mCi) Cd-109 source, a 14 mCi Am-241 source
and a 20 mCi Fe-55 source. The Cd-109 source was the
only source used during the demonstration. The XLi 702
instrument is distributed under a specific Massachusetts
license and a general license, and it is expected that under
normal use an operator would not accumulate a radiation
56
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dose higher than that from naturally occurring radiation. A
health physicist from the Tennessee Department of
Environment and Conservation used a gamma-ray detector
to monitor radiation for half an hour during one day of the
demonstration. Background radiation at the site was 5
microrems per hour (urem/hr). During sample analysis 20
urem/hr was obtained on contact with the sample tray, and
50 prem/hr was obtained on contact with the window port.
The sources are sealed and locked in place in a tungsten
alloy source holder. According to NITON, the sources are
designed to remain secure even underextreme conditions,
so that even if the instrument is broken, crushed or burned
there should be no leakage of radioactive material.
The cadmium source used was originally 10 mCi, and has
a half life of about 15 months. The cadmium source would
have to be replaced every 15 months and disposed of in
accordance with Nuclear Regulatory Commission (NRC)
regulations. The replacement of the source and its
disposal would have to be done by the manufacturer or
their authorized representative.
During the demonstration, the operators wore nitrile gloves
and safety glasses while transferring about 15 grams of
mercury-contaminated soil per sample from the VOA vials
into the sample cups. SAIC continuously monitored
ambient air for mercury, using a mercury vapor analyzer.
Mercury was not detected (0.000 mg/m3) in the air or
breathing zones during the course of the demonstration.
6.2.3 Portability of the Device
Documents the portability of the device.
The NITON 700 Series Analyzers are single piece
units weighing only 0.8 kg (XL! 702) and 1.4 kg
(XLt 792). There are no cables, no separate
processing units. They were easy to set up and
can be carried in a waist belt holder. High
strength injection molding plastic housing
enables them to withstand harsh environments.
Quick-swap batteries allow up to 6-12 hours of
continued use. Samples can be analyzed in less
than five minutes.
The NITON 700 Series Analyzers are single units that are
hand-held. Polyethylene sample cups, Mylar film, filter
discs, polyester filling and a small metal spatula are
required during sample preparation activities. These items
.can be purchased separately from NITON, or directly from
the manufacturer. One hundred small (approximately 40
mm) sample cups, one roll of Mylar film, filter discs,
polyester filling and a small sample tool can fit easily into a
small box. The analyzers, test stands and accessories are
housed in a padded carrying case. The XLi 702 weighs
0.8 kilograms (kg) and is 292 mm by 89 mm by 76 mm.
The XLt 792 weighs 1.8 kg and is 248 mm by 273 mm by
95 mm. The test stand for both units is 278 mm by 63 mm
by 139 mm. During the demonstration, a fully charged
battery pack lasted for almost 8 hours. The instruments
can also operate off a 115 volt electric line.
According to NITON the analyzers willoperate between -7
and 49 ฐC. In addition, the analyzers can operate at a
humidity range of 0-95% relative humidity. During the
demonstration, relative humidity as high as 98.3% was
recorded.
During the demonstration, NITON performed sample
preparation and analysis under a tent. The instruments
were setup in two minutes on a six-foot long folding table.
The small, lightweight battery-operated analyzers could be
'easily carried by hand to another sample location and
operated for about 4-8 hours on one battery pack.
No solvents or acids were used for sample preparation.
The only additional waste generated were the sample cups,
Mylar film, filter discs and polyester filling which were used
during analysis of intrusive samples. Finally, even though
the XLi contains radioisotopes, in most cases no
notification is required if transporting within state
boundaries. This may not be the case when entering
federal properties/The NITON XLi 702 conforms to the
conditions and limitations specified in 49 CFR 173.421 for
excepted radioactive material. (Excepted package
instruments and articles, N.O.S. UN-2911.) In most
countries, the analyzers can be transported in a fully
padded carrying case by plane or car, or shipped as an
ordinary package. For most courier services, no special
labels are required on the outside of the NITON carrying
case or on additional packaging. In the U.S., the XLt 792
can be carried, shipped ortransported in the carrying case
without exterior labeling.
6.2.4 Instrument Durability
Evaluates the durability of the device based on its
materials of construction and engineering design.
NITON introduced the first ever hand-held XRF
analyzer in 1994. They are well designed and
constructed for durability.
57
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The NITON analyzers were designed so that virtually no
measurable radiation can escape when the shutter is
closed. According to NITON, even if the instrument is
broken, crushed or burned there should be no leakage of
radioactive material.
Each sealed isotope source is locked in place in a solid
tungsten alloy source holder. The source is secure in its
housing because the aperture at the end of housing is
smaller than the source and completely sealed. The
source assembly is secured in the instruments case, which
is fitted with tamper-proof screws. Finally, the high
strength plastic housing should withstand harsh
environments. Based on 'observations during the
demonstration, the analyzers were well constructed and
durable. During the three days in which the instruments
were observed, there was no downtime, maintenance, or
repairs. The equipment was not apparently affected by the
three days of almost continuous rain, and relative humidity
as high as 98.3%. The instruments were, however,
operated under a tent.
6.2.5 Availability of Vendor Instruments and
Supplies
Documents the availability of the device and spare
parts.
The NITON 700 Series Analyzers are readily
available for rental, lease, or purchase. Another
analyzer if needed, can be received within 2-6
weeks of order placement. Sample cups, Mylar
film, spatulas, filter-discs and polyester filling
are readily available from NITON or several
supply firms.
During the demonstration, NITON 700 Series Analyzers
and disposable supplies did not have to be replaced. 'If a
replacement analyzer or test stand were required, NITON
claimed it could have been shipped by express courier and
held for pick-up the next day. There are currently 10 XLi
702 units available for rental. At the time of the
demonstration, the NITON XLt Analyzer was a prototype
and replacement parts may have been difficult to obtain.
NITON now has 3 XLt 792 units available for rental. The
instruments must be held for pick-up at the local express
courier office, and can not be delivered to any location
because the instruments contain radioisotopes or an X-ray
tube. The express courier office was located twenty
minutes away from the site. In general, no time would be
lost picking up another unit at a local express courier office
rather than having it delivered the next day to the site by
10:30 a.m. Many express courier offices are open as early
as 8 a.m.
In general, the 700 Series Analyzers are available within
2-6 weeks of order placement. The disposable supplies
(sam pie cups, Mylar film, spatulas, filter discs) if needed for
intrusive analysis could be obtained from the
manufacturers, and shipped directly to the site by overnight
courier. NITON claims the 700 Series Analyzers never
need site-specific calibrations.
58
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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 separately. 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 NITON 700 Series Analyzers XLi 702 (isotope)and
XLt 792 (X-ray tube) 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 NITON XLi/XLt 700 Series
Analyzer costs. No attempt was made to make a direct
comparison between these costs for different methods
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 NITON XLi/XLt 700 Series
Analyzers, and presents a cost summary for a "typical"
laboratory perform ing 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. NITON offers three options for potential users:
1) purchase of the analyzers, 2) monthly rental and
3) analyzer leasing depending on current interest rates
(NITON, 2003a). 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 for three months or less 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 XLi 702 analyzer evaluated during the demonstration
was equipped with Cd-109, Am-241 and Fe-55 sources.
During the demonstration, only the Cd-109 source was
used. The capital equipment costs are based on the
analyzer with one source, Cd-109. The XLt 792 uses a
low-powered, miniature X-ray tube with a silver target as
the excitation source. Both analyzers com e equipped with
a test stand, soil grinder, sieve set and sample cups. A
keyboard and laptop computer are optional, and may be
supplied by the customer if the user wants to operate the
instrument in the bench-top mode.
The cost quoted by NITON includes freight costs to ship
the instrument to the user location when purchasing the
instrument, but does not include the license (radioactive
source) that may be needed to operate the instrument. The
license that is needed to operate the XLi 702 analyzer in
the state of Tennessee cost $900. A $5,000 dollar fully
refundable security deposit is required for all XLi/XLt 700
Series rentals and leases. An eight-hour training session
is mandatory for anyone renting, leasing or purchasing an
analyzer (NITON, 2003a). NITON offers over 100
user/radiation training classes free-of-charge throughout
the year..
59
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7.1.2 Cost of Supplies
The cost of supplies is minimal, based on the supplies
required to analyze demonstration samples! Requirements
vary depending upon whether in-situ or intrusive analysis
is being performed. For purposes of this cost estimate,
only supplies required to analyze soil samples intrusively
are factored into the cost estimate. Disposable supplies
are not required for in-situ analysis. The supplies used
during the demonstration consisted of four consumable
items which were:
XRF sample cups (one per sample)
Mylar film
Polyester filling .
Filter-paper discs
The purchase prices and supply sources were obtained
from NITON. The analyzers are supplied with supplies for
100 samples. Because the user cannot return unused or
remaining portions of supplies, no salvage value was
included in the cost of supplies. (NITON, 2003a) 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 XL-Series 700 Analyzers
were operated using both AC power and a lithium ion
battery pack. The XLi instrument operated for almost 5
hours using one battery pack. (The XLi instrument
observed during the demonstration started at 95% battery
life). The XLt unit operated for 8 hours using one battery
pack. Only the battery charger requires AC.
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 setup, sample preparation, sample analysis, summary
data presentation and instrument packaging at the end of
the day. Setup time covered the time required to take the
analyzers out of their packaging, setup all components,
and ready the devices for operation. Sample preparation
involved transferring samples into the XRF sample cups.
Sample preparation was completed easily, requiring about
one minute per sample. Sample analysis was the time
required to analyze all samples 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 vendor transcribed results from computer
screens to the field chain-of-custody forms. (A printer was
not available in the field.) The time.required to perform all
tasks was rounded to the nearest minute; however, for the
economic analysis, times were rounded to the nearest
hour, and it was assumed that a field technician who had
worked for a fraction of a day would be paid for an entire
8-hour day. Based on this assumption, a daily rate for a
field technician was used in the analysis.
During the demonstration, EPA representatives evaluated
the skill level required for the two field technicians to
analyze and report results for mercury samples.. Based on
these field observations, a high school graduate with the
eight-hour training specific to the 700-Series Analyzers
would be qualified to operate the analyzers. For the
economic analysis, an hourly rate of $15 was used for a
field technician. A multiplication factor of 2.5 was applied
to labor costs to accountforoverhead 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
NITON 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). General trash was
not included as IDW, and is not discussed in this
document.
Lightly contaminated wastes consisted primarily of used
nitrile gloves and Kim-wipes. The gloves were discarded
because they posed a potential health and safety risk
(holes or tears). The rate of waste generation was in
excess of what would be expected in a typical application
of these instruments. In addition, the EPA evaluators
60
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occasionally contributed used gloves to this waste
accumulation point. Wipes were used primarily to clean
any spilled soil off the table and to clean off any moist or
organic material adhering to the spatula which was used to
transfer soil into the sample cups. In cases where cross
contamination is not a major concern (e.g., field screening
orin-situ analysis), lesser amounts of waste would likely be
generated.
Contaminated soil consisted primarily of soil placed in the
XRF sample cups containing a filter paper disc, polyester
filling and then covered with Mylar film. The sample is not
destroyed during preparation and analysis; therefore it is
possible to send the samples off-site for confirmatory
analysis, but for purposes of this economic analysis, it was
assumed that they were discarded.
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. A free, eight-hour
training course is mandatory in order to operate the
analyzers. The users' time and travel expenses to attend
the course are not included. Any licensing fees required
for the radionuclide source were also not included as they
vary from state to state.
Oversight of Sample Analysis Activities. A typical user
of the 700-Series Analyzers 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 reference 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 were included in the economic analysis.
Items Costing Less than $10. The costs of inexpensive
items, such as paper towels, were 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 they also 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, were 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 XLi/XLt 700 Series Analyzers Costs
This subsection presents information on the individual
costs of capital equipment,, supplies, support equipment,
labor, and IDW disposal for the 700 Series Analyzers.
7.2.1 Capital Equipment Cost
During the demonstration, each 700 Series Analyzer
operated for three days, and was used to analyze 197
samples. Figures 7-1 and 7-2 show the relative costs for
the basic capital equipment. These costs reflect the XLi
equipped with Cd-109, while the XLt used a miniature X-ray
tube as the'excitation source. Table 7-1 summarizes the
61
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700 Series Analyzers capital costs for the three
procurement options: rental, lease, and purchase. As
would be expected, Table 7-1 clearly shows that leasing is
the most cost-effective option (in terms of capital costs),
followed by rental, for short-term projects. As project
duration (or use on multiple projects) approaches two
years, the purchase option becomes the most cost-
effective. These scenarios cover only capital cost, not the
cost of optional or user-supplied equipment, supplies,
support equipment, labor, and IDW disposal.
Purchase
"Rental
Lease
Months
Figure 7-1. Capital costs for the XLi (isotope).
The XLi (with Cd-109) sells for $29,095. The cadmium
source (10 mCi) used during the demonstration needs to
be replaced about every 15 months. The cost of replacing
the source is $2,700 and includes source disposal and
software upgrade.
Purchase
Rental
Lease
Months
Figure 7-2. Capital costs for the XLt (X-ray tube).
The XLt (with miniature X-ray tube) sells for $38,095. As
miniature X-ray tubes are quite new, not enough data has
been collected to estimate tube lifetime. The cost of
replacing the X-ray tube is $5000 and includes a new
power supply and software upgrade.
Table 7-1. Capital Cost Summary for the XLJ/XLt 700 Series Analyzers
a
b
Item
Purchase XLi 702 (Isotope)
Monthly Rental of XLi 702
Monthly Lease of XLi 702
Purchase XLt 792 (X-ray tube)
Monthly Rental of XLt 792
Monthly Lease of XLt 792"
$1,333 per month (24-month
$1 ,745 per month (24-month
Quantity Unit Cost
1
1
1
1
1
1
lease with $1
lease with $1
$29,095
$5,190
$1,333
$38,095
$6,800
$1,745
buyout).
buyout).
1 -Month
$29,095
$5,190
$1,333
$38,095
$6,800
$1,745
Total Cost for Selected Project Duration
3-Month 6-Month 12-Month
$29,095
$15,570
$3,999
$38,095
$20,400
$5,235
$29,095
$31,140
$7,998
$38,095
$40,800
$10,470
$29,095
$62,280
$15,996
$38,095
$81,600
$20,940
24-Month
$29,095
$124,560
$31,992
$38,095
$163,200
$41,880
62
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7.2.2 Cost of Supplies
Supplies used during the demonstration included XRF
sample cups, Mylar film, 2.4 cm filters and polyester filling.
NISI soil SRMs were also used during the demonstration
and are included with an instrument purchase.
7.2.3 Support Equipment Cost
NITON was provided with a 10x10 foot tent for protection
from inclement weather during the demonstration. It was
also provided with one table and two chairs for use during
sample preparation and analytical activities. The rental
cost for the tent (including detachable sides, ropes, poles,
and pegs) was $270' per week. The rental cost for the
table and two chairs forone week totaled $6. Total support
equipment costs were $276 per week for rental.
For longer projects, purchase of support equipment should
be considered. Two folding chairs would cost
approximately $40. A 10x10 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 for this 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.
7.2.4 Labor Cost
Two technicians were utilized for three days (17.5 hours, or
35 man hours total)during the demonstration to complete
sample preparation and analysis for both instruments.
Based on a labor rate of $600 per day, total labor cost for
application of both 700 Series Analyzers was $1,800 for the
three-day period. Laborcosts assume qualified technicians
are available locally, and that no per diem costs or travel
costs are applicable. Table 7-2 summarizes labor costs for
various operational periods, assuming 21 work days per
month (on average), 252 work days per year and -one
technician per job site. The costs presented do not include
supervision and quality assurance because these would be
associated with use of any analytical instrument and are a
portion of the overhead multiplier built into the labor rates.
7.2.5 Investigation-Derived Waste Disposal
Cost
NITON generated PPE waste and soil waste, including
sample cups, Mylar film, filter discs and polyester filling.
The PPE waste was charged to the overall project due to
site constraints. The minimum waste volume is a5-gallon
container. Mobilization and container drop-off fees were
$1,040; disposal of a 5-gallon waste soil drum cost $400.
(These costs were based on a listed waste stream with
hazardous waste number U151.) 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 sample
material is generated that requires disposal. Table 7-3'
presents IOW costs for various operational periods,
assuming that waste generation rates were similarto 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
Control
Total
NA
$6,300
NA
$18,900
NA
$37,800
NA
$75,600
NA
$151,200
Table 7-3. IDW Costs
Item
Drop Fee
Disposal
Total
1
$1,040
$400
$1,440
3
$3,120
$1,200
$4,320
Months
6
$6,240
$2,400
$8,640
12
$12,480
$4,800
$17,280
24
$24,960
$9,600
$34,560
7.2.6 Summary ofXLi/XLt 700 Series Costs
The total cost for performing mercury analysis is
summarized in Tables 7-4 and 7-5. These tables reflect
costs for projects ranging from 1-24 months. The rental
option was used for estimating the equipment cost.
Capital cost for equipment rental exceed those for
purchase at approximately six months, so rental is not as
cost-effective for projects exceeding this duration. Finally,
a lease agreement may be a cost-effective alternative to
either rental or purchase for projects lasting less than 21
months. At that point, equipment purchase may be more
cost-effective; however, the decision on which purchase
option to utilize should be made on a case-by-case basis.
63
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Table 7-4. Summary of Rental Costs for the XLi 702 (Isotope)
Item Quantity Unit Unit
Cost
($)
Capital Equipment
Monthly Rental 1 NA $5,190
Support Equipment
Table (optional) - weekly 1 each $5
Chairs (optional) -weekly 2 each $1
Tent (for inclement weather 1 each $270
only) - weekly
To tot SuDDort EouiDrncnt Oost > >
Labor
Field Technician (person day 1 hour $38
IDW
Container and Drop Fee $1,040
Disposal NA week $400
Trt#^i iniA/ rnate
1 ULOI IL/VV wUOlo ~
Total Cost
Table 7-5. Summary of Rental Costs for the XLt 792 (X-ray Tube)
Item Quantity Unit Unit
Cost
($)
Capital Equipment
Monthly Rental 1 NA $6,800
Support Equipment
Table (optional) -weekly 1 each $5
Chairs (optional) - weekly 2 each $1
Tent (for inclement weather 1 each $270
only) - weekly
Tots! SuDDort EciuiDmGnt Ooct ป >
Labor
Field Technician (person day 1 hour $38
IDW
Container and Drop Fee $ 1 ,040
Disposal ' NA week $400
Tnt-^l in\A/ Pnntt
1 UIQI ILJVV VyUOLO ~~ _ ป _______
Total Cost
1 -Month
$5,190
$20
$10
$800
$830
$6,300
$1,040
$400
$1,440
$13,760
1 -Month
$6,800
$20
$10
$800
$830
$6,300
$1 ,040
$400
$1 ,440
$15,370
Total Cost for Selected Project Duration
3-Month 6-Month 12-Month
$15,570
$60
$25
$800
$885
$18,900
$3,120
$1,200
$4,320
$39,675
$31,140
$120
$40
$800
$960
$37,800
$6,240
$2,400
$8,640
$78,540
$62,280
$160
$40
$800
$1,000
$75.600
$12,480
$4,800
$17,280
$156,160
Total Cost for Selected Project Duration
3-Month 6-Month 12-Month
$20,400
$60
$25
$800
$885
$18,900
$3,120
$1,200
$4,320
$44,505
$40,800
$120
$40
$800
$960
$37,800
$6,240
$2,400
$8,640
$88,200
$81,600
$160
$40
$800
$1,000
$75,600
$12,480
$4,800
$17,280
$175,480
24-Month
$124,560
$160
$40
$800
$1,000
$151,200
$24,960
$9,600
$34,560
$311,320
24-Month
$163,200
$160
$40
$800
$1,000
$151,200
$24,960
$9,600
$34,560
$349,960
64
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Tables 7-6 and 7-7 summarize costs for the actual
demonstration. Note that the one-month rental costs of the
XLi/XLt 700 Series units was used for capital costs. 35
hours were required by both technicians to prepare and
analyze the samples for both instruments over a three-day
period. The labor rate presented in this Chapter assumes
one person performs sample preparation and analysis on
197 samples for one instrument over a two-day period.
Table 7-6. XLi 702 (Isotope) Costs by Category
Table 7-7. XLt 792 (X-Ray Tube) Costs by Category
Category
Instrument
Supplies
Support
Equipment
Labor
IDW Disposal
Total
Category Cost
$5,190
$280
$276
$600
$1,440
$7,786
Percentage of
Total costs
66.7%
3.6%
3.5%
7.7%
18.5%
100.0%
Note: The percentages in Table 7-6 are rounded to one decimal place;
the total percentage is 100%.
The cost per analysis when renting the XLi 702, based
upon 197 samples, is $39.52 per sample. The cost per.
analysis for the 197 samples, excluding instrument rental
cost is $13.18 per sample.
The cost per analysis when renting the XLt 792, based
upon 197 samples, is $47.69 per sample. The cost per
analysis for the 197 samples, instrument rental cost is
$13.18 persample.
Category
Instrument
Supplies
Support
Equipment
Labor
I DW Disposal
Total
Category Cost
($}
$6,800
$280
$276
$600
$1,440
$9,396
Percentage of
Total costs
72.4%
3.0%
2.9%
6.4%
15.3%
100.0%
Note: The percentages in Table 7-7 are rounded to one decimal place;
the total percentage is 100%.
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.
A typical mercury analysis cost, along with .percent
moisture for dry-weight calculation, is approximately $35.
This cost covers Sample management and preparation,
analysis, quality assurance, preparation of a data package.
The total cost for 197 samples at $35 would be $6,895.
This is based on a standard turnaround time of 21-
calendar days. The sample turnaround time from the
laboratory can be reduced to 14, 7, or even fewer calendar
days, with a cost multiplier between 125% to 300%,
depending upon project needs and laboratory availability.
This results in a cost range from $6,895 to $20,685. The
laboratory cost does not include sample packaging,
shipping, or downtime caused to the project while awaiting
sample results.
65
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Chapters
Summary of Demonstration Results
As discussed previously in this ITVR, the NITON XLi/XLt
700 Series Analyzers were 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 or source. Collectively, these samples provided the
different matrices, concentrations, and types of mercury
needed to perform a comprehensive evaluation of the
XLi/XLt 700 Series Analyzers.
8.1 Primary Objectives
The primary objectives of the demonstration were centered
on evaluation of the field instruments and performance in
relation to sensitivity, accuracy, precision, time for analysis,
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 successfulfor evaluation of the
NITON XLi/XLt 700 Series Analyzers. Quantitative results
were reviewed. NITON results were determined to be more
precise than laboratory analyses and were comparable in
accuracy to SRMs. Differences between laboratory data
and NITON field data were likely the result of matrix
interferences.
The two primary sensitivity evaluations performed for this
demonstration were the MDL and PQL. Following
procedures established in40CFR Part 136, the MDL for the
NITON XLt (X-ray) instrument is between 13.9 and 69.8
mg/kg. It is likely that the MDL is closer to the lower end of
this range based upon the results for sample Iot62 (referee
laboratory value = 1.4.6 mg/kg) and sample lot 47 (SRM
value = 32.4 mg/kg) which both had one of the seven results
reported as below the NITON detection level indicating that
these values are on the edge of the instruments detection
capability. The lowest calculated MDL for the NITON XLi
instrument is 39.3 mg/kg. Based upon results presented
in the report for samples analyzed close to this detection
limit, it appears that the MDL for the NITON XLi field
instrument is somewhere close to 32 mg/kg. The
equivalent calculated 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 NITON XLt PQL is somewhere between 62.9 mg/kg
and 99.8 mg/kg. The %D for the 99.8 mg/kg SRM is 8.2%.
The NITON XLi PQL is also somewhere between 62.9
mg/kg and 99.8 mg/kg. The %D for the average NITON
XLt result for the 99.8 mg/kg SRM is 9.2%. The referee
laboratory PQL confirmed during the demonstration and
based upon a lower calibration standard is 0.005mg/kg.
The%Dis<10%.
Accuracy was evaluated by comparison to SRMs and
comparison to the referee laboratory analysis for field
samples. This included spiked field samples forevaluation
of additional concentrations not otherwise available. The
results from the XLi/XLt 700 Series Analyzers were
compared to the 95% prediction interval for the SRM
materials and to the referee laboratory results (Method
7471B). NITONXLt data were within SRM 95% prediction
intervals 93% of the time, which suggests significant
equivalence to certified standards. NITON XLi data were
within SRM 95% prediction intervals 91% of the time, which
also suggest significant equivalence to certified standards.
The statistical comparison between the NITON XLt field
data and thereferee laboratory results suggest that the two
data sets are not the same. The statistical comparison
66
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between the NITON XLi field data and the referee laboratory
results also suggest that these two data sets are not the
same. Because the NITON data compare favorably to the
SRM values, the differences between NITON and the
referee laboratory are likely the result of matrix interferences
for field sample analysis. The number of NITON XLt
average values less than 30% different from the referee
laboratory results or SRM reference values; however, was
14 of 26 different sample lots. Only one of 26 NITON XLt
average results have relative percent differences greater
than 100% for this same group of samples. The number of
NITON XLi average values less than 30% different from the
referee laboratory results or SRM reference values was 14
of 24 different sample lots. Zero of 24 NITON XLi average
results have relative percent differences greater than 100%
for this same group of sam pies. Both NITON XLt and XLi
results therefore, can often provide a reasonable estimate
of accuracy for field determination.
Precision was determined by analysis of replicate samples.
The precision of the NITON XLt and XLi field instruments
is better then the referee laboratory precision. The overall
average RSD is 20.0% for the referee laboratory, compared
to the NITON XLt average RSD of 13.1% and the NITON
XLi average RSD of 14.4%. Both the laboratory and NITON
precision goals are within the predicted 25% RSD objective
for precision; expected from both analytical and sampling
variance. Precision was not affected by sample
concentration or matrix.
Time measurements were based on the length of time the
operator spent performing all phases of the analyses,
including setup, calibration, and sample analysis (including
all reanalysis). NITON analyzed 197 samples on a single
instrument in 1,050 minutes (17.5 hours, times 60 minutes,
times 1 analyst per instrument) over three days, which
averaged to 5.3 minutes per sample result. Based on this,
an operator could be expected to analyze 90 samples (8
hours x 60 minutes + 5.3 minutes/sample) in an 8-hour
day.
Cost of the NITON sample analysis 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 the instrument purchase,
and as the sample number increases, the cost per sample
would decrease. A comparison of the field NITON 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 to the project while waiting for
analyses to return from the laboratory (potentially several
mobilizations and dem obilizations, 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 NITON and the Referee Laboratory
Sample Type
Site
Carson River
(Subtotal = 31)
Puget Sound
(Subtotal = 34)
Oak Ridge
' (Subtotal = 54)
Manufacturing
(Subtotal = 78)
Subtotal
Concentration Range
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)
Soil
0
7
3
3
0
0
13
36
62
-r
Sediment
0
0
0
0
10
3
10
0
23
j i
Spiked Soil
0
0
7
0
7
0
14
14
42
SRM
0
0
14
0
14
0
14
28
70
67
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Table 8-2. Summary of NITON XLi/XLt 700 Series Analyzers Results for the Primary Objectives
Evaluation Basis
Demonstration
Objective
Performance Results
NITON XLi/XLt 700 Series
Analyzers
Reference Method
Instrument
Sensitivity
Accuracy
Precision
Time per Analysis
Cost
MDL. Method from 40 CFR Part 136..
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 3 days and
divided the total time by the total number of
analyses.
Costs were provided by NITON 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.
Between 13.9 and 69.8
mg/kg for the NITON XLt.
Approximately 32 mg/kg
for the NITON XLi.
NITON XLt and NITON
XLi PQL; between 62.9
mg/kg and 99.8 mg/kg.
0.0026 mg/kg
0.005 mg/kg
NITON XLt data were within SRM 95% prediction
intervals 93% of the time; NITON XLi data were within
SRM 95% prediction intervals 91% of the time. NITON
and laboratory data did not statistically compare for all
results but NITON results can often provide a
reasonable estimate of accuracy for field determination.
Overall average RSD is 20.0% for the referee laboratory
compared to the NITON XLt average RSD of 13.1% and
the NITON XLi average RSD of 14.4%.
Two technicians performed all setup, calibration checks,
sample preparation and analysis, and equipment
demobilization. Using one technician individual analyses
(excluding sample preparation) took 2 minutes each, but
the total time per analysis averaged approximately 5.3
minutes per sample per instrument.
The cost per analysis based upon 197 samples, when
renting the NITON XLi 702, is $39.52 per sample. The
cost per analysis for the 197 samples, excluding capital
cost, is $13.18 per sample. The total cost for equipment
rental and necessary supplies during the demonstration
is estimated at $7,786. The cost breakout by category is:
capital equipment rental costs, 66.7%; supplies, 3,6%;
support equipment, 3.5%; labor, 7.7%; and IDW, 18.5%.
The cost per analysis, based upon 197 samples, when
renting the NITON XLt 792, is $47.69 per sample. The
cost per analysis for the 197 samples, excluding capital
cost, is $13.18 per sample. The total cost for equipment
rental and necessary supplies during the demonstration
is estimated at $9396. The cost breakout by category is:
capital equipment rental costs, 72.4%; supplies, 3.0%;
support equipment, 2.9%; labor, 6.4%; and IDW, 15.3%.
68
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Table 8-3. Summary of NITON XLi/XLt 700 Series Analyzers Results for the Secondary Objectives
Demonstration
Objective
Evaluation Basis
Performance Results
Ease of Use
Field observations during the demonstration.
Health and Safety
Concerns
Portability of the
Device
Instrument
Durability
Availability of
Vendor
Instruments and
Supplies
Observation of equipment, operating
procedures, and equipment certifications
during the demonstration.
Review of device specifications,
measurement of key components, and
observation of equipment setup and tear
down before, during, and after the
demonstration.
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 NITON XLi/XLt 700 Series Analyzers are very easy
to operate, requiring one field technician with a high
school education, and 8-hour training on the NITON
XLi/XLt 700 Series Analyzers. The analyzers are field
screening tools capable of measuring 25 elements in
seconds. No data manipulation is required.
No significant health and safety concerns were noted
during the demonstration. The analyzers should never
be pointed at any person when the shutters are open.
The NITON XLi/XLt 700 Series Analyzers are hand-held
portable instruments. They are stand-alone units with no
cables, and are easy to set up. A sample can be
analyzed in less than five minutes.
The NITON XLi/XLt 700 Series Analyzers were well
designed and constructed for durability. NITON's XRF
analyzers are the product of a decade of continuous
research and development in XRF technology.
In addition, the Cd-109 (10 mCi) source should be
replaced every 15 months, and only by authorized
personnel.
The NITON XLi/XLt 700 Series Analyzers are readily
available for lease or purchase. A rented analyzer can
be received typically within 10-14 days of order
placement. Sample cups, Mylar film, filter discs, spatula,
and polyester filling are the only supplies needed to
analyze samples intrusively and are available from
several supply firms or from NITON.
69
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Chapter 9
Bibliography
Anchor Environmental. 2000. Engineering Design
Report, Interim Remedial Action Log Pond Cleanup/
Habitat Restoration Whatcom Waterway Site,
Bellingham, W.A. Prepared for Georgia Pacific West,
Inc. by Anchor Environmental, L.L.C., Seattle, WA. J uly
31,2000.
Confidential Manufacturing Site. 2002. Soil Boring Data
from a Remedial Investigation Conducted in 2000.
NITON. 2002 "NITON XLi 700 Series Environmental
Analyzer User's Manual," Version 3.5
NITON. 2002 "NITON XLt 700 Series Environmental
Analyzer-User's Manual," Version 3.5
EPA. 1998 Field Portable X-Ray Fluorescence
Spectrometry for the Determination of Elemental
Concentrations in Soil and Sediment. Revision 0
January.
Rothchild.E.R., R.R.Turner, S.H. Stow, M.A. Bogle, LK.
Hyder, O.M. Sealand, H.J. Wyrick. 1984. Investigation
of Subsurface Mercury at the Oak Ridge Y-12 Plant.
Oak Ridge National Laboratory, 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 1994.
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 D.C.
U.S. Environmental Protection Agency. 1998.
Unpublished. Quality Assurance Project Plan
Requirements for Applied Research Projects, August
1998.
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. 2002a. Region
9 Internet Web Site, www.epa.gov/region9/ind ex. htm I.
U.S. . Environmental Protection Agency. 2002b.
Guidance on Data Quality Indicators, EPA G-5i,
Washington D.C..July2002.
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.niton.com, 2003
70
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Appendix A
NITON Comments
NITON LLC was pleased to participate in this EPA SITE
program with our new generation of field portable x-ray
fluorescence (FPXRF) analyzers. The instruments used in
this study were the NITON LLC Model XLi 702 radioisotope
excitation spectrometer and the Model XLt 792 with
miniature x-ray tube excitation.
Field portable x-ray fluorescence spectrometry has seen
application to the determination of metals in soil and
sediment for some two decades now (Piorek, 1997). It has
become a standard tool in site characterization and
remediation (U.S. EPA, 1996). The technology is well
known and has been extensively described in the literature
(Spittler, et.al., 1985; Piorek, et.al., 1993; Hewitt, 1994;
Shefsky, 1997).
Results
Figure A-1 shows a comparison of laboratory and FPXRF
results from the model XLt 792 with miniature X-ray tube.
The error bars denote 2-sigma variation of the (generally)
seven replicate analyses. We note the consistently worse
precision for the laboratory determinations at the higher
concentration levels, greater than about 200 ppm. W6 note
that the referee laboratory testing was in accordance with
Method 7471A (Cold Vapor Analysis for Mercury
Determination) of SW-846, a technique generally
applicable to a maximum concentration of about 1 ppm.
We suspect the poor precision at the higher levels to be
due to the substantial dilutions necessary to apply this
method at these concentrations.
Given these results, samples 32 and 33 should probably be
considered outliers. They are labeled and appear in the
lower right hand corner of Figure A-1.
We note a slight high bias with respect to laboratory results
for both instruments although in most cases the error bars
overlap the diagonal indicating a one-to-one correlation.
Closer examination of the subset of samples with
concentration of about 300 ppm and less (i.e., where the
laboratory precision.becomes less of an issue) produces
the following correlation coefficients: Referee laboratory vs.
Tube-excitation, R2~ 0.93; Referee laboratory vs. Isotope-
excitation, R* -0.83.
Approximate detection limits for a 120 second
measurement time are about 25 ppm for model XLi 702
(radioisotope excitation) and 15 ppm for the model XLt 792
(miniature x-ray tube instrument). These LODs are as
defined by IUPAC (International Union of Pure and Applied
Chemistry) and computed with reference to the precision
on a blank sample, i.e., a soil not containing mercury
(Thomsen, et.al, 2003, and references therein). They
correspond to what is termed IDL in this ITVR. MDLs are
generally anywhere from two to five times greater than the
IDL, so we can see a correspondence between the LODs
reported above and those reported in the ITVR. Of
perhaps greater interest are the associated limits of
quantitation (LOQ, defined as 3.3 times the LOD), which
This appendix was written solely by NITON. The statements, presented in this appendix represent the developer's point of view and summarize
the claims made by the developer regarding the XLi/XLt-700 Series Analyzers. 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 XLi/XLt-700 Series
Analyzers are discussed in the body of the ITVR.
71
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become about 50 ppm for the x-ray tube and 80 ppm for
the isotope excitation instrument. Although action levels for
mercury in soil vary, some preliminary EPA goals, as noted
in this report, are 23 mg/kg (ppm) for residential and 310
mg/kg (ppm) for industrial soil. We can see, therefore, that
the FPXRF instrumentation finds primary applicability in the
latter field, while still finding use as a screening tool in the
former.
Conclusions
The correlation between laboratory and NITON analyzer
.results is quite good. Note that the XRF analysis of soil is
susceptible to particle size effects, so that sieving to about
250 microns (200 mesh) is recommended. Nevertheless,
the close correlation reported here was achieved with
minimal sample preparation. Improved results would be
expected with additional sample preparation. Precisionwas
also very good, with both analyzers essentially yielding
similar or better precision than the referee laboratory.
We note that lead, arsenic, and zinc are potential
interferants, butall three are probably not significantat less
than about 500 ppm. If lead and arsenic are present atthis
level, then the site has other serious contamination
problems. However, zinc may occur naturally in soil and
could well be above this level. For questionable results
(e.g., large reported measurement uncertainty) the
operator/analyst is counseled to examine the x-ray
spectrum itself.
A clear advantage of field portable x-ray fluorescence is its
non-destructive nature. This allows the same sample to be
sent for confirmatory analysis to eliminate questions or
concerns. However, given the similarity in spread between
laboratory and FPXRF results, this may be a moot point.
It is also important to point out the multielement nature of
this analytical technique as many elements can be
analyzed simultaneously. This is certainly an advantage
where multiple contaminants may be involved.
References
Hewitt, A.D. 1994. "Screening for Metals by X-ray
Fluorescence Spectrometry/ Compton Peak
Normalization Analysis." American Environmental
Laboratory, 6, pp. 24-32.
Piorek, S. and Pasmore, J.R. 1993. "Standardless, In Situ
Analysis of Metallic Contaminants in the Natural
Environment With a PC-Based, High Resolution
Portable X-Ray Analyzer." Proceedings of the Third
International Symposium on Field Screening Methods
for Hazardous Wastes and Toxic Chemicals, Las
Vegas, Feb. 24-26, pp. 1152-1161.
Piorek, S. 1997. "Field-Portable X-Ray Fluorescence
Spectrometry: Past, Present, and Future." Field
Analytical Chemistry and Technology 1(6): 317-329.
Shefsky, S. 1997. "Comparing Field Portable X-Ray
Fluorescence (XRF) to Laboratory Analysis of Heavy
Metals in Soil." Presented at the International
Symposium on Screening Methods for Hazardous
Wastes and Toxic Chemicals, Las Vegas, Jan.
29-31.(Available online at http://
www.niton.com/shef02.htm I)
Spittler, T., Furst, G.,and Tillinghast, V. 1985. "Screening
for Metals at Hazardous Waste Sites: A Rapid,
Cost-effective Technique using X-ray Fluorescence."
Proceedings of the Sixth National Conference on
Management of Uncontrolled Hazardous Waste Sites.
U.S. EPA Method 6200. 1996. "Field Portable X-Ray
Fluorescence Spectrometry for the Determination of
Elemental Concentrations in Soil and Sediment."
Thomsen, V., Schatzlein, D., and Mercuro, D., 2003.
"Limits of Detection in Spectroscopy."Spectroscopy, In
print, Nov. 2003. Pre-prints available upon request.
This appendix was written solely by NITON. The statements presented in this appendix represent the developer's point of view and summarize
the claims made by the developer regarding the XLi/XLt-700 Series Analyzers. 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 XLi/XLt-700 Series
Analyzers are discussed in the body of the ITVR.
72
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1400-
1200
I 1000
a
a.
*M 8oo-
j2
"5
CO
600
X
400.
200-
0
j.
$P
-T-U-
FH
l L
r 7
1 T
1
i
i
r
-i
Sample 32
T
i
H
Sample 33
200 400 600 800 1000
Laboratory Results (ppm Hg)
1200
1400
1600
Figure A-1. Comparison of precision, all samples, laboratory and model XLt
This appendix was written solely by NITON. The statements presented in this appendix represent the developer's point of view and summarize
the claims made by the developer regarding the XLi/XLt-700 Series Analyzers. 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 XLi/XLt-700 Series
Analyzers are discussed in the body of the ITVR.
73
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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 24 separate
sample lots for the NITON XLi instrument and all 26
separate sample lots for the NITON XLt instrument)
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 NITON 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 test1 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 bythe number of samples in their data
set. The effective number of degrees of freedom is then
calculated.
2
V *>
V ฃ
Where:
f
VL
nL
Vv
nv
= 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 sam pies for the vendor data
set.
The degrees of freedom (f) is used to determine the
appropriate T value and used to calculate p at the 0.01
level of significance using the following:
74
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Unified Hypothesis Test
For a specified vendor, let Y,? be the measured Hg
concentration for the f1 replicate of the f sample for
/ = 1,2 landy=1.2 J,. Let Xs = log(Yj), where log is the
logarithm to the base 10. Define xaog to be the average
over all log replicates for the f sample given by:
jr.
Jbg
-1
log
7
z
Where x2,., is approximately a chi-square random variable
with (1-1) degrees of freedom:
-1
- X
and
Denote the estimate of the variance of the log replicates for
the /""sample to be:
1-1
( i y1 / J,
*a = Zto-0 b&Z Z
U-l J. i-1 j-l
Now for the reference laboratory, let Y',;be the measured
Hg concentration for the /" replicate of the fh sample for
/ =1,2 ..... 1' and j = 1,2,...,J',. Denote the reference
laboratory quantities X'/;, x,', and s'2 defined in a manner
similar to the corresponding quantities for the vendor.
Assumptions: Assume that the vendormeasurements, Yf,
are independent and identically distributed according to a
lognormal distribution with parameters u, and o2. That is,
X,;= log(Y,?) is distributed according to a normal distribution
with expected value u, and variance a2. 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:
H0 : ft = fj'j + S, for some Sand i = !,...,!
against the alternative hypothesis that the equality does hot
hold for at least one value of /.
The null hypothesis H0 is rejected for large values of:
tog -X'^-sf -H (j-1 + J'-1)
I'-l 1-1
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 NITON XLi
(Isotope!
SAIC performed a unified hypothesis test analysis to
assess the comparability of analytical results provided by
NITON XLi and those provided by ALSI. NITON XLi and
ALSI both supplied multiple assays on replicates derived
from a total of 24 different sample lots, be they field
mate rials or reference materials. The NITON XLi 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 NITON XLi and ALSI population means for a
given sample lot. Equality of variances is assumed.
Initially, the null hypothesis tested was that, on average,
NITON XLi and ALSI would produce the same results
within a given sample lot. This hypothesis is stated as
H10: (NITON XLi lot log mean) = (ALSI lot log mean)
H10 was rejected in thatthe chi-square statistic was 334.59,
which exceeds the upper 99th percentile of the chi-square
distribution with 24 degrees of freedom having a value of
42.97.
The null hypothesis was rejected in part because NITON
XLi results tended to exceed those from ALSI forthesame
75
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sample lot. To explore this effect, the null hypothesis was
revised to included a bias term in the form of
H20: (NITON XLi 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
312.60, which exceeded the upper 99th percentile of the
chi-square distribution with 23 degrees of freedom with a
value of 41.63. In this analysis, delta was estimated to be
0.0535 in logarithmic (base 10) space, which indicates an
.average upward bias for NITON XLi of 10ฐ'0535=1.131 or
about 13%.
For both hypotheses, the large values of the chi-square
test statistics summarize the disagreement between the
NITON XLi and ALSI analytical results. Furthermore, a
review of the statistical analysis details indicates that the
overall discordance between NITON XLi 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 for the NITON XLi Instrument
Hypothesis Total Sample Lots Excluded Lot DF s2^, Delta.
Chi-square
P-value
H,0 24
H,n 24
None
None
24
23
0.00752
0.00752
0.0000
0.0535
334.59
312.60
0.000000
0.000000
Results of Unified Hypothesis Test for NITON XLt
(X-rav)
SAIC performed a unified hypothesis test analysis to
assess the comparability of analytical results provided by
NITON X-ray and those provided by ALSI. NITON XLt
and ALSI both supplied multiple assays on replicates
. derived from a total of 26 different sample lots, be they
field materials or reference materials. The NITON XLt
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 NITON XLt and ALSI population means for
given sample lot. Equality of variances is assumed.
Initially, the null hypothesis tested was that, on average,
NITON XLt and ALSI would produce the same results
within a given sample lot. This hypothesis is stated as
H10: (NITON XLt lot log mean) = (ALSI lot log mean)
H1O was rejected in that the chi-square statistic was
266.50, which exceeds the upper 99th percentile of the
chi-square distribution with 26 degrees of freedom
having a value of 45.64.
The. null hypothesis was rejected in part because NITON
XLt results tended to exceed those from ALSI for the
same sample lot. To explore this effect, the null
hypothesis was revised to included a bias term in the
form of
H20: (NITON XLt 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
249.17, which exceeded the upper 99th percentile of the
chi-square distribution with 25 degrees of freedom with a
value of 44.31. In this analysis, delta was estimated to
be 0.0480 in logarithmic (base 10) space, which
indicates an average upward bias for NITON XLt of
100048ฐ=1.117orabout12%.
76
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For both hypotheses, the large values of the chi-square
test statistics summarize the disagreement between the
NITON XLt and ALSI analytical results. Furthermore, a
review of the statistical analysis details indicates that the
overall discordance between NITON XLt 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-2. 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-2 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-2. Unified Hypothesis Test Summary Information for the NITON XLt Instrument
Hypothesis
HIQ
H,n
Total Sam
Lots
26
26
pie
Excluded Lot
None
None
DF
26
25
s pool
0.00887
0.00887
Delta
0.0000
0.0480
Chi-square
266.50
249.17
P-value
0.000000
0.000000
77
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