United States
         Environmental Protection
           Office of Research and
           Washington DC 20460
June 2000
Workshop on Source
Emission and Ambient Air
Monitoring of Mercury
         September 13-14, 1999
         Bloomington, MN


                                            June 2000
Workshop on Source Emission and
 Ambient Air Monitoring of Mercury
       September 13 -14, 1999
           Bloomington, MM
   National Risk Management Research Laboratory
      National Exposure Research Laboratory
       Office of Research and Development
       US Environmental Protection Agency
             Cincinnati, OH 45268
                                     Printed on Recycled Paper

This document has been reviewed in accordance with US Environmental Protection Agency (EPA)
policy and approved for publication. The document reflects exchanges of technical information by
scientists and should not be interpreted as committing EPA policy makers in any way. Also, the
mention  of  trade  names  or commercial  products  does  not  constitute  endorsement  or
recommendation for use.


Notice		jj

Contents	jjj

List of Acronyms	 vi

Acknowledgements	'....-	ix

Section 1.  Introduction	1
     1.1    Workshop Structure, Purpose, and Intended Audience	1
     1.2    Background	2
     1.3    Need for Source Emission and Ambient Air Monitoring of Mercury  . . 3

Section 2.  Source Emission Monitoring	   5
     2.1    State-of-the-Science in Manual Methods for Measuring Total and
           Speciated Mercury Stack Emissions	5
     2.2    State-of-the-Science in CEMs .	 .	 . 5
     2.3    Challenges to Implementing CEMs  	7
     2.4    CEM Performance Evaluation		 7
     2.5    Mercury CEM Implementation	 9
     2.6    Speciating CEMs for Control Technology/Process Control
           Evaluations	 .	10
     2.7    Workshop Steering Committee Recommendations for
           Demonstrating the Viability of Mercury CEMs	 11

Section 3   Ambient Air Monitoring	-....'	   	14
     3.1    State-of-the-Science in Methods To Measure Mercury in Ambient Air 14
     3.2    Source/Receptor Relationships,  Atmospheric Fate
           and Transport Considerations, and Short-Term Plume
           Transformations	15
     3.3    Fate and  Transport Research Recommended by the Workshop
           Steering Committee	16

Section 4.  Workshop Summary and Conclusions	18

Appendix A - Workshop Agenda and Presentation and Panel Discussion
Summaries		,19

Workshop Agenda	 20

Workshop Purpose/ Opening Remarks by Scott Hedges	25

Regulatory Perspective on Mercury Monitoring by Fredric Chanania . .	26

                         Contents (continued)

Need for Source and Ambient Mercury Measurement: A Regulatory Perspective
by William Maxwell	29

The Mercury Problem: What Is It? by Thomas Atkeson	31

The CEC and the Development of NARAPs on Mercury in the North American
Environment by Andrew Hamilton	33

Mercury Modeling and Measurements and Their Source Control Implications by
Russell Bullock	 . 35

Measurements  To Evaluate Emissions Controls for Utilities by Thomas Brown  .. 37

Process Monitoring in DOE Mixed Waste Thermal Treatment Systems
by Stephen Priebe	39

Manual Methods for Measuring Total and Speciated Mercury by John Bosch .... 41

CEMs for Measuring Total and Speciated Mercury by Nina Bergan French  	43

Industrial Applications of Ultraviolet DOAS Systems for Mercury Measurements
by Carl Kamme	46

Problems/Issues Associated with Mercury Measurements by Thomas Brown . . . 48

Merits of Dilution Source Sampling: Measurement of Mercury Emissions
by James Schauer		51

Mercury Measurement Research at the EERC by Dennis Laudal .	54

Mercury Measurement Research at EPA NRMRL by Jeffrey Ryan	 56

Use of a Dilution Chamber To Measure Stack Emissions  and Near-term
Transformations by Eric Prestbo		 59

EPA Performance Specification: Optional Use of CEMs by Scott Rauenzahn .... 62

Suitability Testing of CEMs for Mercury by Carsten Rollig	....:... 64

EPA's ETV Program: An Avenue for Testing of Mercury CEMs by Thomas Kelly . 67

Mercury CEM Field Demonstrations by Nina Bergan French	69

                          Contents (continued)

Evaluation of CEMs for Mercury Speciation by Dennis Laudal	72

International Monitoring/Measurement Activities for Atmospheric Mercury
by John Munthe  .	;.	 . .	75

Source/Receptor Relationships for Mercury: Monitoring and Modeling
by Gerald Keeler	77

Manual Speciation Methods for Measuring Atmospheric Mercury:
Applications/Implementation by Matthew Landis	-....-	80

Automated Mercury Speciation Methods and Demonstrations by Robert Stevens 82

Wet Deposition Sampling - Applications/Implementation by Timothy Dvonch	84

Atmospheric Wet Deposition of Mercury in North America by Clyde Sweet  	86

Summary and Concluding Remarks by Scott Hedges	87

Panel Discussion Summaries	88

Appendix B - List of Workshop Attendees	108

                            List of Acronyms
AES      atomic emission spectrometry   DMA/CMC
AF        atomic fluorescence
ALARA    as low as reasonably          DO
          achievable                   DOAS
AMS      alkaline mercury speciation
AMS      Advanced Monitoring System   DOD
ANPRM   Advance Notice on Proposed   DOE
          Rulemaking                  EERC
APCD     air pollution control devices
APPCD    Air Pollution Prevention and    EMC
          Control Division              EMEP
ASTM     American Society of Testing
          Materials                    EMR
ATO FMS  Aerosol Time-of-Flight Mass*    EPA
A&WMA   Air and Waste Management    EPRI
BACT     Best Available Control         ESP
          Technology                  ETV
BAT      Best Available Technology
BIF       Boiler and Industrial Furnace    ED
C        degrees centigrade           F
CAA      Clean Air Act                 FETC
CAM      compliance assurance
          monitoring                   FGD
CCC      chemical coordination center    GC/MS
CEC      Commission for Environmental
          Cooperation                 , HAP
CEM      continuous emission monitor    HEPA
CISWI     Commercial and Industrial Solid
          Waste Incinerator             HWC
CLRTAP   Convention on Long-range     1C
          Transboundary Air Pollution    ICAP
CVAA     cold vapor atomic absorption
CVAAS    cold vapor atomic absorption    ICP
          spectrometry                 ICR
CVAFS    cold vapor atomic fluorescence  INEEL
CWA     Clean Water Act              ISO-IC
DEP      Department of Environmental
          Protection                   IVL
DDT      dichlorodiphenyltrichloroethane
Digital Machine
Numerical Control
dissolved oxygen
differential optical absorption
Department of Defense
Department of Energy
Energy and Environmental
Research Center
Emissions Monitoring Center
European Monitoring and
Evaluation Program
Enhanced Monitoring Rule
Environmental Protection
Electric Power Research
electrostatic precipitator
Environmental Technology
European Union
degrees Fahrenheit
Federal Energy Technology
flue gas desulfurization
gas chromatography/mass
hazardous air pollutant
high efficiency particulate
hazardous waste combustor
ion capture
inductively coupled argon
inductively coupled plasma
Information Collection Request
Idaho National Engineering and
Environmental Laboratory
Isokinetic lodated Carbon
Swedish Environmental
Research Institute

                      List of Acronyms (continued)
MAMCS   Mediterranean Atmospheric
          Mercury Cycle System         PGA
MDL      method detection limit         PCB
MDN      Mercury Deposition Network    PEM
MM       multiple metals               pg/m3
MOE      Mercury Over Europe          PM 10
MESA    mercury speciation adsorption   POP
MSC      meteorological synthesizing    ppb
          center                       ppbv
MWC     municipal waste combustor     ppbw
MWFA    Mixed Waste Focus Area       ppm
NAAEC   North American Agreement on   ppt
          Environmental Cooperation     PRB
NADP    National Atmospheric          PS
          Deposition Program            QA/QC
NAFTA   North America Free Trade
          Agreement                   R0
NARAP   North American Regional       RATA
          Action Plan                  RCRA
NERL     National Exposure Research
          Laboratory                   RELMAP
NESHAP  National Emission Standards
          for Hazardous Air Pollutants    REMSAD
NETL     National Energy Technology
          Laboratory                   RGM
NIST      National Institute of Standards   RSD
          and Technology              RTP
NOX       nitrogen  oxides               SBIR
NO/NO2   nitrogen  oxide/nitrogen dioxide
NOAA    National Oceanic and          scfm
          Atmospheric Administration     SD
NPRM    Notice on Proposed            SEP
NRMRL   National Risk Management     SMOG
          Research Laboratory
NSPS     New Source Performance       SoFAMMS
OAQPS   Office of Air Quality, Planning,   SOX
          and Standards                SPDC
OPL       operating permit limit           STAR
ORD      Office of Research and
OSW      Office of Solid Waste           STTR
PBTS     persistent bioaccumulative
toxic substances
principal component analysis
polychlorinated biphenyl
particulate emission monitor
picograms per cubic meter
particulate matter 10
persistent organic pollutant
parts per billion
parts per billion by volume
parts per billion by weight
parts per million
parts per trillion
Powder River Basin
performance specification
quality assurance/quality
Relative Accuracy Test Audit
Resource Conservation and
Recovery Act
Regional  Langrangian Model of
Air Pollution
Regulatory Modeling System
for Aerosols and Deposition
reactive gaseous mercury
relative standard deviation
Research Triangle Park
Small Business Innovation
standard  cubic feet per minute
standard deviation
Supplemental Enforcement
Sound Management of
Chemical Initiative
South Florida Atmospheric
Monitoring Study
sulfur oxides
static plume dilution chamber
Science to Achieve Results (an
EPA research grant and
fellowship program)
Small Business Technology
Transfer Program

                      List of Acronyms (continued)





semi-volatile organic compound
Toxicity Characteristic Leachate
total gaseous mercury
total maximum daily load
Toxic Substances Control Act
micrograms per dry standard
cubic meter
micrograms per cubic meter
micrograms per square meter
per year
Total Exposure Assessment
United Nations Economic
Commission for Europe
universal treatment standard
UV       ultraviolet
UVDOAS  ultraviolet differential optical
VOC      volatile organic compound
XRF      X-ray fluorescence
%        percent

This Summary Report for the September 13-14, 1999 Workshop on Source Emission and
Ambient Air Monitoring of Mercury was prepared by the Workshop Steering Committee
consisting of Scott Hedges [U.S.  Environmental Protection Agency (EPA), National Risk
Management Research Laboratory (NRMRL)], Jeffrey Ryan (EPA, NRMRL) and Robert
Stevens [Florida Department of Environmental Protection (DEP), formerly of EPA, National
Exposure Research Laboratory (NERL)]. Gratitude is expressed to Science Applications
International Corporation for their efforts in coordinating the workshop and for their assistance
in preparing and assembling the report.  Paper copies of the workshop presentation overheads
and slides can be  obtained from Mr. Scott Hedges (US EPA,  NRMRL) at 202-564-3318.


                                     Section 1
 1.1 Workshop Structure, Purpose, and Intended Audience

 A workshop on Source Emission and Ambient Air Monitoring of Mercury was held on September
 13-14,1999, in Bloomington, Minnesota. The workshop was sponsored by the U.S. Environmental
 Protection Agency's (EPA's) Office of Research and Development (ORD).  The EPA workshop was
 conducted in collaboration with the Air and Waste Management Association (A&WMA) International
 Specialty Conference on Mercury in the  Environment, also  held  in Bloomington, Minnesota
 immediately following completion of the EPA workshop. Mercury monitoring issues were addressed
 at both meetings, and  as such,  many of the presenters at the EPA workshop also  gave
 presentations at the A&WMA Specialty Conference.

 The purpose of the workshop was to discuss the state-of-the-science in  source and ambient air
 mercury monitoring as well as mercury monitoring research and development needs and the roles
 of EPA, the Department of Energy (DOE), other Federal and State agencies,  and industry in
 addressing these needs:  The workshop was open to the public and included  both traditional
 presentations as well as interactive discussions addressing key research  questions and needs.

 Jn addition to a state-of-the-science review, the workshop focused on the  following key issues:
    What are the needs for manual and continuous .source and ambient mercury measurements?
    What steps are needed to demonstrate'total mercury continuous emission monitor (CEM)
    performance so that their use for compliance assurance may be considered?
    What incentives are needed to develop reliable, accurate and cost effective jCEMs and how
    can candidate facilities be encouraged to use them?
    Are there needs for speciated mercury CEMs for control technology research, process control
    monitoring, and to support site-specific risk assessments?                      . ::  v
    Is there a need to conduct source emission and ambient monitoring  research to investigate
    source/receptor relationships, atmospheric fate and transport considerations, and short-term
    plume transformations?

To facilitate discussions of these issues, the workshop included review presentations of the state-of-
the-science in source emission and ambient air mercury monitoring technologies and associated
performance criteria, on-going monitoring programs, and the status of EPA regulatory requirements.
The workshop also included source and ambient mercury monitoring panel discussions to address
the items listed above.

Presenters were from EPA, DOE,  State agencies, industry, academia,  monitoring equipment
manufacturers, and consulting firms. The presentations were followed by two panel discussions:
the first panel discussion addressed source monitoring and testing issues, and the second panel
discussion addressed ambient monitoring issues.

This Workshop Summary Report provides  a summary of: 1) the state-of-the-science in source
emission  and ambient air  mercury monitoring;  2) key issues, findings, and  results  from the
workshop, including the needs for developing total and speciated mercury CEMs; 3) policy and
technical considerations and challenges associated with implementing mercury CEMs, 4) monitoring

data needed to support the development of source/receptor relationships, modeling, and risk
assessment, and 5) recommendations by the  EPA Workshop Steering  Committee for future
mercury monitoring research, performance evaluations and testing.  In addition to the Summary
Report, Appendix A provides the agenda and synopses of the individual presentations and panel
discussions from the workshop, and Appendix B provides the list of workshop participants and
contact information.

The intended audience for this summary report includes: the management and staff of EPA ORD
and EPA Regions and Program Offices [particularly, the Office of Solid Waste (OSW) and the Office
of Air Quality Planning and Standards (OAQPS)], the DOE and other Federal agencies, State and
regional air regulators and scientists, the national and international mercury research community,
developers of mercury monitoring instrumentation, and industry (i.e., representatives from the waste
incineration and coal-fired electric utility industries).

The Summary Report was written by the Workshop Steering Committee consisting of Mr. Scott
Hedges [US EPA, National Risk Management Research Laboratory (NRMRL)], Mr. Jeffrey Ryan
(US EPA, NRMRL) and Mr. Robert Stevens [Florida Department of Environmental Protection (DEP),
formerly of US EPA, National Exposure Research Laboratory (NERL)]. To prepare the report/the
Steering Committee reviewed each of the presentation and panel discussion summaries from the
workshop (summarized in Appendix A) and summarized the state-of-the-sciehce in source emission
and ambient air monitoring of mercury. The Committee then assessed and summarized the
challenges and recommended steps they concluded are necessary (to be taken by EPA and
others) to expedite the development, performance evaluation and implementation of mercury CEMs
for compliance assurance, for process control, and for control technology research. In turn, the
Committee also recommended source emission and ambient monitoring research which they
concluded is necessary to further understand the ultimate fate and transport of mercury.  The
challenges, summaries, and recommendations presented in this Summary Report are based on the
presentations and panel discussions from the workshop and the scientific expertise and judgement
of the Steering Committee. They do not necessarily represent the opinions of the management of
EPA ORD or the Program Offices.

1.2 Background

Mercury contamination, both nationally and internationally, has long been recognized as a growing
problem for both humans and ecosystems.  Mercury is released to the environment from a variety
of human (anthropogenic) sources including  plant effluent discharge, fossil-fuel combustors,
incinerators, chlor-alkali plants, mining, and landfills. Other sources of anthropogenic mercury
release include industrial processes and the disposal of products containing mercury. Since
mercury does not degrade to simpler compounds, once  it is released to the  environment, it will
always be present in one form or another.

Anthropogenic sources of mercury emissions to the atmosphere include fossil fuel combustion
(containing trace amounts of  mercury),  municipal incineration, medical waste incineration, chlor-
alkali plants, and landfills. These emission sources represent a significant contribution to the total
mercury released (including natural and re-emitted) in the  United States. The 1997 Mercury Study
Report to Congress indicated that the deposition of atmospheric mercury has increased by a factor
of two to five over pre-industrial levels [Mercury Study Report to Congress, Vols 1 - V111, EPA,
1997   (EPA  Document  No.:  EPA-452/R-97-003  through  010,   URL  Address:

 http://epa.gov/oar/mercury.html)].  Additionally, most atmospherically-deposited mercury is in the
 form of gaseous or particulate-phase inorganic mercury.  Unfortunately, the inorganic mercury
 released into the environment can be converted, by naturally-occurring biological processes, into
 the highly toxic methyl mercury species.

 Understanding the relationship between source emissions and ambient air concentrations is a
 necessary step to understanding the fate and transport of mercury. Ambient monitoring is a key
 component in understanding these relationships and in the development and validation of mercury
 source/receptor models, and atmospheric fate and transport models. The ambient forms of stack-
 emitted mercury measured by ambient measurement methodologies  are  elemental  mercury,
 reactive gas-phase mercury (primarily in the form of mercuric chloride) and particle bound mercury.
 (Methyl mercury can also be  measured in the atmosphere but this is thought to be due to the
 mercury cycle and not to stack emissions directly.) These three forms of mercury have distinctly
 different chemical and physical properties which result in different atmospheric fates.  For example,
 elemental mercury has a half-life of 6 months to a year due to its low reactivity and insolubility in
 water and is known to be globally transported before being converted and subsequently deposited
 on soil or water. Mercuric chloride has a half-life of hours due to its high sticking coefficient and high
 water solubility, and can be expected to deposit locally (i.e., within a 30-mile radius of a source) as
 well as regionally. Particle-bound mercury can also be deposited locally and regionally.

 When Congress mandated mercury emission studies in 1990 [Clean Air Act (CAA) Amendments],
 researchers and regulators did not realize that mercury speciation plays such a significant role in
 the fate and transport of mercury. As a result, it is important to study source/receptor relationships
 in part through source emission/ambient air monitoring  and wet/dry  deposition monitoring of
 speciated  mercury compounds, and through source/receptor modeling (developed and validated
 from these monitoring data) in order to further understand the origin (source), form (species), and
 quantity of mercury entering water bodies that can potentially become available for methylation and
 bioaccumulation in fish.

 1.3  Need for Source Emission and Ambient Air Monitoring of Mercury

 Improved source emission and  ambient air monitoring  data are needed to assure compliance with
 regulations promulgated to reduce the impact of mercury contamination in the environment, to
 assess and reduce mercury emissions and associated risks, and to further the understanding of the
 fate and transport of atmospheric mercury. Improved source emission and ambient air monitoring
 data, including speciated mercury data, are also needed to develop, validate and employ the air
 dispersion/deposition models used to assess mercury fate, transport and risk.  (There are other
 reasons EPA is interested in these data, e.g.,  long-term trends, but these additional reasons are
 beyond the scope of consideration of this workshop.)

 Currently, there is a need for continuous mercury emissions data to support alternative methods of
 compliance with hazardous waste combustor (HWC) regulations. The use of total mercury CEMs
 represents a promising approach to meeting this data need. There may also be a need in the future
to use total  mercury  CEMs for coal-fired  electric utility compliance (pending the outcome of a
decision this year on whether to regulate mercury emissions from coal-fired electric utility boilers).
 Finally, there is also an increasing need for speciating mercury CEMs: to assist in the design,
development, and evaluation of mercury combustion control technologies; and as a process control
 monitor for coal-fired electric utility boilers.

EPA's mercury stack emission limits for municipal solid waste, medical waste, and HWCs are based
on the measurement of total (combined vapor and particle phase) mercury. EPA's recently released
Phase I Maximum Achievable Control Technology (MACT) rule for HWCs sets total mercury stack
emission limits for cement kilns, incinerators, and lightweight aggregate kilns that burn hazardous
waste.  These combustors  will need to measure  mercury concentrations in their feedstreams,
preferably on a more continuous basis than infrequent manual method techniques. In addition, new
rules will be forthcoming which address mercury emissions from non-hazardous waste cement kilns,
hazardous waste boilers, and commercial and industrial solid  waste incinerators. Each of these
combustor rules have been or will be promulgated by OSW or OAQPS.  They are designed to
encourage the use of total  mercury CEMs by providing permit incentives.  For these  waste
combustion regulations, total mercury CEMs are or likely will be identified as options for compliance

EPA will be making a decision on or before December 15, 2000  on whether to regulate electric utility
boilers for hazardous air pollutants, including mercury. To inform this decision, as well as to better
understand the forms of mercury present and to evaluate existing control strategies, OAQPS sent
a request for mercury emissions data (referred to as an Information Collection Request or  ICR) to
the utility industry for a variety of boiler configurations and types of coal. These mercury emissions
data are due to EPA by June 1, 2000. If the decision is to regulate, the use of total mercury CEMs
likely will be encouraged as a possible regulatory compliance tool.

Accurate ambient air and source emission monitoring data (including the use of CEMs) are also
needed to support the development of air dispersion, deposition and Total Maximum Daily Load
(TMDL) models for atmospheric mercury deposited onto water bodies. A TMDL is a calculation of
the maximum amount of a  pollutant that a water  body can receive and still meet water quality
standards, and an allocation of that amount to the pollutant's sources.

TMDLs are  required by section 303(d) of the Clean Water Act (CWA). This section requires States
to identify waters not meeting water quality standards and to establish TMDLs. (EPA is required to
do this if States do not.) Initially, as States and EPA concentrated on major point source chemical
discharges, TMDLs were usually referred to as wasteload allocations and served as the basis for
effluent limits for point source permits . As the water program grew and the permitting program was
implemented, it became apparent that water quality problems still remained.  The remaining water
quality problems resulted from the cumulative effects of a number of pollutants and the effects from
pollutants from nonpoint sources.

The water quality based approach, of which TMDLs are a key  element, relies upon analysis of
receiving water quality and the contributions of the pollutant causing the impairment from all sources.
The TMDL is the mechanism by which each pollutant source is given an "allocation" of the amount
of pollutant it can discharge  and water quality standards to be  attained. It is important to note that
the largest problems causing impairments are clean sediment,  nutrients and fecal coliform.  Most of
these pollutants are  from nonpoint source discharges and the  TMDL provides a mechanism to
develop control plans that allow for technical and economic tradeoffs.

Mercury TMDLs will be developed  from risk assessments and from the forthcoming water quality
criteria for mercury due  out in 2000.  An accurate understanding of the amount of atmospheric
mercury  deposited onto water bodies (due  to wet and  dry deposition) will  be crucial to the
development of appropriate  TMDLs for mercury.

                                      Section 2
                          Source Emission Monitoring
As indicated, mercury source emission monitoring data are needed to assure regulatory compliance,
to better characterize source emissions, to evaluate the performance  of mercury control
technologies, and to further the understanding of the fate and transport of mercury.  The following
is a discussion of the state-of-the-science in source emission monitoring technologies as well as a
discussion of the research needs and challenges associated with developing and implementing
these technologies.

2.1    State-of-the-Science in Manual Methods for Measuring Total and Speciated Mercury
       Stack Emissions

EPA currently employs four manual methods for measuring mercury emissions: Methods 29/0060,
101,101 A, and 102 for measuring totaj mercury (gaseous and particulate emissions) and the Ontario
Hydro Method (draft) for measuring speciated mercury. Method 101A was specifically developed
for National  Emission  Standards  for Hazardous  Air Pollutants  (NESHAP) in  1991  to  measure
mercury at sewage sludge incinerators. Method 29/0060 was developed to measure multiple metals
including mercury.

The Ontario Hydro Method was developed outside EPA specifically to perform speciated mercury
measurements from coal-fired sources and is currently being used to provide emissions data to the
ICR project.  Once this method is approved by the American Society of Testing Materials (ASTM),
EPA can incorporate it by reference as an approved manual method for measuring speciated

The above mentioned manual methods are based on the same principle, the Method 5 sampling
train.  An extractive sample is withdrawn from the stack isokinetically and the gaseous and
particulate mercury emissions are captured using a filter and series of impingers.  The only major
differences are the solutions used in the impingers to capture gaseous mercury.  The collected
samples  are acid digested and then analyzed specifically for mercury using cold vapor atomic
absorption (CVAA) or atomic fluorescence spectrometry (AES).

2.2   State-of-the-Science in CEMs

There have been significant strides over the last few years to develop reliable and commercially
viable mercury CEMs. Use of CEMs provide the following advantages:

      Real-time emission data
      Direct pollutant measurements
      Potentially less reliance on waste feed characterization (i.e., for incinerators)
      Operational data for system optimization
      Improved process control
      Greater public assurance

In addition, facilities may also realize a significant cost  benefit from reduced feed characterization
costs (for waste incineration applications), improved throughputs, and avoided upgrade costs as a

result of voluntarily implementing CEMs.

Mercury CEMs are similar to most combustion process CEMs in that the emission sample typically
must be extracted from the stack and then transferred to the analyzer for detection. However,
mercury monitoring is complicated by the fact that mercury exists in different forms  (particulate,
oxidized, elemental) and that quantitative transport of all these forms is difficult. In fact, because the
particulate form is difficult to transfer and is also often a measurement interferant, the particulate is
typically filtered out and remains unmeasured.  Similarly, there are known complications with the
quantitative transfer of mercuric chloride as well....

Typically, CEMs  can only  directly measure  (detect) elemental mercury.  CEMs measure total
mercury through the use of a conversion system that reduces the non-elemental  mercury(oxidized
form that is primarily mercuric chloride) to elemental mercury for detection. Although the particulate
mercury can also be reduced to the gaseous elemental form, particulate sample delivery issues
make this impractical.  As a result, for most  commercially  available CEMs, the total  mercury
measured is in fact total gaseous mercury (TGM). The conversion of the nonelemental mercury is
commonly accomplished using a liquid reducing agent (e.g., stannous chloride).  In addition to the
more established wet chemistry conversion methods, dry chemistry or thermal cracking conversion
methods are also being developed.

In general, mercury CEMs can be distinguished by their mercury measurement detection systems.
Detection systems include: cold vapor atomic absorption spectrometry (CVAAS);  cold vapor atomic
fluorescence spectrometry (CVAFS); in-situ ultraviolet differential optical absorption spectroscopy
(UVDOAS); AES; and laser induced fluorescence spectrometry (LIFS) for multiple metals.

The majority of mercury CEM systems employ CVAAS or CVAFS as the detection technique.  These
systems are only able to measure elemental mercury and rely on the conversion of oxidized forms
to measure TGM.  In addition,  these detection techniques are  susceptible  to measurement
interferences resulting from the presence of common combustion process emissions.  Gases such
as sulfur dioxide, hydrogen chloride, hydrogen fluoride, and nitrogen oxides (present in the flue gas
of coal-fired utility boilers) can act as spectral interferants as  well as degrade the performance of
concentrating devices (e.g., gold amalgams).  As such, conditioning systems need to be developed
that remove these interfering gases prior to sample delivery to the detector.

An  alternative to the elemental mercury measurement approach is AES. .With this technique, the
mercury is ionized by a high energy source (e.g., plasma) and the emission energy detected.  The
advantage to this technique is that all forms  of mercury, including particulate-bound mercury, are
capable of being ionized and detected. However, the sample delivery issues still remain. Unless
the particulate fraction can be delivered, this  type of system will also be limited to TGM.

Total mercury CEMs appear to be more mature than has been widely perceived in the past.  The
units are becoming simpler to operate and maintain. The techniques employed to reduce oxidized
species to the detectable, elemental form are less reliant on wet chemical approaches.  In addition,
techniques for managing potential interferants are also more advanced.

Currently, while  there are no commercially available CEMs that  directly measure  the various
speciated forms of mercury, many total gaseous mercury CEMs can be used to indirectly measure
speciated mercury (the elemental  and oxidized forms)  by  determining the difference  between

 elemental mercury and total gaseous mercury. This difference is recognized as the oxidized form.
 Separate mercury measurements are made before and afterthe conversion step in orderto calculate
 the oxidized form.  This indirect speciation method is referred to as "speciation by difference."
 Although the true identity of the oxidized form is not known, mercuric chloride is currently considered
 the major oxidized form of interest.  However,  recent research indicates that other nonchlorinated,
 oxidized forms may also exist.

 The development of direct speciating mercury CEMs will help expedite and enhance mercury control
 technology research and process control evaluations for coal-fired electric utility boilers. Speciating
 CEMs will also help improve the accuracy of site-specific risk assessments required under EPA's
 HWC Combustion Strategy.  It  is assumed that most speciating  CEMs will be based  on mass-
 spectrometry methods or laser-based techniques (e.g.,  photo-dissociation and fluorescence).
 Development of these CEMs will be a challenge, since at first they will likely be complex and
 expensive.                                                             .

 2.3    Challenges to Implementing CEMs

 At this time, EPA regulations require only periodic total mercury emissions measurements (using the
 manual methods) for regulatory compliance. In order for total mercury CEMs to be considered for
 regulatory compliance assurance, acceptable performance will need to be demonstrated. It is this
 lack of demonstrated performance that caused OSW to use total  mercury CEMs for compliance
 assurance only as an option in  the Phase I MACT rule for HWCs.  EPA is not likely to  require
 facilities to install mercury CEMs unless sufficient performance data are available to justify the
 promulgation of a CEM-based standard. Without a mandatory requirement for mercury CEMs,  CEM
 manufacturers and regulated facilities are reluctant to invest in their further development. In addition,
 few opportunities to demonstrate CEM performance exist, and those demonstrations that have  been
 conducted have not been sufficiently robust to fully support mandatory use of mercury CEMs in EPA
 regulations.  As a result, the developmental progress of mercury CEMs has been slower  than
 originally anticipated. Further challenges still remain.

 One is that few total mercury CEMs truly measure total mercury emissions. This is because most
 systems do not measure particulate-bound mercury. The particulate fraction is often filtered out and
 remains unmeasured.   As a result, the total  mercury measurement  is in fact total gas-phase
 mercury, and this could potentially impart a negative bias to the total mercury measurement.  This
 bias could be further amplified as certain types of particulate may actually capture gas-phase
 mercury. It should be noted that the procedure for evaluating mercury CEM performance compares
the total  mercury CEM measurement to that  of the  manual method  which truly measures  total
mercury  (i.e.,  both particulate-bound and gas phase).    Any potential particulate  mercury
measurement bias may be able to be identified by examining the particulate measurement of the
manual method. This may not be a significant  issue for sources where particulate-bound mercury
is not present in  appreciable quantities, but may be significant for high particulate-emitting sources
(e.g., sources with minimal particulate control).  Therefore, the ability to measure the particulate
component is important and should not be ignored.

2.4    CEM Performance Evaluation

Draft Performance Specification 12 (PS 12) entitled "Specifications and Test Procedures for Total
Mercury Continuous Monitoring Systems in Stationary Sources" is the specification to be used for

evaluating the performance of total mercury CEMs at the time of or soon after GEM installation. In
accordance with PS 12, total mercury CEMs that are evaluated need to be capable of measuring the
total mercury concentration (regardless of speciation) of both vapor and solid phase mercury.  PS
12 provides specifications for locating and for installing CEMs and for evaluating performance, as
well as provides procedures to be used during testing and data reduction. The specification outlines
reference method tests to determine relative  accuracy, as well as tests for calibration  error,
calibration and zero drift, and interference checks.

Many of the techniques  contained in  PS 12 are useful tools for evaluating mercury  GEM
performance.  However, in its current form, the appropriateness of PS 12 is questioned. Certain
aspects presented in PS 12, such as gaseous standards for elemental mercury and oxidized
mercury, cannot be implemented since the tools are not currently available. Also, the acceptance
criteria presented may not be appropriate for every application, and therefore, performance  still
needs to be determined on an individual (case-by-case) basis following the data quality objectives
outlined in PS 12.  EPA recognizes that PS 12 can be improved upon, and that PS 12 may be
updated  in the future.  However, these improvements would need to be demonstrated prior to
incorporation into a revised PS  12.   Mercury CEM performance evaluation/data collection
demonstrations would be a  means to examine viable  modifications and  improvements to  this
performance specification.

It is important for future mercury CEM demonstration testing to be open to alternative and improved
methods for evaluating measurement performance.  For example, the European TUV performance
certification programs may provide alternative approaches that can be considered when performing
mercury  CEM performance  demonstration testing.  It may  be possible  that lessons-learned,
evaluation techniques and/or direct advice from the TUV certification program can be used to  assist
EPA mercury CEM performance evaluation testing.  In addition, EPA's Environmental Technology
Verification (ETV) Program should also  be considered as a  resource  to evaluate/verify  CEM

As part of the performance evaluation and data collection (demonstration) process, it is suggested
that combustion sources be selected where the probability of measurement success is high. Initially,
this can be accomplished by selecting sources where the measurement environment is less severe
(e.g., facilities with low particulate matter/acid gas/interferences), prior to demonstration on a more
severe source (e.g., cement kiln, coal-fired utility).  In addition, for emission environments of a more
severe nature, a high probability for field measurement demonstration success can be achieved by
performing more cost-effective,  pilot-scale evaluations under controlled conditions where individual
measurement issues can be examined in detail prior to undertaking costly field evaluations. ORD's
NRMRL - Air Pollution Prevention and Control Division (APPCD) combustion research facility  has
successfully been used in such a manner to conduct pilot-scale investigations of both multiple metal
and mercury CEMs. Similarly, pilot-scale research performed at the  University of North Dakota's
Energy and Environmental Research Center (EERC) has focused on mercury CEM  measurement
issues specific to coal combustion emissions.  Finally, for use in MACT regulations, facilities with
MACT control technologies already installed should be given preference as demonstration sites for
mercury  CEMs if at all possible. This will provide optimal support for the regulatory use of mercury
CEMs in MACT regulations.                               '-     ''

 2.5    Mercury CEM Implementation

 The implementation of mercury CEMs as an alternative means of compliance assurance under the
 EPA HWC MACT regulations will likely require an incremental or phased approach. Among other
 things, progress will depend on the cooperation of regulators (regional and State), the facility, and
 vendors to demonstrate mercury CEM performance. Progress toward CEM implementation can be
 made only if these cooperative arrangements are mutually beneficial. OSWis interested in defining
 what incentives (regulatory or otherwise) and steps need to be taken to encourage facilities to install
 CEMs. However its focus is not directed at undertaking research, but protecting the public and
 meeting the demand for real-time monitoring.

 Although the HWC MACT regulations provide for an option to use mercury CEMs for compliance
 assurance, facilities may be dubious about the benefits (including enhanced process control) that
 would result. Also, it is not currently known if mercury CEMs are in fact appropriate for compliance
 with mercury standards that were based on manual method data, at least without some type of
 translation of those data into parallel continuous emission data or data ranges. This is due, in part,
 to the absence of sufficient information on the full range of emissions that may be encountered and
 measured on a continuous basis by a mercury CEM.

 It is also unknown whether a single measurement-range analyzer will be able to cover the range in
 emissions necessary.  Alternatively, dual-range mercury CEMs may be necessary - one for routine
 emissions and  one to account for spikes.  In addition, even if CEMs were used for  compliance
 assurance, the requirement to characterize and limit the mercury in waste feed is likely to continue.
 If so, this may undercut one incentive for a facility interested in using mercury CEMs - the reduction
 of mercury waste  feed testing requirements. However,  if CEMs are installed and their reliability
 demonstrated,  approaches should be considered to reduce waste feed testing requirements. Using
 CEMs may also allow compliance emphasis to be shifted to stack emission limits, thus enhancing
 public assurance.

 Flexibility in the interpretation of the performance specification procedures is also needed to further
 the implementation of mercury CEMs. However, there needs to be a balance between this flexibility
 and  the  need  of  EPA regional permit writers and regulators  for standardized and  validated
 measurement methodologies to support regulatory compliance.  Implementation of mercury CEM
 measurement procedures will require technical support (from ORD and the Program Offices) to the
 permit writers and regulators to assist in the interpretation and review of test plans and performance
 evaluation approaches.  Although ORD does provide limited technical support in this area, it is
 expected that the level of support will need to be increased to meet the needs of the permit writers
 and regulators.

 The  immediate  need is to evaluate the current levels of mercury CEM performance at various
 sources and not necessarily place performance in a pass/fail category. These performance data can
then be used to determine the suitability of CEMs for regulatory application. Use of mercury CEMs
for compliance assurance monitoring could then  be  based on  the monitoring objectives or
 requirements of the regulated source.

 Unfortunately, few opportunities exist for demonstrating mercury CEM performance.  EPA is currently
 not funding field performance demonstrations. The past OSW performance demonstration test was
 limited in its usable results, primarily due to the complexity of the source tested.  Additional EPA

performance demonstrations have not been considered due to the expense. Although EPA is not
currently funding field performance demonstrations, the ETV Program, in collaboration with NRMRL,
is  planning a  pilot-scale mercury GEM evaluation program that may ultimately include field
demonstrations. This pilot-scale program will evaluate promising monitoring technologies that could,
in the future, be used for a variety of applications, including compliance assurance.

The DOE Mixed Waste Focus Area (MWFA) has also sponsored a limited number of mercury CEM
performance evaluations. While these tests have been relatively successful, they are still limited in
scope and application.  Clearly, furthering the development  and  performance demonstration of
mercury CEMs will require a coordinated and cooperative effort of EPA researchers and regulators,
DOE and other Federal agencies, regional, State and local regulators, industry, and mercury CEM
vendors/developers. This cooperative effort must be mutually beneficial, requiring that incentives
be provided to  a facility to encourage participation  and  cooperation.   Assuming  a HWC
owner/operator is willing to install a mercury CEM, incentives  and  benefits that could be explored

       Obtaining continuous data to improve a facility's own understanding of process variability
       within its system

       Potential tool for the facility itself to evaluate alternative compliance  options

       Increased averaging times to reduce inappropriate influence of emission spikes

       Potentially less stringent waste feed characterization and testing program

       Potential for regulatory implementation extension if needed to install the CEMs and have
       them reach a state of operability

       Less performance stack testing and enforcement quality testing of  operating permit limits

       Less monitoring of OPLs for compliance assurance

       Improved public assurance

       Potential proactive response to anticipated State regulations

       Improved ability to characterize legacy waste.

Many of these types of incentives and benefits may also have application to electric utility, boilers
should a decision be made to regulate hazardous air pollutants from these sources.

2.6    Speciating CEMs for Control Technology/Process Control Evaluations

Because waste combustor regulations (e.g., HWC combustor MACT) limit total mercury emissions,
the use of total mercury CEMs is a logical option for compliance assurance. In contrast, the need
for speciating mercury CEMs from a regulatory perspective is uncertain. However, there is a need
for a speciating mercury CEM both as a mercury control technology research and evaluation tool and

 possibly as a process control monitor.       .                      

 A need  currently exists Jor  speciating CEMs  to support control technology field demonstration
 research for coal-fired utility boilers. Speciated GEMs are needed to determine the species of
 mercury emitted from the wide variety of coals burned in utility boilers, and subsequently to evaluate
 and select appropriate technologies to reduce the species of mercury emitted. To support the
 regulatory determination process for coal-fired utility boilers, EPA ORD, in cooperation with DOE,
 will be supporting a series of field studies to evaluate and demonstrate potential mercury control
 technologies.                -.,-.-,

 These  control technology  demonstrations  will  require  comprehensive  speciated mercury
 measurements as a function of process variation and control technique employed. Most importantly,
 this will offer an opportunity to optimize these candidate technologies. To do so will require timely
 speciated measurements. The use of manual speciation methods such as the Ontario Hydro Method
 (which measures elemental,  oxidized, and particle-bound mercury from coal-fired utility boilers) is
 not practical due to the time and cost of sampling and analysis, even if the analysis is done onsite.
 A speciating mercury CEM is the most viable option for providing these time sensitive data.

 A speciating mercury CEM may also be useful as a process control monitor.  The approach to control
 mercury emissions is based on the mercury form present, and because fuel types and characteristics
 can vary substantially, the mercury species will also vary. Aspeciatina monitor would be an effective
 tool to utilize the most effective mercury control technique(s) and ensure the cost-effectiveness of
 the technique(s).

 Based on the current understanding that the oxidized species of primary interest is mercuric chloride
 and that mercuric chloride is the dominant form of oxidized mercury present, the "speciation by
 difference" technique is an acceptable approach to obtaining speciated mercury measurements. The
 "total" measurement actually represents the total gaseous component and typically does not include
 the particulate matter fraction. This approach is dependent on the reliability of the elemental and
 total gaseous mercury measurements. Unlike total mercury OEMs, direct speciating mercury OEMs
 are not commercially available. Much of the advances in "speciation  by difference" mercury CEMs
 have come about largely due to individual research needs and not because of a regulatory  driver.
 As a result, the state-of-the-science for speciating mercury CEMs is clearly not as advanced  as that
 for total mercury CEMs. However, research conducted by the University of North Dakota EERC has
 clearly demonstrated the viability of this technique.  Because of the  relatively small demand for a
 fully-speciating research instrument, there has been limited commercial interest in its development.
 However, should mercury emission regulations be promulgated for the utility industry, it appears that
 a commercial market for a speciating mercury CEM as a process control tool may well develop.
Workshop Steering Committee Recommendations for Demonstrating the Viability of
Mercury CEMs
Clearly, many obstacles must be overcome in order to fully demonstrate the viability of mercury
CEMs for regulatory compliance, control technology research and for process control. Although EPA
is not currently funding field performance evaluations, the ETV Program (as previously indicated)
may ultimately provide a mechanism for these types of field demonstrations.

EPA also provides funding through the Small  Business Innovation Research (SBIR) Program to

develop and demonstrate new and innovative technologies such as CEMs, and through the "Science
To Achieve Results" (STAR) programs to enable the academic community to sponsor monitoring
research. In addition, DOE's Small Business Technology Transfer Program (STTR) provides funding
to develop mercury CEMs as well as techniques to resolve specific mercury measurement issues.
Similarly, various State agencies have furthered the development of CEMs through their own funding
initiatives.  These initiatives typically focus on the research and development of promising, less
mature technologies rather than the commercially available technologies currently considered for
emissions monitoring application. As a result, technologies developed under these initiatives require
more time (usually several years) to reach the level of maturity needed for demonstration in the field.
However, each of these programs and initiatives is needed to develop and.evaluate the wide variety
of technologies required to further the GEM implementation process.

Also, the Steering Committee concluded that in  order to demonstrate the viability of CEMs for
potential use as a compliance assurance tool:

       EPA should take the initiative in seeking and developing cooperative relationships between
       the regulator/permitter and  the facility in an effort to encourage voluntary GEM use.  The
       Agency should also encourage any interested stakeholders to participate in this cooperative

       Facilities should reach out to their communities and get them involved in the compliance
       assurance process. CEM data can then be used to communicate a facility's ability to comply
       with mercury limits.

      A clear  message needs to be sent to  mercury GEM vendors/developers as to what
       application and performance will be expected from total mercury CEMs. Specifically, what
       measurement ranges are  needed (HWC versus  coal  utility),  desired  performance
       requirements, system on-line duration, and equipment durability.

       Research should  be  performed  at the pilot-scale to investigate and resolve  known or
       suspected mercury CEM measurement performance issues.  This approach provides a
       controlled  environment  to  conduct parametric  investigations  of diverse measurement
       environments [HWC, municipal waste combustor (MWC), cement kiln, coal-fired utilities] prior
       to conducting more costly field performance evaluations. Most importantly, this approach will
       reduce the time needed to conduct a field demonstration  and will greatly improve the
       probability for a successful demonstration  once in the field.

       The role of EPA's ETV Program and the testing of total mercury GEMs should be defined with
       respect to specific EPA Program Office, State or regional needs. Any potential testing should
       be in direct consultation with these groups. The benefits to the CEM vendor Of participating
       in the ETV Program should also be clearly identified.

       Funding should be identified to support field performance demonstration efforts.  Additional
       EPA and DOE funding and possibly funding by  other sources [e.g., Department of Defense
       (DOD),  State  agencies]  is necessary  to  support  these  demonstration programs.
       Collaborative efforts that leverage resources should also be considered.

       Research  is needed to investigate the  development and application  of  mercury gas

       standards. Such calibration standards are called for in PS 12 and would be valuable as part
       of CEM operation (i.e., calibrations, calibration drift checks).

The following recommendations are also provided for the development of speciated mercury CEMs
for control technology evaluations and process control applications:

       Research indicates that certain types of fly ash exhibit catalytic properties that can oxidize
       elemental  mercury  under  certain conditions, including those  associated  with  heated
       particulate filters.  This conversion can lead to an overestimation of the oxidized form of
       mercury, which  in turn can erroneously impact the  interpretation of mercury control data.
       Research is needed to minimize or eliminate this bias.

       Currently, control technology research, primarily for coal-fired utility boilers, represents the
       current market for speciating mercury CEMs. Until such time as a demand for a speciating
       mercury CEM as a process control monitor exists, the advancement of this technology will
       be driven by EPA and DOE's control technology  research needs.  To expand opportunities
       for  process   control application,  speciating  CEM  vendors/developers should  seek
       collaboration with DOE and EPA.  Applying for control technology research grants under the
       EPA SBIR and DOE STTR programs is one avenue to foster this collaboration.

                                      Section 3
                             Ambient Air Monitoring
As previously discussed, in addition to source emission monitoring, there is also a need for accurate
and comprehensive ambient air monitoring data for mercury  (including deposition monitoring).
These data are needed to support the development and validation of air dispersion and deposition
models, the development of TMDLs, and in turn to further the understanding of mercury fate and
transport.   The following  is a discussion of the state-of-the-science in ambient air  monitoring
technologies as well as a discussion of the ambient monitoring  research needs relative to the fate
and transport of mercury.

3.1     State-of-the-Science in Methods To Measure Mercury in Ambient Air

Manual sampling of ambient  mercury can be used  in routine projects (to support  monitoring
networks),  exploratory  projects (for fugitive emission monitoring), special  projects (for aircraft
measurements and chlor-alkali facilities), and to support quality assurance/quality control efforts.
EPA Method IO-5 is the standard manual method for measuring vapor and particle phase mercury
in ambient air. The method for collection and analysis of elemental mercury takes advantage of the
amalgamation property of mercury to pre-concentrate ambient air in a gold-coated bead trap prior
to thermal  desorption and detection using  CVAFS. The method for collection and analysis of
particulate-bound mercury consists of collecting the particulate on a pre-fired glass-fiber filter which
is microwave-digested in nitric acid prior to extraction  and detection  using CVAFS. A complete
description of EPA Method IO-5 can be found  in the "EPA  Compendium of Methods for the
Determination of Inorganic Compounds in Ambient Air, EPA/625/R-96/01a, July 1999"

Examples of currently available manual methods forthespeciation of mercury include: impregnated
(ion exchange) filters; refluxing mist chambers; and annular thermal denuders. Annular thermal
denuders are the most promising methodology for avoiding artifact formation.

Annular denuders provide ambient speciation of elemental, reactive, and particulate mercury without
known interconversion problems.   Denuders are  not a new technology.  Tubular denuders were
previously used in Europe to speciate mercury in stacks and annular denuders have been used for
decades for sulfur dioxide and ammonia determinations.  However, in order to use denuders for
ambient mercury speciation, two key modifications have been made to previous designs. A single
annulus quartz denuder was constructed and coated with potassium chloride to efficiently capture
reactive gaseous mercury or ROM (i.e.; oxidized or ionic mercury), and rather than perform a wet
chemical extraction and subsequent analysis, the quartz denuders are thermally desorbed.  At
approximately 500 degrees Centigrade (C), ROM is quantitatively converted to elemental mercury
vapor and purged directly into a CVAFS detector.  Once desorbed, the denuder is regenerated and
ready for reuse.

In addition to being relatively easy to use, tests show that annular thermal denuders are capable of
obtaining high collection efficiencies [over 97 percent (%) in the 5 to 2,000 nanogram per cubic meter
range]. Denuders can also be used to perform high-resolution sampling at relatively low method
detection limits (MDLs). Furthermore, the manual sampling configuration is relatively inexpensive,
simple, and mobile.

An automated system that houses a CVAFS detection system and utilizes thermal annular denuder
technology has also been introduced by Tekran, Inc.  The Tekran 2537A analyzer is capable of
continuously measuring both elemental mercury and oxidized or ionic mercury.  In addition, recent
advances in particulate mercury measurement technology have been made which utilize a quartz
filter housed  in a quartz chamber.  The chamber is heated to  convert the captured particulate
mercury to elemental mercury prior to measurement in the CVAFS detector. Research is underway
to incorporate this thermal quartz filter technology into the Tekran instrumentation.  As a result,
oxidized, elemental and particulate mercury will be able to be measured at ambient levels.

Deposition monitoring is also integral to understanding the relationships between air  emission
sources of mercury and the concentration of mercury in water bodies.   A Mercury Deposition
Network (MDN), coordinated through the National Atmospheric Deposition Program (NADP), has
been designed to study and  quantify long-term trends associated with atmospheric  fate and
deposition of mercury.  MDN collects weekly samples of wet deposition (rain and snow) for analysis
of total mercury and at some sites, methyl mercury. MDN sites are currently located in the Eastern
United States and in Canada.  A goal of the MDN program is to  expand network coverage to the
entire United States, as is the case for the NADP network. Expanding the network will help provide
additional data needed to further understand source/receptor relationships and the ultimate fate of

3.2    Source/Receptor Relationships, Atmospheric Fate and Transport Considerations, and
       Short-Term Plume Transformations

Recent ambient air monitoring  research has attempted to link mercury emissions from combustion
processes to ambient speciated mercury measurements. A major  uncertainty is the degree to which
standard combustion source speciated mercury measurements (as measured in the stack) compare
to ambient speciated mercury measurements.  Although both  source and ambient  monitoring
systems measure elemental, oxidized (ROM), and particulate-phase mercury species, many factors
exist that likely result in measurements that are not comparable.

For example, the filter component of the source method is operated at a highly elevated temperature
[250 degrees Fahrenheit (F)].  As a result, the level of mercury condensed on particulate will differ
from that condensed at ambient temperatures. Another concern with the source method is that some
fly ashes for coal-fired utility boilers exhibit catalytic properties that can oxidize elemental mercury
under certain conditions. This condition results in a positive bias in the RGM component of the
speciated measurement.  This potential disparity impedes the ability to model source/receptor, fate
and transport relationships.  Clearly, for atmospheric modeling purposes,  source data need to be
collected in a form comparable to the ambient data.

A  significant  disparity between source and ambient mercury  measurements  is that source
measurements do not account for theshort-term atmospheric transformations that take place in the
stack gas plume. Accounting for this is needed since the conversion of mercury species is likely to
occur rapidly from the  stack to plume as a result of changing chemical and physical conditions.
Dilution techniques have been demonstrated to simulate these transformations  to the ultimate
ambient forms. Source data that account for these combustion plume transformations are needed
to  improve the accuracy of atmospheric models.

Plume dilution systems have been designed to characterize these short-term plume transformations.
One such system is the "Static Plume Dilution Chamber" or SPDC. The SPDC acts as a large inert
(Teflon-coated) reaction chamber to form controlled combustion emission plumes by isokinetically
introducing a small volume of flue gas (e.g., 20 liters) into a large volume (e.g., 500 to 1,000 liters).
The SPDC has several variables that can be easily controlled: 1) temperature, 2) dilution ratios, 3)
reaction time, 4) light input, and 5) rainwater.  Both dry deposition (on the sides of the walls) and
mercury washout  by  rainfall can also be  assessed with a SPDC.  This allows users to assess
deposition in the environment and to identify which atmospheric mercury species are removed into
aquatic ecosystems.  In addition to using a mercury filter pack system to collect a sample from the
chamber for particulate mercury, RGM and elemental mercury analysis, the instrumentation is also
set up to measure (via a probe) mercury speciation in the flue gas.  Total mercury in the SPDC is
measured to calculate a SPDC mass  balance.

With speciated source and ambient mercury  measurements that are directly  comparable, valid
source apportionments and modeling can occur. Obtaining source data in its transformed form (i.e.,
in the stack plume) will also provide more  accurate information for site-specific risk assessments.
Such  source-specific  data can also support the understanding of TMDLs, including the need for
regulatory action. We need to improve our identification of differences between source and ambient
measurements, so that mercury source/receptor relationships can be better defined, and accurate
source/receptor models can be developed.

3.3   Fate and Transport Research Recommended by the Workshop Steering Committee

The following monitoring research is recommended to define the relationships between the sources
of mercury and ambient concentrations:

      Research by EPA ORD and others should be  conducted to establish the speciated data
      relationship(s) between conventional, in-stack,  mercury speciation measurement methods
      and ambient mercury speciation measure methods. To do so will require the simulation of
      the short-term atmospheric transformations  taking  place  in  the plume  and ambient
      environment as combustion process emissions exit the stack.  This can be accomplished
      using dilution  techniques, although  other  approaches could  exist.  Ambient speciated
      measurements made directly from diluted combustion emissions can then be compared with
      conventional source speciating measurements to establish relationships between elemental,
      RGM and  particulate-phase  mercury measurements.  These  relationships should  be
      determined for multiple combustion source categories.  Ultimately, this would improve the
      quality of data used by modelers to determine source/receptor relationships.

      Once this  relationship  has been established, source profiles  and speciated mercury
      measurements should be obtained from representative types or categories of emission
      sources,  including resource  recovery  and  medical  waste  incinerators  at different
      geographical locations.  If the ratio of elemental mercury to mercuric chloride to particle-
      bound mercury to total mercury was known for a representative group of sources, it would
      be possible to more conclusively model mercury fate and transport relationships and perform
      TMDL calculations.

      EPA should support the operation and expansion of the MDN program where possible. In
      addition, a  minimum of three to four new air quality monitoring stations should be established

to measure speciated mercury and related elements in the atmosphere in the short-term.
These new monitoring stations should be located at sites considered receptors for emissions
from stationary sources.  These sites should be  maintained for a minimum of 5 years to
assess the impact of mercury emission controls.  Wet deposition samples should also be
collected concurrently with atmospheric measurements.  Currently two sites are being setup
by EPA ORD: one in Florida and one in Ohio. These sites should be operational in mid 2000.
If the ambient mercury speciation instrumentation from these sites proves to be reliable and
provides data on source/receptor relationships important for TMDL validation, it would then
be advantageous to allocate additional funding to expand the number of monitoring sites and
to sustain  these sites beyond the 5 year period.  This short-term sampling may also help
interpret the  long-term  results  of the MDN program,  and potentially demonstrate new
monitoring technologies that may in the future by used by the MDN program.

Future ambient air and deposition monitoring programs  should be developed based in part
on the need to develop, validate, and refine air  dispersion and wet/dry deposition models.
Both monitoring and modeling needs to be addressed simultaneously.

                                    Section 4
                   Workshop Summary and Conclusions

As discussed, the state-of-the-science for both source emission and ambient air mercury monitoring
has advanced substantially over the last several years, particularly in the case of total mercury
CEMs. Research is now needed to develop direct speciating mercury CEMs, to address total
mercury CEM interference and bias, and to investigate and finalize procedures for the evaluation of
mercury CEMs. Research is also needed to further the understanding of the fate and transport of
mercury, particularly an understanding of the short-term transformations that occur in combustion
plumes. This will require additional and precise speciated mercury monitoring at the source, at the
receptor, and most importantly, measurements that account for the stack gas plume atmospheric
transformations.  This monitoring is also needed to develop, validate and refine air dispersion and
deposition models, and to accurately calculate TMDLs. Lastly, collaboration is needed between
EPA, DOE, other Federal and State agencies, and vendors to perform full-scale demonstrations of
these source emission and ambient air monitoring technologies.

In order to promote the development of mercury monitoring systems (particularly CEMs), the
Workshop Steering Committee suggests that EPA continue to provide assistance and guidance to:

      Manufacturers to develop mercury monitoring systems and for industrial sources to install
       these systems.

       The academic community through research grants.

       Federal Agencies through Interagency Agreements.

It is also suggested that EPA ORD continue to inform the EPA Program Offices and Regions, State
and  local permit permitting authorities, industry, and the international community about the latest
developments in manual and continuous systems to measure source and ambient levels of mercury.

Appendix A - Workshop Agenda, Speaker Presentation Summaries, and
Panel Session Summaries

This appendix contains a copy of the workshop agenda followed by summaries of the presentations
and panel discussions from the workshop. This appendix does not constitute an actual proceedings,
since the presentations were informal, and no written versions were required.  Furthermore, speaker
and session summaries are organized according to the order in which they were presented.

                    Workshop on Source Emission and
                    Ambient Air Monitoring of Mercury

Day 1 -Morning

7:30   Registration

8:30   Workshop Purpose/Opening Remarks (Scott Hedges, US EPA, NRMRL)

      Session 1 - Need for Source and Ambient Mercury Measurement (Jeffrey
      Ryan/Robert Stevens Session Chairs)

8:45         Part A - The Regulatory Perspective

                  Regulatory Perspective on Mercury Monitoring (Fredric Chanania, US
                  EPA, OSW - 20 min)

                  Need for Source and Ambient Mercury Measurement: A Regulatory
                  Perspective (William Maxwell, US EPA, OAQPS - 20 min)

                  The Mercury Problem: What Is It? (Thomas Atkeson, PhD, Florida DEP -
                  20 min)

9:45         Part B - Transboundary Considerations

                  The Commission for Environmental Cooperation (CEC) and the North
                  American Regional Action Plans (NARAPs) on Mercury in the North
                  American Environment (Andrew Hamilton, PhD, CEC - 20 min)

10:05       Part C - Fate and Transport/Exposure Considerations

                  Mercury Modeling and Measurements and Their Source Control
                  Implications (Russell Bullock, US EPA, NERL - 20 min)

10:25 Break

11:00       Part D - Process Control Applications

                  Measurements To Evaluate Emission Controls for Utilities (Thomas Brown,
                  DOE, National Energy Technology Laboratory (NETL), formerly Federal
                  Energy Technology Center (FETC) - 30 min)

                  Process Monitoring in DOE Mixed Waste Thermal Treatment Systems
                  (Stephen Priebe, PhD, Bechtel B&W Idaho, Contractor for DOE,  Idaho
                  National Engineering and Environmental Laboratory (INEEL) - 20 min)
11:50 Lunch

Day 1 - Afternoon

      Session 2 - State-of-the-Science in Measuring Mercury Emissions (Jeffrey
      Ryan/Thomas Brown Session Chairs)

1:00         Part A - Mercury Measurement Methodologies

                   Manual Methods for Measuring Total and Speciated Mercury (John Bosch,
                   US EPA, OAQPS - 20 min)

                   CEMs for Measuring Total and Speciated Mercury (Nina French, PhD, Sky
                   + Inc.  - 20 min)

                   Industrial Applications of Ultraviolet Differential Optical Absorbtion
                   Spectroscopy (DOAS) Systems for Mercury Measurements (Carl Kamme,
                   Opsis Inc, Lunde, Sweden - 20 min)

                   Problems/Issues Associated with Mercury Measurements (Thomas Brown,
                   DOE, NETL - 20 min)

                   Merits of Dilution Source Sampling: Measurement of Mercury Emissions
                   James Sehauer, PhD, University of Wisconsin - 20 min)

2:30  Break

3:00         Part B - Mercury Measurement Research and Development Activities

                   Mercury Measurement Research at the EERC (Dennis Laudal, University
                   of North Dakota EERC - 30 min)

                   Mercury Measurement Research at EPA/NRMRL (Jeffrey Ryan, US EPA,
                   NRMRL - 30 min)

                   Use of a Dilution Chamber To Measure Stack Emissions and Near-Term
                   Transformations (Eric Prestbo, PhD, Frontier Geosciences - 20 min)

4:20  Session 3 - Mercury CEM Performance and Evaluations (Jeffrey Ryan/Scott
      Rauenzahn Session Chairs)

             Part A - Methods for Evaluating/Certifying CEM Performance

                   EPA Performance Specifications: Optional Use of CEMs (Scott
                   Rauenzahn, US EPA, OSW - 20 min)

     .              Suitability Testing of CEMs for Mercury (Carsten Rollig, TUV -Rhineland,
                   Cologne,  Germany - 30 min)

                   EPA's ETV Program: An Avenue for Testing of Mercury CEMs (Thomas
                   Kelly, PhD, Battelle -15 min)

5:35  End of Day 1

Day 2 - Morning

8:00         Part B - CEM Performance Evaluations and Demonstrations

                   Mercury CEM Field Demonstrations (Nina French, PhD, Sky + Inc. - 30

                   Evaluation of CEMs for Mercury Speciation (Dennis Laudal, University of
                   North Dakota EERC - 30 min)

9:00  Break

9:30  Session 4 - Panel Discussion of Source Monitoring / Testing Needs (Jeffrey
      Ryan/Nina French Session Chairs)
                   Russell Bullock-US EPA, NERL; Scott Rauenzahn-US EPA, OSW;
                   Stephen Priebe-Bechtel B&W Idaho; Thomas Brown-DOE, NETL; Ronald
                   Baker-Aldora Corp.; John Bosch-US EPA, OAQPS; Catherine Massimino-
                   US EPA, Region X                                    :
                   1)     Do you believe total mercury CEMs areicapable of cost-effectively
                         monitoring emissions for compliance assurance?
                :               Why,or why not? ..-.:           '
                                Which technologies are forerunners, and why?
                               Which technologies are you less sure of and why?
                   2)     What are the greatest concerns associated with CEM operation?
                                What are the risks?
                                What are the technical obstacles (e.g., interferences, filter
                           ,     artifacts, durability, biases)?:  "
                   3)   ,  How should CEM performance be evaluated?
                                What are the most important considerations with respect to
                                CEM performance (e.g., drift, calibration technique,
                                sensitivity, precision, durability, etc)?                ."".
                                Is PS 12 still considered to be the appropriate method for
                                evaluating total mercury CEM performance?
                           ,    Whyorwhynot?     ,
                                Should PS 12 be revised? Who will do it? When?
                                What tools (e.g.,  gas standards, reference materials,
                                comparison methods, techniques)  are needed to fully
                                evaluate CEMs?
                                Are  existing reference methods (i.e., Methods 101A and 29)
                                satisfactory as an accuracy check  or reference point for
                                total mercury CEM (averaged) data?

                   4)     What type of field demonstrations and/or technology
                          improvements/cost reductions are necessary to reduce the risk of
                          implementing total mercury CEMs?
                                What type and how many field demonstrations will be
                                required to fully demonstrate CEMs?
                                What are the types of sources that must be considered?
                                Can nominal and/or worse case monitoring conditions be
                   5)     Where are speciating CEMs needed? ,
                                Is speciation by difference adequate or are direct speciating
                                techniques needed?
                                Are performance specifications needed for speciating
                   6)     Does the CEM technology available today provide an accurate
                          description of the chemical and physical forms of mercury
                          introduced into the ambient air after the stack  emissions have
                          diluted and cooled to ambient temperatures?
                   7)     What is EPA's role in the development of mercury CEMs? What are
                          the roles of others (e.g., DOE, vendors, State, and local)?
                   8)     What actions or outcomes are required to move towards
                          implementing mercury CEMs for compliance assurance?

11:30  Lunch

Day 2 - Afternoon

1:00   Session 5 - State-of-the-Science in Ambient Air Monitoring (Robert Stevens/Gerald
       Keeler Session Chairs)

             International Monitoring/Measurement Activities  for Atmospheric Mercury (John
             Munthe, PhD,  Swedish Environmental Research Institute, Goteborg, Sweden - 20

             Source/Receptor Relationships for Mercury: Monitoring and Modeling - (Gerald
             Keeler, PhD, University of Michigan - 20 min)

             Manual Speciation Methods for Measuring Atmospheric Mercury:
             Applications/Implementation (Matthew Landis, PhD, US EPA, NERL - 20 min)
2:30  Session 5 - State-of-the-Science in Ambient Air Monitoring (Continued)

             Automated Mercury Speciation Methods and Demonstrations (Robert Stevens,
             State of Florida DEP - 30 min)

             Wet Deposition Sampling - Applications/Implementation (Timothy Dvonch, PhD,
             University of Michigan - 20 min)

            Atmospheric Wet Deposition of Mercury in North America (Clyde Sweet, PhD,
            Illinois State Water Survey -10 min)

3:30  Session 6 - Panel Discussion of Ambient Monitoring Needs (Robert Stevens/Carl
      Kamme Session Chairs)
                   Gerald Keeler-University of Michigan; Eric Prestbo-Frontier Geosciences;
                   John Munthe-Swedish Environmental Research Institute; Thomas
                   Atkeson-Florida DEP; Matthew Landis-US EPA, NERL; Clyde Sweet-
                   Illinois State Water Survey; Russell Bullock-US EPA, NERL
      Topics / Questions
                   1) What is the state-of-the-science in measurement methods?
                   2) What are the needs for representative and comparable data?
                   3) Do we need to expand the wet deposition and aerosol mercury
                   monitoring network and add additional atmospheric mercury
                   4) What are the needs for method standardization and ambient reference
                   5) Use of manual vs.  automated sampling techniques.
                   6) What are the needs for speciation?
                   7) What ambient and source inputs are needed for dispersion modeling?
                   8) What is EPA's role in the development of ambient monitoring
                   techniques? What is the role of other groups?
                   9) What does EPA need to do and when?

4:30  Summary and Concluding Remarks (Scott Hedges, US EPA, NRMRL)

4:45  Adjourn

 Workshop Purpose/Opening Remarks

 Presented on September 13,  1999 by Scott Hedges, US EPA, ORD, NRMRL

 Problem Statement
 This workshop was developed because mercury contamination, both nationally and internationally,
 has long been recognized as a growing problem for both humans and ecosystems.  Mercury is
 released to the environment from a variety of human (anthropogenic) sources including fossil-fuel
 combustors, incinerators, chlor-alkali plants, and landfills. Since this metal does not degrade to
 simpler compounds, once it is released to the environment, it will always be present in one form or

 The 1997 Mercury Study Report to Congress indicated that mercury deposition has increased by a
 factor of two to five over pre-industrial levels. In general, anthropogenic emissions constitute the
 most significant releases of mercury in the United States.  Emissions include fossil fuel combustion
 (containing trace amounts of mercury), municipal incineration, medical waste incineration, chlor-alkali
 plants, and landfills.  Other sources of anthropogenic mercury include industrial processes and the
 disposal of products containing mercury.  Additionally, most atmospherically-deposited mercury is
 in the form of gaseous or particulate-phase inorganic mercury. Unfortunately, inorganic mercury
 released into the environment can be converted, by naturally-occurring biological processes, into the
 highly toxic methyl mercury species.

 In order to assess and control future mercury emissions, improved emission estimates from major
 sources are needed, along with an improved understanding of the transport, transformation, and fate
 of the mercury emitted from these sources. As a result, accurate source emission and ambient air
 measurements of mercury species are needed to address these research requirements and to
 ensure compliance with regulations promulgated to reduce the impact of mercury contamination in
 the environment.

 Purpose of Mercury Monitoring Workshop
 In addition to providing  information on the latest developments in speciated and total mercury
 monitoring methods and instrumentation, this workshop was  designed to address monitoring
 research needs and data quality objectives for the EPA Program Offices (in particular the OSWand
the OAQPS) and Regional Offices, the international community, the DOE, the DOD, State agencies,
developers of monitoring equipment, and industry.

The workshop was broken down into six  sessions, including two  panel discussions on source
emission measurements and ambient air measurements, in support of these goals. Additionally, lists
of questions/issues were developed and forwarded to the participants prior to the meeting to'help
focus the panel discussions towards areas of particular interest to the workshop organizers (see
Panel Discussion Summaries for these questions). The panel discussions were intended to examine
points of controversy and develop consensus for future efforts.

Regulatory Perspective on Mercury Monitoring

Presented on September 13,  1999 by Fredric Chanania, US EPA, OSW

Mercury Monitoring
Mercury monitoring is of particular interest to the solid and hazardous waste industries. In general,
source emission monitoring techniques are used to assess treatment related issues, both within and
at the end of a treatment process. Ambient monitoring techniques, on the other hand, are frequently
used to support risk assessment efforts.

Ambient air monitoring can be divided into two categories: ambient air and ambient monitoring.
Ambient air measurements are used to examine post-stack transport and transformation issues (i.e.,
between the stack and the ultimate receptor), while ambient measurements are used to. address
receptor site transport and transformation issues (i.e., from uptake or bioaccumulation.to fish or
human receptors). Although OSW uses air quality control data from treatment processes to perform
ambient air risk assessments, most of its efforts  are focused  on ambient receptor site transport
issues (e.g., mercury transport within a water body) and mercury transformations associated with
uptake and bioaccumulation, including exposures to human and ecological receptors.

Monitoring Result Use
Monitoring results are used to:
      Set national regulatory standards (e.g.. treatment standards, stack emission limits,  and other
      regulatory limits) - After a national treatment standard is set, facilities typically have to comply
      with the standard following State adoption. Thermal burning is  usually regulated through
      stack emission limits/actions; hazardous waste site delisting petitions and other regulatory
      limits, however, are set by OSW.
      Develop methods - OSW develops methods which can be used to accurately and precisely
      measure mercury concentrations in different matrices.
      Assess  facility compliance -  Compliance with  the  standards is determined through
      monitoring, sampling, and analysis.

Mercury Monitoring of Thermal Waste Treatment Systems
Mercury monitoring data are often used to assess the performance of combustion or other thermal
treatment systems. Performance is frequently measured relative to compliance with the following:
stack emission standards, process monitoring OPLs; the Phase IMACT Combustion Rule, Boiler and
Industrial Furnace (BIF)  Regulations,  permit-specific OPLs,  and thermal desorber monitoring
requirements under Subpart X. Detailed discussions of process monitoring OPLs and the Phase I
MACT Combustion Rule include:

Process Monitoring OPLs - Process monitoring OPLs were developed  in response to high stack
emission testing and  compliance costs and can  be used to ensure that stack emissions meet
regulatory  limits.  OPL types include:
      Feedstream monitoring - When feedstream OPLs are used, it is assumed that almost none
      of the mercury entering the stack is captured within the system.  Thus, the feedstream data
      are used to set the outer boundaries for the unit.
      Combustion chamber conditions - Temperature and  other operating conditions in  the
      combustion chambers can  be controlled to reduce/control mercury emissions from certain
      regulated facilities.


       Performance parameters - Since many common Air Pollution Control Devices (APCDs) have
       difficulty capturing mercury, OPLs for APCD performance parameters are less likely to be

 Phase I MACT Combustion Rule - The Phase I MACT Combustion Rule was recently released for
 HWGs. This rule sets new stack emission limits for total mercury [i.e., 47 micrograms per dry
 standard cubic meter (ug/dscm)] for lightweight aggregate hazardous waste kilns, 120 ug/dscm for
 incinerators, and 130 ug/dscm for cement kilns].  Under this rule, facilities with cement kilns,
 incinerators, and low weight aggregate kilns will need to measure mercury concentrations in their
 feedstreams on a more continuous basis.  Facilities with wet scrubbers will also need to monitor for
 a host of system-related parameters on a semi-continuous basis (e.g., hourly or daily).  Facilities
 which use activated carbon injection or carbon beds to control mercury emissions will also need to
 monitor additional parameters related to these  APCDs.  Although approximately 80% of thermal
 facilities are not regulated under the MACT Rule, a new rule is just coming out which addresses non-
 hazardous waste cement kilns. Furthermore, the Commercial and Industrial Solid Waste Incinerator
 (CISWI) rule is approaching proposal.

 Mercury Monitoring of Non-Thermal Waste Treatment Systems
 Non-thermal waste treatment systems will need to monitor their residuals for compliance with the
 following total mercury concentration  standards:
       0.2 milligrams per liter (mg/L) Toxicity Characteristic Leachate Procedure (TCLP) for mercury
       retort nonwastewater
       0.025 mg/L TCLP for all mercury non-retort nonwastewaters
       0.15 mg/L for mercury wastewater
       10 times the universal treatment standard (UTS) for soils or 90% reduction.
 For these numerical standards, total mercury consists of non-speciated mercury obtained from the
 TCLP extraction. Also, there are no OPLs for non-thermal waste treatment systems and  the focus
 is primarily on the output of the treatment system (unlike thermal systems). Furthermore, facilities
 with "high mercury nonwastewaters with organics" typically use incineration /retorting, and facilities
 with "high  mercury inorganic wastewaters" typically use retorting only.

 Key Regulatory Drivers of the Future
 Future standards and regulations will most likely follow present patterns. Therefore, since mercury
 CEMs  will probably  not reach the final stages  of development for some time,  it  is unlikely that
 regulators will commit to developing  a proposal for CEMs in the near future. A Phase II MACT
 Combustion Rule for boilers and halogen acid furnaces, however, will probably be enacted. Finally,
 an Advance Notice  on Proposed Rulemaking  (ANPRM) and Notice on Proposed Rulemaking
 (NPRM) has been issued stating that EPA will be examining the mercury treatment standards for all
 non-thermal and applicable  thermal treatment systems.  This may have a significant impact on
 incineration and retorting systems.

 Implications for Mercury Monitoring
Although there is a policy preference for using continuous sampling and analysis methods, it is
 important to balance  a facility's need to control  monitoring costs against the regulator's need for
 certainty. The Agency must be able to justify continuous sampling and analysis from a "value added"
 perspective. In the future the Agency will also need to determine whether total  and/or speciated
 mercury measurements will  be used to monitor feedstreams (both process and  remedial), waste
treatment residuals (e.g., ash and sludges), and soils.

Within combustion systems, a cooperative effort may be needed to determine whether total or
speciated mercury measurements are more useful. Currently, total mercury measurements are used
to determine MACT compliance from the exit stack. During risk assessments, however, .emphasis
is often placed on obtaining speciated ambient measurements (e.g., methyl mercury). In the future,
EPA will need to determine whether speciated mercury monitoring should be done at the end of the
stack or only at the receptor site.  The Agency will also need to determine whether multiple metal or
mercury monitors are more sensible from a regulatory perspective. It currently appears that EPA
is leaning towards using multiple metal OEMs,  probably because they are more developed and
because many toxic metals other than mercury are already regulated.                     ,

 Need  for  Source   and   Ambient  Mercury  Measurement:   A
 Regulatory Perspective

 Presented on September 13,  1999 by William Maxwell, US EPA, OAQPS

 OEMs are needed to determine compliance with given regulations.  OEMs can also be used for
 control device evaluations, permit compliance, and to obtain data for models.

 A study of electric utility steam generating units for air toxics was mandated by Section 112(n)(1)(A)
 of the CAA. Under this Act, EPA must determine whether regulations are appropriate and necessary
 based on the results of the study. The final report to Congress was issued in February 1998. In this
 report, the hazardous air pollutant (HAP) of greatest concern was mercury from coal fired utilities
 The current due date for regulatory determination is December 15, 2000.  If the determination is
 positive, regulations must be proposed by November 2003 and promulgated by November 2004
 If mercury emission limits are established, CEMs are believed to be the Agency's preferred method
 of determining compliance, assuming they are available, cost effective, etc.

 There  are two types  of mercury CEMs: 1) units that measure total mercury; and 2) units that
 determine the oxidized fraction by the difference between elemental and total mercury.  Speciation
 is important to understanding and modeling dispersion, fate, deposition, and exposure potential of
 mercury. Speciated data will also help the Agency evaluate local, regional, and global impacts
 Further, speciated mercury data may also be beneficial for future risk analyses. Speciation data can
 also be used to evaluate up-front control devices; however, once controls are in place, control device
 evaluations or risk evaluations may no longer be needed.

 If total  mercury measurements are regulated, then it may be more appropriate to measure total
 mercury. For example, many electric utilities burn more than one type of coal. Since different types
 of coal emit different species of mercury at different concentrations, mandatory speciated monitoring
would not make sense for this industry from a regulatory standpoint.

 In addition to the utility industry, the following source categories also need to be considered'
       Municipal waste combustors - Although the current rule does  not include a mercury HAP
       CEM for MWCs, in part because no mercury HAP CEMs were  available when the rule was
       developed, it is possible mercury CEMs could be required under future revisions. It is also
       possible that the required controls may prove as expensive as incineration
       Medical waste  incinerators - Mercury HAP CEMs were not specified for medical waste
       incinerators in the  current HAP CEM rule and are not expected under future revisions due
      to cost considerations.
       Industrial/commercial  boilers - HAP rules have  not  been proposed for industrial and
      commercial boilers.
      Commercial/industrial incinerators - HAP rules have not been  proposed for industrial and
      commercial boilers, however, it is unlikely that mercury HAP CEMs will be specified in future
      rulings due to cost considerations.
      Chlor-alkali plants - Rules for chlor-alkali plants are still under development and the CEM
      requirement is unknown.
      Portland cement plants - Portland cement plants are still being disputed at this time and the
      litigation impacts are unknown.

At this time, total mercury CEMs appear to be the most likely candidate for compliance monitoring,
although many factors are still subject to change.  Total metal and speciated mercury CEMs are also
of interest, and there are reasons for having either one or both of these systems.  Regardless, a
working version of the selected technology is needed by mid-2001, at which time this unit needs to
be tested and compared to the manual methods.  A commercial-ready version is also needed by the
implementation deadline (i.e., within 3 years of promulgation or by November 2007). This leaves
approximately 6.5 years from when data gathering starts to when implementation needs to occur.

In November 1998, EPA issued an ICR which requires that:
       All coal-fired utility units analyze coal for mercury content for the calender year 1999
       Approximately 85 units are required to test for speciated mercury emissions using the Ontario
       Hydro Method
       All data are due to EPA by June 1, 2000.
The ICR data will be used to refine the mercury emissions estimates for utilities. These data will also
be combined with other inputs (e.g., health studies and control options) to inform the Administrator
for regulatory determination.

The Mercury Problem:  What Is It?

Presented on September 13, 1999 by Thomas Atkeson, Florida DEP

The mercury coordinator for Florida  DEP, Dr. Atkeson, noted that he has seen a lot of changes since
1.992. During this period, private, Federal, and State cooperation has contributed to the development
of a multimedia approach to the mercury problem. Over the next 5 years, however, Dr. Atkeson
expects advances to occur that will  allow concerned parties to understand the mercury problem on
its various spatial scales and move toward control.

What Is It?
Mercury is the quintessential multimedia problem, affecting air, water, and soil.  Global and regional
emissions cycles are the primary transport mechanisms of mercury into most fresh waters. The
aquatic cycling of mercury is also  crucial to the "expression" of the mercury  problem.  Although
inorganic mercury inputs have  little consequence by themselves, when mercury is converted to
methyl mercury it is frequently "biomagnified" in the aquatic food chains, to the point at which both
humans and ecological resources are at risk. To effectively address the mercury problem, all three
aspects of the problem need to  be dealt with.

The discovery of high levels of  mercury in the Everglades helped focus attention on the mercury
issue in Florida. Lower concentrations of mercury  in the coastal waters  and rivers and lakes
throughout the State are also problematic. Although Florida's monitoring efforts have been thorough,
a lot of "in-fill" is still needed to form a more accurate  picture of mercury contamination throughout
the State. Although Florida was  the first Southern State to describe the mercury problem, since then
many other States in the South (specifically, the Southern Coastal Plain) have also recognized their
mercury problems.

Is It Natural?                                                           ,            .
When Florida first found high mercury levels in Everglades fish this contamination was initially
attributed  to naturally  occurring  sources (e.g., peat soils),  mainly because there  were no
anthropogenic point sources in the Everglades, Core study results from 1990, however, showed that
the rate of mercury accumulation in  Everglade soils had increased approximately 500% since 1900.
This sharp rise in mercury deposition has been attributed to increased anthropogenic emissions to
the atmosphere.                           ,  ,         V

Where Does the Mercury Come From?
Once it is determined that increased levels are human-induced, it is necessary to determine where
the contamination originated.  This is a difficult issue to address, since there are three components
to the atmospheric mercury cycle (global, regional, and local). Efforts are further hampered by an
early general disinterest in monitoring and controlling mercury emissions. This can be attributed in
part to the lack of political  or legal mechanisms to control/reduce global emissions. With time,
however, the scientific and regulatory community realized that mercury is not just a global problem
and that local, State, and national efforts to reduce emission sources have a significant impact on
levels within the US

Mercury operates on three different spatial scales (global, regional, and local).  Global impacts are
generally associated with elemental mercury entering an area from an unknown, outside source.
In addition to being relatively inert, elemental mercury has a long atmospheric residence time and


circles the globe to average out to a fairly even background level. At the local level (100 kilometers
of a source) and regional (1,000 kilometers of a source) level, however, speciated mercury forms
drive the deposition patterns.  For example, the majority of RGM or mercury(ll) emissions are
generally deposited locally, while fine particle-phase mercury emissions are deposited both locally
and regionally. Therefore, in order to understand where mercury contamination is originating, the
scientific and regulatory community needs to understand the nature of the sources, both locally and
regionally, as well as the global impact. Good speciation data from a wide variety of sources (e.g.,
CEM data) are essential to understanding the atmospheric mercury cycle and selecting appropriate

After several years of surface water monitoring, Florida was surprised to note that global, regional,
and local atmospheric mercury inputs  (the total atmospheric mercury budget) to water sources
accounted for almost 20 times as much mercury (125 to 150 kilograms per year) as surface water
inputs (4 to 6 kilograms per year). It is anticipated that this factor will grow to 30 to 50 times  once
scientists develop the ability to factor dry deposition into atmospheric estimates. Florida is currently
trying to determine: 1) what proportion of the atmospheric budget is originating from different local
and regional sources; and 2) how vigorously it can practically control these emissions to reduce
deposition.  Florida also needs  to account, for global impacts, since global inputs  to coastal
environments can be significant.

Speciation data obtained by EPA and the University of Michigan during a regional transport modeling
pilot study in 1995 were then presented for four different types of sources.  According to the results
of this study, oxidized mercury emissions [observed as mercury(ll)] from a cement kiln, a large.
regional medical waste incinerator, a municipal incinerator, and a coal-fired utility boiler averaged
254%, 955%, 785%, and 6727%, respectively, over several runs.  Since many medical waste
incinerators have low stack heights and low exit velocities, the majority of the oxidized mercury from
the medical waste.incinerator was probably deposited near the source (i.e., in the Everglades).
Furthermore, since South Florida  has the highest per capita reliance on MWCs compared to other
States, the high percentage (approximately 80%) obtained during the study for the MWC may call
for a reassessment of the effect of these facilities on the Florida Everglades.

The Southern Florida Mercury Science Program is also focusing a significant portion of its research
efforts toward the following:
      Atmospheric source apportionment - To include atmospheric chemistry and measurement
      techniques; the  Regional  Transport & Deposition Model; an EPA/DEP "Super Site" for
      intensive  measurements;  EPA/National  Oceanic and Atmospheric Association (NOAA)
      airborne measurements; and a EPA/DEP 3rd Generation Regional Transport and Deposition
     Bioaccumulation  in the aquatic food chain - Methyl mercury levels in  Everglade fish are
      typically seven orders of magnitude above the average water concentration of 100 to 200
      parts per quadrillion. This presents risks to wading birds and panthers.
     Aquatic cycling - To include cycling processes research and the development of the Mercury
      Cycling Model.                                                           .......

The CEC and the Development of NARAPs on Mercury in  the
North American Environment

Presented on September 13, 1999 by Andrew Hamilton, CEC

Two new North American institutions have been established: the North American Agreement on
Environmental Cooperation (NAAEC) and the CEC. The CEC was established in 1994 under the
NAAEC, which was negotiated by the governments of Canada, Mexico, and the United States as a
parallel side agreement to  North American Free Trade Agreement (NAFTA).  The top three
objectives of the NAAEC are to: "a) foster the protection and improvement of the environment in the
territories of the parties for the well being of present and future generations; b) promote sustainable
development based on cooperation and mutually supportive environmental and economic policies;
and c) increase cooperation between  the  parties to better conserve, protect and enhance the
environment, including wild flora and fauna."

The CEC is made  up  of three parts: the  Council, Joint Public Advisory Committee, and the
Secretariat.  The Council consists of cabinet level appointees and acts as the governing body. The
Joint Public Advisory Committee advises the council and is made up of five representatives of each
country. The third component is the Secretariat, which is staffed by representatives of each country
and carries out the work on behalf of the Commission.

The Sound  Management  of Chemicals Initiative (SMOC) is  a major program established  under
Council Resolution 95-05.  SMOC established a framework for cooperation in addressing chemical
pollution in  North America.  The resolution established  a  working group made up of senior
government officials to work with the CEC to implement the decisions and commitments contained
in the resolution. Council Resolution  95-05 deals mainly with persistent bioaccumulative toxic
substances  (PBTS). The Working Group, in consultation with the Secretariat, initially selected four
chemicals [i.e., mercury, dichlorodiphenyltrichloroethane  (DDT), chlordane, and polychlorinated
biphenyls (PCBs)] and established Implementation Task Forces for each. These task forces oversee
the implementation of a NARAP. Additionally, the Substance Selection Task Force was established,
which  oversees the implementation of the process for identifying candidate substances for regional
action under the SMOC initiative.

The substance selection process involves three major steps. Stage I is the nomination stage, during
which governments nominate additional chemicals to the Working Group for inclusion as PBTS. The
evaluation stage, or Stage II,  has two steps: the screening evaluation and the mutual concern
evaluation.  Stage III is the discussion/decision stage.  In this stage, the Working Group prepares
recommendations to ministers for preparation of a NARAP.  Beginning this year, the Substance
Selection Task Force is looking to develop a NARAP for dioxin/furans and hexachlorobenzene over
the next 2 years.

Article 13 of the NAAEC allows the Secretariat to prepare a report on any matter within the general
scope of the annual work plan or, in most instances, within the  scope of the Agreement.  The
Continental  Pollution Pathways Report was developed under Article 13 and is a public document
containing a mercury case study. The report emphasizes that pathway issues are a cross-media
issue (air, land, water, and biota) and that integrated approaches are required. Also, the Air Issues
Program has evolved out of the Continental Pollution Pathways Initiative.

There were two Council Resolutions in 1999.  The first was #99-01, developing a NARAP on
dioxins/furans and hexachlorobenzene.   The second was #99-02, developing a NARAP on
environmental monitoring and assessment.

A concept paper was also developed defining the monitoring program.  Among other things, this
paper discussed  having monitoring  and long-term  ecological  research experts review draft
documents and provide input on monitoring efforts in North America which could be useful for the

The Phase I NARAP on mercury was approved in October 1997. Phase II is currently out for public
review and comment and formal governmental approval is expected in early 2000.

Key elements of the NARAP on environmental monitoring and assessment include: 1) to promote
more  and better collaboration among the parties; and 2) to facilitate effective and  sustained
trinational cooperation in generating adequate, comparable, and continuing data. At the heart of
NARAP is the commitment to develop a coherent system of index and/or reference sites for the three
countries. This system would provide pertinent monitoring and assessment data.  Sampling
protocols are also needed to improve the comparability of methods and procedures applicable to
quality assurance/quality control (QA/QC) and data assessment.

 Mercury Modeling and Measurements and Their Source Control

 Presented on September 13, 1999 by Russell Bullock, US EPA, NERL

 Mr. Bullock asked the audience a broad question "What makes mercury so special?" Or, in other
 words, "Why is mercury getting so much more attention than arsenic?" He then answered this
 question by providing the following information about mercury.
       Mercury has a predominant gaseous fraction in the atmosphere; other atmospheric metals
       are found almost exclusively in the atmosphere as solid aerosols.
       Mercury has  a wide variation in water solubility depending on its chemical form. Also
       mercury's wet deposition efficiency depends on its physical and chemical state. Other metals
       are all effectively wet-scavenged as aerosols.  (Note: Since chemical form has a large impact
       on solubility and other factors, speciated measurements are very important, particularly as
       inputs to models designed to improve our understanding of the mercury cycle.)
       Mercury is mostly found in the atmosphere in its elemental state whereas other atmospheric
       metals are almost always found as compounds.
       Mercury must convert to a methylated form and bio-accumulate in the food chain in order to
       become a serious  human  health risk.   Even though researchers and scientists see the
       atmosphere as the first step in the transport of this toxic substance to areas of damage, they
       need to understand how damage occurs within an ecosystem to really understand the human
       health effects.

 Global atmospheric mercury speciation averages were then presented. Based on these averages,
 approximately 98% of mercury is found in the gaseous state; greater than 90% of this gaseous
 fraction as elemental mercury and the remainder as mercury(ll) compounds (e.g., mercuric chloride
 and other compounds with high vapor pressures). The remaining 2% of mercury associated with
 aerosol particulate matter (presumably mercuric sulfides, mercuric oxides, and other compounds with
 low vapor pressure)  or more volatile mercury(ll)  compounds sorbed to ambient aerosols in the
 atmosphere. Based on this information, it is reasonable to conclude that mercury that is released
 as gaseous mercury compounds can later  be sorbed to  pre-existing particulate aerosols.
 Furthermore, particulate mercury may represent more than 2% of the total atmospheric mercury
 burden in industrial and urban areas.  There is also very little information regarding the oxidation
 state of atmospheric mercury at higher altitudes.

 Mr. Bullock then discussed the mercury emissions inventory used in Regional Langrangian Model
Air Pollution (RELMAP) modeling for the Mercury Study  Report to Congress.   Speciation
 percentages for elemental mercury, mercury(ll), and particulate mercury were: 50%, 30%, and 20%,
 respectively, for electric utility boilers (coal, oil, and gas) and 58%, 20%, and 22%, respectively, for
 HWCs. Speciation percentages were also presented for a number of different source types (e.g.,
 MWCs, commercial and industrial boilers, residential boilers, chlor-alkali factories, Portland cement
facilities, pulp and paper plants, sewage sludge incinerators, areas sources, and other point
sources). The  percentages for HWCs were based on plant-specific  emission rates for elemental
 mercury, mercury(ll), and particulate mercury.  All other percentages presented were based on
modeling assumptions.

Mr. Bullock  then discussed simulation of the deposition of elemental mercury gas and divalent

mercury gas in the US.  After noting that elemental mercury gas emissions are roughly distributed
across the US according to population,  Mr. Bullock then noted that simulated wet deposition for
elemental mercury from US sources was extremely low, less than or equal to 1 microgram per
square meter per year (ug/rrfYyr) across the US.  Furthermore, divalent mercury gas emissions were
also distributed across the US according to population, though there were some rural areas with
higher levels due  to large combustion sources in these areas (i.e., coal fired boilers or HWCs).
Simulated wet deposition levels of divalent mercury gas in the US were extremely high relative to
elemental mercury wet deposition.  .

The annual mercury mass budget (in metric tons) published in the EPA's Mercury Study Report to
Congress was then  presented, including total elemental mercury, mercury(ll), and particulate
mercury deposition across continental US. These results were generated using a 1-year RELMAP
simulation.   According to these results, almost all measured  anthropogenic elemental mercury
emissions (62.3 of 63.5 metric tons) were transported out of the model domain by the wind without
depositing to the surface.  But, for the mercury(ll) in gas form, only about 15.5 of 52.3 metric tons
emitted left the model domain without depositing within the continental US. However, the methods
used to model dry deposition of gaseous mercury(ll) may have been too simple since there are
currently no operational methods to directly measure this phenomenon over vegetated land surfaces.

Vapor pressure and water solubility constitute the  primary differences  between mercury species.
For elemental mercury and mercuric chloride, the vapor pressures are high enough at atmospheric
conditions for gas formation. Furthermore, only a limited amount of atmospheric modeling has been
done on methyl mercury due to certain chemical and photolytic reactions that are assumed to quickly
degrade this species back to the elemental form. This may change,  however, if extreme levels of
methyl mercury emissions and/or ambient concentrations are found in the future.

After briefly discussing the global mercury cycle, Mr. Bullock noted how the quality work done by
schematic developers over the last 5 years has shown that there is much more to tell in the story.
In addition to chemical reactions in plumes from natural sources (e.g., volcanos), researchers and
scientists are just now starting to understand species deposition on trees, vegetation, and wetlands.
It is now also known that this mercury is primarily re-emitted as elemental mercury and that there are
more  gaseous reactions and heterogeneous  reactions dealing with gas  to particle chemistry.
Aqueous chemistry  also needs to be  better understood, especially what happens to mercury in
various types  of  cloud formations.  Mr. Bullock then presented several  cloud-water oxidation
reactions involving mercury (ozone, photochemical, and especially over oceans by chlorine) and
several cloud-water reduction reactions [by sulfur (IV), photoreduction, and by the hydroperoxyl

Mr. Bullock  concluded  with another question,  "What does  all  this mean?" He explained that if
significant oxidation  of elemental mercury is occurring in the gas and/or aqueous phases then all
forms of mercury in air emissions must be controlled to reduce atmospheric deposition from wet and
dry processes. If significant reduction of mercury compounds to the elemental form is occurring in
cloud water, then the scientific community must be underestimating the  rate of emission of reactive
oxidized mercury, since observed mercury wet  deposition rates are too large to be from elemental
mercury  scavenging alone.  If  a  strong reduction/oxidation  equilibrium is  maintained by all
atmospheric processes, then the control of all forms of mercury is equally important.  And lastly,  if
chemical reactions of mercury in air and cloud water are generally slow and insignificant, then control
of ROM and particulate mercury is warranted  and life  would become  much easier for numerical


 Measurements To Evaluate Emissions Controls for Utilities

 Presented on September 13, 1999 by Thomas Brown, DOE,  NETL, formerly
 Mr.  Brown began his presentation with  by verbally illustrating the difficulties  associated with
 measuring mercury in coal fired flue gas.  He asked his audience to imagine a 250,000-mile-long
 pipeline extending from the moon to the earth.  If this pipeline contained flue gas from coal-fired
 power plants, the "plug" of mercury representative of its concentration in power plants would only be
 18 inches long. As expected, the measurement of these low concentration emissions,  normally 1
 part per billion by volume (ppbv) in flue gas, have proven difficult.  Measurement efforts  have been
 further complicated by the need to measure mercury speciation, defined as total speciation of ionic
 or oxidized, or non-elemental mercury that is somewhat soluble in water or in media in coal fired

 Most US coals have mercury concentrations that range  from 20 to 120 parts per billion by weight
 (ppbw), although some coals range from 200 and 300 ppbw. The ratio of vapor-phase  elemental
 mercury to oxidized mercury varies from 10:90 with a nominal 70:30. This ratio is dependent on the
 coal type and interactions between  the  solid- and vapor-phase constituents in  the flue gas.
 Thermochemical equilibrium calculations have been used to predict the mercury species resulting
 from the combustion of different ranks of coals.  These equations  incorrectly predict that post-
 combustion mercury will most likely be present as mercuric chloride and as elemental mercury at
 higher temperatures for bituminous and subbituminous coals. Field sampling results were used to
 develop the following percentages for mercury(ll) in three ranks of coal: 70 to 88% in bituminous
 coal,  15  to 50%  in Powder River Basin (PRB)/subbituminous  coal, and 30% in lignite  coal.
 Furthermore, gas-phase equilibrium for mercury-containing species is not valid in coal-fired systems

 Research has indicated that mercury oxidation is influenced by interactions between the solid and
 vapor-phase constituents in the flue gas. Mr. Brown then discussed the mechanisms involved  in the
 oxidation  of mercury.  If coal combustion  is tracked  from the lump, through  combustion, to
 vaporization,  and then  to conversion  or to ash  formation, the  distribution does not follow
 thermodynamic equilibrium. There are various species of mercury formed but there are no methods
 to measure them other than by measuring  the distribution between elemental and oxidized forms.

 Mr. Brown then discussed a "typical" air  pollution control system for coal-fired  utilities.  These
 systems  typically  consist of a boiler, followed by a particulate removal system [electrostatic
 precipitator (ESP), baghouse, cyclones, etc.], a flue gas desulfurization (FGD) system (wet or dry),
 and a stack.  When operating these systems, it is very important to know the configuration of the
 boiler, the rank of the coal, and the chlorine, sulfur, trace metal, and mercury contents both before
 and after the coal is cleaned and between the boiler and the particulate removal. Approximately 65%
 of industry only use an ESP for particulate  removal. Ten percent instead use a baghouse and the
 remaining 25-30% use a FGD system (95% of which are wet).  Mercury distribution  and the amount
 of control across  each  system varies. Furthermore, based on Method 29 data, the highest
 reductions were found using wet FGD (90%) systems.

A comparison between Method 29 and the Ontario Hydro Method at the inlet and outlet of a wet FGD
 scrubber indicated comparable total mercury results. Outlet elemental mercury concentrations
 obtained  using Method 29 were significantly higher than similarly measured inlet  concentrations.


This can be attributed to the sulfur dioxide in peroxide impingers, resulting in an pverestimation of
the oxidized form.  Both of these methods also show that mercury is oxidized across the FGD

The following collaborative efforts for "Mercury Method Development" were then noted:
       Development and validation of mercury speciation methods for coal-fired utilities, in part to
       address inconsistency issues.
       DOE/Electric Power Research Institute (EPRI) funded a 2-year, 3 million dollar program with
       the University of North Dakota EERC to develop this method.
       The Ontario Hydro Method has been validated at the pilot-scale and full-scale level and the
       protocol is being finalized through ASTM.
       EPA is  also on the advisory team and  ASTM committee to recommend the method as a
       standard for utility flue gas.
       Ontario Hydro is the method of choice for EPA's ICR.
       Coal-fired utilities are required to report coal mercury concentrations and approximately 85
       power plants are required to report mercury speciation and emissions by June 2000. This
       will help provide information for the database  and will help to develop more accurate
       emission modification factors for field control equipment.

Sampling study data for six facilities over 2 years were then discussed. All six facilities used wet
scrubbers and similar coal ranks. The data showed that the elemental mercury was approximately
the same in the inlet as the outlet except for 8 to 20% which measured an increase. This increase
could be due to the control system, measurement errors, or off-gassing.  In the six plants, an average
of 60 to 70% of the total mercury was removed and 80 to 90% of the oxidized mercury was removed.
It can be assumed from these results that most scrubbed plants do remove the oxidized mercury that
would otherwise be put into the environment.

In facilities using Western coal with no enhancement to the removal process, as the temperature,
loss on ignition (LOI),  and carbon content increased, so did mercury's affinity for capture.  The
efficiency of various power plant operations strategies for the removal of oxidized and elemental
mercury indicate the following:
       Coal cleaning operations remove a median of 37% of the elemental mercury and an unknown
       amount of oxidized mercury
       ESP systems remove a median of 15% of the oxidized mercury and 15/30% of the elemental
       Fabric filters remove a median of 30%  of the oxidized mercury and 65% of the elemental
       Scrubbers remove a median of 55% of the oxidized mercury and unknown amount of the
       elemental mercury
       Spray dryers remove a median of 60% of the oxidized mercury and 60% of the elemental
       mercury.                        ,     ;
These  ranges are heavily affected by coal ranks.

Mr. Brown  concluded with a  brief discussion of a novel mercury control operation that uses
nonactivated carbon up front.

 Process Monitoring in  DOE  Mixed  Waste Thermal Treatment

 Presented on September 13, 1999 by Stephen Priebe, Bechtel B&W Idaho,
 (Contractor for DOE, INEEL)

 Dr. Priebe's discussion included the goals of process monitoring, a description of DOE mixed wastes,
 types of DOE treatment systems, DOE monitoring concerns, and raised the question regarding how
 monitoring can be used to overcome barriers.

 Goals of Process Monitoring
 The goals of DOE's process monitoring are simple and not unique.  They are simply to demonstrate
 the control of mercury emissions to below recent and/or future MACT requirements, and to ensure
 compliance with the regulatory limits and the demands of public stakeholders.

 DOE Mixed Waste
 DOE mixed waste is a combination of hazardous and radioactive wastes. As a result, it is regulated
 by both EPA and the Nuclear Regulatory Commission.  Since EPA and the Nuclear Regulatory
 Commission sometimes have mutually exclusive requirements, management of these wastes can
 be complicated. Since DOE is not able to select which requirements it would like to meet, DOE must
 meet them all.

 DOE waste is the legacy of 40 years of nuclear weapons production. It is present at almost 50 sites
 distributed across numerous  congressional districts.   DOE  waste often contains Resource
 Conservation and Recovery Act (RCRA) pollutants, Toxic Substances Control Act (TSCA) pollutants,
 and/or radionuclides; however, the dominating pollutant (from a regulatory perspective) depends on
 the type of waste. This waste is frequently very heterogeneous and often is not well characterized.
 Since DOE first began storing this waste in the 1940s, storage has been inconsistent (e.g., in barrels
 or drums, above ground or below ground). Furthermore, since mercury is nearly ubiquitous in these
 wastes, they are automatically assumed to contain mercury, whether it is actually present or not.

 DOE Treatment Systems
 DOE has a variety of thermal treatment systems, including a high-level liquid waste calciner located
 in Idaho and incinerators located in Oak Ridge, Tennessee; Savannah River, South Carolina;  and
 Idaho.  There are also steam reformers and various joule-heated and plasma melters. All of these
systems have the potential to volatilize  mercury.

 DOE Monitoring Concerns
 Even though  tests have shown mercury reductions of 5 to 95%,  concerns regarding monitoring
 inaccuracies force DOE to assume that all the mercury in the waste is emitted in the offgas (i.e., no
control). Furthermore, compliance is based on comprehensive testing and limiting  the waste feed
to 0.5 to 2 parts per million  (ppm) mercury (under new MACT incineration rules). This will be difficult
to achieve, since accurate analysis of mercury to ppm levels is  extremely hard  to obtain,  and
sampling and analysis of the waste feed is very expensive.  Also,  in addition to being expensive,
waste feed sampling and  analysis increase the risk of personnel  exposure to radionuclides.  To
address risk  concerns, DOE operates under a system called ALARA (as low as reasonably

achievable). Unfortunately, worker safety can be difficult to guarantee since the wastes often have
to be sorted by hand.

DOE Monitoring Uses
DOE could use monitoring technologies for waste feed characterizations (to non-intrusively monitor
"what's going in") or for offgas characterizations (to measure "what's coming out").  Ideally, feed
characterization will replace sampling  and  analysis, which is often costly, time consuming, and
unacceptable to the public. These systems must be capable of non-intrusively monitoring liquid and
containerized solid waste so that the waste  can be monitored without having to be taken out of its
containers. Currently, systems are being developed which use gamma ray activation; these systems
have  been successfully tested at the 100 ppm  range  on  homogenous waste.  Unfortunately,
however, these units have problems with consistency and can currently only be used to analyze
streams with uniformly distributed concentrations.

It is  possible that the new  rules  may  support replacing feed  characterization  with offgas
characterization for compliance. This technology could show some mercury removal from offgas in
lieu of control technology.  In other words, it may allow for mercury control without using a mercury
control technology.  It may also improve the performance of the control technology. Stakeholder
assurance is  also an area of primary current focus.  For example, when a new waste treatment
facility was proposed in Idaho, residents from Jackson, Wyoming (100 miles away) called for the
Idaho facility to hold public meetings across the border in Jackson.  When Idaho DEP refused, the
residents of Jackson sued the Idaho DEP, halting  progress on the new facility.

Barriers to Implementation
Current barriers to implementation include  an uncertain  future for DOE facilities. Even though a
facility is currently being built, there are other facilities that EPA says should not even be opened.
Since the baseline changes so frequently, facilities are unsure whether they will be operating 5 years
from now.

There is also no regulatory driver to install and operate monitoring technologies at facilities. EPA is
not requiring facilities to use these technologies. Facilities are also fearful that CEMs will eventually
be tied to waste feed cutoffs and that their systems could be shut down if these are ever exceeded.
CEM  use is also hindered by the lack of demonstrated performance in the US,  although there have
been a number of applications in Europe. As is often the case with limited government budgets, cost
is a major issue and taxpayers are not willing to spend the extra  money for these systems.  There
are also significant reliability and maintenance issues.

Dr. Priebe ended his presentation by discussing his desires for the future, including testing CEMs
at operating facilities.  DOE has tested a CEM in Oak Ridge and, if the funding is approved, DOE
plans to perform  a longer test (4 to 8 months) at an incinerator in Oak Ridge, Tennessee next year.
Dr. Priebe would also like to work with: 1) EPA to  define specific performance goals and levels of
acceptability;  and 2) permitters to develop a phased approach to implement operation.

 Manual Methods for Measuring Total and Speciated Mercury

 Presented  on September  13,  1999  by  John  Bosch,  US  EPA,  OAQPS
 Emissions Measurements Center (EMG)

 Mr. Bosch's presentation was divided into two parts.  The first part discussed EMC's impact on
 mercury monitoring methods and programs, namely "who they are, what they do, and why they do
 what they do." The second half discussed the manual methods for measuring mercury and their

 EMC  is  in the  business  of  approving emission measurement  methods and  performance
 specifications for regulatory purposes. Although many of the local, State, and regional regulatory
 and permitting agencies negotiate their own emission  methods, performance specifications, etc,
 EMC is often asked to approve, certify, and/or review the methods, technologies, or performance
 specifications implemented  by  these agencies to comply with State/Federal regulations and to
 address permitting authority questions. (Note: Periodic monitoring requirements are responsible for
 50 to 80% of the difficulties/decisions associated with the permitting process.)

 EMC is located within the Emissions Monitoring and Analysis Division of OAQPS. EMC's "sister
 groups" within Emissions Monitoring and Analysis Division focus on emission inventories, ambient
 air monitoring, and modeling. These organizations are tasked with approving nationwide processes
 for modeling or strategy development (e.g., AP 42) based on research obtained from a variety of
 internal and external sources.  Furthermore, many of the models discussed thus far come from
 research developed through the modeling group. The ambient monitoring group is responsible for
 defining  approximately  8 million dollars of ambient monitoring  of toxics throughout the States, 5
 million of which is scheduled to occur this year.  Individuals with suggestions regarding "what needs
 to be done, where, and when" were encouraged to contact the monitoring group and those interested
 in formulating emission factors were encouraged to contact program representatives in the early
 planning stages so that the factors can be added, for example, as an approved method for emission

 EMC performs a number of functions. The EMC group conducts testing on a number of source
 categories in order to obtain data that regulators can use to develop standards and requirements.
 it also advises the regulators on available compliance monitoring techniques and technologies. EMC
 also develops new emission methods and performance specifications although, in the future, it plans
 to concentrate on fostering advances in emission monitoring technologies through collaborative
 efforts with the DOD, academia, and grant programs. EMC has official authority, delegated by the
Administrator, to approve new methods and emission monitoring performance specifications.  This
 authority interfaces with other programs,  such as EPA's  ETV Program and DOD's Inductively
 Coupled Argon Plasma  (ICAP) Program.

 EMC's primary customers are the emissions Standard Division within OAQPS (which is responsible
for developing the regulations), OSW, the Office of Enforcement and Compliance Assurance, and
 State and local permitting authorities.  EMC engineers are also working on the ASTM committee for
ASTM Test Method D  22-03, which  addresses ambient and emissions monitoring.  Whenever
 possible, EMC approves ASTM methods for use in compliance monitoring for Federal and State

environmental regulations. In fact, ASTM methods for opacity, electrical chemical monitoring, NOx
monitoring, etc., have already been incorporated in EMC regulations.

Mr. Bosch encouraged those developing new emission monitoring methods or technologies and
seeking EPA approvals in the future to get EMC involved early in the approval process (i.e., during
test plan development).

Manual Methods for Measuring Total and Speciated Mercury
EPA currently employs four manual methods for measuring mercury: Methods 29, 101, 101A, and
102 for measuring total mercury and the Ontario Hydro Method (draft) for measuring speciated
mercury.  Method 101A was specifically developed for NESHAP in 1991  to measure mercury at
sewage sludge incinerators.  In contrast, Method 29, which measures multiple metals and mercury,
was revised from an  existing method (i.e., Method 5) in 1996.  The Ontario Hydro method was
developed outside EPA for coal fired sources and is used primarily for the ICR project. Once this
method is approved by ASTM, it could be incorporated by reference by EPA as an approved manual
method for measuring speciated mercury. All of these methods are available on the EMC website
atwww.epa.gov/ttn/emc.  (Note: EMC is amenable to modifying any of its methods or performance
specifications, assuming it agrees with the intent of the change and is involved in the process of
designing and implementing the changes.)

After noting that all of these methods employ CVAAS and are  extractive and isokinetic with stack
traverse, EPA Method 29, EPA Method 101 A, and Ontario Hydro Method sampling trains were briefly
discussed. Mr. Bosch then noted that detailed instructions of the various components/steps in these
trains are available on the EMC website.

Mr. Bosch closed by noting that a significant amount of work and funding has been invested in
developing and testing the Ontario Hydro Method. Although this method is not perfect, there is much
information available on how well it performs including significant quantities of field test data. Since
this method is only applicable to coal-fired power plants, field testing and validation testing would
need to be performed before EMC could approve using this method for other source types.

CEMs for Measuring Total and Speciated Mercury

Presented on September 13, 1999 by Nina Bergan French, Sky+ Inc.

Dr. French began by briefly listing the following topics to be discussed during her presentation:
advantages of mercury CEMs; who makes them; how they work; how to use them; characteristics
of speciating mercury CEMs; GEM cost/benefits (and how to put a dollar value next to a facility's
decision to utilize a CEM); how mercury emission CEMs compare to multimedia CEMs; and how a
facility and EPA can work together to implement these systems

Advantages of Mercury CEMs
The advantages of mercury CEMs include:
       Real-time emission data
       Direct pollutant measurements
       Less reliance on waste feed characterization
       Operational data for system optimization.

Who Makes Them
Currently six European vendors (mostly German) offer commercially available mercury CEMs. These
vendors include: Seefelder Messtechnik; Sick Instruments  (which  has taken over  Perkin
Elmer/Bodenseewerk); Opsis, Inc; Semech Metallurgy AB; Verewa (i.e., Durag); and PS Analytical.
Several CEMs are also currently under development including a microwave-based technology for
coal fired utilities from Princeton Plasma Physics Lab and a surface acoustic wave sensor technique
from Sensor Research and Development, Inc. Tennessee Valley Authority and ADA Technologies
are also developing CEMs, however, these companies are not currently funded.  Finally, Techran
has an ambient monitor which could possibly be used as a CEM.

How They Work
In general, CEMs can be distinguished by the detection systems used to measure mercury. These
methods include: CVAA: in-situ UVDOAS; AES; and LIFS for multiple metals. Although the majority
of detection systems employ CVAA, this method only measures elemental mercury and is relatively
expensive.  Also, since many systems (e.g., CVAA) can only measure elemental mercury, a
conversion step may also be needed to convert the speciated mercury (which has already been
separated from interferences) into elemental mercury. In addition to wet chemistry, dry chemistry
or thermal cracking can be used to convert the mercury. Although wet chemistry methods are
currently more common, Dr. French believes that thermal cracking methods are the "wave of the

How To Use Them
The following steps need to be followed to use a mercury CEM:
      Get the sample
      Convert sample to elemental mercury
      Separate vapor from particles
      Separate elemental mercury from other vapors (e.g., using a gold trap)
      Desorb elemental mercury from gold trap (e.g., using a thermal desorber)
      Detect elemental mercury
      Calibrate the detector and reactor.

This process is complicated by the fact that CEM developers rarely use the same combination of
separating, converting, and measuring subsystems.

Speciatinq OEMs
When addressing the question "What is a speciating mercury CEM?", it is important to note the
confusion over the term "speciating".  According to Dr. French, speciating CEMs  "measure" the
difference between elemental mercury and total mercury (i.e., the difference in the amount of total
mercury that is not elemental).  Since most mercury CEMs only measure total mercury, a conversion
step must be used to change non-elemental mercury to elemental mercury, if the detector used in
the CEM can only measure elemental mercury. As a result, measurements must be taken before
and after the conversion step in order to be able to calculate the difference between elemental and
total mercury.

The need for speciating mercury CEMs was then questioned. It is assumed that these units will be
based on mass-spectrometry methods or laser-based techniques (e.g., photo-dissociation and
fluorescence). As a result, they will probably be expensive, complicated, time-consuming to operate,
and pose a high technical risk.  Furthermore, before proceeding with development, it is important to
first determine whether real-time chemical speciation data are needed.  To do this,  scientists,
engineers,  and regulators need to address the following questions/issues:
       Is chemical speciation  a transient phenomena and does speciation  change with  time?
       Do emissions vary with facility conditions (feed, temperature, pressure, etc.)?
       Can chemical speciation be inferred from "sample-and-analyze data"? Is it possible to infer
       these data by coupling total speciating monitors with Ontario Hydro Method data?
       Is it worth the cost/development time?

CEM  Performance
The following sources of CEM performance data were then identified:
       1997 DOE/EPA mercury CEM long-term test
       1997 DOE/EPRI mercury CEM tests at the University of North  Dakota EERC
       European TUV certification test results (five CEMs have been tested thus far)
       European field installation data
      Direct discussions with vendors.

Based on the TUV certification tests, Sick Instrument's CEM (MERCEM) appears closest to meeting
US performance  requirements.  Unfortunately,  however, this system is complex (it uses a wet
conversion system) and is expensive to operate. Ideally, simpler and less expensive alternatives
which utilize dry conversion chemistry and other relatively simple techniques [e.g., batch X-ray
fluorescence (XRF) or simple AES] need to  be developed.   In fact, a  number of companies
(Seefelder Mebtechnik  and others) have already replaced their wet chemistry conversion systems
with dry chemistry processes.  Furthermore, SRI International has also developed a "2-laser in-situ
system" which measures particle/vapor partitioning and concentrations in the part per trillion (ppt)

Dr. French then provided the results of a cost/benefit analysis for facilities that voluntarily implement
CEMs. Based on this analysis, these facilities could realize a total cost/benefit of 70 million dollars
 on an annualized basis, not including savings associated with improved public relations and reduced
 lawsuits.   These gains were associated with  reduced  feed  characterization cost,  improved

throughput, and avoided upgrade costs. With the public relations benefits, gains could be upwards
of 100 million dollars.

Mercury Emission Versus Multimedia OEMs
In general, multimedia GEM systems are just combinations of other measurement techniques [e.g.,
inductively coupled plasma (ICP) and AES; laser and AES; microwave and AES; spark and AES;'
and XRF].  Since these units do not use CVAA, they rarely rely on separation or conversion
techniques.  Furthermore, most  multiple metal OEMs have not been tested for mercury and are
usually more expensive to use than dedicated mercury CEMs.

Dr. French closed with the following suggestions regarding implementing mercury CEMs:
      Develop realistic performance specifications - Revisit daily absolute calibration, on-site
      calibration, and calibration standards.
      Perform validation testing at realistic facilities - Compare the results of these tests to EPA
      requirements, which still need to be defined.
      Perform site specific cost/benefit analyses - These data allows facilities to make low-risk
      decisions about the costs/benefits of CEMs.
Even on a voluntary basis, the likelihood of success for any of these techniques is high.

Industrial Applications of Ultraviolet DOAS Systems for Mercury


Presented on September 13, 1999 by Carl Kamme, Opsis Inc.

Mr. Kamme began his presentation by describing a DOAS system. During operation, light [in the
deep ultraviolet (UV) to infrared range] is sent from a light emitter mounted on the side of the stack
through the stack to a receiver mounted on the other side of the stack. The beam is then transmitted
from the receiver through  a fiberoptic  cable to an analyzer  containing a multiplexer and a
spectrometer.   Elemental  mercury concentrations are  calculated by  applying  spectrometer
measurements taken approximately every 0,01 seconds to the Beer-Lambert Law, which states I2
= I0eca"2 and \n(\2l\i) = c(a,-a2)l. Since measurements are based on the responses that occur as the
light passes through the monitoring path (e.g., stack), sample collection and conditioning systems
are unnecessary.

Next Mr. Kamme described  the configuration used to span and zero calibrate the DOAS system.
During system calibration, a reference gas is sent through the calibration bench and calibration cells
(with mercury vapor pressures), and vented to the outdoors.  Calibration measurements are taken
across the length of the calibration bench, similar to how measurements are taken across a stack.
Although the schematic showed an external manual calibration system, Mr. Kamme noted that some
systems have integrated calibration systems within their systems. Mr. Kamme then noted that the
calibration systems are strongly temperature dependent.

DOAS applications include: power plants, waste incinerators (to mainly monitor mercury), sulphuric
acid production,  chemical industry, mineral wool production, cement industry, fertilizer production,
aluminum smelters, and steel mills. According to German standards, these systems must comply
with a minimum mercury measurement range of 0 to 150 micrograms per cubic meter (ug/m3) and
a minimum measurement time of 10 seconds when installed on boilers above a certain size. These
minimums also comply with the US EPA requirements. In the US, however, installations are certified
according to 40 CFR Part 60 and 40 CFR Part 75.

Mr. Kamme then summarized performance data (Method 29) obtained using an AR 600 Analyzer
at a MWC in Florida.  Results were provided for elemental mercury and sulfur dioxide.  For mercury,
the maximum measurement range for a 1  m path was 0 to 1,000 ug/m3, the lowest TUV-approved
measurement range was 0 to 150 ug/m3, the minimum detectable quantity for a 1  meter path and 30
seconds was 3 ug/m3, and the zero drift for 1 meter path maximum per month was +/- 6 ug/m3.

Similar performance data were also reported  for parameters regulated in Europe according to
German standards for waste incinerators. In this configuration a combination of UV (AR600) and
infrared (AR650) spectrometers are used to measure nitrogen oxide, nitrogen dioxide, sulfur dioxide,
ammonia,  water, hydrogen chloride, hydrogen fluoride, carbon  monoxide, carbon dioxide, and

When DOAS and Method 29 elemental mercury concentrations measured over 4 days at the stack
of an incinerator were compared, elemental mercury concentrations obtained using Methods 29 were
higher than the DOAS results on the first and last day of the test and lower on the days in between.
Comparison of sulfur dioxide and mercury concentrations obtained hourly over an 8-day period

indicates that there is some correlation between sulfur dioxide and mercury concentrations, frequent
variations complicated the comparison.

Mr. Kamme then  discussed the application of a heated DOAS GEM which used an elemental
mercury converter to monitor total mercury at a chlor-alkali factory.  During this application, the
DOAS system was set up to continuously monitor elemental mercury concentrations ranging from
0 to 500 ug/m3 over  an optical path length of 10 to 100 meters.  Since the unit was installed in an
area containing strong magnetic fields, the DOAS system  also had to be electromagnetically

Mr. Kamme concluded his presentation by stating that the DOAS system provides reliable elemental
mercury measurements in stack monitoring applications. After noting that the DOAS system can be
modified (e.g., using a converter and employing an extractive mode) to monitor total mercury, Mr.
Kamme also noted that the DOAS system can be used to provide continuous in-situ measurements
of elemental mercury in chlor-alkali factory applications.

Problems/Issues Associated with Mercury Measurements

Presented on September 13, 1999 by Thomas Brown, DOE, NETL (formerly

Mr. Brown's presentation addressed a variety of issues associated with sampling mercury in flue gas
from coal-fired utilities, including "high particulate loadings prior to the initial APCD, and low loadings
after the primary particulate control device" (70% of the industry), and emission measurements "at
the stacks of wet FGD systems" (approximately 30% of the industry). Although, in general, greater
than 98.5% of the particulate from coal-combustion is removed by the APCDs, the fine particulate
that escapes should be considered before mercury CEMs can be used for compliance in the future.
Mr. Brown then noted that the data to be presented during his presentation was collected as part of
the air and waste management critical review on mercury measurement and control written by NETL,
formally FETC. (Brown, T.D., Smith, D.N., Hargis, R.A., and O'Dowd, W.J., "Mercury Measurement
and Its Control; What We Know, Have Learned, and Need to Further Investigate," Presented at the
Air & Waste Management Association's 92nd Annual Meeting and Exhibition, St. Louis, Missouri,
June 1999.)

Mercury Measurements
Measuring mercury from coal-fired power plants and other sources is complicated by the fact that
mercury  concentrations  need to  be measured to parts per  billion  (ppb) or even  ppt-levels.
Measurement methods are further complicated by the presence of sulfur dioxide, hydrogen chloride,
and other vapor-phase compounds.  Mr. Brown then noted that mercury speciation also plays an
important role, as demonstrated  by the impacts associated  with volatilization, oxidation, and
particulate reactions  (e.g., the adsorption and catalysis of elemental mercury to oxidized mercury).
It is important to consider the different stages  impacting the mercury species  and whether the
mercury is in the vapor of particle-phase.

The distribution of different trace metals associated with the particulate (i.e., less than 5 microns in
diameter) obtained from the stacks of two utilities (a facility firing a western or PRB coal and a facility
firing an  eastern bituminous coal) was then presented.  The  first facility used  a  fabric filter for
particulate control and the second facility used an ESP system, respectively. The unit with the fabric
filter produced approximately 1,000 pounds per year of HAP as compared to the facility with the ESP
system, which produced 6 tons per year.  (Note: The ESP system was  under-operated and was
eventually replaced with  an ESP system which is 99.5% effective at  removing  particulate.) The
distribution demonstrated that fine particulate is being emitted at low levels and has trace levels of
metals associated with it.  When developing monitoring methods for mercury  it is important to
address particulate impacts, since particulate matter can adsorb mercury and/or oxidize elemental
mercury,  even when present at levels equal  to or below the current New  Source Performance
Standard (NSPS) level for particulate emissions of 0.03 pound per  British thermal unit.

After noting that DOE funded researchers have determined that the presence of iron in the fly ash
and certain iron-based compounds impacts the oxidation of elemental mercury (especially in eastern
coals), percent elemental mercury results captured and oxidized across a fixed bed overtime were
then presented. These data were collected from a study in which elemental mercury in a simulated
flue gas was delivered to a fixed bed containing a specific iron-based catalysts.  The data showed
that mercury adsorption was initially observed (i.e., within the first 200 to 400 hours of the test), but
eventually stopped.  Not surprisingly, a similar, but opposite trend (a "mirror image") was observed


 as the elemental mercury was converted to an oxidized form. Based on this study and others, it was
 concluded that an oxidized form rather than elemental mercury is emitted once the equilibrium
 adsorption capacity of the media in the fixed bed (certain iron-based compounds, fly ashes, etc.) is
 reached.   This  conclusion may have a  significant  impact on future mercury  measurements,
 particularly for facilities that need to measure total mercury concentrations at ppt  or ppb levels.
 Partieulate impacts also need to be better  understood in order to develop  appropriate control
 strategies/technologies for the coal-fired utility industry, if regulations are required.

 Mr. Brown then  presented mercury data from a power plant which burned PRB coal.  The data
 represents the mercury as measured using two versions of the Ontario Hydro Method. The first
 version of the Ontario Hydro Method (OH-1) was operated normally, with  the nozzle turned in the
 direction of the flow of flue gas (and fine particulate).  In the second version of the Ontario Hydro
 Method (OH-2), however, the probe was turned opposite to the flow of the flue gas and a particulate
 matter 10 (PM 10) cutter and an  oversized nozzle were  used to  minimize  the amount of fine
 particulate entering the nozzle. Although the OH-1 filter had an order of magnitude more particulate
 than the OH-2 filter, particulate from both filters contained particulate-bound mercury. It should be
 noted, however, that it is not known if the mercury was associated with the particulate as it entered
 the filters  or if the mercury was adsorbed on the particulate as the particulate was collected on the
 filter.  Further, the observed grain loadings of the  OH-2 filter are probably indicative of the grain
 loadings  on  the  outlet (i.e., extremely low); this could  impact particulate and vapor-phase
 concentrations while utilizing mercury CEMs. Since CEMs only measure vapor-phase mercury, not
 particulate-bound, this could "bias low the  amount of  mercury exiting the stack."  Mr. Brown then
 noted that coals  and  fly ashes with relatively fine particulate are  more likely to exhibit higher
 particulate impacts/effects (e.g., adsorption and  conversion  of elemental mercury), but more
 research is required to reach a final conclusion.                                 '         r

 Mr. Brown then compared the percent of elemental mercury oxidized and/or adsorbed across a fixed
 bed for a  variety of fly ashes  (subbituminous or PRB, bituminous, lignite, and oi[-fired).  Results
 obtained from two locations within  an ESP system (i.e., from the first  ESP field,, where coarser
 particles are collected, and from the fifth ESP field,  where fine particles are collected) indicate that
 the bituminous coal fly ash collected from the fifth field indicated more oxidization (and adsorption)
 than the fly ash  from the first field.  These  results support earlier findings indicating that  finer
 particulate may have a tendency to adsorb and oxidize more mercury than coarser particles. Mr.
 Brown then stressed  that this conclusion  needs to be further addressed from  both  a method
 utilization  (e.g., for Method 29 or the Ontario Hydro Method) and compliance perspective (CEMs for
 coal fired utilities, HWCs, MWCs, and other sources).

 Carbon in  the fly ash may also cause difficulties when collected at the front-end of the mercury CEM
 sampling  probe.   The sorption capacities  for both elemental  mercury  and mercuric chloride  at
 different LOIs were then presented along with a comparison of the fly ash results obtained for a
 highly mercury adsorbent and an oxidizing activated  carbon (FGD carbon or LAC from a lignite coal).
All the tests were conducted with either mercury form being carried in a simulated flue gas to a fixed
 bed containing different LOI fly ashes. According to Mr. Brown, the LOI for this fly ash varied from
 0 to 82% with the fly ash being collected from different locations within the power plant. The data
 presented imply  a correlation between an increase in LOI and an increase in mercury (both
elemental  and mercuric chloride) adsorption.  Like the previously presented study results, the data
 indicated the possibility of another fly ash constituent having an impact on  obtaining accurate total
 measured mercury concentrations. Again, Mr. Brown noted that this impact needs to be addressed
and resolved if mercury CEMs are to be required for compliance by coal-fired utilities, since a


significant amount of mercury could be captured on the sampling probes of CEMs. The captured
mercury would need to be accounted  for when trying to meet  ppt and  ppb level  emission

Mr. Brown then presented sulfur dioxide concentrations from the inlet and outlet of a FGD system
installed at a power plant. After noting that the mercury concentrations appeared to vary with the
sulfur dioxide and other flue gas  constituents, Mr.  Brown mentioned NETL's ongoing  efforts to
develop correlations and trends for mercury to these and other flue gas constituents. Furthermore,
since sulfur dioxide is problematic for most mercury CEMs, Mr. Brown stressed that conditioning
systems need to be developed which can remove the sulfur dioxide and other interferences before
the flue gas is delivered to the detectors (which have been proven to work well in the absence of
these gases). Finally, in order to develop speciating mercury CEMs or total mercury CEMs, either:
1) a conditioning system needs to be  developed which can convert total speciated mercury into
elemental mercury; or 2) the development of a detector which can measure speciated forms of
mercury providing total mercury measurements in the presence of the interfering gases  (although
this may prove much more expensive than developing a conditioning system).

Mr. Brown closed by noting that mercury CEM  detectors work well in the absence of the interfering
gases, but that  "front-end systems"  need to be  developed  which can remove vapor-phase
compounds (e.g., hydrogen chloride, hydrogen fluoride, sulfurand nitrogen oxides, and other gases).
These compounds could preclude effective operation and accurate measurement of total mercury
concentrations for most of the current suite of mercury CEMs under development. The conditioning
systems developed to remove these compounds  need to work without  altering the form of the
mercury or the total concentration of the mercury.  After reiterating the importance of particulate-
phase mercury measurements (particularly for coal-fired utilities), Mr. Brown then noted current
difficulties associated with  effectively calibrating  mercury CEMs  (calibration is not typically
problematic with other CEMs,  for example sulfur dioxide or nitrogen oxides). According to Mr.
Brown, accurate and stable calibration techniques need to be developed for both elemental and
oxidized mercury (e.g., mercuric chloride) at the ppb and ppt levels, before CEMs can be used as
a compliance tool. Although some  headway has been made (e.g., regarding particulate impacts and
field calibration techniques), acid  gases and other interferences need to be addressed before a
workable mercury CEM can be deployed which is robust, near maintenance free, and accurate for
measuring mercury in the ppt and ppb range from coal-fired utility flue gas streams.

Merits  of Dilution  Source Sampling:  Measurement of Mercury

Presented  on  September 13,  1999 by James  Schauer,  Water Chemistry
Program, University of Wisconsin-Madison

According to Dr. Schauer, dilution source sampling techniques have been well developed to address
fine particle issues that have received significant attention with the new fine particle standard.
Although in general these methods have not been used for mercury emissions testing,  Dr. Schauer
anticipates that this approach will be used more frequently.  This increase is expected in part
because the sampling method can easily be modified for mercury measurements, but also because
the scientific and regulatory community needs a more advanced sampling technique to  allow it to be
able to characterize particle-phase mercury data and collect complete mercury speciation data.

Measurement of emissions from air pollution sources is often motivated by: 1) a need to comply with
regulatory  or process control requirements; or 2) a desire to relate emissions to the  presence of
pollutants in the environment (via their application in receptor and transport models). Furthermore,
the emissions from many important air pollution sources are injected into the atmosphere in hot
exhaust plumes.  Significant physical and  chemical sampling artifacts associated with chemical
reactions, gas/particle partitioning, and particle size distribution can also occur during the collection
of these hot stack emissions.

Objectives of Source Emission Characterization
Source emission testing is needed to obtain emissions measurements which are: 1) chemically and
physically consistent with ambient measurements; and 2) are integrated with broad-based emissions
characterization measurements (both chemical and physical).  In addition to providing  a real-world
measure of air pollution (via portable samplers), source emission tests can also provide data that can
be used as inputs to state-of-the-art  air pollution models to develop a description of the pollutants
located in the downwind plume.

Portable Dilution Source Sampler
Portable dilution source samplers can be used to take real-world measurements in the field. The
dilution sampler turbulently mixes the hot exhaust emissions with cleaned dilution air to bring the
diluted exhaust to near ambient pressure and temperature conditions, simulating the atmospheric
dilution that occurs downwind of the  plume. The diluted exhaust passes through a residence time
chamber where the semi-volatile compounds are allowed to partition between the gas  and particle
phases. The diluted exhaust can then be sampled from the residence time chamber by the same
techniques used for ambient sampling. In addition to being modular and field portable,  the sampler
can also be used for ultra-trace level measurements.

Dilution source sampling has been used extensively to sample for organic emissions, including
particle-phase organic compounds [by gas chromatography/mass spectrometry (GC/MS)], semi-
volatile organic compounds or SVOCs (by GC/MS), and volatile organic compounds (VOCs). It has
also been used to sample for the bulk chemical composition of particulate matter (including trace
metals by XRF and organic and elemental carbon), particle size distribution measurements (including

particle size-resolved chemical composition using MOUDI impactors), and to perform advanced real-
time single-particle analyses using an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS).

The dilution source sampler was originally developed at Caltech for fine particle emissions. It has
been adapted over the last 5 to 6 years to sample semi-volatile, gas-phase pollutants, and, most
recently, to perform ultra-trace metal analyses. During operation, a sample is withdrawn from the
stack through a heated inlet line that is measured with a Venturi meter.  Downstream of the Venturi
meter the hot exhaust emissions are turbulently mixed with cleaned-up dilution air.  The dilution air
is cleaned with a high efficiency particle adsorption (HEPA) filter and an activated carbon bed. Most
of the diluted exhaust is expelled across a high volume filter where a "high volume of mass is
collected." A portion of the diluted exhaust is pulled into the residence time chamber upstream of the
high volume filter.  The diluted exhaust resides in the residence chamber for approximately 1 minute
prior to being sampled.

The following sections of the sampler were then briefly addressed:
      Dilution Air Conditioning Zone - The dilution air condition zone is composed of a variable
       speed blower, cooler, HEPA-filter, activated carbon bed for removal of contaminants, flexible
       steel  ducts, and an orifice meter  (1,000 liters per minute).  In general, the cooler is not
       needed for most operations.
      Sample Inlet Zone - Near isokinetic sampling is performed in the sample inlet zone using a
       PM10 cyclone to remove  larger particulate matter.  Stack probes (80 centimeters up to 2
       meters) in  the sample inlet zone utilize automated temperature controls to heat the probes
       to 5 to 10 F above the stack temperature. The inlet zone is also equipped with a Venturi
       meter (to measure the flow rate of the stack gas entering the system), pressure tapes,  and
       temperature controls.
      Turbulent Mixing Zone - Stack gas mixing with the dilution air typically occurs at a very high
       Reynolds number (e.g., 10,000).  Sample and dilution air flow rates typically range from 10
       to 50  and 750  to  1,200  liters per minute, respectively.   Depending on the sampling
       requirements, the sampler can be operated over a dilution range of 15:1 to 200:1.  Finally,
       most of the air is expelled outside of the high volume filter and the remainder proceeds to the
       residence time chamber.
      Residence Time Chamber - The 12 inch diameter by 54.5 inch tall residence chamber yields
       a 60 second residence time at a sample flow rate of 100 liters per minute. It is also possible
       to extract samples from parallel sampling systems.
      Sample Collection Zone - Samples can be withdrawn from the residence time chamber using
       ambient air sampling equipment (of virtually any  type),  including  real-time  particle
       measurements and particle size distributions. Furthermore, sample rates control residence
      Particle-size Distributions - Real-time particle size distributions can also be performed using
       the Digital Machine Automation/Computer Numerical Control (DMA/CNC) combination and
       larger particles can be counted using a laser  optical particle  counter.  A  pair of MOUDI
       impactors can also be used to measure: 1) mass and chemical composition as a function of
       size; 2) elemental and organic carbon; 3) trace metals by neutron activation; and 4) inorganic
       ions by ion capture (1C) and colorimetry. Single particle analyses can be performed using
       an ATOFMS.

Source Tests
The dilution source sampler has been used to test the following sources:
      Catalyst-equipped gasoline-powered vehicles


       Non-catalyst automobiles
       Diesel trucks
       Food cooking operations
       Cigarette smoke
       Fireplace combustion of wood
       Wood burning stoves
       Spray coating operations
       NG-fired boilers
       Fuel oil boilers
       Coal-fired boilers
       Roofing tar pots.
A coal-combustion test is scheduled for the Fall 1999; unfortunately this test does not include
mercury measurements.

Sampler Configurations
The versatile sampler has been used to collect samples from a number of sources using a number
of configurations, as described below:
      Stack sampling from boilers, incinerators, and fireplaces
      Motor vehicle sampling using a pre-dilution sampler and dynamometer tests
      Pre-diluted open source sampling associated with agricultural burning
      Pre-diluted closed source sampling associated with cigarette smoke, candle smoke, and
       resuspended particulate matter.

Performance Evaluations                                              
Dilution samplers have undergone extensive performance evaluations to measure particle losses,
comprehensive blank tests, and to assess SVOCs and particle losses.  Dilution samplers have also
been tested for comparison to other source sampling measurements [e.g., motor vehicle VOCs and
trace gases from NG boilers] and for sampling equipment characterization.

Application of Mercury Emissions
In order to apply the dilution sampler to mercury emissions, the sampler will need to be Teflon-
coated and the dilution air cleaning system may need to be modified. Furthermore, virtually any type
of ambient mercury sampling equipment would need to be installed on the system.  Opportunities
are also available to measure total mercury, mercury speciation (of both the gaseous and particulate
phases), and particulate mercury (as a function of size) using dilution samplers.

Dr. Schauer concluded that dilution samplers have been shown to be an effective strategy for
measuring and speciating emissions from air pollution sources.  Furthermore, the application of a
dilution sampling strategy for the measurement of mercury emissions is  expected to enhance
emissions monitoring efforts by allowing:
      Direct application of ambient sampling and analysis techniques to stack sampling (e.g.,
       gaseous and particulate species)
      Integration of mercury emissions data with other advanced emissions characterization efforts
       that will ultimately aid in  mercury modeling efforts.

 Mercury Measurement Research at the EERC

 Presented  on September  13,  1999 by Dennis LaUdal, University of  North
 Dakota EERC

 Initial EERC pilot-scale testing used EPA Method 301 protocols to validate EPA Method 29 as a
 mercury speciation method.  This testing, which was funded by EPRI and the DOE, took place on
 the inlet side of a fabric filter (i.e., the high dust side) during Blacksville bituminous coal combustion.
 (Note: EPA Method 301  uses a quatrain, four samples, and six repetitions.  The resulting data are
 compared internally to determine the biessence precision.) The results clearly showed that the
 elemental mercury added to the flue gas stream was not being measured as elemental mercury by
 EPA Method 29.                                                   

 The EERC pilot-scale test combustor was then described; it is composed of an electric preheater,
 combustor, heat exchanger, pulse-jet baghouse (containing 99% efficient Gore-Tex bags composed
 of Teflon), and a cyclone. The combustor burns approximately 75 pounds of coal per hour and
 generates 130 standard cubic feet per minute (scfm) of flue gas.

 Before EERC could conclude that EPA Method 29 was not correctly speciating mercury, it first had
 to rule out whether "something else was going on." As a result, EERC began examining the following
 mercury speciation methods: the Mercury Speciation Adsorption (MESA) Method, the Tris-Buffer
 Method, the Acetate-Buffer Method, and the Ontario Hydro Method. After initially examining these
 methods, EERC returned to the lab to further study fundamental mercury reactions, measurements,
 and controls at the bench-scale level. EERC found that mercury had a strong tendency to interact
 with sulfur dioxide, nitrogen dioxide, and hydrogen chloride.

 EPA Method 301 provides a  statistical basis for determining precision and bias of the method, but
 not method accuracy. It is an acceptance method which is defined by a percent relative standard
 deviation (RSD) of less than 50% and a bias correction factor of greater than 0.7 but less than 1.3.
 While verifying the Ontario Hydro Method, EERC noted that mercury injected into the system at the
 outlet of the baghouse was unchanged  by the process.  This finding enabled EERC to measure
 method accuracy.

 The Ontario Hydro Mercury  Method is a complicated method which  uses  a series of potassium
 chloride, peroxide, and permangate impingers. This method is currently being used in the field to
 generate legal   data  through the  ICR.    The  method is on   the  EPA web  page  at

The Ontario Hydro Method is a very difficult and complex method, requiring substantial experience
 or training to ensure high quality data. A correction action plan is needed to ensure good data; this
 plan is usually based on field blank and  field spike results.  An independent field audit also helps
 ensure quality results. There are currently a number of labs that are qualified to observe the testing.

 Mr. Laudal closed by noting that the following mercury CEMs have been tested at EERC's facility:
the Perkin  Elmer MERCEM,  the PS  Analytic Sir Galahad,  and  the Sintac Mercury 2000.
 Furthermore, EERC has also conducted bench-scale, pilot-scale, and field tests to examine mercury
 control techniques at a power plant in Michigan (with CEMs), the 3M Oak power plant, and at a plant

in the Midwest.. The bench-scale tests were performed using the PS Analytical and Sintac CEMs.
Field tests were performed using the Ontario Hydro Method.

 Mercury Measurement Research at EPA NRMRL

 Presented on September 13, 1999 by Jeffrey Ryan, US EPA, NRMRL

 EPA NRMRL maintains a program to conduct fundamental and applied combustion Hg emissions
 control research. High quality bench-, pilot-, and field-scale mercury measurements are a critical
 component of this research. To support this goal, EPA NRMRL has established a separate research
 component specifically designed to evaluate manual and CEM methods used to measure speciated
 and total mercury.   NRMRL has also recently expanded its "mission" to provide measurement
 support to the Program Offices and Region Offices.

 Research Approach and Interests
 The main goal of  EPA  NRMRL's Hg  measurements research is to  test the application and
 performance of manual mercury methods and determine how well they perform under diverse
 conditions (e.g., in-house research/field  demonstrations, coal/chlorinated wastes). Although EPA
 NRMRL is primarily focusing on chlorinated waste combustion sources (e.g., HWCs and MWCs),
 NRMRL is also targeting the development of quality tools to evaluate speciating and total mercury
 CEMs. NRMRL is also investigating techniques for measuring other mercury species (e.g., elemental
 mercury), particularly using direct measurement techniques. EPA NRMRL has also tried to use and
 benefit from the University of North Dakota  EERC data and to  further the abilities in speciating
 research for utility boilers and coal combustion.                                           '

 Understanding Manual Methods
 Two years ago, EPA NRMRL began investigating the fundamentals of high temperature mercury
 speciation in combustion systems.  In an effort to better understand this process, EPA NRMRL
 attempted to use several methods [e.g., Draft Method 101B, Ontario Hydro Method, Alkaline Mercury
 Speciation (AMS) Method] to speciate mercury during these pilot-scale combustion experiments.
 Unfortunately, only poor results were obtained. After performing some fundamental testing, EPA
 NRMRL concluded that the poor results could be attributed to the oxidation of elemental mercury in
 the sampling trains.  Since NRMRL was primarily concerned about the  reactivity of chlorineand
 elemental mercury, dynamic spiking tests with chlorine and elemental mercury were performed to
 determine where the oxidation was occurring. These tests indicated that oxidation was occurring
 in the impinger solution.

 This research expanded to the examination of potential interferences and oxidation properties in
 solution during a series of liquid-phase mercury oxidation tests.  During these tests, different
 concentrations of sulfur oxides (SOx) and nitrogen oxides (NOx), and hydrogen chloride and chlorine
 were used.  Mercury was measured during these tests using the Ontario Hydro Method and AMS
 Method. Based on the results, EPA NRMRL concluded that: 1) NOx and SOx by themselves did not
 "present a significant artifact" on the methods; and 2) liquid-phase oxidation of elemental mercury
 as much as 50% was observed as a function  of increased chlorine concentrations (e.g., from 1 to
 10 to 100 ppm).  Furthermore, although less pronounced reactions were observed when HCI and
 SO2 were added to the 10 ppm chlorine tests, no oxidation occurred when sodium thiosulphate was
 added to a 100 ppm chlorine solution.  Since the most  recent update to Method 26 calls for the
 addition of sodium thiosulphate to the alkaline impinger, this was a very significant finding to take into
the field.

Future pilot-scale combustion experiments (under chlorinated waste conditions) are also planned
to evaluate the effectiveness of sodium thiosulphate addition and to compare the Ontario Hydro
Method and Method 29.  Although it has already been shown that there is a positive bias of the
oxidized Hg form using Method 29 under coal combustion conditions, EPA NRMRL is interested in
examining how these methods perform under chlorinated waste combustion conditions. Ultimately,
EPA NRMRL intends to use Method 301-type experiments (with dynamic spiking) to evaluate the
suitability of the Ontario Hydro Method under pilot-scale chlorinated waste combustion conditions.
Although preliminary information indicates that the Ontario Hydro Method may be suitable for
performing speciated Hg measurements from  chlorinated waste combustion conditions,  further
research is needed to substantiate this belief.
Tools To Evaluate Measurement Performance
EPA NRMRL efforts to evaluate measurement performance include the following:
       Characterizing  the overall measurement quality (calibration, digestion  and capture)-
       addition to comparing the Ontario Hydro Method and  Method 29, EPA NRMRL is also
       investigating appropriate acceptance criteria.
       Developing elemental mercury and mercuric chloride dynamic spiking systems for manual
       trains and OEMs- Efforts thus far indicate that dynamic spiking with elemental mercury needs
       to occur beforehand and that spiking/delivering mercuric chloride will prove challenging.
       Evaluating the reliability and uncertainty of elemental mercury permeation devices- Elemental
       mercury permeation devices  may have a  significant impact on the quality of CEM
       calibrations.  Unfortunately, the evaluation of these devices has been complicated by: 1)
       poor/incomplete records on "perm ovens" and 2) confusion associated with the fact that
       permeation tubes are factory-certified using purely gravimetric methods.
       Collaborating with Spectra Gases to evaluate elemental mercury compressed gas cylinders -
       This work will support the development of a gas standard for calibration at several different
       Configuring  a combustion test facility for precise control  of mercury concentration and
       species (elemental and mercuric chloride) as well as  independent control of hydrogen
       chloride, chlorine, SOx, NOx.  and moisture levels- The  EPA NRMRL Rotary Kiln Mercury
       Measurement Test Facility is unique because it is able to exert control over the concentration
       and species of mercury in a combustion atmosphere as well as NOx, sulfur dioxide, hydrogen
       chloride, chlorine, and moisture.  This facility has been  used as a testing area for multiple
       metal CEMs. The Ontario Hydro Method performed  very well during multiple tests, with
       replicate measurements within 5% for total mercury and 7% for speciated mercury.

Mercury CEM Evaluations
Speciating and total mercury  CEMs are needed for mercury  control research.  Currently both
Program and Regional Offices support efforts to identify and  create  opportunities where viable
mercury  CEMs can be made available  for evaluation, as  both  a research tool and  potential
compliance monitor. Pilot-scale testing performed under controlled, varied, representative conditions
needs to be performed, however, before testing can proceed from the lab to the field. This is an
essential step in developing an effective approach to identifying and investigating problem areas and
improving the  probability for successful field demonstrations  for chlorinated waste combustion
conditions. Thus far, EPA NRMRL's approach has been to compare mercury CEM measurements
(speciated and total mercury) to Ontario Hydro Method speciated measurements; this approach is
consistent with the  PS 12 approach.  This approach  also affords EPA NRMRL the opportunity to
investigate issues relative to PS 12 (i.e., drift checks and interference checks).

Potential Mercury GEM Evaluations
Since past mercury CEM evaluations have been constrained by limited mercury GEM availability and
funding, a cooperative evaluation of mercury CEMs during control technology research is needed.
To succeed, participation must be mutually beneficial and CEM vendor participation is essential. If
employed, this approach will provide an opportunity to investigate and address measurement issues
in controlled, realistic combustion environments in preparation for possible field demonstrations.

Measuring Other Mercury Species
EPA NRMRL is interested in  directly measuring other mercury species in addition to elemental
mercury  and mercuric chloride.   Currently,  however,  EPA NRMRL is focusing its efforts on
measuring elemental mercury, since very little is known about this compound and it is difficult to
measure using heat diffusion methods and ionization testing. EPA NRMRL is also interested in new
techniques to determine the effect of nitrogen  dioxide on elemental mercury and "where it goes."

Bench-scale experiments indicate  that the Ontario Hydro Method shows promise as a mercury
speciating method for chlorinated waste combustion conditions;  however,  planned pilot-scale
combustion evaluation tests (with  dynamic spiking) will  help determine actual suitability.  EPA
NRMRL is interested in evaluating viable speciating and total mercury GEMs as research tools and
for potential field demonstration.  Finally, it is critical to know the quality of the tools used to perform

Use of a  Dilution Chamber To Measure Stack Emissions and
Near-Term Transformations of Mercury

Presented on September 13, 1999 by Eric Prestbo, Frontier Geosciences Inc.

From Flue to the Plume                                                          ,
There is  a  data  gap between mercury  speciation in flue gas emissions and ground-based
measurements of mercury air concentrations and wet deposition. Although engineers and scientists
are currently making good mercury speciation measurements in the stack, and researchers are
making good ground-based measurements of mercury speciation and deposition, our understanding
of the chemical and physical transformations of mercury in the near-term emission plume is limited.
Filling this data gap will be critical  as the process to determine the need and extent of mercury
control regulations for point source combustion sources moves forward. In addition to understanding
mercury transformations in the plume, the hypothesis that emissions of RGM  [mercury(ll)]  and
particulate mercury from a combustion source are, efficiently scavenged by rain on a local scale
needs to be experimentally confirmed. Although there are good reactive plume models for mercury
point  source  emissions,  these models  are handicapped by a  lack of good  experimental
measurements of mercury speciation in the near-term plume.

Numerous chemical and physical changes take place as emissions proceed from the stack to the
plume. These changes are impacted, in part,  by different conditions in the stack and atmosphere.
For example, temperatures in the stack range from 70 to 175C, while plume temperature ranges
from -30 to 38C. Plume reaction times are also typically much longer (hours as compared to
seconds) and the available deposition surfaces outside of the stack are more diverse (e.g., water,
trees, soil).   Further, plumes are exposed  to both  light and oxidants, such as  ozone (at
concentrations of 0 to 50 ppbv) associated with photochemical cycles in the atmosphere, both of
which may influence the speciation and transformations of mercury. Condensed water is not present
in the stack, while often there.is immediate droplet formation as the plume forms and of course the
possibility for the plume to interact with clouds, fog and rain.  Particle behavior/characteristics are
also more complex in the plume, particularly with regards to gas to particle conversion.

RELMAP Limitations and Data Gaps
The EPA Mercury Study Report to Congress identifies a number of current limitations and data gaps
for RELMAP.  In this report, EPA notes that additional data are needed, particularly local exposure
assessment data. According to EPA, "there is a lack of adequate mercury measurement data near
the anthropogenic atmospheric mercury sources considered in this report." Additionally, "the lack of
such measured data precludes a comparison of the modeling results with measured data around
these sources." To further his discussion of RELMAP limitations,  Dr. Prestbo then noted that there
is a large difference between the base case  mercury emission  profiles  and the alternative case
mercury emission profiles in  total deposited anthropogenic data (i.e.,  77.9 tons and  48.2 tons,
respectively).  The point being that mercury deposition to sensitive ecosystems  can be strikingly
different depending on the assumptions made in the model.  It is the goal of the following research
on mercury speciation in emission plumes to replace the assumptions made in atmospheric models
with high quality experimental data.

Why Measure Mercury in Combustion Plumes?                                          
It is Important is measure mercury in combustion plumes since the conversion of mercury species
is likely to occur rapidly from the stack to plume as a result of changing chemical and physical
conditions. Furthermore, combustion plume data will contribute to the improvement and accuracy
of atmospheric models, which will be one of the primary tools used to help determine if emission
regulations are needed.

The SPDC acts as a large inert (Teflon-coated) reaction chamber to form controlled combustion
emission plumes by isokinetically introducing a small volume of flue gas (e.g., 20 liters) into a large
volume (e.g., 500 to 1,000 liters). The SPDC has several variables that can be easily controlled: 1)
temperature, 2) dilution ratios, 3) reaction time, 4) light input, and 5) rainwater. Both dry deposition
(on the sides of the walls) and mercury washout by rainfall can also be assessed with a SPDC.  This
allows users to assess deposition in the environment and to identify which atmospheric mercury
species are removed into aquatic ecosystems.  In addition to using a mercury filter pack system to
collect a sample from the chamber for particulate mercury, RGM [mercury(ll)] and elemental mercury
analysis, the experiment is also  set up to measure (via a probe) mercury speciation in the flue gas.
Total mercury in the SPDC is measured to calculate a SPDC mass balance. The capability to mass
balance a SPDC experimental run is the most powerful QA assessment. All the mercury introduced
must be accounted for to provide a confident data interpretation. Finally, mercury speciation is also
measured using mist-chambers that can mimic cloudwater plume interactions.

An "in-stack" comparison of TGM using the MESA Method and the In-Stack Isokinetic  lodated
Carbon Method (ISO-IC) following a  coal flue gas plume test in Unit #8 showed very little disparity,
with a relative percent difference between the means of 1.65% for 12 different events. Furthermore,
an examination of the in-stack speciation [elemental mercury vs mercury(ll)] using the MESA Method
supports the consistency of both the method and the boiler controls. A mass balance comparing
total  mercury to the sum of the species measured with  the SPDC showed good agreement in
general.  It is also possible to conclude, based on a comparison of injected and SPDC measured
elemental mercury and mercury(II) data, that: 1) there  was a rapid transformation of mercury(ll) to
elemental mercury in the simulated plume; or 2) the flue gas speciation was incorrect and nearly all
the mercury entering the SPDC was in the elemental form: Furthermore, some mercury removal was
observed when simulated rain was injected into the SPDC; however, the resulting values do not
support rapid mercury(ll) removal. Predominantly the very minor amount of RGM [mercury(il)] was
seen as dry deposition and some gas-phase concentrations.

The mass balances performed for a waste incinerator were not as good as those found at Unit #8,
but were reasonable.  When no "rain" was added, more mercury(ll) was observed in the air and dry
deposition fractions than the amount injected,  indicating a possible conversion from elemental
mercury to mercury(ll) in the plume.  When "rain" was added, injected mercury(l I) was nearly equal
to measured  mercury(ll), with the majority being  removed to the dissolved rainwater fraction.
Furthermore,  nearly all of the mercury(lI) observed in the SPDC was found in the dissolved dry
deposition or dissolved simulated rainwater fractions. Finally, although the absolute concentrations
were low, there was significant conversion of gas-phase mercury to particulate mercury from the flue
to the plume.                                                    -        :

The following conclusions were made:
     The SPDC method works and is a valuable tool to further understand the probable fate of
      mercury emissions from combustion sources.  ,
     Modelers need more data close to sources. SPDC experiments can provide valuable input
      to help refine local, regional and continental scale models as well as complement source-
      receptor field studies. It may be  beneficial to plan for concurrent SPDC and source-receptor
      field studies.
     When gaseous mercury(ll) is present in the flue gas, its fate is tied to dry deposition and
      scavenging by rain. Although this result was predicted by mercury models, it is important to
      confirm the models with experimental data.

Additional Research Efforts
The following SPDC research efforts were then mentioned:
     Frontier/Center for Air Toxic Metals-EERC/USDOE/EPRI in the Fall 1999- The purpose of
      this  study is to challenge the SPDC  method using the EERC  Pilot-Scale Power  Plant
      capabilities to generate a well- characterized flue gas matrix with mercury species spiking
      and real-time measurements.
     Frontier/ERM/Minnesota Department of Natural Resources Event-Based Deposition Study.
      Summer/Fall 1999 - Rainwater samples from a waste incinerator and an eastern coal plant
      (i.e., the Dickerson Power Plant) will  be used to 'confirm SPDC  results showing  rapid
      rainwater washout of mercury(ll) emissions.
     Improvements in the SPDC Method  - To use a Tekran 2537 and  the new 1130 speciation
      module to obtain real-time measurements of mercury speciation in order to generate mercury
      species conversion curves.
     Confer with atmospheric modelers [e.g., Total  Exposure Assessment Model  (TEAM),
      Combine SPDC experiments with flue gas control technology studies  and high-frequency,
      local-scale, ground-based mercury speciation campaigns.

EPA Performance Specification: Optional Use of CEMs

Presented on September 13, 1999 by H.  Scott Rauenzahn, US EPA, OSW

HWC Phase I MACT Rule
Mr. Rauenzahn opened his presentation by discussing the HWC Phase I MACT rule.  This rule
addresses hazardous waste combustion sources including incinerators, cement kilns, lightweight
aggregate kilns, and others. When the MACT rule was developed, Section 63.8(f) was included to
encourage alternative monitoring approaches. This section, specifically 63.1209(1) or (2), allows any
alternative monitoring approach for OPLs. It also allows permits to require alternative monitoring and
encourages facilities to use CEMs, if the CEMs are at least as good an indicator of compliance as
the OPLs required by the rules.

The MACT rule also proposed a number of performance specifications including: PS 10 for multiple
metals (MM), PS 12 for mercury, PS 13 for hydrogen chloride, and PS 14 for chlorine.  Currently,
however, there are no plans to finalize these specifications, mainly due to concerns whether the data
quality objectives in the specifications are achievable. (Note: For mercury CEMs at cement kilns,
it was found that the specifications were not achievable. PS 13, however, has been demonstrated
at a MWC.) Unfortunately, without a promulgated performance specification for these  monitors,
performance must be demonstrated on a site-by-site basis by individual plants which chose to use

Plans are being made, however, to finalize PS 11 and Procedure 2 for particulate matter CEMs, and
Method 5i is final. (Note: PS 11 is determined based on a correlation between the manual method
and the output from the CEMs,  and Procedure 2 specifies how and when testing  needs to be
performed.) Also, the performance of particulate matter CEMs has been shown  to  meet  the
performance specifications.

Why Would a Facility Elect To Use CEMs?
Some facilities have decided to  voluntarily use CEMs to evaluate compliance options.  One
pharmaceutical company is installing CEMs on its incinerator to assess MACT compliance and to
avoid buying millions of dollars of air pollution control equipment in the future. Furthermore, facilities
that install CEMs now will only need to meet a 0.08 grain particulate matter standard, which is much
easier to meet than the future standard of 0.05 grain.

CEMs can also be used as particulate emissions monitors (PEMs) to identify better approaches for
traditional monitoring.  One study looked at PEMs on a lime kiln.  It took over 600 samples to model
how system variabilities affected final particulate matter emissions. With CEMs, the characterization
process becomes much simpler (less samples and stack time), resulting in cost savings.

There is a need to reach out  to the community and get it involved.   CEM data can be used to
communicate a facility's ability to stay within the limits at any given time. CEMs may also prove to
be important for permitting and State statutes and regulations. As MACT starts requiring CEMs (e.g.,
PS 11, for particulate matter CEMs), States can be expected to become proactive about requiring
CEMs. In fact, one State has already required CEMs in its regulations.

Finally, CEMs can be used to fulfill Supplemental Enforcement. Project (SEP) requirements.  For
example, CEMs are an important alternative for a utility company with a wet stack that cannot use
an opacity monitor.                                   . ,. 

Submittal of Alternative Monitoring Request
To get approval for alternative monitoring with a CEM, a facility needs to coordinate with its
permitting authority before purchasing and testing the GEM to:  1) ensure that the permitting authority
is agreeable to CEM use; 2) answer any questions it may have; and 3) determine what data are
needed to obtain approval from the regulating agency.  For some performance specifications (e.g.,
PS 11), the facility may also need to collect data above the emissions standard to test for possibly
exceeding the standard and tes.ting agreements. It is also important to receive approval of the
demonstration approach and agree on the criteria for accepting the CEMs data for compliance before
proceeding with testing.                                                     

Demonstration of CEMs
Facilities interested in demonstrating CEMs need to follow the procedures found in the promulgated
performance specification. However, these facilities need to use the data acceptance criteria shown
to be achievable at the facilities, rather than the acceptance criteria proposed in the specification.
The timeline associated with  the CEM demonstration  process should be expected to take 1 to 2
years. There is a "shakedown phase" which can take 3 to 6 months, followed by a "demonstration
phase" which can take 6 to 12 months. This, in turn, is followed by an "evaluation phase" that usually
lasts 3 to 6 months.  Of course, these timeframes are approximations that can change with the
complexity of the facility and the CEM being tested (e.g., a multiple metal CEM will probably take
longer than a hydrogen chloride CEM).          '               --.-.

Are CEMs Better than the Status Quo?                              ,
Before a CEM can be substituted for an existing compliance methodology, facilities first need to
confirm that the CEM is at least as a good as the current compliance methodology.  To determine
this,  facilities need  to compare the  uncertainty of the current  compliance approach with the
uncertainty of the CEM.  This can be accomplished,  ideally during the demonstration test, in a
number of ways, including: 1) comparing manual method stack data to CEM data and incorporating
this information in OPLs; and 2) via a "sum of the errors" approach, in which the individual errors
associated with the devices, methods and procedures are summed.  Furthermore, CEMs are usually
better at detecting higher emissions than OPLs.

Incentives for Using CEMs
Facilities which use CEMs are not required to do performance testing (stack testing) for mercury.
These facilities are able to avoid enforcement quality testing of OPLs while their CEM is.operating.
This could have big implication for field streams that are difficult to characterize. Finally, facilities with
operating CEMs do not need monitoring OPLs for enforcement.

Future CEMs Test Failure
If a facility fails to meet a Relative Accuracy Test Audit (RATA), the data obtained  prior to the CEMs
test failure should not be impacted/compromised. Most likely, the facility will be required to repair
the  monitor and retest or establish a new  correlation  curve, which may  result  in more frequent
maintenance requirements. The failure may also cause the data acceptance criteria to be modified
(to reflect the new data), assuming the level of performance is still better than using OPLs.

Suitability Testing of CEMs for Mercury

Presented  on  September  13,  1999  by  Carsten Rollig,  TUV  Rheinland
Sicherheit und Umweltschutz GmbH

TUV testing is performed under the German QA/QC Measures Program. Only TUV tested and
approved instruments are allowed to be used for official measurements. Instruments are tested
onsite after they are installed at a plant. The three part test procedure includes: maintenance testing;
an annual function test conducted by an  independent  measuring institute; and comparison
measurements every 3 to 5 years by an independent measuring institute.  Data acquisition and
reporting are accomplished by an emission computer installed on-site at the plant. This computer,
which is linked to the CEM being tested, evaluates and reports all the test data collected. In some
newer plants, the plant can be controlled through a direct link with the local authority.

TUV Approval-Test Scheme
TUV testing is driven by a need to comply with Federal emission limits for different types of plants.
The objectives are set by a group of experts responsible for establishing test requirements. The test
procedure is executed by an authorized institute and the data obtained  are evaluated by a State
committee and published by the ministry. Finally the instrument (the CEM) can be installed onsite
under the QA/QC Measures Program and periodically monitored by the local authority.

Main Performance Characteristics                                                  .
The TUV test procedure is divided into two parts: a laboratory test and a 3-month field test in which
two devices are installed in the same stack. The following performance characteristics are evaluated
and/or established during a TUV CEM test:
     Setup of analysis function (calibration curve)
     Linearity and interferences
     Detection limit and response time (plant)
     Drift behavior (zero and reference point) (plant)
     Availability and maintenance interval (plant)
     Reproducibility (i.e., the uncertainty between two instruments).       
The TUV field application is used to obtain information on the gaseous matrix (type of plants) and
to identify the smallest full-scale range configuration (typically 1.5 to 3 times the emission limit).

During the laboratory test, the following must be tested on two complete systems:
     System function - Every function has to be tested.
     Instruction manual - The manual needs to  be comprehensive and in German.
     Linearity - Linearity is checked over the full measuring range and needs to be within 2% of
      the measuring  range.
     Measuring range - The measuring range needs to be very close to or within  1.5 to 2 times
      the emission limits.                                                         ,
     Temperature range - The temperature range must be checked for the difference of indoor or
      outdoor installation.  The temperature range needs to be within 5%.
     Line voltage fluctuation - Line voltage fluctuation needs to be within 2%.
     Interference error - Both positive and negative deviations associated with interferences are
      used  to determine interference error; however, these interferences need to be added
      separately.  The interference error needs to be within 4%.
The  majority of these parameters are tested at zero and near 70% of the measuring range.


Mercury test gases are generated using a HOVACAL unit. This unit uses an evaporator to combine
mercuric chloride (in solution) and carrier gas.  Both the concentration of the mercuric chloride
solution and the flow rate of the carrier gas can be modified to achieve the concentrations (e.g., 100
ug/m3) and flow rates (e.g., 2 to 6 liters per minute) needed for testing.

During the field test two independent systems are tested at one plant for a minimum of 3 months.
The following parameters are evaluated during a field test:
      Detection limit - The detection limit needs to be at least 5% of the daily mean emission limit
       for the plant.
      Response time - The response time must be two hundred seconds for 90% of the time.
      Availability - The unit must be available 95% of the measuring  time the unit is in the field.
      Drift behavior - Drift behavior is tested using test standards. Drift is determined based on the
       zero point (at 2 to 3% of the measuring range reference point).
      Analytical function - Analytical function  is very important and is  based on a correlation to the
       manual reference method.
      Reproducibility - Reproducibility is the difference between the two instruments.
      Maintenance interval - An instrument needs to be able to operate at least 1 week without

Manual Reference Method According to GEM
In most cases, the manual reference method according to CEM employs an in-stack filter and a low
concentration potassium permanganate adsorption solution (2%). Although more impingers can be
used, usually only two impingers are needed to collect the total mercury. The choice of materials
used on the sampling train is also very important. Although a glass sampling train is the best,
stainless steel works well. (Note: titanium sampling trains should not be used for mercury.) Finally,
relatively low flow rates are employed (1 to 2.5 liters per minute).

Performance Characteristics CEM - Methods      _'.,'...
The results of two CEM tests performed at two waste incineration facilities were presented.  The
results were fairly good, with  mean  concentrations  of 6  and 100  [Jg/m3,  respectively,  and
reproducibility at 3.5  and 36 ug/m3, respectively.  Repeatability was 1.7 and 18 ug/m3, respectively.
Better results would  be difficult to obtain. Four institutes worked on the testing.

The Definition of the Reproducibilitv
Reproducibility is based on the standard deviation between the two tests and the standard deviation
(SD) is related to the measuring range. Reproducibility (RD) is defined as:
      SD  tf-o.95
The following six CEMs passed TUV testing for mercury: the OPSIS AB Lund AR 602 Z; the Sick
Instruments MERCEM; the Seefelder Mebtechnik Hg Mat 2.1 ; the VEREWA HM 1400; the Semtech


AB Hg 2000; and the Mercury Instruments SM 3. The majority of these CEMs use wet chemistry
methods to treat the sample. Since wet chemistry methods require a lot of maintenance (e.g.,
cleaning), some of the new units use dry chemistry sampling methods, which are relatively low-
maintenance by comparison.

 EPA's ETV Program: An Avenue for Testing of Mercury CEMs

 Presented on September 13, 1999 by Thomas Kelly, Battelle

 ETV Goals
 The primary goal of the ETV Program is  to promote commercially available environmental
 technologies, through EPA-supported performance verification testing. The main function of ETV
 is to provide credible, objective third-party performance data to  purchasers and permitters of
 environmental technologies.

 Twelve ETV Pilots
 The ETV Program consists of 12 pilot programs having the following topic areas:
      Advanced Monitoring Systems (AMS)
      Drinking Water Systems
      P2, Recycling & Waste Treatment Technologies
      Site Characterization  & Monitoring Technologies
      Indoor Air Products
      P2/lnnovative Coatings and Coating Equipment
      EvTEC  (any technology area)
      Air Pollution Control
      Greenhouse Gas Technologies
      Wet Weather Flow Technologies
      P2/Metal Finishing
      Source  Water Protection.

 Battelle is EPA's partner in the AMS pilot. This pilotverifies monitoring technologies for air (ambient,
 source, and indoor air), water, and soil. Thus far AMS verifications have been completed on portable
 nitrogen oxide/nitrogen dioxide (NO/NO2) emission analyzers for combustion sources. Verifications
 are in progress  on open-path optical monitors and on-line turbidimeters. Verification plans are being
 developed for fine particle monitors for ambient air, and for portable analyzers for metals and other
 contaminants in water. The AMS pilot is also interested in verifying mercury monitors, including

 Key Aspects of ETV
The ETV Program is  a voluntary program for commercial-ready technologies;  it does not verify
 prototypes or provide technical or monetary support to developers. Although most of the costs are
currently supported by EPA  funding, vendors are expected to pay a participation fee (which is
expected to increase with time) and to cover "in-kind" costs (e.g., equipment operators andstaff time
to review test plans and reports).  Further, ETV is not an approval or certification process; instead
the outcome is  a quantitative statement of performance during a specific test.

Mercury GEM Testing Through ETV
Data quality is a critical facet of the ETV Program. As a result, the program will capitalize on existing
test procedures and reference methods during future mercury CEM testing. ETV will also try to
collaborate with DOE,  EPA, and othertesting organizations in order to benefit from their knowledge
and experience (i.e., lessons learned). The role of the AMS pilot is to involve CEM vendors, develop
test plans, collaborate in testing, and to prepare verification reports. The product of an ETV test is
a verification report and a summary statement signed by Battelle senior management and an EPA

lab director. These documents state quantitatively how the technology performed during testing.
Since each technology is tested independently, the reports do not include comparisons between
verification tests performed on similar instruments. The test data obtained are used by the AMS pilot
solely to determine the performance of tested technologies, but a collaborative program  could also
be available for uses other than verification (e.g., evaluation of the performance of emission control

More information on the ETV Program is available at http://www.epa.gov/etv.

Mercury CEM Field Demonstrations

Presented on September 14,  1999 by Nina Bergan French, Sky+ Inc.

While working on a project that examined applications and implementations of mercury CEMs for
DOE mixed waste, Dr. French noticed that many people were making "off the cuff remarks" about
mercury CEMs based on a 1997 DOE/EPA test. Due to the poor results of the test, the report was
neither published nor peer reviewed; that is, the developers often did not see the data or results. In
1998, another test was conducted by the DOE/TSCA on an incinerator in Tennessee. In her
presentation, Dr. French discussed results from both tests.

1997 EPA/DOE Test
Three CEMs were tested during the 1997 EPA/DOE test. The CEMs were tested: 1) for suitability
forthe upcoming OSW-MACT rule; 2) to evaluate and revise the draft performance specification (i.e.,
PS 12); 3) to specify calibration techniques and refine experimental test procedures; and 4) to define
the best performance under worst-case conditions.

The Holnam, Inc., cement kiln in Holly Hill,  SC was chosen as one of the test sites. OSW was
regulating three industry types and this site was determined to be the "worst case." It was chosen
      The EPA database showed mercury emissions at 17 ug/dscm without spiking.
      The facility was willing to be the host and duct access was good.
      Cement kilns do not control sulfur dioxide and nitrogen dioxide.
      There were  no wet .scrubbers located at the facility;  therefore, both  elemental and  ionic
      mercury were present

The mercury reference  method  measurements used during the test indicated that mercury exists
almost entirely in the gaseous form, with less than 1% in the particle-bound form.  This finding
indicated that it is not critical to  draw isokinetic samples.  Also, both elemental and ionic mercury
(important for the test) were present.

The three  tested CEMs were manufactured  by Verewa,  now owned by  Durag;  Seefelder
Messtechnik; and Perkin-Elmer (Bodenseewerk), now owned  by Sick Instruments. Descriptions of
each of the CEMs tested are presented below:
      Perkin-Elmer (Bodenseewerk) - The Perkin-Elmer CEM uses a chemical reactor to convert
      speciated mercury to elemental mercury. Following vapor separation, the material is cooled
      and  dried before being collected for about 15 seconds on a cool, gold/platinum trap. A
      heated trap is used to  thermally desorb the mercury with nitrogen  (which minimizes
      interferences). Calibrations are checked with a mercury permeation tube, but no adjustments
      can be made in response to the check.
      Verewa - The Verewa CEM uses heat and chemical reactions to convert speciated mercury
      to  elemental mercury.   An UV photometer (at 253.7 nanometers) and a double-beam
      configuration (to reduce interferences) are employed.  The unit is also not equipped with an
      automatic calibration check, in part because this is not required by German regulations.
      Seefelder Messtechnik - The Seefelder Messtechnik CEM  uses  chemical reactions to
      convert speciated mercury to elemental mercury.  An UV photometer (at 253.7 nanometers)
      is used.  Also, Ecochem Technologies added a 2 micrometer, heated, sintered metal filter to
      the unit to prevent sample lines from  clogging.

1997 EPA/DOE Test Results                                      .              ,
The EPA/DOE study found that the high levels of sulfur dioxide caused extreme interferences. High
maintenance was required,  but due to miscommunication, no daily spot checks were performed.
Also, the monitors were susceptible to clogging from moisture and particles in the stack.  None of
the CEMs met  EPA draft performance specification requirements for either availability or for a
comparison against a reference method.

Obtaining certified calibration material to dynamically spike CEMs with known amounts of elemental
and ionic mercury during the daily calibration checks  was problematic.  The Perkin-Elmer and
Seefelder Messtechnik instruments both used mercury  permeation tubes [not National Institute of
Standards and Technology (NIST) certified] which are only available for elemental mercury, not ionic
mercury  (such as mercuric  chloride). This resulted in a problem  because the  test called for a
calibration that was not even possible.  Also, the CEMs were not designed to  conduct system
calibrations for linearity and  response checks.                      :

The high concentration sulfur dioxide, particulate matter, and moisture  at the Holnam  kiln also
caused a number of problems. It was a huge challenge for these dry, extractive CEM sampling
systems to  measure reactive,  water-soluble species.  The kiln did not have a scrubber in the air
pollution control equipment, resulting in emissions that contained high sulfur dioxide concentrations
(150 to 500 ppm), 94 to 97% relative humidity, and high particulate  matter in the process dust
(particulate matter-bound mercury was not measured).

A site-specific calibration factor was measured  for each CEM. According to Dr. French, it is
important to use an onsite  calibration factor,  which is  based on a comparison with a reference
method.  These calibration factors need to be calculated for each CEM using nine reference method
measurements. The calibration factor is the ratio of the  average reference method response to the
average CEM response.

Some of the issues associated with the draft performance specifications include:
     PS 12 has no guidelines for specific reference materials
      Need to evaluate the entire CEM sampling system
      Permeation tubes with  custom dilution devices are the most viable option,  preferably NIST
      traceable for mercury
     Not exact or calculated; systematic bias is also a problem
      Use Method 101A to measure calibration concentrations.
The door is open for new performance specifications beginning with PS 12, which can then be added
to with experience.

Other test results based on the 1997 EPA/DOE test showed that high  moisture by itself was not a
problem for the Seefelder Messtechnick; however, when it was combined with sulfur dioxide an acid
was created, which, when combined with particulate matter, resulted in plugging.  Both  of these
scenarios required maintenance. The calibration requirements were also fundamentally different for
the European applications.

The bottom line is that this test facility was not a reasonable worst case for HWC applications; it still
leaves questions as to whether CEMs would perform well on a cement kiln.

1998 DOE/TSCA Test Results
The 1998 DOE/TSCA wet stack test was a 2-month evaluation of the Perkin  Elmer MERCEM.
During this test, CEM data were compared to Method 101A data. Mercury concentrations were fairly
low (5 to 60 ug/dscm). The relative accuracies varied (from greater than 300% to 20%) based on
the feed; good accuracies were obtained for liquids, but as the number of particles in the effluent
increased, the accuracies decreased.  This test raised questions about the reference method and
calibration standards.

General Comments
It is important to note that dedicated mercury CEMs are widely used throughout Europe, where the
MWC and HWC emission limit for total mercury (elemental mercury and mercuric chloride) is 50
ug/dscm.  There are a lot of TUV data on their use.  Furthermore, in the absence of high sulfur
dioxide and particulate matter, the CEMs described  in this presentation will perform quite well.

For PS  12 and using  all of the test data,  the information can be summarized in three areas:
interference  gas, absolute calibration,  and calibration standards.  At  the current  performance
specification limit of 500  ppm, the sulfur dioxide level may  need to be lowered  to 100 ppm to be
representative of HWCs. Absolute calibration (with mercury and mercuric chloride) is currently being
done daily; although Europe requires absolute calibration only every 3 months. There needs to be
a way to do  a daily  qualitative check with elemental mercury, which is more realistic with these
instruments.  Also, calibration standard availability, specifically for mercuric chloride and elemental
mercury, needs to be improved.

Mercury CEM performance is not at the required standard and these instruments are large, complex,
and expensive. Ideally, there is a need for simpler, cheaper alternatives (e.g., using dry chemistry)
and a need for realistic performance specifications and validation tests.

Evaluation of CEMs for Mercury Speciation

Presented  on  September 14,  1999 by Dennis  Laudal,  University of North
Dakota EERC

Advantages and Limitations of Mercury CEMs
EERC has been performing bench-, pilot-, and field-scale mercury GEM tests for the last 5 years.
In addition to providing real- or near-real-time results, mercury CEMs may potentially be less costly
than current monitoring approaches and can be used as a feedback for mercury control strategies.
At this time, however, available CEMs can only  be used to measure total mercury (or elemental
mercury) and  are  largely unproven for fossil fuel combustion systems.  Further, in addition to
reliability concerns (e.g., maintenance schedules), the precision  and  bias  have still not been
established for mercury CEMs. Finally, operation is complicated by the fact these systems often need
to use a pretreatment/conversion system prior to the detection portion of the instrument.

Mercury CEMs Tested
EERC has tested three CEMs: the Perkin Elmer MERCEM,  the PS Analytical Sir Galahad, and the
Semtech Hg 2000.  The Perkin Elmer unit was tested with good results at the  pilot-scale level and
PS Analytical^ unit was successfully tested at both the bench and laboratory levels and is scheduled
to be field-tested shortly. Each of these CEMs is discussed in more detail below:
     Perkin  Elmer MERCEM - The Perkin Elmer CEM (MERCEM) measures TGM using a batch
      process (3 to 5 minutes  long) and a gold trap to capture  the mercury.  This large and
      expensive unit also uses stannous chloride to reduce mercury(ll) to elemental mercury and
      a CVAAS to analyze the elemental mercury.  The Perkin Elmer CEM has been certified by
      TUV and is in use at five incineration plants in Europe. Although the unit  is not currently
      being used at a  US facility, demonstration and pilot-scale tests were conducted at a cement
      kiln in  Holly Hills, North  Carolina and at EERC, respectively.  The  unit  has also been
      successfully tested on a mixed-waste incinerator using the RATA protocols at the Oak Ridge
      National Laboratory.
     Semtech Ha 2000 - The lightweight and portable Semtech CEM (Semtech Hg 2000) is
      essentially a Zeeman-modulated CVAAS that continuously monitors elemental mercury. As
      such, this unit can effectively measure elemental mercury  in streams with sulfur dioxide
      concentrations from 250 to 500 ppm. Unfortunately the unit tends to develop excess noise
      in the signal (1 to 3 micrograms per normal cubic meter) and has some problems with zero
      drift. Furthermore, the company, which  is located  in Sweden, is not very responsive to
      customer inquiries.  On the positive side,  Semtech CEM has been certified by TUV and is
      used at several incinerators in Sweden.  The unit has also been successfully pilot-scale
      tested  by EERC and is currently being used at three US power plants.
     PS Analytical Sir Galahad - The PS Analytical CEM (Sir Galahad) also measures TGM using
      a batch process (every 5 to 10 minutes) and a specialized gold trap to capture the mercury.
      The unit uses atomic fluorescence (AF) spectrometry as a measurement technique and has
      a wide measurement range (3 to 7 orders of magnitude). . Unfortunately the unit has
      problems with signal attenuation due to hydrogen chloride and nitrogen dioxide reactions with
      the gold trap and either the hydrogen chloride or nitrogen dioxide must be  removed from the
      gas stream  prior to  the instrument.  (Note: All AF systems which use gold traps have
      problems with hydrogen chloride and nitrogen dioxide reactions. To improve effectiveness,
      these units need to remove either the hydrogen chloride or nitrogen dioxide.)

As noted previously, in order to measure total mercury, some monitors (e.g., the Semtech and Perkin
Elmer CEMs) need to pretreat the flue gas to convert the mercury to elemental mercury to measure
total mercury.  Generally stannous chloride is used to convert mercury(ll) to elemental mercury.
Since the efficiency of this conversion is greatly impacted by the presence of sulfur dioxide, it may
also be necessary to pretreat .the flue gas to remove the sulfur dioxide. It may also be beneficial to
remove  other acid gases (hydrogen chloride, and NOx) to reduce corrosion problems with the
instruments. The  EERC mercury pretreatment/conversion system was then discussed.

Pilot-Scale and Field Test Results
A pilot-scale comparison of the Perkin Elmer and PS analytical CEMs to three impinger-based
mercury sampling methods (i.e., EPA Method 101, Tris-Buffer Method, and the Ontario Hydro
Method) showed  that  both analyzers work well with no pretreatment at the pilot-scale level.
However, these tests were of short duration. The Ontario Hydro results were low since it was not
known at the time that the mercury in the potassium chloride solution needs to  be stabilized with
potassium permanganate prior to analysis.  Both mercuric chloride and elemental mercury were
spiked into the flue gas during these tests. Furthermore, since hydrogen chloride  and sulfur dioxide
levels in flue gases from Blacksville coal combustion are relatively high (e.g., 50 ppm hydrogen
chloride and 1700 ppm sulfur dioxide), these were relatively challenging

A pilot-scale comparison between the Semtech CEM and the Ontario Hydro Method also achieved
good performance (at measuring elemental mercury and total mercury). These results illustrate how
users can speciate the mercury by difference using a  pretreatment/conversion system. This was
also a very challenging test, since hydrogen chloride and sulfur dioxide concentrations in the flue gas
were near 200 and 3,000 ppm, respectively.

Field tests designed to support mercury research, rather than to verify instrument performance, were
also performed using the Semtech and PS Analytical  CEMs  at two lignite plants located  in North
Dakota (the Great River Energy Coal Creek Station and the Minekota Power Cooperative Milton R.
Young Station). A comparison of Semtech  Hg 200 CEM and the Ontario Hydro Method showed
good results (within 20%) for total mercury. Again, these were relatively challenging tests, since the
moisture content of North  Dakota lignites is very high.

Direct comparisons between the Semtech CEM and the Ontario Hydro Method following the firing
of a bituminous coal at a Midwestern plant also yielded reasonable speciation results in the flue gas
over time  (total mercury and elemental mercury), especially considering the relatively  high sulfur
dioxide and hydrogen chloride concentrations in the flue gas.

Conclusions and Recommendations
Mr. Laudal closed with the following  conclusions and recommendations:
     The Perkin Elmer MERCEM,  Semtech Hg 2000, and PS Analytical Sir Galahad have shown
      the ability to measure total vapor-phase mercury with+20% of the wet chemistry methods.
     For all the analyzers to work well, a pretreatment system is needed to remove the majority
      of the acid gases (sulfur dioxide and hydrogen chloride) produced when burning coals with
      high chlorine and sulfur.
     Although mercury CEMs have real potential to accurately measure total mercury, there are
      no commercially available  CEMs capable of measuring speciated mercury  (e.g.,  both
      oxidized and elemental).   A CEM  capable of measuring speciated mercury  may  be
      particularly useful for coal-fired power plants, since different coal types generate  different

ratios between elemental mercury and mercury(ll). These data could eventually be used to
adjust mercury controls (e.g., adsorbent, etc.) and save money at those facilities.
Mercury CEMs must be rigorously tested at the pilot-scale and  in longer-term field tests to
resolve questions regarding accuracy, precision, reliability, and maintainability before they
can be routinely used for mercury measurement in utility flue gas applications.

International    Monitoring/Measurement
Atmospheric Mercury
Activities    for
Presented on September 14, 1999 by John Munthe, Swedish Environmental
Research Institute (IVL)

Most ambient air or stack gas mercury speciation methods are operationally defined and based on
the physical ;and chemical properties of the compounds.  Exceptions include direct spectroscopic
methods, specifically DOAS and Laser Radar (LIDAR). Uncertainties regarding which compounds
should be measured  need to be considered when comparing different sampling and analytical
methods.  .'..                                                     ,

Examples of operationally defined methods include:                       .
       TGM - Sample passes through a filter and is then collected on gold.
       RGM - Material is collected by using a potassium chloride denuder or a mist chamber with
       a hydrochloric acid solution.        ,
       Particulate mercury - This method is dependent on the collection device.

United Nations  Economic Commission for Europe Convention on Long-range Transboundarv Air
The  United Nations  Economic Commission for Europe (UN-ECE) Convention on Long-range
Transboundary Air Pollution (CLRTAP) convention produced the first internationally legally binding
protocols to address air pollution problems on a broad regional basis.  It was initiated after the long-
range transport of sulphur from Europe to Scandinavia was first discovered.

UN-ECE operates under the European Monitoring and  Evaluation  Program (EMEP), which
addresses atmospheric transboundary air pollution.  There are two meteorological synthesizing
centers (MSC)  within EMEP responsible for modeling;  MSC-E in Moscow and MSC-W in Oslo.
MSC-E models metals and  persistent organic pollutant (POP), and MSC-W models  sulfur and
nitrogen. There is also a chemical coordination center (CGC) in Oslo, which is  responsible for
collecting data from all the countries that have signed the CLRTAP protocols.

Under the CLRTAP protocols, approximately 35 countries have agreed to reduce emissions using
best available technologies (BATs). The first CLRTAP protocol (for sulfur) was developed in 1980.
Since then protocols for VOCs,  nitrogen, metals (including mercury),  and POPs  have been
developed. The first protocol for POPs and heavy metals (for mercury, cadmium, and lead) was just
recently signed in 1998.  Data reporting for metals and POPs is voluntary.

The following mercury data are publically available in  Europe:
      Ambient air measurements reported to EMEP CCC
      TGM concentrations  from Sweden, Norway, Finland, and Ireland
      Wet deposition total mercury data from Sweden, Finland, Norway, Germany, and Ireland
Unfortunately, no data are routinely being collected for methyl mercury or any other mercury species.

Rorvik, Sweden, TGM data show the differences in mercury concentrations over the last 20 years.
In the 1980s, there were significant episodes of high concentrations from regional sources in central
Europe. During the  last 4 to 5 years, these concentrations have completely disappeared. The


 baseline for the 1990s is below-2 nanograms per cubic meter. ..In addition, wet deposition of total
 mercury at Swedish monitoring sites decreased from 1995 through 1997. *              :

 Research on Atmospheric Mercury in Europe
 The following two European Union (EU)-funded projects are currently operating in Europe: Mercury
 Over Europe (MOE) and Mediterranean Atmospheric Mercury Cycle System (MAMCS). The main
 goal of MOE is to determine sources of methyl mercury and other mercury species in wet deposition
 in Europe. MOE is responsible for collecting data on mercury emissions data (including speciation)
 and the chemistry of mercury in flue gases and ambient air. MOE also develops process and long-.
 range transport models. MAMCS maintains an emission inventory, performs field measurements,
 and performs process and long-range transport modeling.

 A number of different measurement techniques have been used by MOE and MAMCS to obtain the
 following speciated atmospheric mercury measurements: TGM, RGM, gaseous monomethylmercury,
 gaseous dimethylmercury, particulate  mercury,  and total  mercury and  methyl mercury in
 precipitation.  For TGM, Tekran, Gardis, and manual gold trap methods have been used. A mist
 chamber, annular denuders, and tubular denuders (both automatic and manual) have been used to
 measure RGM. For particulate matter, AES mini traps are mainly being used, as well as Teflon
 filters.  Modified mist chambers are being used to measure gaseous monomethylmercury.  TGM,
 RGM, and particulate  matter  measurements have been obtained from 10  sites and gaseous
 monomethylmercury measurements have been obtained from two sites.  Both organizations have
 also attempted size fractionation for particulate mercury but have not been very successful.

 A comparison of TGM results shows that there is some scattering in the data,  indicating that the site
 location for the measurements could be improved.  Using four different techniques for  RGM,
 preliminary results show a general trend for each technique and fair scattering.

 Local and regional sources   have  a relatively  small  impact  on ambient  atmospheric TGM
 concentrations.  Regional sources, however, have a relatively large impact on particulate mercury,
 and local sources have a moderate influence on RGM, although the reasons for this impact are not
 very well understood.  Speciated mercury data are needed to better understand mercury impacts.
Also, a hemispheric or global perspective needs to be developed using TGM data.

Source-Receptor Relationships for  Mercury:  Monitoring  and


Presented on September 14, 1999 by Gerald Keeler, University of Michigan,
Air Quality Laboratory

Dr.  Keeler  opened his presentation  by noting that he intended to  address receptor versus
deterministic approaches for defining source-receptor relationships for atmospheric mercury, as well
as some of the difficulties and uncertainties associated with these approaches. He then credited the
research performed by the University of Michigan and US EPA NERL over the last 7 years. This
research was funded by US EPA, the State of Florida, the Great Lakes Protection Fund, and NOAA.

Ultimately mercury researchers are interested in understanding "what  is driving the loading in fish,"
in part due to consumption advisories in effect for fish caught in US waterways.  Since source-
receptor relationships are very complex and involve numerous interactions between multiple factors,
Dr. Keeler noted he would limit his presentation to "source-receptor relationships to the atmosphere"
(i.e., the impact atmospheric deposition has on the cycling of mercury in the environment) and not
address uptake by the fish.

Understanding source emissions, particularly mercury speciation and  co-emitted tracer species, is
essential to understanding source-receptor relationships.  This can  be approached by applying
source data to a mathematic  model to define what happens with  these emissions.  It is also
necessary to be able  to describe  and account for the processes  that remove these different
compounds, including elemental mercury and mercury(ll) atmospheric chemistry relationships.  As
mentioned during previous discussions, removal from the atmosphere is largely dependent upon the
form of the mercury (elemental, reactive, or particulate). Finally, atmosphere-surface processes,
including dry deposition and surface re-emission, need to be understood.  Unfortunately, most
atmospheric models only provide loadings to a water body and do not address air/water exchanges
or the processing of pollutants at the surface of a water body or as they come into contact with biota.

Dr. Keeler then presented the following conclusions:
     The importance of local versus regional sources varies dramatically as a function of location -
       For example, approximately 70%  of  the mercury deposited  in  Southern  Florida (the
       Everglades) comes from local sources, as  compared to only 40% for the Great Lakes.
       Furthermore, these proportions are expected to change from year to year depending upon
       meteorology and source activities.
     Incomplete  characterization of mercury emissions limits  mercury modeling and risk
       assessment activities.
     Atmospheric mercury chemistry further complicates mercury speciation considerations - The
       reduction/oxidation chemistry of mercury emitted from sources (i.e., the rate at which it
       transforms from the reactive to elemental form as it is transported) complicates speciation
      Dry deposition equals wet deposition - Dry deposition is poorly understood, in part because
       of difficulties measuring and modeling this factor. In general, however, dry deposition can
       be assumed to be approximately equal to wet deposition in most of North America.

      Lack of ambient measurements of mercury forms (species) limits improvement of model
       parameterizations and ground-truth for models - More data are needed to refine models so
       that they correlate well with actual conditions.
 Two approaches can be used to define source-receptor relationships: a source-receptor approach
 and a meteorological approach.

 Source-Receptor Approach
 The University of Michigan often uses a receptor-oriented approach (that does not rely on emission
 data) to define source-receptor relationships. When this approach is employed, monitoring stations
 are set up at the receptors  of interest (e.g., the Great Lakes).  This approach depends on the
 researcher's ability to measure the species for which he/she wants to define the source-receptor

 The receptor-orientated approach was applied during the Great Lakes Atmospheric Mercury Project.
 During this 2-year-long project (from 1995 through 1996) the University of Michigan measured gas-
 and particle-phase mercury every sixth day for a 24-hour period.  Seasonal particle-phase mercury
 averages based on 120 samples per site and statistically different concentrations for the northern
 and western sites were slightly lower than the average concentrations for the southern and eastern

 When individual mercury measurements are compared to other parameters collected on the same
 frequency,  the structure in the data can be used to identify what factors are influencing the results
 (e.g., meteorological). The database obtained from this Great Lakes Study is one of the largest of
 its kind and includes trace element data  as well  as TGM  concentration (via gold traps).  When
 particulate-phase mercury results are coupled with other parameters (zinc, lead,  iron, manganese,
 copper, bromine, sulfur, and selenium) site-by-site associations (120 samples for each site) can be
 made between the various trace metals and particulate-phase mercury. These comparisons can be
 used to help determine what is "driving the source of the mercury and the other trace elements."

 Dr. Keelerthen discussed the variation obtained between two sites, 30 miles apart. Based on the
 results presented, Dr. Keeler was able to determine that very little of the deposition at the northern
 site was due to coal combustion or iron/steel manufacturing, and that the southern site was impacted
 more by incineration and iron/steel manufacturing activities.  These data show that by coupling
 mercury with other elements, "the signature of the coupled element can tell where the mercury is
 coming from."

 Meteorological Approach
The second approach used to define the source-receptor relationship involves using meteorological
information to calculate back trajectories that coincide with the sampling events.' During a March 10,
 1995 monitoring event, high  particulate mercury concentrations  were obtained  across the  entire
network, particularly at the Lake Ontario Point Petrie site [71 picograms per cubic meter (pg/m3)].
 It is possible, once this information is combined with a hybrid monitoring approach and the removal
processes are accounted for, to assess the contribution of particulate mercury from the Great Lakes
 Basin to the Great Lakes.  This analysis has been used to develop a map which shows mercury
contributions to the Great Lakes on a pg/m3 basis.                                   .

After noting that particulate-mercury results showed a pronounced source-receptor relationship, Dr.
Keeler noted that the source-receptor relationships obtained for the gas-phase mercury results were
not as pronounced.  This was attributed to the fact that the study was measuring TGM only, since


RGM could not be measured in 1995.  Additional data were then presented which indicated that
sources in the south were responsible for elevated elemental mercury concentrations. Unfortunately,
"there were no strong signatures in the data."

Recent RGM data (from the last 1.5 years) clearly indicate that elemental mercury and RGM do not
correlate well. As a result, none of the TGM data collected during the Great Lakes Study will provide
the "signal  mercury researchers are interested in." These data also show that RGM  can be
measured in the ambient environment, as demonstrated by the fact that RGM concentrations rose
when the wind  shifted in the direction of an incinerator located approximately 4 kilometers from the
monitoring site.

RGM was also measured during a dry deposition study in Florida during  the winter of 1998/1999.
The purpose of this study, which was funded by the Florida DEP and EPA, was to determine the
impact of dry deposition to the Florida Everglades in the winter. During this study, researchers noted
that RGM levels tend to follow a diurnal pattern. Researchers also observed that when dew was
present at the sampling site, most of the RGM was removed from the atmosphere to the dew.

After noting that RGM is very important to modeling  deposition to bodies of  water, Dr. Keeler
presented wet, RGM, and particulate mercury deposition to Lake Michigan model results.  These
results, which were obtained from the LLMBS project, showed that wet deposition was responsible
for introducing  the majority of the mercury to Lake Michigan (over 600 kilograms  per year), but that
combined RGM and particulate mercury deposition rates almost equaled wet deposition rates.

The University of Michigan  has also been developing source-based  models which combine
emissions data with high resolution meteorological data to model mercury deposition to  specific
water bodies on a small-scale basis (i.e., 1 to 5 kilometer grid spacing). Dr. Keeler then presented
modeling results obtained by applying data accumulated over a 24-hour period (when a front passed
across the Great Lakes) to a wet deposition model. In  the first scenario modeled with these data,
the modelers assumed that only RGM was emitted during this 24-hour period.  To support this
assumption, the modelers had to. appropriately convert  the emissions data from the EPA Report to
Congress database. In the second scenario modeled with these data, modelers assumed that only
elemental mercury was  emitted during the 24-hour period.  The model results obtained for the
different scenarios differed by approximately 2 orders of magnitude; the  second scenario yielded
results that indicate that almost no deposition to Lake Superior. These data support the need for
speciated emission data from the stacks.

After noting that the results  obtained during a similar analysis  (elemental mercury only and RGM
only) for a dry deposition source differed by approximately 2.5 orders of magnitude, Dr. Keeler then
noted that  techniques have  been  developed to measure dry deposition.  As a result, it is now
possible to use dry deposition measurements to "ground truth" the deposition calculations in the

Dr. Keeler closed by responding to the question "Which do you need more,  monitoring or modeling?"
According to Dr. Keeler, both types of data are needed.  In particular, speciated emissions data (to
be used for modeling) and speciated ambient data (to  enable  modelers to verify the models) are

Manual  Speciation   Methods   for  Measuring   Atmospheric
Mercury: Applications/Implementation

Presented on September 14,  1999 by Matthew S. Landis, US EPA, NERL

Elemental, reactive, and participate mercury behave very differently in the atmosphere. As a result,
speciated mercury data are needed to support atmospheric transport and deposition modeling efforts
and to evaluate bioaccumulation, exposure, and risk assessment. Fortunately, methods to measure
ambient ionic or ROM and particulate mercury are improving.

Challenges To Measuring RGM
There are a number of challenges associated with measuring RGM in the ambient atmosphere,
many of which may be attributed to the need to measure the compounds at trace levels. Not only
does the methodology used to measure RGM need to completely reject the much larger elemental
mercury component,  it also needs to be one to two orders of magnitude more sensitive than total
mercury methods.  Since RGM  is relatively  "sticky," the methodology must also be able to
quantitatively "pass" RGM to the collector. Finally, the RGM method  must also exclude particulate-
phase mercury while avoiding filter artifact.

Ambient Speciation Methods
Examples of currently available  ambient speciation methods include: impregnated (ion exchange)
filters; refluxing mist chambers;  and annular thermal denuders. Annular thermal denuders are the
most promising methodology for avoiding artifact formation.

Annular Thermal Denuders
Denuders are not a new technology. Tubular denuders were previously used in Europe to speciate
mercury in stacks and annular denuders have been used for decades for sulfur dioxide and ammonia
determinations.  In order to use  denuders for ambient  mercury speciation, however, two key
modifications were made from the previous designs.  A single annulus  quartz  denuder was
constructed and coated with  potassium chloride to efficiently capture  RGM at a flow rate of 10 liters
per minute, and rather than perform a wet chemical extraction and  subsequent analysis, the quartz
denuders are thermally desorbed. At approximately 500C, RGM  is quantitatively converted to
elemental mercury vapor and purged directly into a CVAFS. Once desorbed the denuder is
regenerated and ready for reuse.

In addition to being relatively easy to use, annual thermal denuders  are capable of obtaining high
collection efficiencies even at relatively high mass loadings, as demonstrated during laboratory
testing at Frontier Geosciences, Seattle, WA. During this laboratory study, the collection efficiency
obtained for mercury chloride was  97.8% for a total mass loading of 5 nanograms and 97.2% for a
12 nanogram loading.          .

Denuders can also be used to perform high-resolution sampling at  relatively low MDLs: The mean
field blank for the potassium chloride annular denuder was determined to be 2.21  2.26 picograms;
this translates to MDLs from 0.3 pg/m3 for a 12 hour sample to 3.8 pg/m3 for a 1 hour sample at a
flow rate of 10 liters per minute. In fact, during tests in Baltimore, Maryland; Research Triangle Park,
North Carolina; and the Florida  Everglades, the minimum RGM concentrations (5.4; 3.5; and 2.5
pg/m3, respectively) were never below the detection limit of the method.

This method is highly accurate; precision has been demonstrated to be excellent Approximately 10%
RSD) even at concentrations as low as 4 pg/m3.

Role of Manual Sampling
In light of the availability of the Tekran, Inc. automated speciation sampler, which utilizes the thermal
denuder methodology, Dr.  Landis  pointed out that there is still  a substantive role  for manual
speciation methodologies.  Manual sampling can be used in routine projects (to support monitoring
networks),  exploratory projects (for fugitive  emission  monitoring),  special projects (for aircraft
measurements and chlor-alkali facilities), and to support QA/QC efforts (via collocated precision
efforts). Although there are a number of factors that can limit these efforts (cost, expertise, etc.),
these can be partly overcome through more collaborative approaches.  For example, the cost and
expertise needed to perform routine projects could be overcome by  setting up a monitoring network
in which the samples are sent back to a central laboratory for analysis. In addition to reducing costs,
quality assurance is improved by this centralized  approach (by using one person and one lab to
analyze the sample).

EPA NERL Research Initiatives
Future EPA NERL research initiatives will focus on speciation method evaluation (both in the lab and
in the field) and applied research (including aircraft measurements, arctic depletion events, and
fugitive emissions).  It is anticipated that the laboratory method evaluation efforts will concentrate on
evaluating method accuracy, comparability, and interferences, while the field evaluation efforts will
focus on two sites in Florida and Ohio.

The annular  denuder  methodology  provides ambient speciation  of elemental,  reactive,  and
particulate mercury without known interconversion problems. Dr. Landis also noted that low denuder
MDLs allows for high resolution, low concentration sampling.  Furthermore, the manual sampling
configuration is relatively inexpensive, simple, and mobile.

Automated Mercury Speciation Methods and Demonstrations

Presented on September 14, 1999 by Robert Stevens, Florida DEP

Mercury in the atmosphere exists primarily in three distinct forms. They are elemental mercury,
RGM, and particle bound mercury.  Most researchers believe the atmospheric RGM is in the form
of mercuric chloride. The rationale  for this assumption isthat mercuric chloride would be formed
during the high temperature combustion processes in such sources as incinerators and fossil- fueled
power generating facilities. These sources use fuels that contain mercury and chlorine in ratios that
favor the formation of mercuric chloride. These three forms of mercury have very different chemical
and physical properties. Particle bound mercury and mercuric chloride have much higher deposition
rates than the relatively unreactive elemental mercury. For example mercuric chloride has a half life
of hours due to its high deposition and water solubility.  Elemental mercury, on the other hand, has
a half-life in the atmosphere of 6 months to a year.  The forms may be interconverted in the
atmosphere and in various reservoirs. Particle bound mercury half-life is dependent on the size of
the particle. For particles less than 2.5 micrometers in diameter, the half-life is days. For particles
greater than 2.5 micrometers, the half-life is hours.

In source characterization studies conducted  in South Florida in  1995, Method 29 and a DOAS
system were used to speciate the forms of mercury emitted from a resource recovery incinerator.
In this study elemental mercury represented 87% of the mercury emissions. The balance was in the
form of RGM. A few percent of the mercury emissions were in the form of particle bound mercury.
Similar results were also observed in the stack emissions from a medical waste incinerator in South
Florida.   These  mercury source studies revealed that RGM emissions could potentially  be
responsible for contaminating nearby sensitive ecosystems.  At that time a reliable method  to
measure atmospheric levels of RGM did not exist.

Difficulties Measuring RGM
In order to measure expected atmospheric concentrations (1 to 100 pg/m3), the measurement
method  must be one to two  orders  of magnitude more sensitive than methods currently used  to
measure total  mercury.   In  order to accomplish  this,  EPA considered and assisted in the
development of a unique automated annular denuder system that concentrates atmospheric aliquots
of RGM on an  annular denuder for  subsequent thermal release into a Tekran 2537 mercury AF
analyzer. The analyzer consists of a Teflon-coated impaction inlet to remove coarse  particles,
coupled to  a  potassium  chloride-coated quartz annular denuder inside a thermally regulated
oven/housing.  This in turn is coupled to a Tekran 2537A mercury AF analyzer.

RGM Sampling Phase
The denuder and inlet during the 1 to 2 hour sampling phase are maintained at 50C. The denuder
captures all RGM while passing elemental mercury.  The sampling flow rate is 10 liters per minute.
At this flow rate and with the unique potassium chloride-coated annular denuder, the RGM (mercuric
chloride) diffuses to the walls of the denuder and is quantitatively removed from the sample stream,
while allowing the elemental mercury to pass to the Tekran 2537 for analysis. After a 2 hour
collection time the denuder is heated to 50CPC. The RGM is converted to elemental mercury. The
elemental mercury flows to the Tekran 2537 and is measured and reported as RGM. This instrument
has been used in several field studies. Elemental and RGM measurements from Dexter, Michigan
indicated that RGM concentrations increased throughout the day, reaching as high as 28 pg/m3. The


ROM then began to disappear as the humidity increased as expected, due to RGM's (as mercuric
chloride) high water solubility.

Ambient measurements from a test in Baltimore, Maryland indicated that ROM was present at about
20 to 40 pg/m3 for a number of hours before the wind shifted to a southerly flow.  At that point, for
approximately 10 hours, levels of RGM were well above the background values.  In both cases the
concentrations of elemental mercury remained relatively constant.  This indicates that mercury
emissions from the source, an incinerator about 7 kilometers south of the monitoring site, were
largely in the form of RGM.

In summary, the potassium chloride-coated quartz annular denuders have proven quantitatively
effective in collecting RGM. RGM is thermally (at approximately 500C) converted to elemental
mercury. The Tekran 1130  has demonstrated its' utility in several ambient mercury studies.

For future  research, Tekran has incorporated continuous particulate collection abilities (in addition
to RGM) into mercury speciation instrumentation. It appears that this technology will be effective in
quantifying mercury emissions on a routine basis rather than relying solely on research from power
plants and incinerators.

Wet Deposition Sampling - Applications/Implementation

Presented on September 14, 1999 by Timothy Dvonch, University of Michigan

Several groups around the globe have measured wet deposition using a variety of wet deposition
collectors and frequencies (daily, weekly, monthly). In general, most of these approaches have been
relatively successful at quantifying seasonal mercury deposition.  The next step  in addressing
mercury deposition is to  determine its origin, particularly when it is being  deposited from the
atmosphere to sensitive  ecosystems.  Accordingly, Dr. Dvonch's  presentation  addressed a
framework collection  system developed by the  University of Michigan to both quantify annual
deposition and to investigate source-receptor relationships and source apportionment approaches.
Because of the time-scales and distances associated with the transport and deposition of mercury
[mercury(ll) and  particulate], measurements need to be taken daily to ensure accurate source-
receptor relationships. Other air quality pollutants/parameters should be measured concurrently, to
provide a comparison which  can help explain some of the observed mercury processes.  It is also
important to: 1) incorporate clean techniques; 2) insure sample stability; 3) minimize sample artifacts
and losses; and 4) minimize  the potential for dry deposition (using a wet only approach)

UM-B Wet-Only Automatic Precipitation Collector
The  UM-B wet-only automatic precipitation collector was modified from  the MICE collector by
replacing the large Teflon-coated funnel with an acrylic insert so that two separate sampling trains
could be independently quantified. The mercury sampling portion of the collector uses a borosilicate
glass funnel with a Teflon bottle and a glass "p  trap" which serves as a  vapor lock.  The trace
element sampling portion of the system uses a polypropylene funnel. In order to measure to pg/m3
levels in the atmosphere, the whole sampling system is acid cleaned to ensure that  valid data can
be collected.

The UM-B collector was evaluated using collocated measurements collected during field sampling.
Losses to the funnel surfaces were also evaluated, among other factors. The evaluation indicated
that in addition to being accurate andprecise, the collector minimizes the potential for dry deposition
and sample artifacts and losses.  Over the last 5 years a number of UM-B collectors  have been set
up at multiple sites in the Eastern US.

UM-B  collectors were  used in the Everglades and  Davie,  Florida during the South Florida
Atmospheric Monitoring Study (SoFAMMS), and in Chicago during the Lake Michigan Mass Balance
Study (LMMBS).  During the SoFAMMS study, data were collected from five Everglades sites during
summer of 1995 and from the Davie site for a full year (from the summer of 1995 to the summer of
1996).  Data from these tests  were applied to the receptor model, which uses a "principal component
analysis (PCA)  followed by a  multiple linear regression of absolute factor scores against mercury to
perform a source apportionment of the mercury measured during the deposition." With this approach,
"PCA is used to reduce the dimensionality of a data set of interrelated variables so that a minimum
number of factors can explain the maximum amount of variance in that data." This is  accomplished
by referencing the trace element data collected with the mercury results.

When PCA is applied to  air quality data, the factors identified often represent specific source types
(e.g, waste incinerators,  marine sources, oil combustion sources, and crustal sources). The results
obtained from the Everglade  samples collected during the SoFAMMS test indicated that the output
for Factor 1 (waste incinerators) had high loadings for lead and  antimony. Significant factors were

also established for the marine, crustal, and oil combustion components.  Using this approach,
researchers were able to account for 71% of mercury measured using wet deposition.  Following
analysis, the researchers were also able to apportion 77% of mercury deposition at that site over the
1-year period.  Factors such as  crustal sources, incineration, oil combustion, marine sources,
arsenic, copper, and zinc were identified.

Dr. Dvonch then emphasized the importance of performing event measurements of precipitation.
Not only can trace element data be used for receptor-modeling, but more meteorological approaches
can also be used. This approach was used in Southern Florida during the SoFAMMS study.  Radar
images and data obtained every 6 minutes from National Climatic Data Center were used to track
the path of individual storm cells by known source types to the precipitation sampling sites. This
independent receptor-oriented approach was used to confirm  and provide a more robust analysis
of the source apportionment using trace element data.

The LMMBS project also used the same PCA,  multiple  linear regression approach  to source
apportioning the mercury collected via wet deposition during the 16-month study in Chicago.  Up to
83% of the mercury was explained using this approach. A meteorological-based analysis was also
used  to  independently  confirm  the  relationships  established  with the trace  element  data.
Researchers were also able to identify significant differences according to the transport pattern (i.e.,
the path the air followed to the receptor site).

Dr. Dvonch then noted that daily event sampling does not provide a small enough time resolution.
A lot of variability exists from one event to the next. Sequential sampler data obtained manually
during a single rain storm illustrated the changes (e.g., spiking) in concentrations that occurred
during a single rain storm as conditions changed.  A automated sequential sampler was developed
using the UM-B framework.  This event sampler is designed so that one bottle is collected per day
over a 7-day period. Using this approach, bottles are changed based on the volume received or
other programable parameters such as time.

Dr. Dvonch closed by noting that in order to examine source-receptor relationships and determine
source apportionment, discrete precipitation events need to be sampled and trace elements need
to be  quantified (in addition to mercury). Also, dispersion/deposition models need to be  compared
to event data to "ground truth" the models.

Atmospheric Wet Deposition of Mercury in North America

Presented on September 14,1999 by Clyde Sweet, Illinois State Water Survey

The MDN is part of the NADP.  The NADP Program is designed to make long-term measurements
of the chemistry of wet deposition. The program is organized as a cooperative effort among Federal,
State, and some private and local organizations. Each "partner" in this program is responsible for
the collection and analysis of samples from its site.

Mercury cycling and transformation in the atmosphere and water is a very complicated process.
Current efforts focus on wet deposition testing because dry deposition testing is  very difficult to
perform overthe long-term at remote, rural sites using inexpensive equipment and procedures. Also,
wet deposition contributes approximately 50% of the total mercury input to surface water from the
atmosphere.  Furthermore, RGM and particulate  mercury are (preferentially) scrubbed from the
atmosphere by precipitation and wet deposition more efficiently than elemental mercury.

The majority of the MDN sites are currently located in the Eastern States along the northern tier and
the Gulf Coast.  (Note: Four sites are also located in Canada and some MDN sites are monitoring
methyl mercury.) The results obtained from MDN are fairly uniform except in Southern Florida.

Mercury wet deposition measurements (from 1997-1998 MDN results) were compared to RELMAP
and TEAM simulation results for the following five areas: Minnesota, Central Pennsylvania, Southern
Florida, Northeast Texas, and Northern Maine/New Brunswick.  The MDN  results presented
generally agree with the simulation estimates", except for Central Pennsylvania where higher levels
of mercury wet deposition were predicted by the models [greater than 20 ug/m2/yr from RELMAP and
15 to 30 ug/m*/yr from TEAM,  as compared to 7 to 10 ug/nvVyr measured by MDNJ.'  This may
indicate a problem with the model for that region.

Goals and Future Directions ,  ..,    ..........         ,              ,....
A good goal for the future is to expand the network to cover the United States and Canada, like.the
acid rain network.  The  NADP would/also like to target the evaluation of long-term trends. To
accomplish this, sites within the network will need to commit for a minimum of 5 years. Data could
also be used to support a database for research and modeling studies, and to develop a baseline
to evaluate the effectiveness of future controls on mercury. In the future, the NADP would also like
to add other toxics such as trace metals, pesticides, and industrial organics, to its monitoring

Summary and Concluding Remarks

Presented on September 14, 1999 by Scott Hedges, US EPA, ORD, NRMRL

Mr. Hedges closed the conference by summarizing future mercury related activities for EPA ORD
and follow-on actions to the conference.

Future EPA ORD Activities:
Based on pre- and post-conference activities, EPA ORD needs to:
      Provide assistance and encourage manufacturers to develop mercury monitoring/sampling
      systems and for industrial sources to install these systems; EPA's ETV Program and the EPA
      and DOE SBIR programs are vehicles for this assistance.
      Provide assistance and encouragement to the academic community through research grants;
      EPA's environmental research grant and fellowship (STAR) programs are additional types
      of vehicles to provide this assistance.
      Provide assistance and encouragement to the military through Interagency Agreements.
      Continue collaboration with DOE.
      Make the EPA Program Offices and Regions, State and local permitting authorities, industry,
      and the international community aware of the developments in manual and continuous
      systems to measure mercury.

Panel  Discussion Summaries

A.1    Introduction
Two panel discussions were held during the workshop; the first addressed source monitoring/testing
needs and the second addressed ambient monitoring needs. Each panel discussion opened with
an overview emphasizing key findings and issues presented during the workshop. After each source
panelist briefly discussed what he or she thought were the most critical and controversial issues, an
open discussion period was initiated.  It was assumed that the issues discussed by the panelists and
audience would be based on the list of questions and topics provided to workshop attendees prior
to the workshop. The goal of the panel discussions was to work toward consensus on these critical

Each panel session contained two co-chairs and seven to nine panelists. Each panel session also
had a facilitator (one of the co-chairs) as well as a note-taker to help discussions proceed. The focus
of each panel and copies of the questions provided to workshop attendees are included in the written
summary generated for each panel session.

B.1    Focus/Emphasis of Panel Discussion of Source Monitoring/Testing Needs
The Panel Discussion of Source Monitoring/Testing Needs (otherwise known as the "source panel")
concentrated on the needs and barriers ("Catch 22") to developing and implementing mercury CEMs
and associated performance specification protocols for use in regulatory compliance. For discussion
purposes, it was hypothetically assumed that mercury emissions from the major combustion sources
(e.g., utility boilers and waste incinerators) will be regulated. Research CEMs are also needed to
fill in fate and transport and source-receptor research gaps. (Filling these gaps will provide valuable
information to be used in the regulatory decision process.)

B.2    Source Panel Members
Jeffrey Ryan and Nina Bergan French were the source panel chairs  and Russell Bullock,  Scott
Rauenzahn, Stephen Priebe, Thomas Brown, Ronald Baker, John Bosch, and Catherine Massimino
served as panelists.
      Questions/Topics for Source Panel Discussion
      Do you believe total mercury CEMs are capable of cost-effectively monitoring emissions for
      compliance assurance?

      Why or why not?

      Which technologies are forerunners, and why?

      Which technologies are you less sure of and why?

2)    What are the greatest concerns associated with CEM operation?

      What are the risks?

      What are the technical obstacles (e.g., interferences, filter artifacts, durability, biases)?

3)    How should CEM performance be evaluated?

      What are the most important considerations with respect to CEM performance (e.g., drift,
      calibration technique, sensitivity, precision, durability, etc)?

      Is PS 12 still considered to be the appropriate method for evaluating total mercury CEM

      Why or why not?

      Should PS 12 be revised? Who will do it? When?

      What tools (e.g., gas standards, reference materials, comparison methods, techniques) are
      needed to fully evaluate CEMs?

      Are existing reference methods (i.e.,  Methods 101A and 29) satisfactory as an accuracy
      check or reference point for total mercury CEM (averaged) data?

4)    What type of field demonstrations and/or technology  improvements/cost reductions are
      necessary to reduce the risk of implementing total mercury CEMs?

      What type and how many field demonstrations will be required to fully demonstrate CEMs?

      What are the types of sources that must be considered?

      Can nominal and/or worse case monitoring conditions be defined?

5)    Where are speciating CEMs needed?

      Is speciation by difference adequate or are direct speciating techniques needed?

      Are performance specifications needed for speciating CEMs?

6)    Does the CEM technology available today provide an accurate description of the chemical
      and physical forms of mercury introduced into the ambient air after the stack emissions have
      diluted and cooled to ambient temperatures?

7)    What is EPA's role in the development of mercury CEMs? What are the roles of others (e.g.,
      DOE, vendors, State, and local)?

8)    What actions or outcomes are required to move towards implementing mercury CEMs for
      compliance assurance?

B.4   Summary of the Source Monitoring/testing Needs Panel

B.4.1  Chair Comments

Jeffrey Ryan. US EPA NRMRL
Mr. Ryan opened  by summarizing the following applications/ideas for mercury CEMs presented
during the first day of the workshop:

       Compliance: CEMs are needed for compliance monitoring; however, efforts to use CEMs for
       compliance are hampered by the following "Catch 22:" 1) as a market driven technology,
       CEM developments/advances occur in response to regulatory actions/mandates; however,
       2) before regulatory requirements mandating CEM use can be set, technology performance
       needs to be demonstrated.

       Control Technology Research: CEMs capable of measuring both total and speciated mercury
       are needed to advance control technology research. In addition to methods/technologies
       which calculate oxidized mercury by subtracting elemental from total mercury measurements
       (and assuming that the oxidized portion is mercuric chloride). Technologies are also needed
       which can directly measure different oxidized forms of mercury.

       Process Control: CEMs are  needed for measuring total  and speciated mercury  during
       process control applications.  Again, a method/technology which calculates speciation by
       difference can be used for these applications.  It may also be possible to tie CEMs into the
       process control systems as part of neural networks.

       Source-receptor and Fate and Transfer Modeling: CEMs can also be used to support source-
       receptor and fate and transfer modeling research.  There is a clear need to relate stack,
       plume, and ambient measurements. Based on presentations made earlier in the workshop,
       current dilution techniques can be used to effectively simulate mercury transformation as
       emissions exit the plume.  In addition to advancing the scientific community's understanding
       of mercury emissions, source-receptor and fate and transport data are needed to support the
       regulatory determination process.

In general, however,  the workshop focused primarily on using CEMs for compliance monitoring.
Based on presentations during the workshop, not only do there appear to be many viable  CEMs
currently in existence, but less complicated models/techniques are being continually developed (e.g.,
wet conversion techniques are being replaced with dry chemistry techniques). Although current
regulations do not require CEM use, they do provide for and encourage their application.  According
to Mr. Ryan, the panel/workshop participants need to define what factors encourage CEM use.

Finally, the following points were made:
       Performance Specs: The current performance specifications are still in draft form and should
       be used  as guidance.  They are open to  modification, as long as the changes  are
       scientifically justified.
       Emission Ranges: mercury emission levels differ based on their origin (e.g., utility boilers,
       HWC, or cement kilns). As a result, we need to define the concentration ranges  that  CEMs
       need to measure and the conditions they operate under.

Mr. Ryan closed by noting that the purpose of the panel is to define/address obstacles and issues
associated with using mercury CEMs for compliance assurance and to develop  a list of actions,
outcomes, responsible parties, etc., to further CEM use.

Nina Berqan French. Skv+ Inc.
After noting that Mr. Ryan had already summarized many of the points she believed needed to be
made,  Dr. French stressed that for mercury CEM implementation to occur, users need reliable
("strong") operation data which allow users to confidently assess  how CEMs will perform during
facility applications. As a result, scientists, facilities, and EPA need to work together to collect these


data .(e.g., data which support and define claims that "gold traps can handle sulfur dioxide).  Dr.
French then asked each of the panel members to briefly respond  to the issues raised by the
questions distributed before the workshop.    ,

B.4.2   Panel Member Comments

Stephen Priebe. Bechtel B&W Idaho
From a user perspective, Dr. Priebe asked "Why should I (use CEMs) unless I absolutely have to?"
Not only are CEMs data viewed as fairly unreliable, many potential users are concerned about
maintenance difficulties (e.g., obtaining parts from Europe), unit life-span, reliability, cost, and the
possibility that voluntary CEM use could eventually result in CEMs being written into their permits.
Furthermore, many potential users may not want to voluntarily use CEMs since they do not really
want to know what is happening.

Scott Rauenzahn. US EPA OSW
EPA cannot require facilities to install  CEMs unless sufficient data  are available to justify the
promulgation of a CEM-based standard.  Since facilities are not required to install CEMs, EPA is not
able to obtain data on the application of CEMs. This "chicken and egg" scenario has hindered the
application of CEMs for compliance purposes.

While EPA was able to overcome this obstacle for particulate CEMs (by collecting data as part of an
EPA effort), its  preference is to use facility-provided data to justify further CEM-based performance
specifications and standards.  This can be best accomplished by collecting quality data from the
largest segment (i.e., industry) where CEMs can be used.

Since thus far EPA has only specified total mercury CEM standards; future compliance requirements
will probably be developed for total mercury CEMs ratherthan elemental mercury CEMs. Since there
are not enough elemental mercury "numbers" available to set a standard, it will be difficult to develop
elemental mercury CEM requirements in the near future.  Additionally, since the speciated fraction
is more likely to end up in  water bodies, total mercury CEMs are more likely to be  used as an
ambient tool and speciated CEMs are more likely to be used as a research and risk/fate assessment
tool (although manual methods may be more appropriately used to characterize a source).

Catherine Massimino. US EPA Region X
From the perspective of a hazardous waste combustion permitter, Ms. Massimino is concerned
about the day-to-day performance of mercury CEMs after they are implemented at actual, operating
combustion facilities. This information is essential, since it has to be incorporated in an enforceable
fashion into a permit. To reach this goal, an acceptable performance specification (e.g., PS 12) and
good field calibration techniques are needed:

The final acceptance criteria  for the performance specification also need to be resolved. When
developing these criteria, the  following questions need to be addressed:
       Can currently available monitors meet the final acceptance standards?
       What level of monitor performance can we live with?
       Can  the  performance specifications, the  monitor capabilities, and  the standards for
       combustion facilities be "matched up"?

Another issue  that needs to be addressed is whether CEM data can also be used to assess risk.
This is largely  dependent on the capabilities of the  monitors and the permitter's ability to "tie back


to the risk numbers" (e.g., if the mercury risk standard is a tenth of the mercury standard, it may be
difficult to use CEM data to assess risk).  This will probably become a larger issue in the future.

Additionally, the CEM monitors specified in the performance specifications need to be commercially
available; maintainable (via a local vendor or, at a minimum, from a company with a US presence);
economical (since duplicate systems will probably need to be installed at most HWCs which use
CEMs  as their primary control); and reliable (i.e., operable/online for periods greater than a week).

A phased-in approach to CEM use was suggested to address concerns whether current CEMs are
able to meet the acceptance criteria  in the current performance specification (PS 12). During the
phase-in period, monitor performance needs to be correlated to waste characteristics, operating
limits, and the manual method.                      .......

Ms. Massimino concluded by listing the following benefits that facilities may experience if they use
CEMs:                                                                          .
       Potentially larger operating windows and less conservative limits
      Public assurance                                                          .
       Improved ability to characterize legacy waste.

Ronald Baker. Aldora Technologies
Mr.  Baker opened by noting that  his  presentation  was  designed to address  what can be
demonstrated using PS 12 from  a  vendor's perspective  (i.e., how the 130 ug/dscm  standard
cascades down through the performance specification).

There are four tests within PS 12: the interference test, the calibration drift test, the calibration error
test, and the relative accuracy test. Mr. Baker commented  on each of these tests:

       Interference Test: Mr. Baker noted that: 1) there are minor differences in how technologies
       deal  with interferences (e.g., sulfur dioxide and/or particulate); and 2) that TUV  uses
       acceptance criteria that are similar to PS 12 and have been fully demonstrated for certain
       mercury analyzers, and they therefore should not be an issue.

       Calibration Drift Test: During a calibration drift test, an analyzer has to achieve a repeatability
       goal in comparison to a standard over seven consecutive 24-hour periods. In support of this
       test, Mr. Baker noted recent successes over the last year calibrating against compressed gas
       cylinders of elemental mercury (similar to how a NOx analyzer is calibrated against nitrogen
       oxide rather than nitrogen dioxide). He proposed, based on these results, that total mercury
       analyzers could be calibrated daily against elemental mercury. In locations where the
       standard is 130 ug/dscm, Aldora is "comfortable" with concentrations of 20 to 150 ug/dscm,
       although  calibration  gas vendors need to make  more developments and  gain more
       experience in developing products to address these  concentrations.

       Calibration Error Test: Three concentrations are tested during the calibration error portion of
       the certification and performance specification process. In locations where the standard is
       130 ug/dscm and concentrations of 50 or 100 ug/dscm are expected, errors within  10% of
       the reference concentration (at 5 or 10 ug/dscm) can be accomplished.

       Relative  Accuracy Test:  After stating that the relative accuracy test receives the most
       attention of the four tests mentioned under the PS 12, Mr. Baker noted that the "bottom line


       yardstick" is 20% relative accuracy or 10% of the standard. Many CEMs (carbon monoxide
       or sulfur dioxide) are passing on 10% of the standard at lower concentrations.  In locations
       where the standard is 130 ug/dscm, 13 ug/dscm can usually be accomplished downstream
       of a wet scrubber.

In response to complaints regarding monitor complexity, Mr. Baker noted that vendors are asked to
develop "generic" analyzers to address a variety of industries (e.g., utilities, hazardous waste, etc.)
and concentrations. Monitor complexity  can be reduced to optimize instrument application after
specific applications are identified. Additionally,  issues regarding service, parts availability, and local
representation are a function of the market and the number of installations.

Thomas Brown. DOE NETL (formerly FETC)
CEMs are not ready to be installed in any  facility in the US, particularly the utility industry where the
nominal mercury concentration is  10 ug/dscm.  In addition to producing  a variety of flue gas
conditions, associated in part with burning three different ranks of coal at over 1,100 facilities in the
US, the emissions from  the  utility industry commonly contain  compounds that interfere  with
measurement accuracy [sulfur dioxide (300 to 3,500 ppm); hydrogen chloride; and nitrogen dioxide
(typically 5% of NOx)].

Although monitors are currently available which can measure mercury concentrations ranging from
20 to 130  ug/dscm, none of these CEMs are capable of routinely and reliably measuring mercury
concentrations at coal-fired utilities. Impacts from fine particulate, mercury adsorption, mercury
conversion, etc., still need to be addressed, perhaps through the application of up front conditioning
systems (to remove hydrogen chloride, sulfur dioxide, and nitrogen dioxide, although the last is more

Furthermore, vendors need to be worked with to test CEM performance under controlled, pilot scale
tests in which one or more types of coal are  fired.  These tests should be long-term and designed
to assess particulate impacts. They should also  be designed so that different concentrations of sulfur
dioxide and hydrogen chloride can be injected  into the flue gas.

In conclusion, the effective application of CEMs across the entire utility industry is complicated by
variations  between facilities (due to the different types of coal, controls, etc.) and may eventually
prove to be impossible. CEM application will  also be impacted by the limits set for coal-fired utilities
(e.g., if the limit for coal-fired utilities is set  between 5 to 10 ug/dscm rather than 10 ug/dscm or
above, this will have a big  impact on CEM use).  Finally, field testing has to be done and calibration
systems (with elemental and oxidized mercury) have to be developed so they can be run through
the conditioning systems into the analyzers.

John Bosch. US EPA OAQPS
EPA OAQPS  is currently involved in a study, scheduled to be completed by the end of next summer,
which will be used to help determine whether coal-fired utilities will be regulated. If EPA decides to
regulate this industry, periodic and continuous compliance monitoring will be required, probably using
CEMs. If CEMs have  not been  demonstrated  to be useful when the regulations  are developed,
monitoring alternatives will be specified in the regulations.

After stating that permitting and air toxic issues may also have an influence on future mercury CEM
use, Mr. Bosch noted the recent advances in CEM technologies and possible improvements to PS

12. Mr. Bosch then suggested that EPA field test a number of GEM technologies to assess optimum
performance and to obtain data to revise PS 12.

After revising the PS 12 standard, OAQPS is considering using the EPA ETV Program to expand
the number of technologies/vendors  known to be capable of meeting  the PS 12 standards.
Ultimately OAQPS and ETV data could be used by the emission standard division director to justify
including CEMs in the regulations.

Russell Bullock. US EPA NERL
Mr. Bullock stated his need, as a modeler, to be able to explain the differences between source and
ambient monitoring data (post-stack reactions and their impact on ambient concentrations). Contrary
to the expectations of some ("We need you to model the emissions and ambient conditions because
we cannot afford to measure them"), ambient and source data are needed in order to develop good
models.  Although a draft model can be developed based on the first principles of science (e.g.,
chemical and physical reactions), emissions data (especially source data) and ambient data are both
needed to test whether the most important parameters and reactions in the  atmospheric processes
are adequately addressed by the model. Only after the models are fully developed and tested in this
manner can they then be used as a substitute for ambient monitoring. Source data will always be
required, even by fully developed and tested models, to assure that the emissions rates simulated
by the model are accurate.

After noting the  difference between research and compliance mode monitoring, Mr. Bullock
emphasized the importance of obtaining speciation data (the difference  between oxidized and
elemental mercury in emissions) for research and model development.  After the models have
developed the level of complexity needed to account for conditions in the  atmosphere, it may be
possible at that point to reduce/simplify monitoring requirements to TGM measurements.

Mr. Bullock concluded by noting that although source sampling at the stack provides important
information, air quality simulation models need to be developed which address plume reactions
immediately after emission.  In order to better understand the condensation and sorption of oxidized
mercury gases on particulate  in the atmosphere, reactions within the first  10 to  30 seconds  after
emission need to be better understood. This may be accomplished through dilution sampling.

B.4.3  Open Discussion

James Kilqroe. US EPA ORD
EPA ORD  has  a substantial  budget  for control technology  projects, including measurement
technologies. If it is assumed the Agency decides to regulate mercury from utility boilers, a 2 to 4
year test program will  need  to  be developed which  uses CEMs to evaluate different control
technologies so that real-time, parametric data can be obtained.  Assuming a number of CEM
vendors participate in this study, this  program  may provide a good  opportunity to promote the
development of CEMs by obtaining data which could later be used to assess whether CEM monitors
have the potential to be used  as compliance assessment tools. Mr. Kilgroe closed by noting his
intention to encourage EPA to work more closely with dilution samplers to understand speciation out
of the stack.

In response to Mr. Kilgroe's  comments, Mr.  Brown noted that DOE  is  planning to release a
solicitation in December 1999 or January 2000 regarding demonstrating/evaluating mercury control
technologies. He believes CEMs will play an important role in this study, allowing DOE to collect


data within a couple of days  or weeks which Would normally take months to a year to collect
manually.  He encouraged GEM vendors interested in becoming involved with DOE and EPA studies
to contact him and Mr. Kilgroe.

Fredric Chanania. US EPA OSW
Mr. Chanania  cautioned  that many of the points made thus far were  made from  a research
perspective and do not reflect regulatory ("real world") conditions or events.  Although the challenges
for coal-fired power plants are very different from the challenges faced by HWCs, this is a reflection
of differences associated with the level of scrutiny, regulatory history, and nature of the emissions
(e.g., sulfur dioxide) from these facilities.

Additionally, there are currently a number of tools ("hammers and carrots") available to the HWC
industry which are not currently available for the electric utility industry. To address this need, EPA
OSW is about to begin a program which encourages facilities to use CEMs not for compliance
purposes, but to generate data on CEM performance and to obtain data to  improve a facility's ability
to understand variability within their system and how they can meet the standards.  As an incentive
to enter this program,  EPA is allowing these facilities to use very long averaging times (to account
for spikes) and (potentially) allowing these facilities an extra year to install APCDs to meet MACT

Although EPA is emphasizing the use of incentives ("carrots"), OSW is taking a broad-based look
at mercury treatment standards in the ANPRM for Mercury.  Although thus  far EPA has not directed
specific waste types towards specific types of units (i.e., specific types of incinerators or systems with
specific air pollution control or monitoring devices), this may be a possibility in the future. OSW is
aware that many facilities have anxieties about compliance issues and is interested in defining what
steps need to be taken to  get facilities to install CEMs. OSW's focus, however, is not research, but
protecting the public and meeting its demand  for real-time monitoring.

Mr. Chanania then  noted that EPA is not currently targeting the development of nationally codified
specifications or a national PS 12 capable of fitting every type of machine/situation; instead EPA is
encouraging the development of site-specific approvals/permits  developed  under  the current
guidance. From a policy perspective, Mr. Chanania then noted that participants need to remember
that science informs but science does not control. As a result, policy makers can not always wait
until they have "perfect data" before proceeding with sorhe level 6f regulation/policy development and
that sometimes informed assumptions or "best guesses" need to be used to get policy started.

John Jenks. New Jersey PEP
Although mercury may be the single most toxic air pollutant, a large amount  of circular logic ("chicken
and egg", etc.) is interfering with the development of approaches to deal with this pollutant.  It is
necessary to stop "researching (the issue) to  death" and start employing a phased-in approach to
address mercury monitoring needs.  Furthermore, the "flaws" in PS 12 should not be used as a
justification to stall CEM use,  since a more stringent standard can  be phased-in at a later date as
more information  becomes available.  This can be done either using regulations or incentives
(preferably).                                                  ,    '

Dr.  French  and Mr. Rauenzahn  responded that this would be best  accomplished  by providing
incentives  to  facilities  to  install   CEMs  and  not  focusing  on  compliance   and/or  the
revision/implementation of the PS 12  procedure.  Additionally, Mr. Rauenzahn believes that the
processes and procedures defined in PS 12 were essentially "final," but that data are needed to set


the acceptance criteria and that hopefully over the next couple of years these data can be obtained
(potentially by category).

Catherine Massimino. US EPA Region X
When justifying alternate monitoring to the public, there is a need to justify why alternate monitoring
is not being used for compliance.  When,developing a permit, phasihg-in these data for use in
compliance with time should be considered.  Furthermore, this intent should be clearly stated up

Evan Granite. DOE
The  workshop emphasized the use of UV-based CEMs. In response to Mr. Granite's question
whether mass spectrometer or atomic emissions spectrometers could potentially replace UV-based
CEMs, Dr. French responded that this is possible (and a promising simplification), but since CVAA
systems can be made to work,  she could not predict that atomic mass spectrometry will replace
these methods.

Dana Oliver. Pioneer Chlor Alkali Company. Inc.
When a new regulation/standard is anticipated which is expected to use instrumentation that still
needs to be developed, industry wonders whether it can meet the specification/regulation when it
comes out and whether the data collected using these new monitors can be used against them if the
monitors indicate the facility is not complying with the regulation.  Not only does industry want to work
with ERA to help develop technologies for monitoring, but it also wants to develop real standards that
can be both met and monitored.  In the long run, a collaborative, long-term approach to implementing
CEMs will result in a standard EPA, industry,  and the public can live with.

Scott Rauenzahn. US EPA OSW
Mr. Rauenzahn questioned whether mercury CEMs could be used if the mercury emissions
standards for boilers were raised from  10 ug/dscm  to  150  ug/dscm.  Mr. Brown responded that
because the majority of coal-fired units  produce -levels of 10 ug/dscm, the monitor has to work at
these lower limits with higher concentrations of other interfering gases.

Dennis Laudal. University of North Dakota
Mr. Laudal then stated that although mercury CEMs are available to monitor concentrations near 10
ug/dscm, their reliability  and consistency needs to be proven over time, through real  world
applications.  In response, Mr.  Baker noted  that some mercury CEMs are currently capable  of
monitoring sources with higher emissions and, similar to sulfur  dioxide monitors, these CEMs will
eventually evolve to the point where they can be used to reliably monitor low concentrations sources
(e.g., achieve single digit detectabilities).

Nina Bergan French. Sky+ Inc.
Dr. French questioned whether utility lobbies would effectively block mercury CEM.implementation
since the technologies could be easily improved by orders of magnitude. Mr. Brown responded that
there are significant technical obstacles that need to be overcome, which is the focus of the

John Bosch. US EPA NRMRL
The Enhanced Monitoring Rule (EMR), which was later replaced by the Compliance Assurance
Monitoring (CAM) Rule, potentially affected a large number of sources and could have resulted in
the installation of 100,000 CEMs. Although this is not the case with coal-fired utility boilers, once EPA
demonstrates CEMs for these applications, EPA also hopes to use the data to encourage the
broader application and expanded use of these technologies.

William Haas. Ames Laboratory
(The chair restated the goal of this panel: to identify what needs to be done to begin implementation
of mercury CEMs.) Mr.  Haas proposed that EPA ETV and TUV collaborate to demonstrate CEM
suitability for compliance monitoring.  Mr. Kilgroe responded that EPA OAQPS intends to use the
ETV Program, which can only test commercial-ready technologies, to the maximum extent possible
to support its efforts.

James Kilgroe. US EPA NRMRL
The inlet loadings used to  develop MWC regulations for incinerators (200 to 1,500 ug/dscm) were
significantly higher than the inlet loadings experienced by utility boilers (approximately 10 ug/dscm).
If the Agency decides to target 90%  control in this industry,  CEMs with an operating range of 1
ug/dscm will be needed.  Based on Mr. Kilgroe's experience, this will be a significant technical

Lee Alter, Northeast States for Coordinated Air Use Management
In response to Dr. French's question regarding what needs to be done to begin implementing
mercury CEMs, Mr. Alter noted that in  order to implement CEMs at utilities, it is necessary to be able
to distinguish total from speciated forms in order to facilitate trading. Since total CEMs will most likely
be proposed for use, this may impede the development of an effective utility program (since these
CEMs do not distinguish between elemental and ionized mercury).  This comment was echoed by
some members of the panel.

Ronald Baker. Aldora Technologies
Mr. Baker tied Mr. Alter's discussion to the redundancy issue by suggesting the use of two monitors,
one to measure total mercury and one to measure elemental mercury. In addition to obtaining on-
going, real-time total and elemental mercury concentration data for trading purposes, facilities would
be equipped with a backup monitor in the event one  monitor goes offline.

Warren Corns, PS Analytical
As a clarification, Mr. Corns noted that AF-based technologies can achieve sensitivities near
nanograms per cubic meter levels, even in flue gas matrices, making these technologies almost 500
times more sensitive than  needed to support their application at coal-fired utilities.

Jeffrey Ryan. US EPA NRMRL
Based on implementation-related discussions thus,far, Mr. Ryan noted that there are opportunities
to implement CEMs but that first EPA needs to identify and prioritize which types of sources they
need to be implemented at first.  This will be partially driven by the incentives used to encourage
facilities to use CEMs (e.g., opportunities to expand  operating envelopes or delay implementation
of the regulations).  It also appears that hazardous waste facilities, particularly facilities with wet
scrubbers, will be the most amenable to implementing CEMs. There is still a need to determine how
to develop the performance specifications for individual sites using the current guidelines. For these
first  applications, the acceptance criteria will need to remain somewhat  open-ended or "to-be-


determined" at a later date.  Ultimately, however, EPA needs to define which sources find the
incentives to test OEMs the most appealing.

Stephen Priebe. Bechtel B&W Idaho
Dr. Priebe pointed out that there is a need to determine how to initiate interaction between the
regulator/permitter and facility to encourage voluntary GEM use.  Who is responsible for initiating
interactions between the facility, permitter/regulator, or an independent group (e.g., an industry
group) needs also to be determined.                                        .

According to Mr. Brown, this needs to be done at the local level (not through Washington). Also,
based on his personal experiences, many trade associations contain members who are opposed to
moving ahead with environmental regulation. Since these organizations are run by consensus, they
tend to be more conservative when facing environmental change. Also, Mr. Brown has had better
success with voluntary incentive programs when approaching individual companies rather than trade
organizations or industry groups.

William Haas. Ames Laboratory
If TUV and ETV collaborate to evaluate the suitability of these monitors, this will most likely be done
using the TUV model. As a  result, these tests will be performed at specific sites, which  can be
viewed as a 50,000 dollar incentive for those facilities.  Furthermore, TUV also has significant testing
competence, which can be used to ensure that appropriate test plans are developed under the
technical guidance of the developer.

Scott Rauenzahn. US EPA OSW
As a private company, TUV would need to be paid to participate in this effort. Also, TUV-generated
data belong to whoever paid for testing (although many vendors are willing to release these data),
and thus are not always publicly available.  This fact will need to be overcome in order for  data
reciprocity to occur.  Additionally, there are huge  differences in the methods and approaches used
in the two programs which would also need to  be addressed.

Thomas Kelly. Battelle
Although the ETV Program initially considered using data obtained elsewhere to verify technologies,
this is no longer an option.

Dennis Laudal. University of North Dakota
From the vendor's  perspective, the fact that the ETV Program is not a certification process is a
definite drawback.

James Kilaroe. US EPA NRMRL
It is not necessary to spend  too much time debating ETV, since ETV has committed to testing
commercially-ready mercury monitors (although  the specific details of these tests still need to be
worked out) and EPA plans to use this approach to support the implementation of these monitors.

Jeffrey Ryan. US EPA NRMRL
What do EPA and DOE need to do to obtain the information needed to move  these technologies
forward? Does EPA need to develop the conditioning systems?

Ronald Baker. Aldora Technologies
In orderto move forward, a cylinder of gas needs to be certified against Method 29. This will provide
a reference from which acceptable tolerances can be developed.  Incentives can also be given to
encourage calibration gas vendors to develop gases at given concentrations.

PS Analytical
Why should an absolute standard be calibrated against Method 29 if there is an absolute method for
measuring how much mercury is in a cylinder of gas? This saturation method, which uses volume
measurements from a pool of mercury at a fixed temperature, was published in 1985. As mentioned
by another participant, the technique, however, does not work for UV light sources.

Comment (Unknown  Participant)
ASTM should be approached about defining/developing terminology and procedures for testing CEM
suitability, including checks for automatic zero, span drift, calibration error, etc.

Eric Prestbo. Frontier Geosciences
EPA is currently considering regulating coal-fired utility boilers; however, the resulting monitoring
requirements are still unknown (i.e., whether CEMs will be required or whether quarterly testing will
be sufficient).  Also the  concentrations in the coal-fired utility industry do  not vary as much as
concentrations within the HWC industry, due to the fact that mercury concentrations in different coals
only vary by a factor of three. Also, the upcoming ICR data will most likely show that concentrations
in coal and flue gases are dramatically lower than expected (up to a factor of 2) due to coal switching
in response to the sulfur dioxide regulations. These data will probably have a significant impact on
whether a regulation is put in place.  Furthermore, if mercury concentrations in coal flue gas are
regulated, a standard  of approximately 1  ug/dscm will have to be targeted to observe a visible
emission impact (more than a 10% reduction). Finally, since it will probably take billions of dollars
to develop, research, and implement/install CEMs in coal-fired utility power plants, as a taxpayer Dr.
Prestbo believes that society would benefit from using these resources to learn more about mercury
fate, instead of learning how to calibrate  CEMs for these  utility applications.   Perhaps a better
approach would be to obtain the aid of the utility industry (both monetary and technical) to study the
fate and effect of mercury in coal instead of focusing our efforts toward developing regulations
requiring CEM use.

Jeffrey Ryan. US EPA NRMRL
In response to these comments, Mr. Ryan noted that the panel is seeking to identify technological
improvements to CEMs given potential applications and did not plan to discuss whether utilities
should be regulated.

Fredric Chanania. US EPA OSW
Based on experiences with public's response to EPA's plan to better understand HWC emissions,
the public will not care what EPA finds  out about mercury emissions; they just want EPA to make
sure the emissions are as low as possible.

Eric Prestbo. Frontier Geosciences
As an alternative, Dr. Prestbo suggested using this funding to educate the public about  mercury.

Jeffrey Ryan. US EPA NRMRL
Based on today's discussion, some of the information needed to move forward on certain fronts is
currently available.  However, a phased-in approach to address the steps required to define
information needs, to identify and provide incentives to sources, etc., will need to be employed.

C.1    Focus/Emphasis of the Panel Discussion of Ambient Monitoring Needs

The Panel Discussion of Ambient Monitoring  Needs (otherwise known as the "ambient panel")
concentrated on the status and role of ambient mercury speciation methods and models to quantify
source-receptor relationships. It was designed to address the needs and requirements to set up
ambient and wet deposition measurement stations/networks at several urban locations. It also
discussed what source, ambient and meteorological data are needed to support regulatory decisions
as well as what mercury exposure/bioaccumulation/TMDL modeling are needed.

C.2    Ambient Panel Members
Robert Stevens and Matthew Landis were the ambient panel chairs and Gerald Keeler, Eric Prestbo,
John  Munthe, Thomas Atkeson,  Matthew Landis, Carl Kamme, and Russell Bullock served as

C.3    Question/Topics for the Panel Discussion of Ambient Monitoring Needs

1)     What is the state-of-the-science in measurement methods?

2)     What are the needs for representative and comparable data?

3)     Do we need to expand the wet deposition and aerosol mercury monitoring network and add
       additional atmospheric mercury measurements?

4)     What are the needs for method standardization and ambient reference method(s)?

5)     Use of manual versus automated sampling techniques.

6)     What are the needs for speciation?

7)     What ambient and source inputs are needed for dispersion modeling?

8)     What is EPA's role in the development of ambient monitoring techniques? What is the role
       of other groups?

9)     What does EPA need to do and when?.

C.4    Summary of the Panel Discussion of Ambient Monitoring Needs

C.4.1   Chair Comments

Robert Stevens. Florida PEP
Mr. Stevens opened by summarizing the principal focus for the panel as follows:

       "The panel will concentrate on the status and role of ambient mercury speciation and the
       methods and  models used to quantify source-receptor relationships. It will address the
       needs and requirements to set up ambient and wet deposition measurement stations and
       networks at several urban locations. The panel will also discuss what source, ambient, and
       meteorological data are needed to support regulatory decisions, as well  as what mercury
       exposure, bioaccumulation, and TMDLs are needed."

After noting that ambient measurements are  often used to develop TMDLs, bioaccumulation
estimates, and source-receptor relationships,  Mr. Stevens mentioned that the panel was at a
disadvantage since there is only a handful of source profiles in the US. According to Mr. Stevens,
the last major effort  to generate a complete set of  source profiles  was performed  in 1982 in
Philadelphia (using receptor modeling for fine and coarse particulate for three major sources - an
incinerator, a coal-fired power plant, and a smelter). Furthermore, only limited work is currently being
done in the US (e.g., in Glenn Cass and John Watson's laboratories).

Mr. Stevens closed by suggesting that source, ambient, and modeling efforts need to be "brought
together" (collaborative efforts, with similar agendas).  Mr. Stevens then asked each of the panel
members  to  briefly discuss  ambient monitoring issues identified as the focus of the panel.

C.4.2  Panel Member Comments

Thomas Atkeson. Florida PEP
Dr. Thomas Atkeson,  Florida DEP, outlined mercury research needs in relation to  EPA's application
of the TMDL approach.  He noted that many of the topics of concern had already been  discussed,
and that the  EPA Office of Water and Office of Air are currently collaborating with Florida and
Wisconsin on two TMDL pilot projects to study the effects of atmospheric mercury on water bodies.
In the past, water and air programs at both the national and State level have been criticized for being
"separate"; however, more collaborative efforts have  been taking  place  in recent  years,  as
demonstrated by projects examining air-water interactions in the Great Lakes and Chesapeake Bay.

When the CWA was first developed, a cycle of monitoring, assessment, and remediation activities
was established. Although monitoring and assessment efforts are commonplace, remediation efforts
(e.g., feedback into watershed management) have not progressed to the same degree.

Initially,   TMDLs   were  developed   to  assess  relatively  straightforward   source/effect
relationships/impacts [e.g., determining how much biological oxygen demand can be introduced to
a water body  by a sewage treatment plant without causing a dissolved oxygen (DO) violation].  With
time, EPA's approach to assessing impacts broadened, such that once a water body is classified as
impaired, EPA has to identify and control the source of the impairment. (Note: A water body can be
determined to be impaired if does not conform to all the criteria associated with its classification type.
For example, if someone determines that the fish from  a Class III lake cannot be eaten, the lake will
be classified  as impaired and EPA will  need to begin investigating and controlling  the pollutant
source(s)  responsible for the problem).

EPA is currently considering expanding its approach to address  impairments to water bodies
attributed  to contaminants from the atmosphere. If this approach is employed, the CWA and CAA
will be "married" so that air sources may be regulated based on water problems.  Furthermore, the
resulting TMDL's for mercury will be driven by EPA's risk assessment for mercury and forthcoming
water quality criteria (due in 2000).


 In response to these changes, ambient, source, and modeling representatives need to be ready to
 answer questions about source-receptor relationships, specifically what proportion of the mercury
 deposited in an area is coming from within the different States and the US (which the States or
 Federal governments may be able to control in some fashion) and what proportion is coming from
 farther afield.  This is particularly important for Florida, since 95 to 98% of mercury present in the
 Florida Everglades came out of the atmosphere.

 Therefore, to better estimate the amount and form of mercury, emissions data need to be obtained
 and provided to modelers and regulators responsible for recommending regulatory strategies to
 reduce exposure to mercury.

 Clyde Sweet.  Illinois Water Survey
 Clyde Sweet, Illinois Water Survey, discussed the development of the North American Mercury
 Deposition Network. The approach used to develop the network is to set up a number of sites across
 the region (similar to the National Atmospheric Deposition Program) coupled with a smaller number
 of research sites where source-receptor modeling, dry deposition testing, and other mercury-related
 research could occur.

 Since this proposal was developed, approximately 40 MDN sites have been added to the network,
 which, when coupled with some of the smaller wet deposition networks already in existence, can be
 used to form a NADP acid rain-style network,  at least for the Eastern US.  Dr. Sweet emphasized
 the need to maintain these sites over a long enough time period to establish the effectiveness of
 mercury emission controls.

 Finally, two research sites are being set up in Ohio and Florida with funds provided by EPA NERL.
 Hopefully these sites will also help answer questions which cannot be answered based on work done
 at wet deposition-only sites (e.g., sources of mercury, dry deposition, etc.).

 John Munthe. 1VL Swedish Water and Air Pollution Research Laboratory
 Dr. John Munthe,  IVL Swedish Water and Air Pollution Research Laboratory, Goteborg, Sweden,
 explained that when speciating mercury, both in emissions and ambient air, it is important that
 research goals be understood. These goals then help in establishing and prioritizing EPA Agency
 needs. Since mercury is known to be a toxic element, society may benefit more from using current
 research funding to control emissions. However, EPA must first identify the form of mercury that is
 being emitted  to better design the most effective controls.   For example,  the control used for
 elemental mercury would be very different from the control technology used for mercuric chloride

 Source-receptor relationships for mercury are being investigated so that the regulatory and scientific
 community can determine where the mercury is originating and determine how to control its impact
 In Europe,  the UNEC has  focused its control efforts on apportioning mercury emissions and
deposition to different countries. In many cases, emission limits and reductions are used to reduce
depositions to  sensitive areas.  This  is accomplished by apportioning the emissions to different
sources (or source categories) and relying on atmospheric modeling results.

To ensure that sound atmospheric modeling  results are obtained, however, the regulatory and
scientific community needs: 1) good total and speciated mercury emission  measurements;  2) a
thorough understanding of mercury reactions in the atmosphere; and 3) atmospheric data which can
 be used to modify/validate model results. Although it may not be practical to measure the speciated
emissions from all major sources, research efforts need to be focused on measuring speciated


emissions from all the major source categories, so that this information can be used to update
emission inventories.

Eric Prestbo. Frontier GeoSciences
Dr. Prestbo, Frontier GeoSciences, suggested that the following three items are needed to support
mercury efforts: 1) a national deposition network; 2) data obtained close to sources; and 3) the
capability to do mercury field calibrations for CEMs.

In order to develop the deposition network, methods for validating the available models need to be
developed. After noting that results from the NADP sites have shown that the US sulfur dioxide
controls have had a dramatic effect on sulfur dioxide/nitrogen dioxide deposition in the Northeast,
Dr.  Prestbo noted that similar comparisons and effects of control regulations may be possible for
mercury deposition if US monitoring efforts begin coordinating with each other (before the mercury
controls are put in place) in support of this goal.  Dr. Prestbo then suggested that EPA may want to
actively ensure that the different testing groups cooperate with each other and use similar mercury
measurement  methods.  Additionally, "super sites" are also needed for speciation testing, event
sampling, and  other mercury-related research.

The availability of mercury deposition data close to sources is limited. Although a similar, but more
complex, study was done in Florida/there are currently no data in the US documenting mercury
rainwater deposition  underneath a plume  from an isolated single  source  during a rain event.
Accordingly, new studies need to be performed in which event sampling is performed both upwind
and downwind (e.g.,  10 kilometers) of a source as a  simple weather system moves across the
country.  This kind  of data would be highly useful to determine the local mercury  deposition
contribution from combustion point sources.  Currently,  EPA is largely  limited to modeling  local
mercury deposition from combustion plumes.

Finally, emphasis needs to be placed on  developing improved field calibration techniques for
speciation of mercury using CEMs. Without real-world calibration techniques for mercury speciation
in flue gas, the data will always be subject to relatively high uncertainty.

Gerald Keeier. School of Environmental  Engineering. University of Michigan
Dr.  Keeier, from the University of Michigan's School of Environmental Engineering, proposed in 1995
that MDN set up an intensive monitoring  event sub-network as part of the regional long-term
monitoring network.  This sub-network would allow a number of research questions to be answered
(including how different forms of mercury are being removed). Data collected from a number of
specific source areas (e.g.,  coal burning and oil  burning) would aid in determining source-receptor
relationships. Dr. Keeier suggested that EPA consider this proposal for application in the near future.

According to Dr. Keeier, the biggest uncertainty associated with TMDL efforts is the uncertainty
associated with the forms and  amounts of mercury emissions and ambient  air concentrations. In
order to improve the performance of TMDL models coupled to watershed effect studies, better data
are needed. Furthermore, major source categories need to be studied, particularly with respect to
day-to-day and seasonal variation in emission patterns.

Finally, opportunities to perform coupled emission deposition studies should be utilized, so that
researchers/modelers can investigate the chemistry and transport of mercury in the atmosphere.
Aircraft measurements, receptor  site measurements of the major forms  of mercury (mercuric

chloride, elemental and particle bound mercury), and speciated mercury emissions are vital inputs
to the current source-receptor models.

Karl Kamme. Opsis. Inc.
Karl Kamme, Opsis Inc., related his experience with mercury measurements using the  DOAS
technology.  His studies suggest that both fenceline and source characterization are needed to
address source emission characteristics. The DOAS technology is currently being used by ORD and
EPA's Office of Enforcement to measure fugitive mercury emissions from chlor-alkali operations in
the United States. In addition, the DOAS technology is approved by the European testing laboratory,
TUV, to measure in-stack emissions of elemental mercury from incinerators and fossil fuel powered
electric utilities. Mr. Kamme also noted that his company's efforts to get industry to install "fenceline"
applications have been hindered by concerns that the data obtained using these systems can be
used against them.

Matthew Landis. US EPA Research Triangle Park (RTF)
Dr. Landis, US EPA RTP, observed that when developing a model for estimating emission transport,
deposition, bioaccumulation, etc., the ultimate goal is to set up a model with predictive ability, so that
the model can be used to test different load reduction scenarios and their effect on deposition to
water bodies  and endpoint concentrations  in fish.  Dr. Landis then noted that researchers and
regulators need to make sure that the knowledge, tools,  and models needed to support ongoing
aquatic systems  research are in place so we can "go from the source to deposition in the water

C.4.3  Open  Discussion

Robert Stevens. Florida PEP
Before opening the floor to questions/comments, Mr. Stevens noted that setting up a station under
a plume is not a trivial exercise. In fact, two stations will be set up (west of Ft.  Lauderdale, Florida,
and north of Columbus, Ohio) within the next year to characterize local and regional emissions. The
data from these "super sites" will be used to characterize atmospheric concentrations of various
forms of mercury, both in the atmosphere and in wet deposition.

Thomas Brown. DOE NETL (formerly FETC)
According to the panel, there needs to be a connection  between the source and the deposition.
Under the EPA ICR, both EPRI and DOE are funding testing at sites for mercury speciation in flue
gas. DOE and EPRI have  also contributed funding to examine static plume dilution and total and
total speciating mercury OEMs. Mr. Brown is interested in discussing the potential for performing
deposition studies for these sites.  One utility site in particular is an excellent location for performing
a joint EPA/DOE deposition study (a 1,100 megawatt plant, with three stacks and speciated mercury
in the flue gas, which is located in an isolated, relatively pristine area in Minnesota).

Fredric Chanania. US EPA OSW
Information on specific sources and their impacts on mercury receptors may eventually be obtained
from data submitted to fulfill permit reporting requirements.  Currently, Mr. Chanania knows of one
permit in which a  hazardous waste cement kiln is required to periodically submit ambient monitoring
data.  More  permits with  local ambient monitoring requirements  are  expected  in the  future,
particularly in areas where  the local permitters are uncertain that emission goals will be met within
their area.  It may also be possible that EPA will be willing to offer regulatory incentives (e.g.,
flexibility) to facilities willing to perform ambient monitoring.


The CAA requires that the Administrator must reduce mercury emissions by 90% in the near future.
The CAA does not, however, directly address "tying in" a particular emission effect to a specific
source.  From a regulatory perspective, this can be interpreted as "do what you can now, we'll figure
out the details later." Thus, if the goal is to build momentum behind source control/care needs to be
taken to ensure that researchers/regulators do not display too much uncertainty regarding the fate
and transport data/methods.

Perhaps an alternative approach would be to focus on cutting the mercury in wet deposition in half
and to dedicate resources on deposition studies (via MDN networks) rather than trying to identify the
"right" sites to control based on fate and transport research.

Thomas Atkeson. Florida PEP
In 1992  Dr. Atkeson was privy to the results of a Swedish study of forested catchment lakes. The
study concluded that there was  such a large proportion of the deposited mercury tied up in the
watershed that if deposition was cut by 50%, it would take 500 years for the lake to re-equilibrate to
a new load. A recent study from Sweden, however, appears to indicate that reductions in Eastern
Europe emissions have resulted  in reduced deposition in Southern Sweden and surprisingly rapid
decreases in lake  effects.

John Munthe. IVL Swedish Water and Air Pollution Research Laboratory
In response to Dr.  Atkeson's comments, deposition reductions of close to 50% have been observed
in the West Coast of Sweden. There has also been a reduction in mercury concentrations in fish
approaching 10%.

Thomas Atkeson. Florida PEP
The most advanced aquatic models indicate that shallow wetlands,  like the Florida Everglades, will
experience more rapid and quantitatively significant responses to deposition changes than less
dynamic, less shallow water bodies.

Russell Bullock.  US EPA NERL
Mr. Bullock, US EPA  NERL, commented that when Congress mandated research and science
directed emission cuts in 1990, researchers and regulators did not realize at that time that speciation
of mercury would make a significant difference. At that point, researchers and EPA were focused
on gaseous and particulate mercury.

Given the new appreciation of speciation issues and effects, significant benefits can be realized if
researchers and regulators are able to determine which forms of mercury cause the most problems
and concentrate  on controlling just those emissions.  In order to  provide appropriate modeling
scenarios, speciated mercury measurements are needed from the representative source types (i.e.,
medical waste incinerators, resource recovery incinerators,  and coal and oil-fueled power plants).
Currently the official method for measuring mercury emissions provides only total gaseous and
particulate mercury.    According  to  Mr.  Bullock, "I  and my ORD colleagues  consider this

 James Kilgroe. US EPA NRMRL
 After voicing his support for much of the work the panel mentioned, Mr. Kilgroe noted that if the
 government decides to regulate mercury, the Agency will need good information to develop/evaluate
 cost-effective strategies to control emissions and make good policy decisions. In addition to reliable
 data on plant emissions (speciated and total), cloud chemistry, and mercury transport, the Agency
 will also need to know which types of emissions can be considered local, global, and/or regional

 Paul  Mathai. US EPA Office of Toxic Substances
 EPA is developing a national action plan for addressing mercury for all media (air, water, etc.). This
 work  needs to be "tied-in" with other program activities and measurement studies so that a more
 holistic plan is developed. Sector-based measurement techniques also need to be developed which
 define how to plan to measure the success of a reduction in each of these sectors (e.g., utilities and
 medical waste).

 In response to Mr. Mathai's comment, Dr.  Atkeson noted that mercury is just a trace gas in
 emissions, an ultra-trace gas in the atmosphere, and an ultra-trace gas in water. As a result, "it has
 no direct significance to anything, except that it bioaccumulates in fish." Thus bioaccumulation in fish
 can be used to indicate the outcome.

 Comment (Unknown Participant)
 The CAA amendments of 1990 were an amalgam of efforts specified by Congress for EPA. Among
 these "efforts" was an attempt to force EPA to  perform mercury risk assessments before risk
 management steps were taken. These studies were a good first step to require EPA to use the risk
 paradigm in decision making. Since researchers/scientists do not have a benign tracer that can be
 used to track mercury emissions from sources to their receptors (fish), they have to use models to
 assess risk and impact. Unfortunately, since there currently are not enough data to check whether
 the models are right, and there  are not enough models of different processes to  check against
 current data, progress has been  slow.

 Two field studies are currently being performed in an attempt to get the information needed to help
 eliminate this "Catch 22." The first study is being performed at a power plant near Lake Superior; this
 study is examining  mercury  transport from the power plant, downwind into the water system, and
 through the methylation process taking place along the margins of Lake Superior.  The other study
 is being performed  cooperatively with Canada; the purpose of this study is to determine what type
 of mercury in the lake system is taken up by the fish (e.g., newly deposited mercury or mercury from
 disturbed sediments). If the  second study determines that the mercury in fish is from accumulated
 mercury sources in the watershed (e.g., disturbed sediments), then management steps for sources
 may take decades to show an impact. If the study indicates that mercury in  the fish "originates" from
 new deposition, more rapid responses may be realized from the management steps.

 By the time these studies are completed (in approximately 5 years), hopefully new information on
the health effects of mercury, which is the second branch in the EPA risk assessment paradigm, will
 be available. When combined with information regarding exposure levels, this information can be
 used to make informed risk management decisions regarding mercury emissions.

John Ackerman. US EPA Region IV
EPA ORD has a research plan which is currently available for comment and should be finalized
within the next couple of months. Since long-term monitoring is often classified as routine, the NADP
MDN was developed. It may be a good idea, within the next year, to address what is known about
monitoring and develop an approach to monitoring across media. Furthermore, researchers need
to make correlative measurements which can be related to the mercury concentrations.  Finally,
within the next 2 years, researchers, EPA, and others need to establish a baseline and specify future
monitoring requirements.

It is also very important that States use the correct scale of model when estimating TMDLs.
Unfortunately, finding a model which is bigger than an urban airshed model (50 kilometers), but
smaller than the entire US (hopefully near about 200 kilometers) will be difficult. [Note: During these
efforts, Region IV has gained some experience with the Regulatory Modeling System for Aerosols
and Deposition  (REMSAD) model, which it can share with others.] Also, the results of the mercury
pilots mentioned by Thomas Atkeson should be available next spring.

Russell Bullock. US EPA NERL
The REMSAD model uses the exact same parameterization for the deposition of elemental mercury
(via a chemical reaction, chemical oxidation, precipitation, and wet deposition) as specified in the
RELMAP.  This parameterization was originally developed by Petersen et al. in Europe  using a
Lagrangian model with a horizontal resolution of 150 kilometers. Since the REMSAD is a fixed-grid
Eulerian-type model (which resolves the atmosphere in  a much different manner), Mr.  Bullock
cautioned that the REMSAD mercury model should be tested using good emission and deposition
data before it is broadly applied.

 Appendix B - List of Workshop Attendees
 John Ackerman
    Office:  404-562-9063
    Fax:    404-562-9019
    E-mail:  ackermann.john@epamail.epa.gov
    61 Forsyth St. SW
    Atlanta, GA 30303-3014
 Lee Alter
    Office:  617-267-8540
    Fax:    617-742-9162
    E-mail:  lalter@nescaum.org
 Northeast States for Coordinated Air Use Management
    129 Portland Street                     ,
    Boston, MA 2114
 Stuart Arkley
    Office: 651-296-7774
    Fax:   651-297-2343
    E-mail: stuart.arkley@pca.state.mn.us
 Minn. Pollution Control Agency
    520 Lafayette Rd
    St. Paul, MN 55155-4194
Thomas Atkeson
    Office: 850-921-0884
    Fax:   850-414-1390
    E-mail: thomas.atkeson@dep.state.fl.us
 Florida DEP
    2600 Blair Stone Road
    Tallahassee, FL 3299-2400
Dwight Atkinson
    Office: 202-260-2771
    Fax:   202-260-9960
    E-mail: atkinson.dwight@epa.gov
    401 M Street S.W.
    Washington, DC 20461
Ronald Baker
    Office: 914-683-5920
    Fax:   914-683-1029
    E-mail: ron@aldora.com
Aldora Technologies
    8 Paret Lane
    Hartsdale, NY 10530-3003
Steve Balogh
    Office: 651-602-8367
    Fax:   651-602-8215
    E-mail: steve.balogh@metc.state.mn.us
Metropolitan Council Environmental Services
    2400 Childs Road
    St. Paul, MN 55016-6724
Dr. Cathy Banic
   Office: 416-739-4613
   Fax:   416-739-4211
   E-mail: cathy.banic@ec.gc.ca
Atmospheric Environment Service
    4905 Dufferin Street
    Downsview, Ontario M3H5T4
John Bosch
   Office: 919-541-5583
   E-mail: bosch.john@epa.gov
   MD-19, USEPA Mailroom
   RTP, NC 27711
Thomas Brown
   Office: 412-386-4691
   E-mail: Thomas.Brown@NETL.doe.gov
   626 Cochrans Mill Road
   Pittsburgh, PA 15236-0940
Russell Bullock
   Office: 919-541-1349
   E-mail: BULLOCK.RUSSELL@epamail.epa,
   MD-80, USEPA Mailroom
   Research Triangle Park, NC 27711

John F. Buresh
   Office: 651-602-4865
   Fax:   651-602-4869
   E-mail: bures002@gold.tc.umn.edu
Metropolitan Council Environmental Services
   455 Etna Street, Suite 34
   St. Paul, MN 55101
Gary Cacciatore
    Office: 714-986-7694
    Fax:   714-577-8739
Rosemont Analytical
   4125E. Lapalma
   Anaheim, CA
Brian Caldwell
    Office: 715-887-4576
    Fax:   715-887-4513
    E-mail: Brian_Caldwell@vul.com
Vulcan Chemicals
    Highway 73 South
    Port Edward, Wl
Joshua Caron
    Office: 207-866-0100
    Fax:   207-866-2055
    E-mail: jcaron@srdcorp.com
Sensor Research and Development Corporation
    5 Godfrey Drive
    Orono, ME 4473
Fredric Chanania
    Office:  703-308-8420
    E-mail:  CHANANIA.FRED@epamail.epa.gov
   401  M Street S.W.
   Washington, DC  20460
Randy Chase
    Office:  517-327-2660
    Fax:    517-241-7499
    E-mail:  chaserj@state.mi.us
Michigan DEQ - Air Monitoring
    106 West Allegan
    Lansing, Ml 48933
 E. D. Chikhliwala
    Office:  818-347-4369
    Fax:    818-347-5639
    E-mail:  ecochem@sprynet.com
EcoChem Analytics
    22605 Vaierio
    West Hills, CA 91307
 Dr. Warren T. Corns
    Office:  44-1689-891211
    Fax:    44-1689-896009
    E-mail:  wtc@psanalytical.demon.co.uk
 P.S. Analytical Ltd.
    Unit 3 Crayfields Industrial Estate,
    Main Road, Orpinaton
    Orpington, Kent BR5 3HP
 Todd Crawford
    Office:  919-733-7199
    Fax:    919-715-0890
    E-mail: todd.crawford@ncmail.net
 NC Div of Air Quality
    4403 Reedy Creek Rd
    Raleigh, NC 27607
 Nathan Domyahn
    Office:  612-241-2270
    Fax:   612-241-6070
    E-mail: ndomyahn@grenergy.com
 Great River Energy
    17845 East Hwy 10
    Elk River, MN  55330-0800
 Grant Dunham
    Office:  701-777-5034
    Fax:   701-777-5185
    E-mail: gdunham@eerc.und.nodak.edu
    PO Box 9018
    Grand Fork, ND 58202-9018

Jim Dunn
ax:    423-576-5380
:-maii:  e7d@ornl.gov
Bechtel Jacobs Co.
   PO Box 4699
   Oak Ridge, TN 37831-7345
Stan Durkee
    Office:  202-564-6784
    Fax:    202-565-1915
                                        200 M Street
                                        Washington, DC 20460
Timothy Dvonch
    Office:  734-615-3484
    E-mail:  dvonch@umich.edu
                                    University of Michigan
                                        University of Ml,
                                        SPH rm 1608A, 109 Observatory
                                        Ann Arbor, Ml 48109-2029
Brian Elliott
    Office:  612-623-3666
    Fax:    612-623-3354
    E-mail:  belliott@cleanwater.org
                                    Clean Water Action Alliance of Amer.
                                        326 Hennepin Avenue East
                                        Minneapolis, MN  55414
Xinbin Feng
    Office: 46-31-7722866
    Fax:   46-31-7722853
    E-mail: feng@inoc.chalmers.se
                                    Dept of Inorganic Chem, Goteborg, U.
                                        Kemivagen 10
                                        Goteborg,  S 412 96 Goteborg
Danny France
    Office: 706-355-8738
    Fax:   706-355-8744
    E-mail: france.danny@epamail.epa.gov
                                        980 College Station Rd
                                        Athens, GA 30605
Nina Bergan French
    Office: 707-265-0300
    Fax:   707-265-0200
    E-mail: nina@skyplus.com
                                    Sky Plus Inc
                                       PO Box 5299
                                       Napa, CA 94581-0299
Kevin Galbreath
    Office: 701-777-5127
                                    Energy & Env. Res. Ctr, UNO
                                        15 North 23rd Street
                                        Grand Fork, ND 58203
Behrooz Ghorishi
    Office: 919-541-5419
    Fax:   919-544-5690
    E-mail: bghorish@gmgw.com
                                    ARCADIS Geraghty & Miller
                                       4915 Prospectus Drive, Suite F
                                       Durham, NC 27713
W.E. Gittler
   Office: 610-432-8860
   Fax:   610-432-8870
   E-mail: william_gittler@praxair.com
                                    Praxair, Inc
                                       1141 N. Broad St
                                       Allentown, PA 18104-2911
Carl Gohdes
    Office: 651-451-1710
    Fax:   651-457-7684
    E-mail: carl@durag.com
                                    Durag, Inc
                                       1970 Christenson Ave
                                       St. Paul, MN 55118

Evan Granite
   Office: 412-386-4607
   Fax:   412-386-6004
   E-mail: granite@NETL.doe.gov
Department of Energy
   NETL PO Box 10940 MD-84-206
   Pittsburgh, PA  15236-0940
Carlton E. Greene
   Office: 202-778-2257
   Fax:   202-778-2201
   E-mail: cegreene@hunton.com
Hunton & Williams
    1900 K Street, NW, Suite 1200
    Washington, DC 20006
Kerri Gurmendi
   Office: 214-665-7393
   Fax:   214-665-6762
   E-mail: gurmendi.kerri@epa.gov
    1445 Ross Avenue 6PD-O
    Dallas, TX 75202-2733
Bill Haas
    Office: 515-294-4986
    Fax:   515-294-6963
    E-mail: haas@ameslab.gov
Ames Laboratory, USDOE
    28 Spedding Hall, Iowa State Univ.
    Ames, IA 50011-3020
Tim  Hagley
   Office:  218-722-2641
   Fax:    218-723-3916
   E-mail:  thagley@mnpower.com
Minnesota Power
    30 West Superior Street
    Du.luth.MN 55802
Andrew Hamilton
    Office:  514-350-4332
    E-mail:  ahamilto@ccemtl.org
Head Science Div. Commission for Envir. Coop.
    393 St. Jacques St W, Suite 200
    Montreal, Qebec H2Y1N9
Richard Hardegger
    Office:  612-832-2600
    Fax:    612-832-2601
    E-mail:  rhardegger@barr.com
 Barr Engineering Co.
    4700 West 77th Street
    Minneapolis, MN 55435-4803
 Richard Hargis
    Office:  412-386-6065
    Fax:    412-386-4579
    E-mail:  hargis@NETL.doe.gov
 US Department of Energy-NETL
    626 Cochrans Mill Road
    Pittsburgh, PA 15236
 Tiina Harju
    Office:  358-9-456-4723
    Fax:    358-9-456-7022
    E-mail: tiina.harju@vtt.fi
 VTT Chemical Technology
    PO Box 1403 (Betonimiehenkuja 5)
 Scott W. Hautala
    Office:  218-262-6856
    Fax:   218-262-6823
    E-mail: HautiS@aol.com
 Hibbing Taconite Company
    PO Box 589
    Hibbing, MN  55746
 Scott Hedges
    Office:  202-564-3318
    Fax:   202-565-0075
    E-mail: Hedges.scott@epa.gov
    201 M Street
    Washington,  DC

 Robb Heger
    Office: 972-458-6569
    Fax:   972-458-6455
    E-mail: robb.heger@forneycorp.com
 Forney Corporation
    3405 Wiley Post Road
    Carrollton, TX 75006-5185
 Daniel Heiser
    Office: 208-426-0616
    Fax:   208-426-0617
    E-mail: dheiser@dmi.net
 Western Research Corp.
    2019 Silver Creek Lane
    Boise, ID 83706
 Jonathan Hermann                        US EPA, ORD/NRMRL
    Office: 513-569-7839                      26 W. MLK, MS 235
    Faxi   513-569-7680                      Cincinnati, OH 45268
    E-mail: Herrmann.Jonathan@epa.mail.epa.gov
 Neal Mines
    Office:  612-625-1066
    E-mail:  neal@mailandnews.com
 University of Minnesota
    2208 Milwaukee Ave.
    Minneapolis, MN 55404
 Anne M. Jackson
    Office:  651-296-7949
    Fax:   651-297-8676
    E-mail:  anne.jackson@pca.state.mn.us
Minn. Pollution Control Agency
    520 Lafayette Rd
    St. Paul, MN 55155
John Jenks
    Office:  609-530-4041
    Fax:    609-530-4504
    E-mail:  jjenks@dep.state.nj.us
    380 Scotch Rd
    Trenton, NJ  8620
Hongming Jiang
    Office: 651-296-7670
    Fax:   651-297-2343
    E-mail: hongming.jiang@pca.state.mn.us
Minnesota Pollution Control Agency
    520 Lafayette Road N
    St. Paul, MN 55155-4194
Carl Jones
    Office: 714-986-7685
    Fax:   714-577-0529
    E-mail: carl.jones@frco.com
Rosemont Analytical
   4125 E. Lapalma
 '  Anaheim, CA  92807-1802
Carl Kamme
    Office: 760-752-3005
    Fax:   760-752-3007
    E-mail: carl.kamme@opsis.se
Opsis Inc.
    1165 Linda Vista Dr. #112
    San Marcos, CA 92069
Rick Karpinske
    Office: 612-330-6083
    Fax:   612-330-6357
    E-mail: richard.g.karpinske@nspco.com
Northern States Power Co.
   414 Nicollet Mall R58
   Minneapolis, MN 55401
J. Kasajanow                             Verewa Umwelt und Proxebmesstechnik GmbH
   Office: 492102740017                   Kollau Str. 105
   Fax:   492102740028                   Hamburg,  22453                  .
   EHTTajh.jkasajanow@01019freenet.de info@durag.de

Gerald Keeler
   Office: 734-936-1836
   Fax:   313-764-9424
   E-mail: jkeeler@umich.edu
                       University of Michigan
                          1530 SPH I
                        :  Ann Arbor, Ml 48109-2029
Thomas Kelly
   E-mail: kellyt@battelle.org
Jim Kilgroe
   Office: 919-541-2854
   E-mail: KILGROE.JIM@epamail.epa.gov
                       US EPA, NRMRL
                          MD-65, USEPA Mailroom
                          Research Triangle Park, NC 27711
Gary Killen
    Office: 702-298-1105
    Fax:   702-298-1151
    E-mail: killengr@sce.com
                       SC Edison
                          2700 Edison Way
                          Laughlin, CA 89029
Thomas Kurzawski
    Office: 651-451-1710
    Fax:   651-457-7684
    E-mail: thomas@durag.com
                       Durag, Inc
                           1970 Christenson Ave
                           St. Paul, MN 55118
David Lamb
    Office:  214-812-8482
    Fax:    214-812-8673
                           400 N Olive St LB 81'
                           Dallas, TX 75201
Mathew Landis
    Office:  919-541-4841
    E-mail:  LANDIS.MATTHEW@epamail.epa
                       US EPA, NERL
                           MD-46, USEPA Mailroom
                           Research Triangle Park, NC 27711
Leonard N. Lapatnick
    Office:  973-430-8129
    Fax:    973-733-9281
    E-mail:  leonard.lapatnick@pseg.com
                       Pub Service Electric & Gas Co
                           80 Park Plaza, T16G
                           Newark, NJ  07102
Dennis Laudal
    Office:  701-777-5138
    E-mail:  dlaudaM
                       University of North Dakota
                           Grand Fork, ND 58202-9018
 Leonard Levin
    Office:  650-850-7929
    Fax:    650-855-1069
    E-mail:  llevin@epri.com
                           3412 Hillview Avenue
                           Palo Alto, CA 94303
Julia Lu
    Office:  416-739-4274
    Fax:    416-739-4318
    E-mail: julia.lu@ec.gc.ca
                       Environment Canada
                           4905 Dufferin Street
                           Toronto, ON  M3H5T4

 J. Brian Martin
    Office:  705-458-3304
    Fax:   705-458-3301
    E-mail: brian.martin@ec.gc.ca
 Env. Canada Centre for Atmos. Res.
    R.R. #1
    Egbert, ON LOL1NO
 Catherine Massimino
    Office:  206-553-4153
    Fax:   206-553-8509
    E-mail: massimino.catherine@epamail.epa,
    1200 6th Avenue, WCM-127
    Seattle, WA 98101
 Paul Matthai
    Office:  202-260-3385
    Fax:   202-260-0178
    E-mail: matthai.paul@epamail.epa.gov
    401 M Street S.W.
    Washington, DC 20460
William Maxwell
    E-mail:  maxwell.bill@epa.gov
Evelyn Meagher-Hartzell
    Office:  513-569-5867
    Fax:    513-569-4800
    E-mail:  ehartzell@pol.com
    2260 Park Ave
    Cincinnati, OH 45206
Sandra J. Meischen
    Office:  256-386-3539 or 3594
    Fax:    256-386-2191
    E-mail:  mmcole@tva.gov
Tenn Valley Auth-Env Res & Serv. Ctr
    P.O. Box 1010, CEB1C-M
    Muscle Shoals, AL  35662-1010
William Miller
    Office: 215-736-5200
    Fax:   215-736-5240
MG Industries
    48 Skyline Drive
    Chalfront, PA 18914
William Mills
    Office: 708-524-2166
    Fax:   708-524-2170
    E-mail: wmills1@icarus.uic.edu
University of Illinois at Chicago
    815 S. Grove Ave.
    Oak Park, IL 60304
John Munthe
   Office: 46-31-7256256
   Fax:   46-31-7256290
   E-mail: John.Munthe@ivl.se
Swedish Env. Research Center
Sumitra R. Ness
   Office: 612-832-2766
   Fax:   612-832-2601
   E-mail: sness@barr.com
Barr Engineering Co.
   4700 West 77th Street
   Minneapolis, MN  55435-4803
Deborah Ng
   Office: 801-538-6170
   Fax:   801-538-6715
State of Utah/Division of Solid & Haz. Waste
    P.O. Box 144880
    Salt Lake City, UT 84114-4880

Glenn A. Norton
   Office:  515-294-1035
   Fax:   515-294-3091
   E-mail: norton@ameslab.gov
  Ames Laboratory
      Iowa State University
      Ames, IA 50011
Corey Ohme
    Office: 334-270-5664
    Fax:   334-279-3044
    E-mail: cdo@adem.state.al.us
  Alabama DEM
      1400" Coliseum Blvd
      Montgomery, AL 36110
Dana Oliver
    Office:  225-642-1863
    Fax:    225-642-1882
    E-mail:  dsoliver@piona.com
   Pioneer Chlor Alkali Co., Inc.
      P.O. Box 23
      St. Gabriel, LA 70776-0023
James M.Parker
    Office:  406-748-5026
    Fax:    406-748-5040
   Montana Power Company
      PO Box 38
      Colstrip, MT 59323
 Eric Prestbo
    Office:  206-622-6960
    E-mail: ericp@frontier.wa.com
   Frontier Geosciences
      414 Pontiuf Ave N
      Seattle, WA 98103
 Stephen Priebe
    Office:  208-526-0898
    E-mail: priebesj@inel.gov
   Bechtel B&W Idaho
       PO. Box1625, MS 3875
       Idaho Falls, ID 83415-3875
 William C. Rankin
    Office: 423-336-4512
    Fax:   423-780-2505
    E-mail: WCRankin@corp.olin.com
   Olin Corporation
       1186 Lower River Road; PO BOX 248
       Charleston, TN 37310
 Scott Rauenzahn
    Office: 703-308-8477
    E-mail: RAUENZAHN.SCOTT@epamail
      401  M Street S.W.
      Washington, DC  20460
 John Rhodes
     Office: 512-345-0778
     Fax:   512-795-9876
     E-mail: jrrhodes97@aoi.com
   Rhodes Consulting
       Austin, TX  78759
 Michael Ricciardi
     Office: 608-252-5627
     Fax:   608-252-7098
     E-mail: mricciardi@mge.com
    Madison Gas & Electric Co.
       PO Box 1231
       Madison, Wl 53701-1231
 Joann Rice
     Office: 919-541-3372
     Fax:   919-541-1903
     E-mail: rice.joann@epa.gov
       Durham, NC 27711

 Carsten Rollig
    Office: 49(0)221 806 2422
    Fax:   49(0)221 806 1349
    E-mail: tuv_immission@compuserve.com
    Am Grauen Stein
 iliam D. Rosario
    Office: 919-541-5308
    Fax:   919-541-5600
    E-mail: rosario.iliam@epamail.epa.gov
    Emission Standards Division/MD 13
    Research Triangle Park, NC 27711
 Tom Rose
    Office: 208-426-0616
    Fax:   208-426-0617
    E-mail: tomrose@dmi.net
 Western Research Corp.
    2019 Silver Creek Lane
    Boise, ID 83706
 Richard Rosvold
    Office:  612-330-2807
    E-mail: richard.a.rosvold@nspco.com
 Northern States Power Co.
    414 Nicollet Mall R58
    Minneapolis, MN 55401
 Mary Jo Roth
    Office:  612-241-2449
    Fax:   612-241-6229
    E-mail: MJRoth@GREnergy.com
 Great River Energy
    17845 East Highway 10
    Elk River, MN 55330-0800
Jeffrey Ryan
    Office:  919-541-1437
    E-mail:  RYAN.JEFF@epamail.epa.gov
    MD-04, USEPA Mailroom
    Research Triangle Park, NC 27711
Frank Schaedlich
    Office:  416-449-3084
    Fax:    416-449-9298
    E-mail:  fhs@tekran.com
Tekran Inc.
James Schauer
    Office: 608-262-4495
    E-mail: jschauer@engr.wisc.edu
University of Wisconsin
    University of Wl, Water Science & Engineering
    Lab rm# 148, 660 N. Park St.
    Madison, Wl 53706
Dan Schneeberger
    Office: 416-449-3084
    Fax:   416-449-9289
    E-mail: drs@tekran.com
Tekran Inc.
    Toronto,  M3A1A3
Gary Schuettpelz
   Office: 715-799-6152
   Fax:   715-799-6153
   E-mail: gschuett@mail.wiscnet.net
Menominee Indian Tribe
   PO Box 670
   Keshena, Wl 54135
Richard Schulz
   Office: 701-777-5218
   Fax:   701-777-5181
   E-mail: rschulz@eerc.und.nodak.edu
   PO Box 9018
   Grand Fork, ND  58202-9018

Voiker Siemens
   Office: -5798
   Fax:   -7129
   E-mail: Volker.Siemens@vtt.fi
  VTT Chemical Technology
      Betoniemiehenkuja 5
      Espoo,  FIN-02044VTT
Werner Sigl
   Office: 4.97533E+11
   Fax:   4.97533E+11
Steve Smokey
    Office: 701-745-3387
    Fax:   701-745-3312
    E-mail: ssmokey@GREnergy.com
  Great River Energy
      4001 Hwy 2004
      Stanton, ND 58571-9402
Dr. Douglas Steele
   Office: 202-564-6759
   Fax:   202-564-2917
   E-mail: steele.doug@epa.gov
      402 M Street, SW
      Washington, DC  20460
Paul Stenberg
   ' Office: 760-752-3005
    Fax:   761-752-3007
    E-mail: Paulsf86@prodigy.net
   Opsis Inc.
      1165 Linda Vista Dr. #112
      San Marcos, CA 92069
Robert K. Stevens
    Office: 919-541-3156
    E-mail: STEVENS. ROBERT-K@epamail
   State of Florida DEP
      RTP, NC  27711
Peter Stockwell
    Office: 44(0)1689891211
      Crayfields Ind. Estates, Main Road
      Orpington, Kent BR5 3HP
Mark Strohfus
    Office: 612-241-2491
    Fax:   612-241-6033
    E-mail: mstrohfus@GREnergy.com
   Great River Energy
      17845 East Highway 10, PO Box 800
      Elk River, MN  55330-0800
Greg Susanke
    Office: 202-260-3547
    Fax:   202-260-3453
    E-mail: susanke.greg@epa.gov
   EPA Office of Pol. Prev & Toxics (7404)
      401 M Street S.W.
      Washington, DC  20460
Edward Swain
    Office: 651-296-7800
    Fax:   651-297-7709
    E-mail: _edward.swain@pca.state.mn.us
   Minn. Pollution Control Agency
      520 Lafayette Rd
      St. Paul, MN 55155
Clyde Sweet
    Office:  217-333-7191
    E-mail:  csweet@sws.uiuc.edu
   Illinois State Water Survey
      2204 Griffith Drive
      Champagne, IL 61820

Joy Taylor
    Office:  517-335-6974
    Fax:    517-241-7499
    E-mail:  taylorj1@state.mi.us
 Michigan DEQ - Toxics Unit
    106 West Allegan
    Lansing, Ml  48933
Clifford J. Twaroski
    Office:  612-832-2642
    Fax:    612-832-2601
    E-mail: ctwaroski@barr.com
Barr Engineering Co.
    4700 West 77th Street
    Minneapolis, MN 55435
Winona Victery, Ph.D.
    Office:  415-744-1021
    Fax:    415-744-1678
    E-mail:  victery.winona@epa.gov
US EPA, Region IX
    75 Hawthorne St. PMD1
    San Francisco, CA 94105
Jeri Weiss
    Office:  617-918-1568
    Fax:    617-918-1505
    E-mail: weiss.jeri@epa.gov
US EPA, Region I
    1 Congress St. Suite 1100 (CME)
    Boston, MA  02478
Doug Welch
    Office:  541-278-4621
    Fax:    541-278-0168
    E-mail:  welch.doug@deq.state.or.us
Oregon Dept. Of Environmental Quality
    700 SE Emigrant, Suite 330
    Pendleton, OR 97801
David Whipple
    Office: 562-699-7411x2909
    Fax:   562-692-5103
    E-mail: dwhipple@lacsd.org
County Sanitation Dist. Of LA County
    1955 Workman Mill Road
    Whittier, CA 90607
Wilfried Winkler
    Office: 49-0-8152-7710
    Fax:   49-0-8152-79972
    E-mail: seefelder@t-online.de
Seefelder Messtechnik
    Muehlbachstrasse 20
    Seefeld,  82229
Christopher K. Winterrowd
   Office: 919-541-1847
   Fax:   919-544-4590
   E-mail: cwinterr@gmgw.com
ARCADIS Geraghty & Miller
   4915 Prospectus Drive, Suite F
   Durham, NC 27713
Randy L. Wright
   Office: 207-866-0100
   Fax:   207-866-2055
   E-mail: rwright@srdcorp.com
Sensor Research and Development Corporation
   5 Godfrey Drive
   Orono, ME  4473
                                            118      "&U.S. GOVERNMENT PRINTING OFFICE: MOO 550-101/20032


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