Approved for public release; distribution is unlimited. ERDC/CERL TR-05-3 

X-Ray Fluorescence-Based Multi-Metal 

Continuous Emission Monitor 

Development 

K. James Hay, Bruce E. Johnsen, and 

John A. Cooper 

January 2005

Construction Engineering Research Laboratory 

Extraction 

System 

Sampling 

and 

Analysis 

System 

ERDC/CERL TR-05-3

January 2005

X-Ray Fluorescence-Based Multi-Metal Continuous 

Emission Monitor: Development 

K. James Hay 

Construction Engineering Research Laboratory 

PO Box 9005 

Champaign, IL 61826-9005 

Bruce E. Johnsen and John A. Cooper 

Cooper Environmental Services 

10170 SW Nimbus Avenue, Suite H5 

Portland, OR 97223-4340 

Final Report 

Approved for public release; distribution is unlimited. 

Prepared for U.S. Army Corps of Engineers 

Washington, DC 20314-1000 

Under Work Unit #CNE-B091 
ABSTRACT: Army demilitarization incinerators will need to comply with the Hazardous Waste Combustor National Emission Standards for Hazardous Air Pollutants that will regulate metals and metal compounds listed under 

the Clean Air Act Amendments. A large problem for these incinerator operations is limited knowledge of the types 

and quantities of emitted metals. Compliance may be determined only through trial burn emission tests because of 

this limitation. A continuous emission monitor (CEM) for multi-metals will provide the emission data, a tool to help 

meet compliance requirements, and the opportunity to adjust burn strategies for increased production. The XCEM 

multi-metal CEM was developed using x-ray fluorescence (XRF) as the analytical method and an automated sampling system that provides extractive batch sampling onto a filter tape. The system is operated with user-friendly 

WonderWare® software that provides automation, calibration routines, and report generation. A prototype XCEM 

was tested in the laboratory with a spiked gas stream against U.S. Environmental Protection Agency Reference 

Method 29 for four sample runs. The XCEM met the relative accuracy criteria for four of seven metals. A fieldready XCEM was built for demonstration at the 1236 Deactivation Furnace at Tooele Army Depot, Utah. 

DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. 

Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. 

All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be 

construed as an official Department of the Army position unless so designated by other authorized documents. 

DESTROY THIS REPORT WHEN IT IS NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. 
ERDC/CERL TR-05-3 iii 

Contents 

List of Figures and Tables ............................................................................................................... v

Conversion Factors........................................................................................................................ vii

Preface............................................................................................................................................. viii

1 Introduction ................................................................................................................................1

Background......................................................................................................................... 1

Objective............................................................................................................................. 3

Approach ............................................................................................................................ 3

Mode of Technology Transfer ............................................................................................. 3

2 XCEM Development...................................................................................................................4

XCEM Description .............................................................................................................. 5

Extraction System..........................................................................................................................5

Sampling and Analysis System .....................................................................................................7

Control System..............................................................................................................................9

Integration of Sensors....................................................................................................... 10

Operator Accessible Control Screens..........................................................................................10

Administrator Accessible Control Screens...................................................................................17

Sampling Platform Modifications ...................................................................................... 19

Quality Assurance Modifications..................................................................................................19

Ease-of-use Modifications ...........................................................................................................23

Safety Modifications ....................................................................................................................24

3 Laboratory Testing...................................................................................................................25

Mercury Sampling............................................................................................................. 25

Experimental................................................................................................................................25

Mercury RIF Results....................................................................................................................25

Mercury Oxidation Automation ....................................................................................................26

Mercury XCEM Results ...............................................................................................................27

Method 29 Comparison Tests ........................................................................................... 27

Spike Injection System ................................................................................................................27

Test Design..................................................................................................................................30

XCEM Results During Method 29 Testing ...................................................................................31

XCEM vs M29..............................................................................................................................37

Method 29 and XCEM Precision and Accuracy ...........................................................................39
iv ERDC/CERL TR-05-3 

4 Field-ready XCEM ....................................................................................................................43

5 Summary and Conclusions....................................................................................................46

References.......................................................................................................................................48

Abbreviations and Acronyms .......................................................................................................49

Report Documentation Page.........................................................................................................51 
ERDC/CERL TR-05-3 v 

List of Figures and Tables 

Figures 

1 Schematic of XCEM components minus the control computer.............................. 5

2 XCEM analysis system, computer control, and sampling cassette ....................... 6

3 XCEM sampling cassette ....................................................................................... 7

4 Gas sampling process in the sample cassette....................................................... 8

5 X-ray detection process.......................................................................................... 8

6 Component Control screen .................................................................................. 11

7 Diagnostics screen............................................................................................... 12

8 Metal Concentration screen during M29 testing................................................... 12

9 Quality Assurance screen .................................................................................... 13

10 Temperature Trend screen ................................................................................... 14

11 Pressure Trend screen......................................................................................... 14

12 Flow Trend screen................................................................................................ 15

13 Concentration Trend screen................................................................................. 15

14 Data output screen............................................................................................... 16

15 Alarm screen ........................................................................................................ 17

16 Set QA Ranges screen......................................................................................... 18

17 Set Analog Ranges screen................................................................................... 19

18 XCEM QA program............................................................................................... 20

19 PLC control for the XCEM.................................................................................... 21

20 Zero and span test plunger .................................................................................. 22

21 Pd wire-mounted for QA....................................................................................... 22

22 XCEM sampling cassette and XRF control panel ................................................ 24

23 Schematic of Hg capture for first phase experiments .......................................... 26

24 RIF Hg capture efficiency versus air flow rate through filter ................................ 26

25 XCEM elemental concentrations during M29 testing........................................... 32

26 XCEM cadmium versus other spiked metals during M29 testing......................... 35

27 Comparisons of XCEM and M29 concentration by run........................................ 40

28 XCEM and M29 normalized concentrations by element...................................... 41

29 New Component Control Screen for XCEM software interface ........................... 43
vi ERDC/CERL TR-05-3 

30 XCEM cassettes................................................................................................... 44

31 XCEM extraction system and cassette and chassis ............................................ 44

32 XCEM with cabinet door open.............................................................................. 45

33 XCEM with computer system installed at TEAD .................................................. 45

Tables 

1 Army hazardous waste combustors....................................................................... 2

2 Evaluation of spike injection options .................................................................... 29

3 Test conditions during M29 sampling................................................................... 31

4 Elemental concentrations at XCEM and M29 Ports during pre- and 

post-tests.............................................................................................................. 36

5 Relative accuracies of M29 Port versus XCEM Port during pre- and 

post-tests.............................................................................................................. 36

6 Reported XCEM and M29 concentrations............................................................ 38

7 Average metal concentrations for each sampling run.......................................... 38

8 XCEM and M29 relative accuracies ..................................................................... 39
ERDC/CERL TR-05-3 vii 

Conversion Factors 

Non-SI* units of measurement used in this report can be converted to SI units as 

follows: 

Multiply By To Obtain 

degrees Fahrenheit (5/9) x (°F - 32) degrees Celsius 

feet 0.3048 meters 

inches 0.0254 meters 

 

*Système International d’Unités (International System of Measurement), commonly known as the metric system. 
viii ERDC/CERL TR-05-3 

Preface 

This study was conducted for Headquarters, Department of the Army under Program Element 063728A, “Environmental Technology Demonstration”; Project 

002, “Environmental Compliance Technology”; Work Unit CNE-B091, “Hazardous Air Pollutants Technology Demonstrations.” The peer reviewer was Thomas 

Logan, U.S. Environmental Protection Agency, Office of Air Quality and Planning and Standards, Air Measurements and Quality Group. 

The work was performed by the Environmental Process Branch (CN-E) of the 

Installations Division (CN), Construction Engineering Research Laboratory 

(CERL). The CERL Principal Investigator was Dr. K. James Hay. Part of this 

work was contracted to Cooper Environmental Services under DACA42-02-P0072, DACA42-01-R-008, and DACA42-00-P-0245. The technical editor was 

Linda L. Wheatley, Information Technology Laboratory. Dr. Kirankumar V. 

Topudurti is Chief, CN-E, and Dr. John T. Bandy is Chief, CN. The associated 

Technical Director was Gary W. Schanche. The Director of CERL is Dr. Alan W. 

Moore. 

CERL is an element of the U.S. Army Engineer Research and Development 

Center (ERDC), U.S. Army Corps of Engineers. The Commander and Executive 

Director of ERDC is COL James R. Rowan, EN, and the Director of ERDC is 

Dr. James R. Houston. 
ERDC/CERL TR-05-3 1 

1 Introduction 

Background 

The U.S. Environmental Protection Agency (EPA) is developing regulations for 

Hazardous Waste Combustors (HWC) as part of Title III of the 1990 Clean Air 

Act Amendments (CAAA) in the form of a National Emission Standards for Hazardous Air Pollutants (NESHAP). The U.S. Army possesses many demilitarization furnaces that will need to comply with these regulations. Of most concern is 

being able to meet the requirements for metals and metal compounds listed under the CAAA. These incinerator operations have a large problem because of 

limited knowledge of the types and quantities of metals emitted. Compliance 

may be determined only through trial burn emission tests because of this limitation. These tests are expensive and require worst-case scenario burns. The air 

permits that are then issued are based on these worst-case burns and impose 

limitations on the demilitarization facilities. A continuous emission monitor 

(CEM) for metals would provide the emission data, a tool to help meet compliance requirements, and the opportunity to adjust burn strategies for increased 

production and sustainability. In addition, the HWC NESHAP suggests that a 

CEM would be the preferential method of emission accountability. 

Multi-metal CEMs being developed are based on elemental sensors using laserinduced breakdown spectroscopy (LIBS) or inductively coupled plasma (ICP). 

None of the LIBS monitors has successfully met the EPA-proposed Performance 

Specification 10 (PS-10 1996) for continuous multi-metal monitors. Only one of 

the ICP units, developed by Thermo Jarrell Ash Corporation, has been successful 

in meeting the relative accuracy (RA) criteria of the PS-10 (Seltzer 2000). The 

multi-metal CEMS technology appears to have practical limitations such as its 

complexity, high initial cost, and high operating costs. The U.S. Army Engineer 

Research and Development Center, Construction Engineering Research Laboratory (ERDC/CERL) decided to pursue the development of the X-ray fluorescence 

(XRF)-based continuous emission monitor (XCEM) because it had the potential 

to be a reliable and accurate CEM without these limitations. 

The basic approach of the XCEM is to draw a continuous representative sample 

of stack gas to a stilling chamber where a smaller metered sample is extracted 

and passed through a chemically treated filter that collects metals in the particu-
2 ERDC/CERL TR-05-3 

late and vapor phases. Following sampling, the filter is passed through an XRF 

analyzer where the masses of up to 19 metals are measured. This approach was 

originally tested in 1997 at an EPA test incinerator, where the filters were analyzed offline (French 1998). Cooper Environmental Services (CES) further developed this method into an online system tested under the ERDC/CERL Waste 

Minimization and Pollution Prevention Program at MSE Technology Applications, Inc.’s (MSE-TA’s) research incinerator in Butte, MT (Bryson et al. 2000). 

The results were encouraging because the XCEM met the PS-10 RA requirements for chromium (Cr) and lead (Pb). Many of the other requirements were 

unmet, however, and further development was needed. It was at this point that 

ERDC/CERL began funding the development of XCEM technology under their 

Hazardous Air Pollutants (HAP) program. Table 1 lists the Army’s 19 existing, 

new, or planned hazardous waste combustors (Josephson 2003). 

Table 1. Army hazardous waste combustors. 

Location Type Waste Treated Status GO or CO 

Sierra AD APE 1236 CS Existing GO 

Tooele AD APE 1236 CS Existing GO 

Tooele AD APE 1236 Test Furnace – CS Existing GO 

McAlester AAP APE 1236 CS Existing GO 

Hawthorne AAP APE 2210 CS New CO 

Fort Richardson APE 1236 CS New GO 

Kansas AAP APE 1236 CS Existing CO 

Crane AAP APE 1236 CS New GO 

Lake City AAP APE 1236 Off-spec conventional Existing GO 

Picatinny Arsenal APE 1236 Waste R&D propellants New GO 

Pine Bluff Arsenal Fluidized Bed Pyrotechnics and Obscurants New GO 

Pine Bluff Arsenal APE 1236 Off-spec pyrotechnics Existing GO 

Radford AAP Kiln Off-spec propellants Existing GO 

Deseret CA Chemical Chem Existing GO 

Umatilla AD Chemical Chem New GO 

Pine Bluff Arsenal Chemical Chem New GO 

Anniston AD Chemical Chem New GO 

Pueblo CA Chemical Chem Planned GO 

Anniston AD Kiln De-Painting wastes Planned GO 

GO – Government Owned CO – Contractor Owned CA – Chemical Activity 

CS – Conventional Stockpile Chem – Chemical Stockpile APE - Army Peculiar Equipment 

AD – Army Depot AAP – Army Ammunition Plant R&D – Research and Development
ERDC/CERL TR-05-3 3 

Objective 

The overall objective of the HAP program is to develop cost-effective technologies 

to help the Army meet current and future demands of HAP regulations. The 

specific objective of the work reported here was to develop a multi-metal CEM 

for use at an Army installation. It is important that this monitor be easy to 

transition to the Army by incorporating characteristics that make it compatible 

with Army operations and expectations, such as user friendliness and 

affordability. Ultimately, the desired exit criterion under the HAP Program is 

for the monitor to meet the complete requirements of the proposed PS-10 under 

field conditions. This objective will be pursued in a follow-on report. 

Approach 

The XCEM was developed under this project through contracts with CES 

(DACA42-00-P-0245 and DACA42-01-R-008). A prototype was constructed incorporating necessary improvements determined from the Butte testing, such as 

user friendliness, automation, and the capability to monitor mercury (Hg). This 

prototype was then tested in the laboratory by comparing it against the EPA 

Reference Method 29 (M29). A new monitor was constructed and readied for 

demonstration at the 1236 production deactivation furnace at Tooele Army Depot (TEAD), UT. 

Mode of Technology Transfer 

This technology was developed through the ERDC/CERL HAP Program, which 

uses 6.3 advanced development and field-testing funds. The HAP Program is 

part of the Army Environmental Quality Technology (EQT) Program. As part of 

the EQT process, a technology transfer plan is being developed by the Army Environmental Center (AEC) for this technology and other qualified technologies 

under the HAP program. A User’s Guide and a Resource Manual have been developed to accompany the XCEM for field training and reference (CES 2001a,b). 

This report will be accessible through the World Wide Web (WWW) at URL: 

 http://www.cecer.army.mil 
4 ERDC/CERL TR-05-3 

2 XCEM Development 

Regulators, government agencies, and industry have expressed support for development of instrumentation capable of continuous measurement of metals 

from stationary sources. The EPA recently reemphasized its position in the final 

Maximum Achievable Control Technology (MACT) standard for hazardous waste 

incinerators. In this standard, continuous monitoring is placed at the top of the 

Compliance Monitoring Hierarchy and underscored as the “strong preference” 

(Federal Register [FR] 52925). The incentives provided in the MACT standard 

for using multi-metal CEMs include bypassing feedstock measurement and decreased requirements for performance testing. In addition, end users of multimetal CEMs have real-time access to process control information and the potential for enhanced public acceptance. 

Over the past few years, CES has developed instrumentation capable of continuous multi-metal measurement. The CES approach uses XRF to measure stack 

gas particulate matter (PM) that has been concentrated on a filter. In 1997 CES 

demonstrated the feasibility of this approach using an offline continuous sampling system at an EPA test incinerator in North Carolina (French 1998). Further adaptation of the approach led to an online XCEM capable of determining 

metal concentrations every 10 to 15 minutes. The prototype XCEM was successfully tested in 1999 at the MSE-TA test facility (Bryson et al. 2000). During 

these tests, the XCEM demonstrated an RA for two MACT metals, Cr and Pb, of 

less than 20 percent. Further refinement was needed, however, to meet EPA’s 

PS-10. Specifically, the MSE-TA report recommended that the following tasks 

be performed: 

1. Sensor Integration: Integrate temperature and pressure sensors into a userfriendly computer interface. 

2. Sampling Platform Modifications: Modify the sampling platform for improved 

ease-of-use, and integrate an automated quality assurance (QA) program into the 

sampling platform design. 

3. Mercury Sampling: Conduct additional laboratory testing for Hg capture efficiency and automation of XCEM Hg oxidation system. Conduct further Hg RA 

testing. 

4. Spike Injection System: Develop an injection method capable of supplying adequate concentrations of metals for routine testing. Conduct further XCEM RA 

testing using the new spike injection system. 
ERDC/CERL TR-05-3 5 

This chapter presents a general description of the XCEM and the improvements to 

the XCEM that address the first two recommendations made in the MSE-TA report: 

sensor integration and sampling platform modifications. 

XCEM Description 

Figure 1 shows major XCEM components and relative flows. The XCEM comprises three major subsystems: an extraction system, sampling and analysis 

system, and control system. 

Extraction System 

The extraction system is designed to transport a representative sample of stack 

gas from the stack to the filter tape. It includes a probe, 1-inch-diameter tubing, 

stilling chamber, and flow measurement and control components. Temperature 

is measured at five locations, and all tubing prior to the filter is heat traced. 

Extraction 

System 

Sampling 

and 

Analysis 

System 

Figure 1. Schematic of XCEM components minus the control computer. 
6 ERDC/CERL TR-05-3 

The extraction system draws an isokinetic sample from the stack using a largediameter probe. The gas is transported to a 3-inch-diameter stilling chamber, 

which slows the gas velocity, decreasing the Stokes number so that small quantitative subsamples can be extracted. The subsample, less than 1 percent of the 

gas sample in the stilling chamber, is removed from the stilling chamber through 

a one-quarter-inch-diameter extraction tube. Inside the extraction tube, a dilution and mixing chamber allows the addition of chlorine and other gases to dry 

and oxidize the sample. The oxidized sample is then drawn through a resinimpregnated filter (RIF) where particulate and vapor phase metallic species are 

concentrated for subsequent XRF analysis. After passing through the filter, the 

gas is dried with a Universal Analyzer dryer, measured with a mass flow controller, and returned to the stack through a diaphragm sampling pump. A postfilter pressure transducer provides assurance that no leaks are present in the 

system. The volume of the remaining 99 percent of the stilling chamber stack 

gas is measured and returned to the stack using a regenerative blower. The entire extraction system is shown in Figure 1. 

The XCEM software interface controls key extraction system components including: thermocouples, a pressure transducer, blower, pump, and several flowmeters. Temperature, flow, and pressure data are automatically recorded in an 

electronic database. Figure 2 shows the sample cassette atop the XRF analyzer 

next to the computer control enclosure. 

Figure 2. XCEM analysis system, computer control, and sampling cassette. 
ERDC/CERL TR-05-3 7 

Sampling and Analysis System 

Once the stack gas subsample leaves the stilling chamber, it is drawn into a 

sample cassette (Figure 3). This cassette contains a stepper motor, infrared tape 

break sensor, and filter tape mounted on reels. Stack gas entering the cassette 

is transported through the extraction tube across a 0.3 cm2 spot on the filter 

tape. Every 12 minutes the filter tape in the cassette is advanced from the sampling location to the analysis position located 1 inch away. A Kevex-Spectrace 

QuanX XRF instrument (Thermo Kevex, Thermo Electron Corp., Waltham, MA) 

then analyzes the metals mass concentrated on the filter. Following analysis, 

the sample is advanced again and collected on a take-up reel. Figure 4 shows a 

schematic of this process. During the XRF analysis, x-rays are emitted from the 

x-ray tube onto the filter tape sample. Resultant x-rays are produced that are 

characteristic of the metals on the sample (Figure 5). These x-rays are detected 

by the XRF detector and a signal that is proportional to the mass for each metal 

is sent to the computer. The computer acquires these signals and compares it to 

known mass per signal ratios developed during calibration. XRF results are 

then reported as micrograms per sample. 

Figure 3. XCEM sampling cassette. 
8 ERDC/CERL TR-05-3 

Figure 4. Gas sampling process in the sample cassette. 

Figure 5. X-ray detection process. 
ERDC/CERL TR-05-3 9 

Since XRF is nondestructive, metal mass on the take-up reel is available if 

needed for subsequent chemical analysis. Each cassette holds a 2–4 week supply 

of tape and is engineered to be portable and easily removed. It is anticipated 

that each XCEM will come with two cassettes, which will enable the operator to 

exchange tapes in a clean environment and transport the entire cassette into the 

field. An additional benefit of having two cassettes is a duplication of components. In the event of equipment failure, the duplicate cassette can be in place 

within a few minutes, decreasing instrument downtime. The cassette is designed to fit directly onto the XRF instrument and includes interlocks to prevent 

the XRF from operating when the cassette is not in place. 

The QuanX energy dispersive XRF has an electronically cooled lithium drifted 

silicon detector. Located immediately above the detector is a permanently 

mounted palladium rod, which is analyzed with each sample to determine if instrument drift is occurring. As an additional QA source, a rod is mounted on a 

pneumatic plunger near the detector. This rod has an epoxy coating with significant quantities of Cadmium (Cd), Cr, Hg, and Pb. Each day the XCEM activates 

the plunger and extends the rod into the analysis area for span and zero tests. 

Detection limits for the XRF are determined by filter blank concentrations and 

analysis time. If a sample is taken every 10 minutes, detection limits for all of 

the MACT metals are less than 3.5 μg/m3 (micrograms per cubic meter). Detection limits can be improved by increasing sampling time. The XRF automatically determines metals concentration and uncertainties. The data are then 

transmitted to a second computer, which runs the WonderWare® software control interface. 

Control System 

XCEM flows and temperatures are controlled using WonderWare® software 

interface on a personal computer. This interface records pressure, temperature, 

metals concentrations, QA data, and sampling times, and prints a hard copy 

report with each sample analysis. An electronic copy of the data is kept in a 

WonderWare® database, which cannot be altered without being flagged. These 

data can be made available over a local intranet or a secure Internet website. A 

second personal computer runs the XRF software. 

Automating the XCEM to make it a user-friendly tool was a primary objective of 

this work. The automation and control features that were developed are 

discussed in the next section. 
10 ERDC/CERL TR-05-3 

Integration of Sensors 

The MSE-TA report recommended computer control of XCEM components, data 

storage, and QA. In response to this recommendation, the XCEM has been fully 

automated using a WonderWare® software interface. This interface includes a 

variety of screens that allow the user to control components, diagnose problems, 

view concentration trends, and output data. Each screen contains an alarm signal in the lower right-hand corner that flashes if some component of the system 

is not working or if the metals’ concentrations exceed user-defined limits. The 

XCEM interface is password protected and can be accessed by either an operator 

with limited XCEM control or an administrator with full user rights. 

Operator Accessible Control Screens 

The computer interface allows the user to view a number of screens that present 

operational data for control of the XCEM. Those screens are presented below. 

Component Control Screen 

The Component Control screen (Figure 6) contains a schematic of the XCEM system. This schematic includes icons representing key XCEM components and 

real-time data for temperatures, pressures, and flows. Adjacent to the schematic, a System Start/Stop button begins and completes sampling with a single 

click. This screen also provides users with the option of manually adjusting individual components of the sampling system. Users logged on as operators can 

control heaters or turn the pump and blower on by double clicking on the appropriate icon and responding to the pop-up dialogue box. Users logged on as administrators have the further capability of controlling flow rates and valves. 

This page is considered the “home page” for the interface and can be accessed 

from any screen by clicking on the house icon in the lower left-hand corner of the 

page. 
ERDC/CERL TR-05-3 11 

Figure 6. Component Control screen. 

Diagnostics screen 

The Diagnostics screen (Figure 7) is a read-only interface designed to give the 

operator an easy-to-read system status check. The Diagnostics screen displays 

current temperature, flow, QA and metal concentrations and lights indicating if 

the system is functioning properly. Buffer ranges defined by the system administrator for each component are displayed on this screen. Measurements that 

fall within these buffer ranges are given a green light. Measurements slightly 

beyond the range are signified with a yellow light, and data significantly beyond 

the buffer range warrant a red light. Yellow and red lights are listed as alarms 

by the XCEM interface. 

Metals Concentration screen 

Up to 20 real-time metals’ concentrations are displayed on the Metals Concentration screen (Figure 8). Operators can graph up to eight of these concentrations 

simultaneously and access a 12-hour rolling average chart that displays High 

Volatile Metals (HVM), Semi-Volatile Metals (SVM), and Low Volatile Metals 

(LVM). The chart was developed in accordance with the MACT rule for hazardous waste incinerators and can be set to include buffer ranges to alert the operator of high metal concentrations in the stack. As with all graphs within the 
12 ERDC/CERL TR-05-3 

XCEM interface, the Metals Concentration graph’s time axis can be set to display data for periods between a few hours up to 6 weeks. 

Figure 7. Diagnostics screen. 

Figure 8. Metal Concentration screen during M29 testing. 
ERDC/CERL TR-05-3 13 

Quality Assurance screen 

The Quality Assurance screen (Figure 9) is a read-only display that shows historical QA results. Palladium (Pd) is measured with each sample while daily 

span and zero tests for key metals are conducted at user-defined times. The time 

at which the latest QA check was undertaken is also listed in a text box on the 

right-hand side. 

Trends screens 

Trends for temperature, pressure, flow, and metals concentrations are all displayed as individual screens by the XCEM computer interface (Figures 10–13). 

Each screen can display up to eight trends simultaneously and can be customized to include combinations of data from the other trends screens. For example, 

stack temperature and metals concentrations can be graphed simultaneously. 

All figures can be printed by using the Print Trend button in the lower righthand corner of the screen. 

Figure 9. Quality Assurance screen. 
14 ERDC/CERL TR-05-3 

Figure 10. Temperature Trend screen. 

Figure 11. Pressure Trend screen. 
ERDC/CERL TR-05-3 15 

Figure 12. Flow Trend screen. 

Figure 13. Concentration Trend screen. 
16 ERDC/CERL TR-05-3 

Data output 

The control program automatically saves QA and metals concentration data. 

XCEM operators have the option to convert the data to a comma-delimited format that is readily opened using Microsoft® Excel or other spreadsheet programs. Using the Data Output screen (Figure 14), the operator can select up to 6 

weeks of historical data. The output is automatically averaged over a userdefined sample period. Data output includes: 

1. Sample date 

2. Sampling time 

3. Concentrations of analyzed elements 

4. Uncertainty in concentrations of analyzed elements 

5. Pressure in sampling loop 

6. Temperatures 

7. Main line, oxidant and sample flows 

8. Data flag and code if red alarm is triggered. 

Data are automatically flagged if a potential problem occurred (i.e., a parameter 

is outside the user-defined QA limits/ranges). The XCEM administrator defines 

acceptable boundaries for all temperature, flow, and pressure readings as well as 

QA parameters, individual metal concentrations, and 12-hour average concentrations. 

Figure 14. Data output screen. 
ERDC/CERL TR-05-3 17 

For chain-of-custody purposes, neither the operator nor the administrator can 

change the recorded data in the XCEM database without flagging the data. 

Alarms 

When an alarm condition exists, a flashing red alarm signal is shown at the bottom right of each screen and a discussion of the alarm condition is shown in the 

upper right of each computer screen. Detailed information about the alarm can 

be found on the Alarm screen (Figure 15). Alarm conditions include filter tape 

breakage, diagnostic or QA parameters out of the buffer range, sampling cassette 

lids incorrectly mounted, and 12-hour rolling averages out of the buffer range. 

When an alarm condition is remedied, it remains listed in the Alarm screen with 

green, blue, or black font colors. The XCEM will continue to sample despite an 

alarm condition; however, data will be flagged. 

Administrator Accessible Control Screens 

Only an individual logged in as an administrator can set component and QA 

buffer ranges, scale analog readings from the instrument and bypass the normal 

instrumentation routines. Administrator access is password protected. The following screens are only accessible by an administrator. 

Figure 15. Alarm screen. 
18 ERDC/CERL TR-05-3 

Set QA Ranges 

Administrators can set buffer ranges using the Set QA Ranges screen (Figure 

16). Low and high target ranges are entered on this page. Measurements that 

fall within the target range will give a green light on the Diagnostics screen. 

Red light ranges are also defined. When measured data lies between the target 

range and red light range, a yellow light is displayed on the diagnostics screen 

and an alarm is signaled. 

Administrators using the Set QA Ranges screen can also set the hour of the day 

that a QA analysis will occur, conduct an immediate zero/span test or a peak 

shape test, and view milli-ampere (mAmp) readings for instrumentation. 

Set Analog Ranges 

Administrators also have access to the Set Analog Ranges screen for XCEM (Figure 17). This screen relates the 4 to 20 mAmp signal received by components to 

a scale used by the program. For example, a flow meter may have a 4 mAmp 

signal designated as 0 scfm (standard cubic feet per minute) and a 20 mAmp 

signal designated as 12 scfm using this screen. 

Figure 16. Set QA Ranges screen. 
ERDC/CERL TR-05-3 19 

Figure 17. Set Analog Ranges screen. 

Sampling Platform Modifications 

The XCEM sampling platform was modified to provide automated QA features 

and improve operator ease-of-use. 

Quality Assurance Modifications 

The XCEM was reengineered to include an automated, user-friendly QA program (Figure 18). A WonderWare® software package has been developed with a 

custom programmable logic controller (PLC) to control key components and independently run QA features (Figure 19). 

QA features for the XCEM focus upon the two numbers required to determine 

stack gas concentration: mass of the metal on the filter and sample volume. 

Metal mass on the filter is determined in micrograms per spot using the XRF 

while sample volume is in dry standard cubic meters per spot as determined by 

mass flow meters. A spot is equal to the area on the filter tape scanned by the 

XRF analyzer. The XCEM program builds in automated redundancy and daily 

QA checks for measuring both mass and volume. Acceptable QA boundaries are 

user-defined. If the measured values fall outside of these boundaries, such as 
20 ERDC/CERL TR-05-3 

when instrument drift occurs, the software package will signal an alarm and flag 

the data. All QA measurements are logged in the XCEM database and are 

available for use by Microsoft® Excel and Access or compatible data management 

programs. 

M29

Figure 18. XCEM QA program. 
ERDC/CERL TR-05-3 21 

Figure 19. PLC control for the XCEM. 

Mass measurement QA 

XCEM mass measurements are determined using a KevexSpectrace QuanX 

XRF. For this project, the XRF analyzer was calibrated using thin film standards made by pipetting a National Institute of Standards and Technology 

(NIST)-traceable standard solution containing equal masses of silver (Ag), 

arsenic (As), Cd, Cr, Hg, Pb, and selenium (Se) onto a Mylar film. A series of 10 

standards with varying concentrations were analyzed by the XRF, and a linear 

relationship between x-ray intensity and mass was determined. The XRF is 

stable over a period of months and typically requires calibration only about once 

every 6 months. 

XRF zero and span tests are conducted examining blank filter tape and a metal 

rod attached to a pneumatic plunger mounted below the sampling cassette (Figure 20). At a user-defined time of day, the XCEM begins the QA process by advancing clean, unexposed filter tape into the x-ray beam area and analyzing the 

blank tape as a zero test. Immediately following this test, the plunger extends 

the multi-metal standard rod into the beam area. The rod, which contains relatively high concentrations of Cr, Hg, Cd, and Pb, acts as a span test. The zero/ 

span test typically takes 20 to 30 minutes. 
22 ERDC/CERL TR-05-3 

To check for instrument drift and provide a continuous assurance that the XRF 

is giving precise, repeatable mass measurements, a Pd wire has been permanently mounted in the XRF x-ray beam analysis region (Figure 21). The Pd is 

measured with every sample, allowing for continuous comparison to preceding 

values determined when the instrument was last calibrated. 

Figure 20. Zero and span test plunger. 

Figure 21. Pd wire-mounted for QA. 
ERDC/CERL TR-05-3 23 

Flow measurement QA 

In addition to mass measurements, the XCEM assures quality flow measurements using a redundant mass flow meter in-line with the existing flow controller. When QA mass measurements are engaged, the software interface diverts 

flow out of the flow controller and through the second mass flowmeter. The two 

flow rates are then compared. If a significant difference is determined, an alarm 

will be posted and the data will be flagged. Having a redundant flow meter provides two additional benefits. It can act as a back-up method for measuring concentrations if the flow controller breaks down, and the QA mass flow meter can 

be periodically removed and sent out for recalibration without affecting the 

XCEM normal operations. 

Extraction system QA 

The accuracy of the extraction system can be evaluated periodically (e.g., every 6 

to 12 months) by spiking metals directly into the XCEM. A spiking system was 

developed that uses a NIST traceable standard solution and a nebulizer. This 

spiking system, which is inexpensive to operate, demonstrated good precision 

and was able to spike a variety of metals over a wide concentration range. Using 

this approach, XCEM-reported metal concentrations can be compared with results from either an M29 sample train or a filter grab sample. The XCEM spiking system and results of M29 comparison tests are discussed later. 

Ease-of-use Modifications 

In earlier XCEM versions, the sampling platform was permanently mounted to 

the top of the QuanX XRF. The updated XCEM, however, has been reengineered 

to include a sampling cassette that is attached with only four thumbscrews to 

the XRF analysis platform. The sampling cassette is lightweight (about 25 

pounds) and can be removed from the analyzer in under 5 minutes (Figure 3). 

No tools are required to disconnect the electronics’ plug, screws, and two pneumatic lines on the cassette. Once removed, the cassette is self-supporting, but a 

special transport plate is available. It is anticipated that the next version of the 

XCEM will come with at least two sampling cassettes. Every 2 to 4 weeks, when 

the XCEM filter tape has been fully exposed, operators will be able to rapidly 

change sampling cassettes and transport the cassette containing the exposed 

tape to a separate work area. In the work area, technicians will be able to 

change filter tapes in a clean environment and conduct routine preventative 

maintenance on the cassette. It is anticipated that a technician would be able to 

carry out these tasks in under an hour. 
24 ERDC/CERL TR-05-3 

Safety Modifications 

The portable sampling cassette contains a mounted filter tape, a stepper motor, 

pneumatic plungers, lead shielding, and a tape breakage sensor (Figures 3, 20, 

and 22). The cassette cover is positioned to trigger interlocks so that sampling 

cannot take place unless the covers and shielding are properly positioned. 

In addition to increased efficiency in exchanging filter tapes, the portable cassette ensures that the tape is not contaminated prior to installation into the unit. 

Another benefit is the system redundancy provided by the cassette. If the stepper motor, plungers, or tape are damaged, the XCEM operator can rapidly exchange cassettes and ensure monitor uptime. 

Figure 22. XCEM sampling cassette and XRF control panel. 
ERDC/CERL TR-05-3 25 

3 Laboratory Testing 

This chapter addresses the last two recommendations that were presented in the 

MSE-TA report (Bryson et al. 2000): Hg sampling and the spike injection system. As discussed in the previous chapter, additional laboratory testing was 

needed to evaluate and optimize the Hg capture efficiency of the automated oxidation system, and to compare XCEM mercury measurements with M29. A 

spike injection system was developed so that M29 comparison tests with six 

metals in addition to Hg could be performed in the laboratory. This chapter also 

presents the results of these M29 comparison tests. 

Mercury Sampling 

Experimental 

Optimization of the XCEM Hg sampling efficiency was accomplished in two 

phases. In the first phase (Figure 23), elemental Hg was generated using a Hg 

permeation tube in a controlled temperature environment. The elemental Hg 

vapor was then converted to mercuric chloride using chlorine gas. The resulting 

mercuric chloride was then captured on a 47-mm diameter RIF that was backed 

up by a second 47-mm diameter RIF. Any Hg vapor that was not trapped by the 

RIFs was captured with a carbon-impregnated filter (CIF). Analysis of the relative concentrations on the two RIFs and CIF were conducted to determine if 

breakthrough was occurring. In the second phase, Hg was generated using the 

XCEM nebulization system and a stock multi-element standard from VHG Labs, 

Inc. (Manchester, NH). The Hg was injected directly into the XCEM sampling 

system and analyzed in real time. The XCEM real-time data were compared to 

results from a modified EPA M29 sampling train. 

Mercury RIF Results 

The primary purpose of first-phase Hg testing was to determine RIF vapor phase 

Hg capture efficiencies under varying flow, temperature, and oxidant conditions. 

Figure 24 shows a typical capture efficiency curve when flow rates varied. In 

this series of tests, conducted with a filter temperature of 140 °F (60 °C), the primary RIF collected greater than 90 percent of the Hg when flow rates through 
26 ERDC/CERL TR-05-3 

the filter were less than 0.8 dry standard Lpm/cm2 (liters per minute per square 

centimeter). These results indicate that the RIF could capture greater than 90 

percent of vapor phase (elemental) Hg under typical operating conditions. 

Vent

Vent

Air intake

Air intake

Hg 

Generator

Mass Flow 

Meter

Vacuum 

Pump Vacuum 

Pump

Reaction Chamber

Chlorine 

Gas 

(10% )

Mass Flow 

Meter

2-10 lpm

20 ml/min

1-2 lpm Open Face 

Filter Holder

RIF

CIF

CIF

Rotameter Rotameter

RIF 

RIF 

CIF 

Figure 23. Schematic of Hg capture for first phase experiments. 

 

0

25

50

75

100

0.00 0.50 1.00 1.50

Flow Through Filter (Lpm/cm2

)

% Captured Hg° on Filters

RIF1

RIF2

CIF

Figure 24. RIF Hg capture efficiency versus air flow rate through filter. 

Mercury Oxidation Automation 

The XCEM continuously extracts a small subsample, on the order of 0.5 Lpm, of 

stack gas from the stilling chamber. Prior to collection on the RIF, this subsample enters a dilution/oxidation chamber where an oxidizing agent, such as chlorine gas, is used to convert the elemental Hg to ionic phase Hg, which can then 

be captured on the RIF. The calculations that determine the settings for the oxidant valve, flowmeter, and dilution have all been automated and are fully integrated into the XCEM computer control system. 
ERDC/CERL TR-05-3 27 

Mercury XCEM Results 

During the second phase of Hg testing, the XCEM total Hg measurement capability was determined using an M29 sampling train. Mercuric nitrate and other 

metallic compounds of interest were spiked into the XCEM extraction system 

and were simultaneously collected by the RIF and an M29 sampling train. Four 

M29 tests were conducted, with each test lasting 3 hours. Since the XCEM determined Hg concentrations every 12 minutes, a time-weighted average was 

used to compare XCEM and M29 results. 

Overall the XCEM and M29 Hg concentrations were in good agreement. The average XCEM Hg concentration was 135 ± 8 μg/m3 (micrograms per cubic meter) 

while the average M29 result was 122 ± 6 μg/m3. On average, an 11 percent difference existed between reported sampling run concentrations, which is within 

M29 uncertainty. No indication of filter trapping inefficiencies was evident because the XCEM reported slightly higher Hg concentrations than M29. During 

testing, about 7 percent of the Hg was in the vapor phase as defined by the M29 

front half/back half measurement. 

The XCEM/M29 Hg RA for the four test runs was 20.4 percent, which when 

rounded to two significant digits marginally meets the PS-10 RA criterion. This 

number was calculated using the method described in PS-10. The RA will decrease with increased numbers of runs, so that it is estimated that the RA would 

decrease to about 18 percent if more runs with similar results had been conducted. 

Overall the M29 results demonstrate that the XCEM can adequately trap and 

measure Hg concentrations under realistic test conditions. 

Method 29 Comparison Tests 

Spike Injection System 

Approach 

The quality of the XCEM mass measurements is routinely evaluated with the Pd 

quality control standard, zero, and span checks. However, a spiking system is 

required to confirm XCEM transport and collection efficiencies. An ideal spike 

injection system should have the following capabilities: 

• Can inject all MACT metals at levels well above detection limits 

• Repeatable precision 
28 ERDC/CERL TR-05-3 

• Easy and safe to implement 

• Relatively inexpensive to operate 

• Able to produce an aerosol with high transmission efficiency 

• Quantifiable. 

Several options were reviewed which could potentially meet the above criteria 

(Table 2). These options included: 

• Nebulization. A solution containing elements of interest is aspirated into a 

gas stream. The resulting droplets dry and create an aerosol of salt particles. 

• Aerosolization. A spiked powder is suspended in a carrier gas that is injected into the stack gas stream. Methods of aerosolizing a spiked powder include moving a deposit under a gas jet, fluidized bed plus elutriator, or microscrew injection. 

• Evaporation. A compound of a spiking element with a well-defined boiling 

point is raised to a temperature above its boiling point. This takes place in 

an inert carrier gas that is introduced into the stack gas. 

• Combustion/aspiration. A solid or liquid containing spiking elements is 

burned in a carrier gas. The combustion products containing the spiking 

elements are carried into the stack gas with the carrier gas. Oils containing 

a variety of elements are available and could be readily burned. Solids would 

need to be specially prepared and there would be a greater tendency for the 

elements to remain in the ash. 

• Electric spark. A high voltage spark or arc is created between two carbon 

electrodes containing spiking elements. The sparking process generates fine 

particles with the spiked elements. 

• Hydride generation. An inert gas is bubbled through a solution containing 

the spiking elements. Sodium tetraborohydrate is added to the solution. The 

hydride-forming elements are exchanged with the carrier gas and carried to 

the stack. 

• Specialty gas. A commercially prepared and certified gaseous mixture containing the required spiking elements. 

After reviewing the options, nebulization was selected as the preferred alternative due to its simplicity, potential for extended operation, and quantification advantages. Nebulizers have been used to successfully generate aerosols for a 

number of years (Ylatalo et al. 2000; Flagan and Seinfeld 1988; Fuchs and Stutugin 1966). They are relatively inexpensive and easy to use. In addition, NIST 

traceable laboratory standards are available for all metals of interest. These 

standards are available in a wide variety of concentrations (From 1 to 2000 

μg/mL) and have a guaranteed shelf life of 1 year. 
ERDC/CERL TR-05-3 29 

Table 2. Evaluation of spike injection options. 

Option Advantages Disadvantages 

1) Nebulization 

Ease of use 

Low cost 

Readily available standards 

Humidity affects nebulization rate 

Potential water super-saturation in 

stack sample 

2) Aerosolization Ease of use 

Low cost 

Uniformity of powder issues 

Potential agglomeration issues 

Quantification is difficult 

3) Evaporation Ease of use 

Low cost 

Loss of large particles to walls 

Different temperatures required for 

different elements 

4) Combustion/ Aspiration 

Ease of use 

Low cost 

Readily available standards 

Carrier particles produced by the 

combustion process 

Potential safety issues 

5) Electric Spark Precision 

Ease of use 

Potential safety issues 

Engineering expense 

Quantification difficulties 

6) Hydride Generation Ease of use 

Low cost 

Cost of components 

Instability of hydrides 

Not all metals are available 

7) Specialty Gas Independent certification Cost of gas 

Availability of gas 

Design 

During nebulization, compressed air is pushed into the bottom of a nebulizer cup 

containing a liquid solution. The compressed air exits the cup at the top and 

creates a partial vacuum, which draws liquids out with the air. A DeVilbiss 

nebulizer (Illinois Tool Works, Glendale Heights, IL) was used for these tests. 

The nebulizer included an impaction plate designed to prevent large droplets 

from escaping. 

For the M29 testing, the nebulization system produced 100 liters per minute 

(Lpm) of spiked gas with concentrations between 115 and 180 μg/m3 for seven 

metals: Ag, As, Cd, Cr, Hg, Pb, and Se. A commercially available solution standard (VHG Labs, Manchester, NH) was used to spike the gas stream. The standard solution contained 100 μg/mL of each metal in 5 percent nitric acid. For 

each test run, standard solution was added to the nebulizer cup, which was then 

weighed. Following nebulization, the cup was reweighed and the amount of 

nebulized solution was determined. 

About 5 Lpm of spiked aerosol from the nebulizer cup was injected into a vertical 

four-inch diameter pipe. Another 95 Lpm of dry air was drawn into the pipe 

with the spiked aerosol. The pipe, which was 3-ft long, was heat traced and kept 

at about 220 °F (103 °C). The addition of heat and dry air served to rapidly dry 
30 ERDC/CERL TR-05-3 

the nebulized particles. It is estimated that the typical dried particle size was on 

the order of 0.2 microns in diameter once it exited the 4-inch tubing. The combined 100 Lpm of spiked gas was then drawn into the stilling chamber for extraction by the XCEM and M29 probes. 

Spiking evaluation 

The DeVilbiss nebulizer showed good precision over the 4 days of M29 testing. 

The overall nebulization rate, as determined by mass measurements, was 0.23 ± 

0.01 mL/min. This represents a 4 percent relative standard deviation (RSD). 

Following M29 testing, further nebulization tests under more controlled conditions have demonstrated improved precision and an RSD of less than 1 percent. 

Although the nebulizer precision was good during M29 testing, the mass of nebulized solution could not be used to accurately predict stack concentrations. 

Despite the overall quantification issue, nebulization remains a promising approach. The current nebulization system is able to precisely provide all elements 

of interest over a wide range of concentrations allowing for an effective XCEM 

test range of 1–2000 μg/m3. It is relatively inexpensive, safe, and easy to operate, and a wide variety of metals are available as NIST traceable standard solutions. 

Test Design 

To test XCEM accuracy, four modified M29 test runs were conducted from 4–7 

November 2000. During these tests, simultaneous samples were collected by the 

XCEM and an M29 sampling train. Simulated “stack gas” was provided by 

nebulization of a metals solution containing equal concentrations of As, Cd, Cr, 

Hg, Pb, Se, and Ag. The M29 sample probe extracted the stack gas from a 2-

inch-diameter pipe located approximately 3 feet downstream of the XCEM extraction tube. Both sampling sites were at least eight diameters downstream 

and two diameters upstream of any flow disturbance as required by EPA sampling protocols. During testing, XCEM and M29 temperatures, flows, and pressures were held constant. No XCEM dryer was used for the M29 tests since water content was determined to be less than 1 percent of the volume. Test 

parameters are listed in Table 3. 

The M29 sample was collected isokinetically while the XCEM extracted subisokinetically from the stilling chamber. The stilling chamber design slows stack 

gas and allows for non-isokinetic sampling due to its low Stoke’s number (Cooper 

et al. 2000). 
ERDC/CERL TR-05-3 31 

Table 3. Test conditions during M29 sampling. 

Test Parameter Test Parameter 

Main Line Flow (scfm) 3.52 ± 0.02 Stilling Chamber Temperature ~ 230 °F 

XCEM Sample Flow (sLpm) 0.58 ± 0.003 Temperature at M29 Impinger Inlet ~ 230 °F 

M29 Flow (sLpm) 4.1 ± 0.2 Temperature at M29 Impinger Outlet < 52 °F 

Nebulization Rate (mL/min) 0.23 ± 0.01 M29 Sample Time (min) 180 

Nebulizer Metal Concentration 

(μg/mL) 100 Ambient Relative Humidity 40 - 60% 

Nebulized Metals As, Cd, Cr, Hg, 

Pb, Se, Ag Ambient Temperature 55 - 65 °F 

Metals were nebulized using the XCEM spike injection system. The nebulized 

standard solution, provided by VHG labs, is NIST traceable and contains 

100 μg/mL of each metal in 5 percent nitric acid. Particle size for the test was 

estimated to be on the order of 1 micron or less. During the M29 tests, the nebulization rate was very stable and varied by no more than 5 percent. 

The XCEM exhibited no mechanical or functional problems during the 4-day test 

period, which included over 150 test runs. 

XCEM Results During Method 29 Testing 

XCEM results by element 

The XCEM reported metal concentrations in μg/m3 every 11.7 minutes for each of 

the nebulized metals (Figure 25). Every 2 to 3 hours, spiking was stopped to refill the nebulizer cup. Since the refilling process took about 5 minutes, it reduced 

concentrations for one XCEM sample run. These concentration changes are 

shown as deflections in Figure 25 and illustrate the sensitivity of the instrument 

to changes in metal concentration. The horizontal magenta lines indicate the 

respective metal M29 concentration for the duration of each M29 sample. 

To evaluate the XCEM instrument stability, a Pd rod is situated directly above 

the x-ray tube and provides Pd concentrations with every sample. For these 

tests, the Pd QA rod had an effective concentration of 140 ± 1.0 μg during the 4-

day test period with a precision of better than 1 percent (Figure 25). The consistent Pd concentrations during M29 testing indicate that no XRF instrument drift 

occurred. 
32 ERDC/CERL TR-05-3 

ARSENIC

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

CADMIUM

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

CHROMIUM

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

Figure 25. XCEM elemental concentrations during M29 testing. 
ERDC/CERL TR-05-3 33 

MERCURY

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

LEAD

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

SELENIUM

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

Figure 23 (Cont’d). XCEM elemental concentrations during M29 testing. 
34 ERDC/CERL TR-05-3 

SILVER

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nebulizer Refilled

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

PALLADIUM

130

135

140

145

150

155

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Effective Conc. (μg)

Average Palladium effective concentration

One SD from Avg. Pd Concentration

5% from Avg. Pd Concentration

Nov. 4 Nov. 7 Nov. 5 Nov. 6

PALLADIUM

0

25

50

75

100

125

150

175

200

348 363 378 393 408 423 437 452 467 482

Sample ID No.

Conc. (μg/m3)

Nov. 4 Nov. 7 Nov. 5 Nov. 6

M29-1 M29-4 M29-2 M29-3

Figure 23 (Cont’d). XCEM elemental concentrations during M29 testing. 
ERDC/CERL TR-05-3 35 

XCEM metal concentrations during the 4 days of testing were highly correlated. 

For example, in comparison to Cd, all of the metals exhibited a correlation of 

0.95 or better and had a slope between 0.95 and 1.17 (Figure 26). The choice of 

Cd was purely arbitrary, and similar relationships would be seen if another 

metal was chosen. The slope is expected to be close to 1 because all the metals 

were spiked with the same concentration. Differences in correlation are expected 

to be due primarily to XRF calibration and spectral measurement uncertainties. 

The high degree of correlation and relatively uniform slope indicate good uniformity in the relative concentration of the spiked stack gas. 

y = 1.17x - 7.35

R2

 = 0.95

0

50

100

150

200

250

0 50 100 150 200

Cadmium Conc (μg/m3)

Chromium Conc (μg/m3)

y = 1.04x + 0.49

R2

 = 0.98

0

50

100

150

200

0 50 100 150 200

Cadmium Conc (μg/m3)

Mercury Conc (μg/m3)

y = 1.07x - 7.46

R2

 = 0.95

0

50

100

150

200

0 50 100 150 200

Cadmium Conc (μg/m3)

Lead Conc (μg/m3)

y = 1.02x - 0.99

R2

 = 0.98

0

50

100

150

200

0 50 100 150 200

Cadmium Conc (μg/m3)

Selenium Conc (μg/m3)

y = 0.95x + 0.83

R2

 = 0.97

0

50

100

150

200

0 50 100 150 200

Cadmium Conc (μg/m3)

Silver Conc (μg/m3)

y = 0.97x - 2.12

R2

 = 0.98

0

50

100

150

200

0 50 100 150 200

Cadmium Conc (μg/m3)

Arsenic Conc (μg/m3)

Figure 26. XCEM cadmium versus other spiked metals during M29 testing. 
36 ERDC/CERL TR-05-3 

Pre- and post-tests at XCEM Port versus Method 29 port 

QA testing was conducted before and after each of the four M29 test runs. During QA testing, an open-faced filter holder containing an RIF and CIF was used 

to collect a grab sample from the M29 port. This filter combination, developed by 

CES, is called a Hazardous Elemental Sampling Train (HEST), and has been 

tested in a variety of stack environments as a way of quickly evaluating stack 

gas metal concentrations (Johnson et al. 1998). The HEST samples were analyzed using a laboratory XRF and compared to the XCEM reported concentrations for the concurrent run. Results for the pre- and post-tests are shown in 

Table 4. Overall, the XCEM reported average metal concentration was 138 ± 13 

μg/m3 while the M29 port test average concentration was 126 ± 12 μg/m3 (including Ag). Comparing the average metal concentration is important because all 

metals were spiked at identical concentrations. Especially useful is comparing 

the average concentrations for all metals during one sampling event (e.g., run 2 

pre-test or run 3 post-test). It appears that the averages are within the standard 

deviation between the two ports and that the deviations are similar. Using the 

M29 port results as the “true” value, the XCEM reported concentrations fell 

within the 20 percent RA criterion in PS-10 for all metals except Ag (Table 5). 

These calculations were performed using the eight sets of sample values for each 

metal. The M29 port concentration for Ag was low by 17 percent relative to all 

other reported metal concentrations, while the XCEM Ag concentration was in 

good agreement with reported concentrations for other spiked metals. 

Table 4. Elemental concentrations at XCEM and M29 Ports during pre- and post-tests. 

XC M29 

Port XC M29 Port XC M29 

Port XC M29 

Port XC M29 

Port XC M29 

Port XC M29 

Port Avg SD % 

RSD Avg SD % 

RSD

PRE 115 110 122 110 132 114 126 123 123 115 123 110 117 96 124 6 5 114 5 5

POST 138 146 137 147 165 152 148 166 153 150 147 147 133 126 148 10 7 151 8 5

PRE 141 138 147 140 167 143 156 154 150 142 149 138 139 115 152 9 6 143 6 4

POST 133 141 136 148 148 146 147 163 139 145 136 143 131 117 140 6 4 148 8 5

PRE 128 109 124 115 144 118 134 125 120 117 130 113 117 87 130 8 6 116 5 5

POST 122 118 120 119 135 123 129 133 121 122 125 119 118 95 125 6 4 123 5 4

PRE 120 120 136 122 133 124 128 135 116 122 125 121 118 95 126 7 6 124 6 5

POST 128 116 137 116 142 122 133 133 120 122 128 118 121 90 131 8 6 121 6 5

128 125 132 127 146 130 137 142 130 129 133 126 124 103 134 6 5 130 6 5

TEST

As Cd Cr Hg Pb Se Ag XCEM (No Ag) M29 (No Ag)

1

2

3

4

AVERAGE

Table 5. Relative accuracies of M29 Port versus XCEM Port during pre- and post-tests. 

Element RA Meets EPA-Proposed Criterion1

Arsenic 8.8 Yes 

Cadmium 11.3 Yes 

Chromium 17.0 Yes 

Mercury 8.3 Yes 

Lead 4.4 Yes 

Selenium 10.5 Yes 

Silver 27.6 No 

1

 EPA-proposed PS-10 for Multi-Metal CEMs requires an RA Criterion of 20%. 
ERDC/CERL TR-05-3 37 

XCEM vs M29 

XCEM and M29 analytical data 

During M29 testing, the XCEM reported stack gas concentrations for As, Cd, Cr, 

Hg, Pb, and Se in μg/m3. In addition to an electronic copy, the XCEM printed a 

hard copy of the results after each test run. Metals concentrations used in this 

report are the same as the XCEM hardcopy output with the exception of corrections to As and Hg concentrations. After testing and before receiving the M29 

results, the XRF was recalibrated using a duplicate/new set of calibration standards. At that time, it was determined that the original standards’ Hg concentrations were too low by 17 percent, giving a reported concentration that was too 

high. As such, the XCEM-reported Hg concentrations were reduced by 17 percent. 

Except for Hg, all of the elements were in good agreement following calibration. 

During recalibration, however, it was discovered that a 10 percent As correction 

factor, which had been used in the shakedown period, had accidentally been left 

in the XRF calibration equation. All XCEM concentrations used in this report 

were determined without the use of correction factors. Accordingly, the XCEMreported As concentrations were reduced by 10 percent. 

After making these corrections, CES received the M29 data from an independent 

laboratory, Chester LabNet. Included with the M29 data were results from 

blank and spike tests. No changes were made to M29 laboratory results with the 

exception of a blank subtraction to account for Se in the M29 blank. 

XCEM vs M29 test results 

XCEM and M29 concentrations for the four M29 test runs are shown in Table 6. 

Reported concentrations for the two methods are in good agreement for all elements except Ag. 

No apparent overall bias is evident between the two methods. Indeed, the overall average non-Ag metal concentrations reported by the two methods are within 

a few percent of each other. This trend holds true for each sample run (Table 7) 

and indicates that it is probable that no particulate loss occurred in the sampling 

system. 
38 ERDC/CERL TR-05-3 

Table 6. Reported XCEM and M29 concentrations. 

Concentration Avg. % Element Method Run 1 Run 2 Run 3 Run 4 Average Diff. 

As XCEM 

M29 

128 

140 

131 

149 

120 

129 

117 

130 

124 

137 10 

Cd XCEM 

M29 

131 

158 

138 

166 

121 

156 

124 

151 

129 

158 19 

Cr XCEM 

M29 

149 

152 

156 

159 

139 

153 

131 

146 

144 

152 6 

Hg XCEM 

M29 

139 

117 

145 

131 

131 

118 

126 

121 

135 

122 -11 

Pb XCEM 

M29 

139 

120 

140 

131 

127 

111 

117 

96 

131 

114 -15 

Se XCEM 

M29 

134 

122 

141 

146 

127 

132 

123 

130 

131 

132 1 

Ag XCEM 

M29 

128 

10 

133 

9 

120 

10 

117 

53 

125 

21 -951 

XCEM 

(No Ag) 

Avg 

SD 

% RSD 

137 

8 

6 

142 

8 

6 

127 

7 

5 

123 

5 

4 

132 

7 

5 

M29 

(No Ag) 

Avg 

SD 

% RSD 

135 

18 

13 

147 

14 

10 

133 

18 

14 

129 

20 

15 

136 

17 

13 

4 

Table 7. Average metal concentrations for each sampling run. 

M29 Run 

No. 

XCEM Avg. Metal 

Conc. (μg/m3) 

M29 Avg. Metal Conc. 

(μg/m3) 

Percent 

Difference 

Run 1 137 135 1.5 

Run 2 142 147 3.4 

Run 3 127 133 4.5 

Run 4 123 129 4.6 

Average 132 136 3.5 

1

 Metal concentrations are an average of As, Cd, Cr, Hg, Pb, and Se for each run.

The strong average concentration correlation is reflected in the positive RA results (Table 8). Even with only four sampling runs, the RA for As, Cr, Hg, and 

Se meets the PS-10 RA criterion of 20 percent. During formal M29 certification, 

a minimum of nine runs is recommended by EPA’s proposed PS-10. Had the 

XCEM been tested for nine runs, it is estimated (by using a value of nine for the 

number of sample runs in the PS-10 RA calculation) that Pb would have also met 

the RA criterion. The only MACT metal that would not meet the RA criterion 

was Cd with an RA of 23 percent. Since M29 Cd concentrations were, on average, 15 percent higher than other M29 reported concentrations, it is believed 

that differences in the Cd concentration are a function of a high M29 bias as discussed in the next section. 
ERDC/CERL TR-05-3 39 

Table 8. XCEM and M29 relative accuracies. 

Element 

RA with 

Four M29 

Runs 

Est. RA 

with Nine 

M29 Runs 

Arsenic 14.3 13.0 

Cadmium 22.7 21.6 

Chromium 13.1 11.0 

Mercury 20.4 17.8 

Lead 21.3 19.3 

Selenium 16.2 13.2 

Silver 721.7 662.6 

In contrast to the other spiked metals, Ag XCEM and M29 concentrations do not 

show good agreement. The average Ag concentration during M29 testing was 

reported as 21 ± 21 μg/m3, while the XCEM Ag concentrations during the four 

runs was 131 ± 8 μg/m3. This M29 average Ag concentration is more than five 

standard deviations from the average M29 non-Ag concentration of 136 ± 18. 

Although the pre- and post-test results did indicate some potential difference in 

the Ag concentrations, the average reported M29 port concentration of 103 ± 15 

μg/m3 was still five-fold higher than the M29 test run results. The laboratory 

that performed the M29 analysis believes some analytical problems were possible for Ag and cites the fact that Ag and Sb are the only elements exempted from 

spike recovery criteria by the standard method. For these reasons (and since the 

Ag spike did not meet the 80 to 120 percent recovery criterion), it is believed that 

the M29 Ag numbers were inaccurate. 

The consistency between the overall average XCEM and M29 concentrations is 

important because it indicates that particle loss did not occur during testing. 

The consistency in the elemental concentrations also indicates that elemental 

fractionation was not occurring. Except for Ag, all 24 reported metal concentrations during each of the test runs were within the combined 5 percent XCEM and 

13 percent M29 uncertainties (Figure 27). 

Method 29 and XCEM Precision and Accuracy 

As discussed in the last section, no indication of particle loss or chemical fractionation was observed by either method during M29 testing. As such, all elements should have been present in equal concentrations at both the XCEM and 

M29 ports. In this situation, a hypothetical unbiased method’s reporting of elemental concentrations for a given sample run would be randomly distributed 

above and below the “true” elemental concentration. The average elemental concentration would then be a method’s best estimate of the “true” concentration in 

the stack, and the range of distributions around and about the average 
40 ERDC/CERL TR-05-3 

concentration would reflect the method’s precision. Elemental concentrations 

consistently and significantly above or below the average concentration would 

indicate measurement problems. Figure 28 shows elemental concentrations for 

each sample run that have been normalized to the average elemental concentration. Normalized concentrations in Figure 28 were calculated using 

Equations 1 and 2. 

RUN 1 

0

50

100

150

200

As Cd Cr Hg Pb Se Ag

Concentration (μg/m3)

XCEM

M29

*

RUN 2 

0

40

80

120

160

200

As Cd Cr Hg Pb Se Ag

Concentration (μg/m3)

XCEM

M29

*

RUN 3 

0

40

80

120

160

200

As Cd Cr Hg Pb Se Ag

Concentration (μg/m3)

XCEM

M29

*

RUN 4 

0

40

80

120

160

200

As Cd Cr Hg Pb Se Ag 

Concentration (μg/m3)

XCEM

M29

*

 * Expected concentration of all elements should be the same. 

Figure 27. Comparisons of XCEM and M29 concentration by run. 
ERDC/CERL TR-05-3 41 

Arsenic

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Cadmium

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Chromium

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Mercury

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Lead

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Selenium

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Silver

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Run 1 Run 2 Run 3 Run 4

Normalized Concentration

XCEM

M29

Figure 28. XCEM and M29 normalized concentrations by element. 
42 ERDC/CERL TR-05-3 

X

X

X e

n = [Eq 1] 

where, 

Xn = Normalized XCEM concentration for an element during a sampling run 

Xe = Reported XCEM concentration for an element during a sampling run 

X = Average of reported XCEM As, Cd, Cr, Hg, Pb, and Se concentrations 

during a sampling run 

M

M

M e

n =

 [Eq 2] 

where, 

Mn = Normalized M29 concentration for an element during a sampling run 

Me = Reported M29 concentration for an element during a sampling run 

M = Average of reported M29 As, Cd, Cr, Hg, Pb, and Se concentrations during a sampling run. 

In Figure 28, all XCEM normalized concentrations are within 10 percent of the 

average elemental concentration, and two-thirds of the values are within 5 percent of the average elemental concentration. This is consistent with an XCEM 

estimated one-sigma uncertainty of 5 percent. For the M29 samples, however, 

only As and Se have all reported concentrations within 10 percent of the average 

M29 elemental concentration. Two-thirds of the M29 values are within 13 percent of the M29 average, which is consistent with a M29 one-sigma precision of 

13 percent. Interestingly, M29 Cd and M29 Pb concentrations have the greatest 

deviation from the M29 average, 16 percent high and 16 percent low, respectively, and are the two elements with the highest RAs relative to the XCEM. 

The M29 Cd is, on average, 19 percent higher than the XCEM, and the M29 Hg 

is, on average, 11 percent lower. This indicates that much of the RA difference 

between the XCEM and M29 for Cd and Pb may be a product of M29 bias. 

Overall, the normalized concentrations indicated one-sigma uncertainties of 

about 5 percent for the XCEM and 13 percent for the M29. This M29 uncertainty is in good agreement with the EPA uncertainty estimate of 10 to 15 

percent (MACT 1999b). The M29 normalized concentrations showed significant 

inter-elemental differences indicating a possible method bias, which could be 

responsible for RA differences. 
ERDC/CERL TR-05-3 43 

4 Field-ready XCEM 

CES constructed a new XCEM for testing at the TEAD facility. This prototype 

incorporates all the changes described in the previous chapters. It also includes 

a modified ThermoNoran QuanX energy dispersive XRF analyzer (Thermo 

Kevex) for metal detection. The QuanX is capable of simultaneously measuring 

19 elements and a Pd QA standard. In addition, an eductor downstream of the 

stilling chamber is used to pull the stack gas through the extraction system. 

This change is indicated in the slightly modified main component screen of the 

custom WonderWare® (Progressive Software, Albany, OR) software interface 

(Figure 29). 

Figure 29. New Component Control Screen for XCEM software interface. 

As described in the previous chapters, all day-to-day functions of the XCEM have 

been automated including flow and temperature control, concentration determination, and QA routines. Flow, temperature, concentration, pressure, and error 

messages are automatically recorded in a secure database. The data can readily 

be imported into excel or an equivalent program for subsequent analysis. Flows, 
44 ERDC/CERL TR-05-3 

temperatures, concentrations, and pressure are logged in real-time on the 

screen. Images of the new XCEM and its components are shown in Figures 30–

33. Installation of this unit at TEAD is described in more detail in a follow-on 

technical report. 

Figure 30. XCEM cassettes. 

Figure 31. XCEM extraction system and cassette (left) and chassis (right). 
ERDC/CERL TR-05-3 45 

Figure 32. XCEM with cabinet door open. 

Figure 33. XCEM with computer system installed at TEAD. 
46 ERDC/CERL TR-05-3 

5 Summary and Conclusions 

The XCEM has been developed to provide for automated operations. It now includes features that improve ease-of-use and QA. The XCEM extraction, measurement, and data recording systems have been fully automated using a flexible 

WonderWare® software interface. The revised XCEM has been equipped with 

an automated daily zero and span check, as well as a mechanism for checking 

instrument drift, with every sample. 

The XCEM RIF displayed good capture efficiencies for vapor phase Hg under 

reasonable temperature and flow conditions. The XCEM measured the mercuric 

nitrate injected during M29 comparison tests with a 20.4 RA using four test 

runs. This number meets the EPA’s proposed PS-10 RA criterion when rounded 

to two significant digits. It is estimated that a larger number of test runs would 

bring that value below 20, so that the XCEM will likely also meet the RA criterion for Hg in future testing. 

A nebulization spiking approach was used to provide very precise concentrations 

of all MACT metals over a wide range of concentrations (1 to 2000 mg/cm3). The 

XCEM agreed well with the M29 test runs for all elements except Ag. The 

XCEM displayed better precision than M29 and was able to report data every 12 

min during the 4-day test period. M29 Ag concentrations differed dramatically 

from any other M29 or XCEM reported concentration. For this reason, and because of laboratory QA issues, it is believed that the low M29 Ag concentrations 

are a result of M29 sampling or analysis error. 

The XCEM met the proposed PS-10 RA criteria for As, Cr, Hg, and Se with only 

four sample runs. It is estimated that the XCEM would also have met the Pb RA 

criterion if nine tests had been conducted. Cadmium, with an RA of 23 percent, 

did not meet the RA criterion. 

Although the simulated stack gas contained the metals of interest and relatively 

high concentrations of nitric acid (~100 ppm), the simulated stack gas did not 

contain sulfur dioxide, fly ash, or nitrogen dioxide as might be seen in an actual 

incinerator stack. For this reason, additional testing under actual stack conditions is needed to ensure that the XCEM can perform as well in the field as it did 

for these tests. 
ERDC/CERL TR-05-3 47 

A new XCEM incorporating the changes made in this report was constructed and 

installed at TEAD where it underwent M29 comparison tests under real incinerator conditions. The installation and field testing of the XCEM at TEAD are 

presented in a follow-on technical report. 
48 ERDC/CERL TR-05-3 

References 

Bryson, S., C. Whitworth, and S. Kujawa. (2000). Final Report – Test and Evaluation of an X-Ray 

Fluorescence Based Multi-Element Metals Continuous Emission Monitor. Prepared for U.S. 

Army Corp of Engineers by MSE-TA, Inc., Butte, MT. 

Cooper Environmental Services (CES). (2001a). “XCEM User’s Guide,” Beaverton, OR, 2001. 

__________. (2001b). “XCEM Resource Manual,” Beaverton, OR, 2001. 

Cooper, J., B.E. Johnsen, K.J. Hay, and W. Watson (2000). Continuous Hazardous Element 

Analysis System for Ambient and Emissions Monitoring. Presented at regional AWMA 

Conference: Recent Advances in the Science and Management of Air Toxics. April 10, 2000. 

Flagan, R.C., and J.H. Seinfeld (1988). Fundamentals of Air Pollution Engineering, Prentice-Hall, 

Englewood Cliffs, NJ, pp 59-62, 146-159, 359-384. 

French, N. (1998). 1997 Performance Testing of Multi-Metal Continuous Emissions Monitors. 

Summary Report Prepared for the U.S. EPA and U.S. DOE by Sky+, Napa, CA. 

Fuchs, N.A., and A.G. Stutugin. (1966). Aerosol Science, edited by CN Davies, Academic Press, 

London, pp 1-30. 

Johnsen, B., J. Cooper, and B. Richards (1998). Evaluation of a Hazardous Elemental Sampling 

Train During EPA’s Continuous Emission Monitoring Test. Presented at Pacific Northwest 

AWMA Conference and International Conference on Incineration and Thermal Treatment 

Technologies. October 1, 1998. 

Josephson, Paul. (2003). Hazardous Waste Combustor Management Plan – AEC. 

Maximum Achievable Control Technology. (1999). Final Standards for Hazardous Air Pollutants 

for Hazardous Waste Combustors. Federal Register 52828-FR53077, Vol. 64, No. 189. 

__________. (1999b). Final Technical Support Document for HWC MACT Standards. Vol III. 

Selection of MACT Standards and Technology. Chapter 13. USEPA Contract 68-D2-0164. 

PS-10 (1996), Proposed Performance Specification 10 for Metal CEMS (Proposed 04/19/96) Found 

on the EPA website at: http://www.epa.gov/ttn/emc/propperf.html. 

Seltzer, M.D. (2000). “Performance Testing of a Multimetals Continuous Emissions Monitor”, J. Air 

Waste Mgt. Assoc., Vol. 60, No. 6. 

Ytalatalo, S., H. Toivonen, and J. Lehtinen. (2000). Authentication of Air Samples by Aerosol. 

Aerosol Science and Technology 33:419-426. 
ERDC/CERL TR-05-3 49 

Abbreviations and Acronyms 

AEC U.S. Army Environmental Center 

CAAA Clean Air Act Amendments (of 1990) 

CEM continuous emission monitor 

CERL Construction Engineering Research Laboratory 

CES Cooper Environmental Services 

CIF carbon-impregnated filter 

EPA U.S. Environmental Protection Agency 

ERDC U.S. Army Engineer Research and Development Center 

EQT Environmental Quality Technology 

HAP Hazardous Air Pollutants 

HEST Hazardous Elemental Sampling Train 

HVM high volatile metals 

HWC hazardous waste combustors 

ICP inductively coupled plasma 

LIBS laser-induced breakdown spectroscopy 

LVM low volatile metals 

M29 EPA Reference Method 29 

mAmp milli-ampere 

MACT Maximum Achievable Control Technology 

MSE-TA MSE Technology Applications, Inc. 

NESHAP National Emission Standards for Hazardous Air Pollutants 

NIST National Institute of Standards and Technology 

PLC programmable logic controller 

PM particulate matter 

PS-10 EPA Performance Specification 10 

QA quality assurance 

RA relative accuracy 

RIF resin-impregnated filter 

RSD relative standard deviation 
50 ERDC/CERL TR-05-3 

SCFM standard cubic feet per minute 

SVM semi-volatile metals 

TEAD Tooele Army Depot (Utah) 

XCEM XRF-based continuous emission monitor 

XRF x-ray fluorescence 

Chemical elements 

Ag silver 

As arsenic 

Cd cadmium 

Cr chromium 

Hg mercury 

Pb lead 

Pd palladium 

Se selenium 
REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188 

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the 

data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing 

this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-

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1. REPORT DATE (DD-MM-YYYY) 

01-2005 

2. REPORT TYPE 

Final

3. DATES COVERED (From - To) 

5a. CONTRACT NUMBER 

 

5b. GRANT NUMBER 

 

4. TITLE AND SUBTITLE 

X-Ray Fluorescence-Based Multi-Metal Continuous Emission Monitor: 

Development 

5c. PROGRAM ELEMENT NUMBER 

 

5d. PROJECT NUMBER 

622784AT41 

5e. TASK NUMBER 

002 

6. AUTHOR(S) 

K. James Hay, Bruce E. Johnsen, and John A. Cooper 

5f. WORK UNIT NUMBER 

CNE-B091 

8. PERFORMING ORGANIZATION REPORT 

NUMBER 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

U.S. Army Engineer Research and Development Center (ERDC) 

Construction Engineering Research Laboratory (CERL) 

PO Box 9005 

Champaign, IL 61826-9005 

ERDC/CERL TR-05-3 

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 

U.S. Army Corps of Engineers 

441 "G" Street NW 

Washington, DC 20314-1000 

 

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14. ABSTRACT 

Army demilitarization incinerators will need to comply with the Hazardous Waste Combustor National Emission Standards for Hazardous Air Pollutants that will regulate metals and metal compounds listed under the Clean Air Act Amendments. A large problem for 

these incinerator operations is limited knowledge of the types and quantities of emitted metals. Compliance may be determined only 

through trial burn emission tests because of this limitation. A continuous emission monitor (CEM) for multi-metals will provide the 

emission data, a tool to help meet compliance requirements, and the opportunity to adjust burn strategies for increased production. The 

XCEM multi-metal CEM was developed using x-ray fluorescence (XRF) as the analytical method and an automated sampling system 

that provides extractive batch sampling onto a filter tape. The system is operated with user-friendly WonderWare® software that provides automation, calibration routines, and report generation. A prototype XCEM was tested in the laboratory with a spiked gas stream 

against U.S. Environmental Protection Agency Reference Method 29 for four sample runs. The XCEM met the relative accuracy criteria for four of seven metals. A field-ready XCEM was built for demonstration at the 1236 Deactivation Furnace at Tooele Army Depot, Utah. 

15. SUBJECT TERMS 

emissions hazardous wastes incinerators 

continuous emission monitor (CEM) demilitarization 

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