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90–163PS 2004

MERCURY EMISSIONS: STATE OF

THE SCIENCE AND TECHNOLOGY

HEARING

BEFORE THE

SUBCOMMITTEE ON ENVIRONMENT, TECHNOLOGY,

AND STANDARDS

COMMITTEE ON SCIENCE

HOUSE OF REPRESENTATIVES

ONE HUNDRED EIGHTH CONGRESS

FIRST SESSION

NOVEMBER 5, 2003

Serial No. 108–34

Printed for the use of the Committee on Science

(

Available via the World Wide Web: http://www.house.gov/science

(II)

COMMITTEE ON SCIENCE

HON. SHERWOOD L. BOEHLERT, New York, Chairman

LAMAR S. SMITH, Texas

CURT WELDON, Pennsylvania

DANA ROHRABACHER, California

JOE BARTON, Texas

KEN CALVERT, California

NICK SMITH, Michigan

ROSCOE G. BARTLETT, Maryland

VERNON J. EHLERS, Michigan

GIL GUTKNECHT, Minnesota

GEORGE R. NETHERCUTT, JR.,

Washington

FRANK D. LUCAS, Oklahoma

JUDY BIGGERT, Illinois

WAYNE T. GILCHREST, Maryland

W. TODD AKIN, Missouri

TIMOTHY V. JOHNSON, Illinois

MELISSA A. HART, Pennsylvania

JOHN SULLIVAN, Oklahoma

J. RANDY FORBES, Virginia

PHIL GINGREY, Georgia

ROB BISHOP, Utah

MICHAEL C. BURGESS, Texas

JO BONNER, Alabama

TOM FEENEY, Florida

RANDY NEUGEBAUER, Texas

RALPH M. HALL, Texas

BART GORDON, Tennessee

JERRY F. COSTELLO, Illinois

EDDIE BERNICE JOHNSON, Texas

LYNN C. WOOLSEY, California

NICK LAMPSON, Texas

JOHN B. LARSON, Connecticut

MARK UDALL, Colorado

DAVID WU, Oregon

MICHAEL M. HONDA, California

CHRIS BELL, Texas

BRAD MILLER, North Carolina

LINCOLN DAVIS, Tennessee

SHEILA JACKSON LEE, Texas

ZOE LOFGREN, California

BRAD SHERMAN, California

BRIAN BAIRD, Washington

DENNIS MOORE, Kansas

ANTHONY D. WEINER, New York

JIM MATHESON, Utah

DENNIS A. CARDOZA, California

VACANCY

SUBCOMMITTEE ON ENVIRONMENT, TECHNOLOGY, AND STANDARDS

VERNON J. EHLERS, Michigan, Chairman

NICK SMITH, Michigan

GIL GUTKNECHT, Minnesota

JUDY BIGGERT, Illinois

WAYNE T. GILCHREST, Maryland

TIMOTHY V. JOHNSON, Illinois

MICHAEL C. BURGESS, Texas

VACANCY

SHERWOOD L. BOEHLERT, New York

MARK UDALL, Colorado

BRAD MILLER, North Carolina

LINCOLN DAVIS, Tennessee

BRIAN BAIRD, Washington

JIM MATHESON, Utah

ZOE LOFGREN, California

RALPH M. HALL, Texas

ERIC WEBSTER Subcommittee Staff Director

MIKE QUEAR Democratic Professional Staff Member

JEAN FRUCI Democratic Professional Staff Member

OLWEN HUXLEY Professional Staff Member

MARTY SPITZER Professional Staff Member

SUSANNAH FOSTER Professional Staff Member

AMY CARROLL Professional Staff Member/Chairman’s Designee

ADAM SHAMPAINE Majority Staff Assistant

MARTY RALSTON Democratic Staff Assistant

(III)

C O N T E N T S

November 5, 2003

Page

Witness List ............................................................................................................. 2

Hearing Charter ...................................................................................................... 3

Opening Statements

Statement by Representative Vernon J. Ehlers, Chairman, Subcommittee on

Environment, Technology, and Standards, Committee on Science, U.S.

House of Representatives .................................................................................... 9

Written Statement ............................................................................................ 10

Statement by Representative Mark Udall, Minority Ranking Member, Subcommittee on Environment, Technology, and Standards, Committee on

Science, U.S. House of Representatives ............................................................. 10

Written Statement ............................................................................................ 11

Prepared Statement by Representative Nick Smith, Member, Subcommittee

on Environment, Technology, and Standards, Committee on Science, U.S.

House of Representatives .................................................................................... 12

Witnesses:

Dr. Thomas A. Burke, Professor and Associate Chair, Department of Health

Policy and Management, Johns Hopkins University, Bloomberg School of

Public Health

Oral Statement ................................................................................................. 13

Written Statement ............................................................................................ 15

Dr. David P. Krabbenhoft, Research Scientist, United States Geological Survey

Oral Statement ................................................................................................. 17

Written Statement ............................................................................................ 19

Dr. George R. Offen, Senior Technical Leader, Air Emission and By-Product

Management, Electric Power Research Institute

Oral Statement ................................................................................................. 23

Written Statement ............................................................................................ 25

Mr. Kenneth A. Colburn, Executive Director, Northeast States for Coordinated Air Use Management

Oral Statement ................................................................................................. 29

Written Statement ............................................................................................ 31

Discussion

Lessons Learned From the State of Florida Research ...................................... 34

The Difference Between Methylmercury and Elemental Mercury .................. 34

Human Response to Methylmercury Exposure ................................................. 35

Fresh Water vs. Marine Water ........................................................................... 35

Development of Specific Technologies for Mercury Abatement ........................ 36

Federal Regulation’s Effect on Mercury Reduction ........................................... 37

Relationship Between Government Regulation and Technology Development ................................................................................................................... 37

How Federal Agencies Are Responding .............................................................. 38

Thimerosal ............................................................................................................ 39

What Happens to Mercury When It Enters the Natural Environment .......... 40

Scientific Basis for EPA Standard ...................................................................... 41

Mercury in the Chesapeake Bay ......................................................................... 41

The Basis for National Academy of Science’s Recommendation ...................... 43

Page

IV

The Effect of Regulation on Innovation .............................................................. 44

Department of Energy Effort to Create New Technologies .............................. 45

The Cause of the Decline of Mercury in the Florida Study .............................. 45

Eliminating Mercury Emissions ......................................................................... 46

Tracking Mercury Once It Has Been Emitted From a Plant ........................... 47

Global, Local, and Regional Sources of Mercury ............................................... 48

Fish Consumption in the Seychelle Island Studies ........................................... 50

Effects on Wildlife ................................................................................................ 50

Closing Comments ............................................................................................... 52

Appendix 1: Biographies and Financial Disclosures

Dr. Thomas A. Burke, Professor and Associate Chair, Department of Health

Policy and Management, Johns Hopkins University, Bloomberg School of

Public Health

Biography .......................................................................................................... 54

Financial Disclosure ......................................................................................... 55

Dr. David P. Krabbenhoft, Research Scientist, United States Geological Survey

Biography .......................................................................................................... 56

Dr. George R. Offen, Senior Technical Leader, Air Emission and Byproduct

Management, Electric Power Research Institute

Biography .......................................................................................................... 57

Financial Disclosure ......................................................................................... 58

Mr. Kenneth A. Colburn, Executive Director, Northeast States for Coordinated Air Use Management

Biography .......................................................................................................... 59

Financial Disclosure ......................................................................................... 60

Appendix 2: Additional Material for the Record

Letter from Kenneth A. Colburn, Executive Director, NESCAUM, dated November 21, 2003, to Hon. Vern Ehlers, Chairman ............................................ 64

Letter from George R. Offen, Sr. Technical Leader, Emissions/Combustion

Product Management, EPRI, dated January 8, 2004 ........................................ 66

Modeling the Atmospheric Fate and Transport of Mercury Over North America, by Christian Seigneur, Krish Vijayaraghavan, Kristen Lohman, and

Prakash Karamchandani ..................................................................................... 69

Global Source Attribution for Mercury Deposition in the United States, by

Christian Seigneur, Krish Vijayaraghavan, Kristen Lohman, Prakash

Karamchandani, and Courtney Scott ................................................................. 80

Comments by The Annapolis Center for Science-Based Public Policy ................ 96

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MERCURY EMISSIONS: STATE OF THE

SCIENCE AND TECHNOLOGY

WEDNESDAY, NOVEMBER 5, 2003

HOUSE OF REPRESENTATIVES,

SUBCOMMITTEE ON ENVIRONMENT, TECHNOLOGY, AND

STANDARDS,

COMMITTEE ON SCIENCE,

Washington, DC.

The Subcommittee met, pursuant to call, at 2:08 p.m., in Room

2318 of the Rayburn House Office Building, Hon. Vernon J. Ehlers

[Chairman of the Subcommittee] presiding.

2

3

HEARING CHARTER

SUBCOMMITTEE ON ENVIRONMENT, TECHNOLOGY, AND

STANDARDS

COMMITTEE ON SCIENCE

U.S. HOUSE OF REPRESENTATIVES

Mercury Emissions: State of

the Science and Technology

WEDNESDAY, NOVEMBER 5, 2003

2:00 P.M.–4:00 P.M. 2318 RAYBURN HOUSE OFFICE BUILDING

Purpose

On November 5, 2003 at 2:00 p.m., the Subcommittee on Environment, Technology, and Standards of the House Science Committee will hold a hearing on that

state of the science and technology regarding mercury emissions. The subcommittee

will hear testimony on the health effects of mercury, the transport and fate of mercury in the environment, and the technologies that are being developed to control

mercury emissions from coal-fired power plants.

The Committee plans to explore several questions, including:

• What do we know about the relationship between mercury exposure from fish

consumption and adverse human health effects?

• To what extent is mercury deposition in the environment local, regional, or

global?

• What do we know about how different kinds of mercury become available in

the environment in a manner that can adversely affect human health? Is

there a difference between new and old mercury and between anthropogenic

and naturally produced mercury?

• What technologies are available or being developed to control mercury pollution from power plants? What do we know about the effectiveness and cost

of these technologies?

Witnesses

Dr. Thomas Burke, Professor and Associate Chair, Department of Health Policy

and Management, Johns Hopkins University Bloomberg School of Public Health. Dr.

Burke served as a member of the National Academy of Sciences’ Committee on the

Toxicological Effects of Mercury. He received his Ph.D. in epidemiology from the

University of Pennsylvania.

Dr. David Krabbenhoft, Research Scientist, United States Geological Survey. Dr.

Krabbenhoft is a principal investigator on the Mercury Experiment to Assess Atmospheric Loading in Canada and the U.S. (METAALICUS) project. He received his

Ph.D. in geochemistry and hydrogeology from the University of Wisconsin-Madison.

Dr. George Offen, Senior Technical Leader, Air Emission and Byproduct Management, Electric Power Research Institute (EPRI), the research arm of the utility industry. Dr. Offen manages EPRI’s research and development program to reduce nitrogen oxides, sulfur dioxide particulate and toxic emissions from utilities. He received his Ph.D. in mechanical engineering from Stanford University.

Mr. Ken Colburn, Executive Director, Northeast States for Coordinated Air Use

Management (NESCAUM). Prior to joining NESCAUM, Mr. Colburn served as New

Hampshire’s air director. He received his M.B.A. from the University of New Hampshire.

General Background

Under the Clean Air Act, the Environmental Protection Agency (EPA) is required

to regulate mercury emissions from coal-fired power plants. Under a consent decree,

the agency has agreed to promulgate a Maximum Available Control Technology

(MACT) regulation by December 15, 2003. At the same time, the agency has proposed, through the Clear Skies Act, to regulate mercury emissions as part of a

4

multi-pollutant trading scheme, and several other multi-pollutant bills are also

pending in Congress.

There is significant debate about how and to what extent mercury emissions

should be regulated. There are many critical science and technology questions that

underpin this debate. These include: what do we know about the adverse health effects of mercury?; to what extent do mercury emissions deposit locally?; is newly deposited mercury more reactive than legacy mercury?; what is the state of technology

development to control and monitor mercury? The state of the science and technology must be well understood in determining the best course to follow in mercury

regulation.

Issues

• Do the levels at which the U.S. population is exposed to mercury

through fish consumption have an adverse health effect?

According to the Centers for Disease Control, eight percent of U.S. women of

childbearing age have mercury blood levels that exceed those considered safe by the

EPA. People are exposed to mercury through consumption of contaminated fish. In

2000, a panel of the National Research Council (the operating agency of the National Academy of Sciences) assessed the state of the science regarding the health

effects of methylmercury from fish consumption. (Methylmercury is the form of mercury that accumulates in the food chain.) The panel examined epidemiological studies, animal studies, and other relevant data and concluded that there is an adverse

health effect from methylmercury through fish consumption. However, in 2003, an

update of one of the largest epidemiological studies, conducted in the Seychelles Islands, showed no effect from fish consumption.

• Is mercury deposition local, regional or global?

The extent to which mercury deposition is local is an important factor in determining whether mercury emissions should be reduced through a trading scheme or

at every plant. Trading schemes assume that the benefit will be the same regardless

of where the emissions reductions are achieved, i.e., that there is little or no local

impact of the pollutant. The science of mercury cycling through the environment is

complex, and deposition patterns depend on the form of the mercury. Studies have

shown mercury deposition far from sources, demonstrating that deposition can be

global. However, there appears to be a gradient of deposition, with highest deposition downwind and close to sources. The hearing will examine what we know about

the local effects of mercury emissions from power plants.

• Would slowing emissions of mercury from power plants decrease mercury levels in fish?

There are large amounts of legacy mercury (from both man-made and natural

sources) already in the environment. Because of this, critics of regulation argue that

any reduction in current emissions will be overwhelmed by mercury already in the

environment. However, recent research results suggest that new mercury may be

more active than old mercury, indicating that achieving reductions now would have

an effect on levels in fish. Additionally, mercury emissions from municipal and medical waste incinerators have been regulated since the mid-90s, and in Florida (where

there are a large number of these incinerators), levels of mercury in wildlife have

decreased substantially since the regulations were put in place. The hearing will examine what we know about the relative reactivity of new mercury vs. legacy mercury.

• What levels of reductions are or will likely be feasible?

At some plants, mercury removal rates of more than 90 percent have been shown

using technologies that are primarily intended to remove other pollutants such as

sulfur dioxide, nitrogen oxides and particulate matter. However, the type of coal

used largely determines the type of technology needed to remove mercury. Plants

that use sub-bituminous coal (found in the Western U.S.) will not likely see large

reductions from existing technologies and will probably have to use a new technology such as activated carbon injection. The hearing will examine what kind of

reductions will result, and at what cost, from existing technologies and technologies

under development.

Detailed Background

Health Effects

Mercury is widespread and persistent in the environment. At high-level exposures, mercury is a serious neurotoxin and instances of population poisonings have

5

been well documented. The U.S. population is primarily exposed to mercury in low

doses through fish consumption (and not through breathing it in from the air like

many other pollutants). The form of mercury that is found in fish is methylmercury

(MeHg). In 2000, a National Research Council (NRC—the operating agency of the

National Academy of Sciences) panel evaluated what we know about the health effects of mercury. Reviewing the three major epidemiological studies (Faroe Islands,

New Zealand and preliminary results from the Seychelles) as well as animal studies, the panel found that a range of health effects has been observed with severity

varying primarily with the size of the dose. The report stated that the fetus is the

most sensitive, and prenatal exposures have been shown to interfere with the

growth and migration of neurons and can cause irreversible damage to the developing central nervous system. At the low dose exposure that is associated with fish

consumption by the mother, infants may appear normal during the first few months

of life, but later display deficits in subtle neurological endpoints such as IQ. The

report also noted that there is evidence that MeHg affects other systems as well—

a correlation has been found between consumption of contaminated fish and the risk

of cardiovascular disease such as acute myocardial infarction.

The EPA has set the reference dose (RfD) for mercury based on the Faroe Islands

study. (A reference dose is an estimate of the daily exposure that the human population can withstand without an appreciable risk of adverse effects over a lifetime—

or the level of exposure that can be considered safe.) A recent study released by the

Centers for Disease Control and Prevention found that approximately eight percent

of women of childbearing age in the U.S. had mercury levels exceeding the level considered safe by the Environmental Protection Agency for protecting the fetus. Mercury contamination in fish has led health departments in 45 states to issue freshwater fish consumption advisories. These advisories warn people to limit consumption or avoid altogether certain species of fish from certain bodies of water.

In the last several months, there has been significant debate about the health effects of mercury from fish consumption following the May 2003 publication of the

Seychelles study, which found no effect of mercury from fish consumption (the Faroe

Islands and New Zealand studies did show an effect). At the time the NRC report

was issued in 2000, the panel reviewed preliminary results from the Seychelles

study, and stated that, ‘‘because there is a large body of scientific evidence showing

adverse neurodevelopmental effects, including well-designed epidemiological studies,

the committee concludes that an RfD [reference dose] should not be derived from

a study, such as the Seychelles study, that did not observe any association with

MeHg.’’

Sources and Emissions

There are three major sources of anthropogenic mercury emissions—medical

waste incinerators, municipal waste incinerators and coal-fired power plants. In addition, mercury is released from natural sources, such as volcanic eruptions and

degassing and vaporization from the Earth’s crust. The EPA estimates that worldwide emissions produced by human activities rival and may greatly exceed natural

sources.

Total anthropogenic sources in the U.S. are approximately 158 tons per year. Coal

burning power plants are currently the biggest source of anthropogenic mercury pollution in the U.S., producing approximately 48 tons per year (or 40 percent of U.S.

anthropogenic emissions). The Federal Government does not currently regulate coalfired utilities with respect to mercury. The EPA regulates the other two major

sources, municipal and medical waste incinerators, at 90 and 94 percent reductions

respectively.

Annual global emissions are estimated to range between 2,000 and 6,000 tons per

year, of which China is believed to emit approximately 1,000 tons annually.

Emissions from Coal-Fired Power Plants

There are small amounts of mercury in coal. Once the coal is burned, the mercury

becomes a gas and enters the atmosphere. Mercury is emitted from power plants

in three forms—1) elemental mercury, 2) oxidized mercury (also called reactive mercury or ionic mercury) which is primarily mercury chloride, and 3) mercury attached

to particulate matter. All three of these forms will eventually deposit in the environment and could cause adverse health effects, however the differences are important

in terms of where they deposit in the environment and what technologies can be

used to reduce them from power plants. The form of the mercury emission depends

on the type of coal and the burning process. Both bituminous (Eastern) and subbituminous (Western) coal have approximately the same total quantity of mercury,

but the form in which it is emitted varies. Bituminous coal (found primarily in the

eastern U.S.) contains chlorine and so when this type of coal is burned, approxiVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00009 Fmt 6633 Sfmt 6621 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
6

mately 70–80 percent of emissions are oxidized mercury. Sub-bituminous coal (found

primarily in the western U.S.) does not contain chlorine and so approximately 70–

80 percent of emissions are elemental mercury. The amount of mercury attached to

particles depends upon how efficient the burning process is—the less efficient, the

more particulate mercury will be emitted. The total quantity of mercury emissions

is similar between the various types of coal.

Deposition

Where mercury deposits (locally, regionally or globally) once it is released from

the power plant is a major source of debate because of its implications for regulation. If mercury deposition is primarily global, then regulation through a trading

scheme makes sense. Regulation through trading programs assumes that it does not

matter where the reductions are achieved, and that there is little or no local health

effect from the emissions. However, if deposition is primarily local, then trading pollutants can lead to ‘‘hot spots’’ because certain plants will buy credits instead of

achieving reductions. If there is a significant local health effect from emissions, then

regulation should be done at each utility to address this local effect.

In addition, if mercury circulates globally, then since the proportion of U.S. emissions as compared to global emissions is small, it would be difficult to trace unilateral emissions reductions to health improvements in the U.S. However, if mercury

deposits locally or regionally, reductions in the U.S. will likely lead to health improvement in the U.S.

This is an area where the science is not clear. The past 15 years of research have

revealed widespread mercury contamination globally from diffuse sources. However

mercury is not evenly distributed, and higher levels have been observed downwind

from sources. The key to understanding this phenomenon is unraveling the complexities of how mercury transforms from one form to another in the environment. Deposition patterns also depend on the form of the mercury. Oxidized mercury is watersoluble and will deposit quickly, depending somewhat on weather conditions, likely

within 60 miles of the source. Thus, the emission of oxidized mercury is primarily

a local and regional issue. Elemental mercury can stay in the atmosphere for one

to three years and enters the global pool of mercury. Eventually, all mercury in the

atmosphere will be oxidized and deposited.

Researchers hypothesize that there is not an even blanket of mercury deposition

across the globe, but that near emissions sources, there is greater deposition and

then there is a gradient of lower deposition rates as you move farther away from

sources. This is backed up with data from sediments—in more remote locations,

there is significantly less mercury. According to data from mercury monitoring stations nationwide, the highest deposition rates occur in the southern Great Lakes,

the Ohio Valley, the Northeast, and scattered areas of the Southeast—the areas

around and downwind of coal-fired power plants. More research is needed to clarify

this issue.

Control Technologies

The control technology that can be used to remove mercury from emissions depends on the type of coal burned (and thus the form of the mercury) as well as the

plant’s current emissions control technology configuration. Coal that has a high

chlorine content (and thus produces oxidized mercury) can often be effectively controlled by scrubbers (used primarily to control sulfur dioxide). However, wet scrubbers are only effective at removing mercury chloride and so control can vary from

less than 10 percent removal to greater than 90 percent removal depending on the

type of coal burned. Fabric filters and electrostatic precipitators (ESP), used primarily to remove particulate matter, can effectively capture mercury that is attached to particles. For a wide variety of coal types and control configurations, recent full-scaled demonstrations have proven the effectiveness of powdered activated

carbon (PAC) injection. This technology can be retrofit on existing boilers with minimal new capital equipment, and is effective on bituminous and sub-bituminous

coals. However, PAC has yet to be used at a commercial scale.

An associated set of issues relates to the fact that the ash collected at power

plants is used in industrial processes such as concrete production. The greater the

carbon content of the ash, the less useful it is in these industrial processes. Large

amounts of activated carbon are used to remove elemental mercury from the emissions. In order to keep the ash commercially viable, both an electrostatic precipitator and fabric filter are required - the ESP removes the mercury, and the ash

(without mercury) can be collected in the fabric filter.

The cost of controlling mercury depends on the type of control technology used.

Purchase of wet scrubbers, selective catalytic reducers, electrostatic precipitators

and fabric filters are major capital investments, however all of these technologies

7

achieve mercury reductions as a co-benefit of other pollutant reductions. The extent

to which these technologies are used will depend on the regulation of these other

pollutants. Powdered activated carbon (PAC) does not require a major capital investment, and the primary cost is the purchase of the activated carbon sorbent itself.

It is difficult to estimate how much PAC will cost because it is not yet used commercially, however costs have been estimated to range from less than $1 per megawatt

hour (MWh) to $3 per MWh. PAC is also a percent reduction technology, meaning

that the same amount of activated carbon will reduce a certain percentage of the

mercury regardless of the total quantity. Therefore, PAC is more cost-effective the

greater the amount of mercury present.

Monitoring Emissions

Measuring mercury emissions from utilities is a challenge because of the very

small amount of mercury emitted by each source, but measurement technologies are

improving. Currently, the best way to measure mercury emissions is through wet

chemistry (the Ontario Hydro method). This method is accurate and will indicate

the form of the mercury being emitted. The drawbacks are that it is expensive and

measures a short snapshot in time (about two hours). Instrumentation methods,

which continually measure mercury emissions, are currently under development.

Methylation

In order to cause adverse health effects, the dissolved mercury in water must become methylated (transformed into a new chemical compound with a methyl group

attached). Researchers hypothesize that it is sulfur-reducing bacteria that methylate

mercury. More research is needed on what causes mercury to become methylated.

Chemical, biological and physical elements appear to affect methylation, and the

limiting factor varies by location. For instance, in the Florida Everglades, a study

has shown that sulfate load is the primary driver of methylation, while in the San

Francisco Bay, it appears that wetland restoration spurs methylation, and the mode

is unclear.

Once produced, methylmercury easily accumulates in the tissues of aquatic organisms and becomes more concentrated as it goes up the food chain. The concentration of a pollutant at the top of a food chain can be thousands or even millions of

times greater than the concentration of the pollutant found in water. It is through

fish consumption that mercury enters humans and other wildlife and causes health

effects.

Witness Questions

Questions addressed to Dr. Thomas Burke:

• What did the National Research Council panel find about the relationship between low-dose mercury exposure and adverse human health effects? Are subpopulations differentially affected by mercury exposure?

• To what extent have studies published since the panel issued its report in

2000 altered our knowledge about the health effects of mercury?

• What are the future research needs with respect to understanding the health

effects of mercury?

Questions addressed to Dr. David Krabbenhoft:

• What do we know about how mercury reacts in the atmosphere and what determines its deposition? To what extent is deposition local, regional or global?

• What do we know about the relative reactivity of old vs. new mercury and

anthropogenic vs. natural mercury?

• What does research tell us about the extent to which reducing mercury deposition will reduce mercury levels in fish?

• What are the future research needs with respect to understanding how mercury cycles in the environment?

Questions addressed to Dr. George Offen and Mr. Ken Colburn:

• To what extent do control technologies in use today at utilities reduce mercury pollution from utilities? What determines the effectiveness of these technologies at reducing mercury emissions?

• What are the major technologies in development today to control mercury

emissions from utilities? What do full-scale demonstrations tell us about the

likely effectiveness and cost of these technologies?

8

• What are the major barriers to development of technologies to control mercury emissions from power plants?

9

Chairman EHLERS. Good afternoon. I am pleased to welcome everyone to this afternoon’s hearing on the science and technology

underlying a vital environmental and public health issue: mercury

pollution.

Mr. Gutknecht just asked how I knew that he was interested in

this issue, and I said it must be your mercurial disposition, which

is unfair, because he is a very stable, solid person. But mercury has

been around for a long time. We have been fascinated with it for

a long time. And we have only, in the past few centuries, realized

that it is a major public health issue.

This hearing is particularly timely. As most of you know, the Environmental Protection Agency is due to release a proposed mercury regulation this December, and there are also many bills pending in Congress to regulate mercury emissions from utilities, including the President’s Clear Skies Act.

I am pleased to hold a hearing to examine the critical science

and technology questions that underpin this policy debate. I expect

that this subcommittee can serve as a forum for Members to undertake sober, calm, and fair-minded reviews of the science as Congress considers this important environmental and public health

issue.

In my home state of mercury—pardon me, in my home state of

Michigan—really, I am not from another planet. In my home state

of Michigan, mercury pollution is a growing concern. People are exposed to mercury through eating contaminated fish. And of course,

we have four of the Great Lakes touching our shores, and we have

more boats registered per capita than any other state, so you know

we have a lot of fisherman and many people eating fish. Since

1988, the Michigan Department of Community Health has issued

a fish consumption advisory for all of Michigan’s 11,000 inland

lakes as a result of mercury contamination. And throughout the

U.S., the Centers for Disease Control estimate that approximately

eight percent of women of child-bearing age have levels of mercury

in their blood that exceed the level considered safe by the Environmental Protection Agency. This is a matter of special concern for

pregnant women.

We certainly have a problem, but the solution must be informed

by science. We will hear today from experts from academia, Federal

and State Government, and industry.

These witnesses will address a wide range of science and technology questions that inform the mercury debate. These include:

‘‘What do we know about and how precisely can we determine the

relationship between adverse human health effects and mercury

exposure from fish consumption? To what extent is mercury deposition in the environment local, regional, or global? What do we know

about how different chemical forms of mercury become available in

the environment in a manner that can adversely affect human

health? And what technologies are available or are being developed

to control mercury pollution from power plants?’’

There is much to discuss and discover. Today, we want to

thoughtfully review the current state of mercury pollution science

and technology before new policies are put into place. We are here

to learn. I look forward to the testimony.

[The prepared statement of Chairman Ehlers follows:]

10

PREPARED STATEMENT OF CHAIRMAN VERNON J. EHLERS

Good afternoon! Welcome to this afternoon’s hearing on the science and technology underlying a vital environmental and public health issue—mercury pollution.

This hearing is certainly timely. As most of you know, the Environmental Protection

Agency is due to release a proposed mercury regulation this December, and there

are also many bills pending in Congress to regulate mercury emissions from utilities, including the President’s Clear Skies Act.

I am pleased to hold a hearing to examine the critical science and technology

questions that underpin this policy debate. I expect that this subcommittee can

serve as a forum for Members to undertake sober, calm, and fair-minded reviews

of the science as Congress considers this important environmental and pubic health

issue.

In my home state of Michigan, mercury pollution is a growing concern. People are

exposed to mercury through eating contaminated fish. Since 1988, the Michigan Department of Community Health has issued a fish consumption advisory for all of

Michigan’s 11,000 inland lakes as a result of mercury contamination. And throughout the U.S., the Centers for Disease Control estimates that approximately 8 percent of women of childbearing age have levels of mercury in their blood that exceed

the level considered safe by the Environmental Protection Agency.

We certainly have a problem. But the solution must be informed by science. We

will hear today from experts from academia, Federal and State government, and industry.

These witnesses will address a wide range of science and technology questions

that inform the mercury debate. These include: What do we know about and how

precisely can we determine the relationship between adverse human health effects

and mercury exposure from fish consumption? To what extent is mercury deposition

in the environment local, regional, or global? What do we know about how different

chemical forms of mercury become available in the environment in a manner that

can adversely affect human health? And, what technologies are available or being

developed to control mercury pollution from power plants?

There is much to discuss and discover. Today we want to thoughtfully review the

current state of mercury pollution science and technology, before new policies are

put in place. We are here to learn. I look forward to the testimony.

Chairman EHLERS. The Chair now recognizes Congressman

Mark Udall, the Ranking Minority Member on the Subcommittee,

for his opening statement.

Mr. UDALL. Thank you, Mr. Chairman.

I want to welcome the panel and thank our distinguished Chairman for convening this hearing regarding mercury emission science

and technology issues. The United States, as the Saudi Arabia of

coal, has used this abundant resource to our advantage. Coal powered our Industrial Revolution and continues to provide energy to

our power plants. However, as we are all aware, the use of coal has

well documented negative environmental and health consequences.

I am very encouraged, as I know the Chairman is and many of you

here, that emission rates at coal-fired power plants for sulfur dioxide and nitrogen oxides have been cut by more than half since

1970. But I believe we can, and must, do more.

Clean air is an environmental and public health necessity. Mercury is a persistent, bioaccumulative toxin. In recent years, Federal

and State governments have taken actions to reduce the use of

mercury and to control its emission from medical and municipal

waste incinerators. Now it is time to move forward with a cost-effective, rational plan to reduce mercury emissions from coal-fired

power plants.

According to a 1997 EPA report to Congress, coal-fired power

plants are the greatest human source of mercury emissions into

our air. As a result, as the Chairman mentioned, the EPA is currently drafting a new standard to limit mercury emissions from

coal-fired power plants. The level of the reduction has not yet been

11

determined, but we expect the regulations to be finalized this December for implementation in the year 2008.

I realize that utilities and the coal industry have concerns about

the cost of controlling these emissions and the efficacy and the

availability of control technologies. We should do what we can to

ensure the costs are minimized and the technologies are sound. I

believe there is an opportunity to develop, manufacture, and market control technologies here in the U.S. and to the rest of the

world. We are, of course, not the only nation that utilizes coal. All

you have to do is look at the great coal reserves in China as one

example. We should be promoting technologies, clean technologies

here and abroad, and we should move ahead aggressively to take

advantage of these economic opportunities associated with this

goal.

Today, our distinguished witnesses will give this committee some

insights into the science and technology of reducing mercury emissions and suggest what further studies need to be completed in

order to get the information to make knowledgeable policy decisions. This will help us, I believe, to get closer to determining how

to use preventative measures to ensure that the risks of mercury

pollution attributable to coal-fueled power plants are minimized, if

not eliminated altogether.

Finally, Mr. Chairman, I know that at least one group, the Institute of Clean Air Companies, that wishes to contribute to the

record for this hearing. Therefore, I would ask unanimous consent

that the record be held open for 10 days to receive testimony from

the Institute of Clean Air Companies and any other groups that

may wish to submit testimony.

Chairman EHLERS. Without objection, so ordered.

Mr. UDALL. With that, Mr. Chairman, I would yield back with

one other observation. I know you have very few political opponents, but I am sure there are some of them that would like to

send you, if not to the moon, to Mercury, so we will keep in mind

your comments earlier as we began the hearing.

[The prepared statement of Mr. Udall follows:]

PREPARED STATEMENT OF REPRESENTATIVE MARK UDALL

Mr. Chairman, thank you for convening this hearing regarding mercury emission

science and technology issues.

The United States—as the ‘‘Saudi Arabia of coal’’—has used this abundant resource to our advantage. Coal powered our industrial revolution and continues to

provide energy for our power plants. However, as we are all aware, the use of coal

has well-documented negative environmental and health consequences.

I am very encouraged by the fact that emission rates at coal-fired power plants

for sulfur dioxide and nitrogen oxides have been cut by more than half since 1970—

but I believe we can and must do more. Clean air is an environmental and public

health necessity.

Mercury is a persistent, bio-accumulative toxin. In recent years, Federal and State

governments have taken actions to reduce the use of mercury and to control its

emission from medical and municipal waste incinerators. Now it is time to move forward with a cost-effective, rational plan to reduce mercury emissions from coal-fired

power plants.

According to a 1997 EPA report to Congress, coal-fired power plants are the greatest human source of mercury emissions into our air. As a result, the EPA is currently drafting a new standard to limit mercury emissions from coal-fired power

plants. The level of reduction has not yet been determined, but we expect the regulations to be issued this December for implementation at the beginning of 2008.

12

I realize that utilities and the coal industry have concerns about the cost of controlling these emissions and the efficacy and availability of control technologies. We

should do what we can to ensure the costs are minimized and the technologies are

sound.

I believe there is an opportunity to develop, manufacture and market control technologies here in the U.S. and to the rest of the world. We are not the only nation

that utilizes coal. We should be promoting cleaner technologies here and abroad,

and we should move ahead aggressively to take advantage of the economic opportunities associated with this goal.

Today, our distinguished witnesses will give this committee some insights into the

science and technology of reducing mercury emissions and suggest what further

studies need to be completed in order to get the information needed to make knowledgeable decisions. This will help us get closer to determining how to use preventive

measures to ensure that the risks of mercury pollution attributable to coal-fueled

power plants are minimized, if not eliminated altogether.

Finally, Mr. Chairman, I know of at least one group—the Institute of Clean Air

Companies—that wishes to contribute to the record for this hearing. Therefore, I

ask for unanimous consent that the record be held open for ten days to receive testimony from the Institute of Clean Air Companies and any other groups that may

wish to submit testimony.

Chairman EHLERS. Thank you. Since I have asthma, I am used

to going without oxygen, so I might actually survive. The temperature might be a bit of a problem, however.

If there is no objection, all additional opening statements submitted by the Subcommittee Members will be added to the record.

Without objection, so ordered.

[The prepared statement of Mr. Smith follows:]

PREPARED STATEMENT OF REPRESENTATIVE NICK SMITH

I want to thank Chairman Ehlers and Ranking Member Udall for holding this

hearing on the science of mercury emissions. And I would like to thank our witnesses for sharing their opinions with us today.

As a farmer, I understand that we are caretakers of the land. Farmers understand that what they put in the land can come out in our food and water. If we

are not careful with the land we can do significant damage to its productive capacity, our environment, and animal and human health. Therefore, we must use responsible practices to maintain or improve the quality of our environment.

While farmers have learned much from thousands of years of tradition, modern

science has revolutionized our understanding of agriculture. When we consider the

impact of pollutants, such as mercury, science must be our guide in understanding

the costs and benefits. This requires rigorous research, understanding where pollutants come from, where they go, what they do when they get there, and how they

affect the land, animals and people.

We must be caretakers of our environment so that our children and grandchildren

can enjoy and use it as much as we have. I applaud the Chairman and Ranking

Member for guaranteeing that science is used in making these decisions.

Chairman EHLERS. At this time, I would like to introduce our

witnesses. And we are fortunate to have an outstanding group of

witnesses before us, broadly representative of the scientific and

technical knowledge. I might mention we do not have anyone specifically from the environmental community. That will be dealt

with at some other time, but we wanted to try and get the science

and technology out first.

First of all, we have Dr. Thomas Burke, who is a Professor and

Associate Chair of the Department of Health Policy and Management at the Johns Hopkins University Bloomberg School of Public

Health. Dr. Burke served as a member of the National Academy of

Sciences Committee on the toxicological effects of methylmercury.

Second, we have Dr. David Krabbenhoft. He is a research hydrologist for the United States Geological Survey, better known by its

acronym, USGS. I had a son who spent one summer working for

13

the USGS. Next, we have Dr. George Offen. He is the Senior Technical Leader of the Air Emission and Byproduct Management at

the Electric Power Research Institute, which is the research arm

of the utility industry, better known by its acronym, EPRI. And finally, Mr. Ken Colburn is the Executive Director of the Northeast

States for Coordinated Air Use Management, an association of

Northeast State Air Directors. As a Midwesterner, I can assure you

that there is plenty of air in the Northeast. Previously, he served

as New Hampshire’s Air Director.

As our witnesses presumably have been informed, spoken testimony is limited to five minutes each. And in case you are not familiar with our system, we have the little timers, one here and one

on your table. It will glow green for talk for the first four minutes,

yellow for sum up for the next minute, and red for the stop sign.

And so I ask for you to observe the stop signs. We may give traffic

citations if you don’t.

With that, after you have finished your testimony, Members of

the Committee will each have five minutes to ask questions. And

if there are a lot of questions, we may go an additional round.

We will start with Dr. Burke. Dr. Burke, you are recognized.

STATEMENT OF DR. THOMAS A. BURKE, PROFESSOR AND ASSOCIATE CHAIR, DEPARTMENT OF HEALTH POLICY AND

MANAGEMENT, JOHNS HOPKINS UNIVERSITY, BLOOMBERG

SCHOOL OF PUBLIC HEALTH

Dr. BURKE. I appreciate the opportunity to speak with you today.

I am Tom Burke. I am a professor at the Johns Hopkins School of

Public Health. I am epidemiologist and risk assessor, and I am also

the Principal Investigator of the CDC Center for Excellence in Environmental Public Health Tracking, and I am currently working

with about 20 states and major municipalities on issues of environmental exposure and public health outcomes. And I must say that

mercury exposure and potential health impacts are a very important priority for the States. I am also a member of the National

Academy of Sciences Board on Environmental Studies and Toxicology, and I currently co-chair the EPA National Pollution Prevention and Toxics Advisory Committee. Perhaps most importantly for

today’s meeting, I was a member of the—as you mentioned, the

NAS panel that took a look at the toxicological effects of

Methylmercury.

Before joining Hopkins, I served as a regulator and a health official. I was Deputy Commissioner of Health for the State of New

Jersey and also Director of Science for the New Jersey DEP, so I

participated firsthand in fishing advisories and some very difficult

policy decisions.

My testimony today will focus on the questions that you have

given to me.

First I wanted to give a very quick overview of what the Academy Panel found in our evaluation of the scientific basis for the

EPA reference dose, which is really the starting point for the regulatory actions.

The charge to the Committee was to evaluate the scientific evidence, and we looked at a broad range of the available information,

both from animal studies and from human studies, and really foVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00017 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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cused down on three major epidemiological studies. We met with

the investigators to understand their methods and results and

looked at and identified from this the most important, critical public health effects. We were concerned that mercury exposure effects

different sub-populations differently and focused, to be most protective of public health, on the most vulnerable sub-population: unborn children. Therefore, we selected neurodevelopmental deficits

as the most important, well-documented health effect.

The three studies we looked at, one in the Faroe Islands, one in

New Zealand, and one in the Seychelles, were epidemiologic studies

of maternal exposure and neurological development—maternal exposure to mercury and neurological development in children. Now

two of these studies were positive, and the Seychelles study, at that

time, did not show an association.

Based upon the public health principle of using a public health

approach, we decided to use a positive study (they were all very

well conducted) as the basis for our recommendations to EPA, the

scientific basis for moving forward. We also conducted an analysis

of population exposure here in the U.S. Now the large majority of

Americans are at low-risk of adverse effects from mercury exposure, but as you mentioned, there is an important sub-population,

high consumers of fish, that may, in fact, be at levels of concern.

And we estimated that based upon women of child-bearing age and

consumption patterns, there may be as many as 60,000 children

born each year, not with adverse effects, but at elevated risk because of their mother’s exposure.

Now a major question right now, particularly in light of the release of a new revision or an update of the Seychelles study, is— is the scientific basis for the National Academy of Science’s conclusions—has that changed? We released our report in July of 2000,

and since that time, there have been a number of new studies. Perhaps the most important is this longitudinal update on the

Seychelles Island study, which continued to observe the children to

age 9. The new study or the new update is, in fact, not a new study

but a continued evaluation. And it must be recognized that it

doesn’t represent a new study but rather a refinement of ongoing

surveillance.

The question has been raised: ‘‘If this data were available, would

it have changed the weight of the evidence?’’ The latest data from

the Seychelles study were not available at the time of the NRC report; however, the Committee did consider the possibility that updated results might confirm the previous negative findings at the

Seychelles. In evaluating the overall weight of the evidence, we still

felt that, with three well conducted studies, it was most appropriate to select a positive study, the Faroe study, as the basis for

public health protection. Therefore, I feel, and I must say that I

have discussed this with a number of my colleagues on the Committee, that the new update does not change the scientific basis for

the Committee’s conclusion.

A few other important studies you mentioned are the recently

published result of the CDC look at exposure, where 8 percent of

women were at levels of exposure of concern, have also confirmed

our initial assessment of that small portion of the population that

is at risk. And I might add at the time of our work, we were conVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00018 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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cerned about potential implications on cardiovascular effects. There

has been also new evidence there.

So to conclude, I would like to kind of sum up where the future

direction should be. The update does not change the fundamental

conclusions of the National Academy’s report. There have been new

studies. We are constantly reducing uncertainty and learning more.

But as of this point, we still feel that there is a strong public

health basis for the current EPA RFD, that this provides a sound

and justifiable foundation for our efforts to protect public health.

That being said, there are a number of important research issues

that need to be undertaken, including getting a better idea of the

exposure in this country, of the regional differences, identifying

populations at high risk, and particularly, understanding the

sources and levels of mercury contamination in our food supply. Finally, we need to better understand the interaction of mercury with

other pollutants that we are exposed to, such as PCBs, to really get

a better understanding of the long-term public health implications.

Thank you.

[The prepared statement of Dr. Burke follows:]

PREPARED STATEMENT OF THOMAS A. BURKE

Mr. Chairman and Members of the Subcommittee:

I thank you for the opportunity to testify today concerning the public health effects of mercury exposure. I am Dr. Thomas Burke, Professor and Associate Chair

of the Department of Health Policy and Management at the Johns Hopkins

Bloomberg School of Public Health, and I am founding Co-Director of the Hopkins

Risk Sciences and Public Policy Institute. I am an epidemiologist and risk assessor

and my major research interests focus on understanding and preventing the public

health impacts of environmental exposures. I am also the Principal Investigator for

the CDC Center of Excellence in Environmental Public Health Tracking at Johns

Hopkins and am working with 20 states and major cities to improve our capacity

to track hazards, exposures, and health effects that may be related to the environment. I am also a member of the National Academy of Sciences Board on Environmental Studies and Toxicology and serve as Co-Chair of the U.S. EPA National Pollution Prevention and Toxics Advisory Committee. Perhaps most relevant to today’s

hearing I served as a member of the National Research Council Committee on the

Toxicological Effects of Methylmercury.

Prior to joining the faculty of Johns Hopkins I served as Deputy Commissioner

of Health for the State of New Jersey and Director of Science and Research for the

New Jersey Department of Environmental Protection. As a State official I was directly involved in the public policy decisions to protect the environment and public

health, including many fish consumption advisories. I have a first hand appreciation

for the difficult interface of science and policy in developing practical and protective

approaches to public health and environmental regulation.

My testimony today will focus upon the questions that the Subcommittee has

asked me to address.

What did the National Research Council panel find about the relationship

between low-dose mercury exposure and adverse human health effects?

Are subpopulations differentially affected by mercury exposure?

In response to a request from the Congress, the NRC established the Committee

on the Health Effects of Methylmercury to evaluate the body of evidence that led

to the EPA reference dose RfD (1). The charge also included evaluating newly available data that may not have been considered by the Agency, and consideration of

sensitive subpopulations that may be impacted by consumption of contaminated

fish. The Committee conducted and extensive review and weight of evidence evaluation of the available published literature on the health effects of mercury from both

animal and human studies, and met with the investigators of major epidemiological

studies to examine their methods and findings. Mercury exposure can cause a wide

range of adverse effects throughout the life span and there are extensive data on

effects on the developing brain.

16

Subpopulations may be differentially affected by mercury exposure. Therefore, to

be protective of public health, the Committee focused upon the most vulnerable subpopulation, unborn children. We selected neurodevelopmental deficits as the most

sensitive well documented effect, the critical effect for the derivation of an RfD.

The Committee carefully evaluated three large well designed epidemiological studies of the relationship between prenatal methylmercury exposure from maternal

consumption of fish and subsequent neurodevelopmental deficits. In the Faroe Islands (2) and New Zealand (3) studies mercury exposure was associated with adverse neurodevelopmental outcomes. In the Seychelles (4) no relationship with adverse outcomes was observed. After considering the results of the three studies and

the weight of the evidence the Committee concluded that a positive study provides

the strongest public health basis for the development of public health and regulatory exposure guidance. The Faroe Island study was recommended as the critical

study for the development of the RfD. Based upon the benchmark dose derived from

this study, the Committee concluded that the EPA RfD of .1ug/kg per day is scientifically justifiable.

The Committee also conducted an analysis of population exposure levels and

found that the large majority of Americans are at low risk of adverse effects, but

some high fish consumers may be at risk of high mercury exposure. Based upon

available fish consumption surveys for woman of childbearing age it was estimated

that 60,000 children may be born each year with an elevated risk of adverse

neurodevelopmental effects due to maternal mercury exposure.

To what extent have studies published since the panel issued its report in

2000 altered our knowledge about the health effects of mercury?

The NRC report was released in July of 2000. Since that time there have been

a number of studies that have made important contributions to the body of knowledge concerning the public health impacts of mercury exposure. Perhaps the most

notable is the recent longitudinal update of the Seychelles Island study (5) which

reports on the continued observation of the cohort to 9 years of age. The results of

the update reaffirm the earlier findings of no significant adverse neurological effects

related to of in utero mercury exposure. The update provides important information

on the Seychelles cohort as the children grow older. However it must be recognized

that the findings do not represent a ‘‘new’’ study, but rather provide a refinement

of the ongoing surveillance.

The question has been raised ‘‘If the Seychelles update were available to the NRC

Committee would the recommendations have been different?’’ The latest data from

the Seychelles study were not available at the time of the NRC report; however the

Committee did consider the possibility that updated results might confirm previous

negative findings. In evaluating the overall weight of the evidence of three well conducted studies, two positive and one negative, it was deemed appropriate to select

a positive study as the basis for public health protection. I therefore feel that the

recent report adds to our knowledge, but does not change the scientific basis for the

Committee’s conclusions.

Other studies that have been published since the release of the NRC report have

confirmed some of the findings and concerns of the Committee. CDC’s National

Health and Nutrition Examination Survey found that eight percent of women of

child bearing age had blood mercury levels that indicate exposures above the current RfD (6). This confirms the findings of the Committee’s margin of exposure analysis that found there is a small but important percentage of the population with exposures in the range of public health concern. In addition, a recent epidemiological

study has found an association between mercury exposure (measured by toenail

mercury concentration) and myocardial infarction (7). The need to better understand

potential links between mercury exposure and cardiovascular disease and hypertension was among the research recommendations of the Committee.

What are the future research needs with respect to understanding the

health effects of mercury?

There are a number of important continuing research needs if we are to improve

our understanding of the public health impacts of mercury exposures in the U.S.

population. The most fundamental need is to measure actual exposure levels in the

population to identify those at highest risk, examine geographic differences, and improve our epidemiological surveillance to identify and prevent any related adverse

health outcomes. Since there are fish consumption advisories throughout virtually

all regions of the country, state health and environmental officials need improved

tools to evaluate exposure and provide the public with better information about preventing exposures and health risks. Surveillance of mercury sources, exposures, and

possible health related outcomes should be included in the developing CDC National

17

Environmental Public Health Tracking Network. Tracking can provide a foundation

for U.S. based epidemiological investigations, guide the development of more effective regulatory strategies and enable us to measure our progress.

Better tracking of the mercury concentrations in fish and throughout the food supply is also needed. This will improve both our assessment and communication of

mercury risks. Currently available information on important food sources is extremely limited. Consumers have little information resulting in enormous confusion

and limiting the effectiveness of risk communication and prevention efforts.

Research is also needed to understand the potential impacts of mercury exposure

throughout the life span. Little is known about possible long-term effects of exposure. This research should include examination of possible cardiovascular, reproductive, neurological, immunological and carcinogenic effects.

Research should also include evaluation of the health implications of interaction

of mercury with other pollutants. For example, what are the health implications of

cumulative exposures to mercury and persistent organic pollutants from dietary exposure? How do concurrent exposures to PCBs and other potential neurotoxic pollutants impact potential population health risks?

In conclusion, mercury is one of the most well studied environmental pollutants.

Its potential harmful effects have been well documented in both human and animal

studies. There is tremendous public concern about the potential adverse health effects of mercury, particularly regard the health and development of children. New

studies have contributed important new insights, yet there remain a number of unanswered questions particularly concerning the full range of public health impacts

from long-term low-level exposures. In the long-term the reduction of population exposures and management of mercury risks will depend upon our ability to recognize

and reduce mercury emissions. In the meantime the current EPA RfD provides a

sound and justifiable foundation for our efforts to protect the public’s health.

Thank you very much for this opportunity to address the Subcommittee.

References

1. National Research Council. 2000. Toxicological Effects of Methylmercury. National Academy Press, Washington, D.C. 344 p.

2. Grandjean, P. et al. 1997. Cognitive deficit in 7-year-old children with prenatal exposure to methyl mercury, Neurotoxicol. Tertol 19:417–428.

3. Crump, K.S., Kjellstrom, T., Shipp, A.M., Silvers, A., Stewart, A. Influence

of prenatal mercury exposure upon scholastic and psychological test performance: benchmark analysis of a New Zealand cohort. Risk Anal. 1998 Dec.,

18(6):701–713.

4. Davidson, P.W., Myers, G.J., et al. 1998. Effects of prenatal and postnatal

methyl mercury exposure from fish consumption on neurodevelopment: Outcomes at 66 months of age in the Seychelles Child Development Study, J.

Am. Med. Assoc. 280:701–707.

5. Myers, G.J., et al. 2003. Prenatal methylmercury exposure from ocean fish

consumption in the Seychelles child development study. The Lancet

361:1686–1668.

6. Schober, S.E., Sinks, T.H., Jones, R.L., Bolger, P.M., McDowell, M., Osterloh,

J., Garrett, E.S., Canady, R.A., Dillon, C.F., Sun, Y., Joseph, C.B., Mahaffey,

K.R. 2003. Blood mercury levels in U.S. children and women of childbearing

age, 1999–2000. JAMA 2, 289(13):1667–1674.

7. Guallar, E., Sanz-Gallardo, M.I., van’t Veer, P., Bode, P., Aro, A., GomezAracena, J., Kark, J.D., Riemersma, R.A., Martin-Moreno, J.M., Kok, F.J.

2002. Mercury, fish oils, and the risk of myocardial infarction. N. Engl. J.

Med., 347(22):1747–1754.

Chairman EHLERS. Thank you.

Dr. Krabbenhoft.

STATEMENT OF DR. DAVID P. KRABBENHOFT, RESEARCH

SCIENTIST, UNITED STATES GEOLOGICAL SURVEY

Dr. KRABBENHOFT. Mr. Chairman and Members of the Subcommittee, thank you for this opportunity to present, on behalf of

the U.S. Geological Survey, this statement regarding ‘‘Mercury

Emissions: State of the Science and Technology.’’

18

Although humans have been using mercury in a variety of ways

for the past 2,000 years, mercury has been cycling in the environment for a much longer period of time. Over the past 100 years,

however, human activities related to industrialization and modernization have increased the amount of mercury cycling the environment and subsequent deposition to the landscape by a factor of

about three to five over pre-industrial times.

The conversion process of inorganic mercury, which comprises

the vast majority of mercury in the atmosphere, to methylmercury,

known as methylation, has an overwhelming importance on the exposure of humans and wildlife and the environment. Were it not

for methylation, bioaccumulation of mercury in the environment

would only happen under extremely rare circumstances.

My testimony today seeks to describe a general understanding of

the current state of science regarding mercury transport fate in the

environment. While constructing this testimony, I have focused on

the four questions your Subcommittee has asked of me.

Question one: ‘‘What do we know about how mercury reacts in

the atmosphere and what determines its deposition, and to what

extent is deposition local, regional, or global?’’ The amount of mercury contributed from each of these geographic source types at any

particular location can range widely. In truly remote settings

where equally high levels of mercury in food webs can occur, contributions from global mercury sources likely dominate, whereas in

settings near emission sources, the local contributions are likely

more important.

One critical scientific advance of researchers over the past decade

has been the ability to discriminate the three principle forms of

mercury in the atmosphere, and those are: reactive gaseous mercury; gaseous elemental mercury; and particulate mercury. Although greater than 95 percent of the mercury in the atmosphere

is gaseous elemental mercury, what deposits onto the landscape

are the other two forms of mercury. As such, understanding the

processes that regulate the transformation of these forms of mercury is critical for being able to predict where mercury from a particular source will deposit.

Question two: ‘‘What do we know about the relative reactivity of

old versus new mercury and anthropogenic versus natural mercury?’’ Mercury is an element, and as such, all mercury is ‘‘natural.’’ However, its reactivity and mobility is controlled by the details of its chemical form, and several of man’s activities serve to

change its chemical form. For example, mercury in coal is largely

found as traces in the mineral pyrite, which is relatively stable if

left undisturbed. However, upon combustion, much of the mercury

in the coal is reduced to the gaseous elemental mercury state,

thereby increasing its post-emission transport distance and reactivity.

Recently, researchers have begun to address the question of old

versus new mercury in the environment. The terms ‘‘new’’ and ‘‘old’’

do not refer to sources, but rather how long that mercury has been

in the environment. Results thus far have clearly shown that experimentally administered new mercury is much more apt to become methylated and incorporated into the food web than old merVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00022 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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cury probably because of physical and chemical differences in these

two mercury pools.

Question three: ‘‘What does research tell us about the extent to

which reducing mercury emission deposition will reduce mercury

levels in fish?’’ Past studies at point source contaminated sites in

areas where atmospheric deposition has declined tell us that fish

mercury levels generally follow mercury-loading rates. The timing

in the recovery, however, can vary substantially from years to decades. The extent of the recovery will likely be proportional to the

fraction of the deposition rate at any specific location that is eliminated.

Lastly, question four: ‘‘What are the future research needs with

respect to understanding how mercury cycles in the environment?’’

First, research to improve our understanding of chemical forms of

mercury from emission sources, changes that occur after release

and during transport, and controls on deposition patterns. Second,

research to help refined estimates of the relative contributions of

both natural and anthropogenic mercury emissions. Third, research

to improve our understanding of what factors control the far-ranging observed differences among ecosystem types in terms of their

sensitivity to mercury loading and what non-source control strategies can man consider to reduce methylmercury production and exposure. Lastly, research to help develop an understanding of the

mercury sources and sites of methylation that are responsible for

high levels of mercury in marine food webs. The vast majority of

mercury research over the past 15 years has been done on freshwater ecosystems, but few insights can be transferred from those

freshwater systems to the marine environment from which most

consumed fish are harvested.

Mr. Chairman, this concludes my remarks, and I would be happy

to respond to questions by Members of the Subcommittee.

[The prepared statement of Dr. Krabbenhoft follows:]

PREPARED STATEMENT OF DAVID P. KRABBENHOFT

Mr. Chairman and Members of the Subcommittee, thank you for this opportunity

to present, on behalf of the U.S. Geological Survey, this statement regarding ‘‘Mercury Emissions: State of the Science and Technology.’’ This statement seeks to describe a general understanding of the current state of science regarding mercury

transport and fate in the environment, focusing on the four questions posed by the

Subcommittee.

Background

Although humans have been using mercury in a variety of applications for more

than 2000 years, mercury has been cycling in the environment for a much longer

time through natural occurrences such as volcano eruptions. Over about the past

100 years, however, human activities related to industrialization and modernization

have increased substantially the amount of mercury released to the environment,

particularly via atmospheric emissions. Most researchers have concluded that rates

of atmospheric deposition of mercury on average are about 3–5 times greater presently than in historic times. Once deposited on oceans, land or freshwater systems,

a portion of the mercury re-emits back to the atmosphere. As a result of the mercury re-emission process, fluxes from land and oceans to the atmosphere are now

about three times higher than pre-industrial periods, and mercury contributions

from these ‘‘natural sources’’ constitute about two thirds of the mercury emissions

presently. Although these re-emissions come via ‘‘natural sources,’’ the increased

amount of mercury cycling in the environment is driven by the increased amount

of mercury introduced from human sources.

The overall increase in the amount of mercury cycling in the environment has resulted in exacerbated mercury exposure to food webs, including humans, and the

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widespread awareness of these levels has led to consumption advisories for elevated

levels of mercury in fish. Concerns about environmental mercury pollution and contamination of aquatic food webs stem largely from the human health risks of dietary

exposure to methylmercury, the dominant form of mercury in the edible flesh of fish

and aquatic mammals, and the form of mercury that is the focus of most environmental studies today.

The widespread geographic extent and adverse consequences of methylmercury

pollution continue to prompt considerable scientific investigation. The conversion of

inorganic mercury, the form comprising the vast majority of mercury in the atmosphere, to methylmercury (methylation) results from a series of very complex, processes that are facilitated by naturally occurring bacteria. Scientists now understand

that the methylation process primarily occurs in anaerobic (oxygen free) sediments

in aquatic ecosystems. In addition, we know that the methylation process involves

the intersection of the environmental sulfur cycle with the environmental mercury

cycle. The end result of these complex processes is a net increase in the overall toxicity of mercury, such that if mercury were not methylated in the environment, it

likely would only reach levels of toxicological concern in rare instances.

1. What do we know about how mercury reacts in the atmosphere and

what determines its deposition? To what extent is deposition local, regional or global?

Although there is general agreement that atmospheric mercury emissions and

transport pathways are the phenomenon that are chiefly responsible for the widespread mercury contamination, particularly for remote and semi-remote areas, scientific understanding of the processes controlling the region of influence of a specific

emission source is still an active area for research. Establishing the region of influence for various mercury emission sources has been evaluated through several

means, including: intensive site-specific monitoring, numerical modeling, and historical reconstruction of anthropogenic effects through dated cores of sediment and ice.

Together, all these scientific approaches have yielded considerable improved understanding of the relationships between atmospheric mercury sources and deposition

areas, but it should be stressed that this is still an area of evolving understanding.

One of the critical scientific advances of researchers over the past decade has been

the ability to discriminate the three principal forms of mercury that exist in the atmosphere:

• particulate mercury associated with settling particles,

• reactive gaseous mercury (RGM), and

• gaseous elemental mercury.

These three forms largely are determined by the chemical species (speciation) in

which the mercury exists, that is, whether it is in a neutral, uncharged state as in

gaseous elemental mercury, or in a charged state. Mercury in the atmosphere is

largely (>95 percent) gaseous elemental mercury, although most of what deposits is

composed of the other two forms of mercury (particulate and RGM). Particulate and

reactive gaseous mercury have relatively short travel distances (up to tens of kilometers) and small residence times in the atmosphere, whereas gaseous elemental

mercury exhibits global-scale transport and has an average atmospheric residence

time of about one year. As such, understanding what controls the transformation

from gaseous elemental mercury to particulate or RGM, is critical for being able to

predict where mercury will deposit from an emission source.

Presently, scientists believe that mercury depositing in remote settings, at long

distances from substantial sources, is derived from the transformation in the atmosphere of gaseous elemental mercury by ozone and possibly several other atmospheric

oxidants. On the other hand, mercury deposited near emission sources is likely to

be released as particulate mercury or RGM. Atmospheric emission sources, especially those related to human activities, have extremely variable amounts of the

three forms of mercury, and as such the region of influence of a specific emission

source can be quite variable and difficult to predict in the absence of source-specific

measurements. Scientists have been able to match deposition patterns measured on

the ground using mercury speciation measurements at a limited number of combustion sources and numerical models that simulate post emission oxidation reactions.

This lends credence to many of the assumed important factors controlling sourcereceptor relationships for mercury.

Reliable records of temporal trends in mercury deposition at a specific site also

can be useful for evaluating mercury sources through time. Temporal trends in mercury deposition can be obtained by using dated sediment and/or glacial ice cores,

where a variety of scientific tools are used to establish the age of various horizons

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in the core, for which a mercury concentration can be measured. Sediments from

lakes, reservoirs, and bogs have been used in the past for historical reconstructions

of mercury deposition. These historical reconstruction efforts have proven to be useful for evaluating local-to-global mercury sources. Scientists using this approach

have successfully documented changes to mercury deposition from natural and

human-related mercury emissions over thousands of years, and illustrated that mercury contributions at any particular location can range from local to global, and the

source attribution can change dramatically over time.

In remote and semi-remote areas of North America that lack local sources of anthropogenic mercury, the rate of mercury accumulation in many lake sediments has

increased by a factor of 2 to 4 since the mid-1800s or early 1900s. Dated ice cores

are also a useful means to infer mercury deposition, albeit at high altitudes or in

very remote polar settings. An ice core from the Fremont Glacier, Wyoming, demonstrated several key findings. It illustrated how variable mercury deposition can

be at any particular location through time, and how various mercury sources can

dominate a depositional period. For this specific location in Wyoming, the ice core

revealed that:

(1) mercury deposition rates after industrialization have ranged has a high as

20 times greater than pre-industrial periods;

(2) at times, volcanic eruptions located in the northern and southern hemisphere have resulted in recognizable, short-lived, periods of high mercury

deposition;

(3) upwind regional uses, such as the California Gold Rush, are clearly observed; and

(4) about 70 percent of the mercury deposited in this location over the 270 year

time period recorded by the ice core is attributed to global human activities.

Ascertaining the local, regional, or global mercury source contributions to any particular location is difficult. At any location, the amount contributed from each of

these three geographic source types could range widely. In truly remote settings, the

contributions of mercury from globally distributed sources will likely be more important; whereas, in settings nearer emission sources the local contributions will likely

predominate. Future abilities to predict the fractions from these sources will rely

on improved understanding of mercury speciation at various sources, transport processes and reactions, and deposition processes.

2. What do we know about the relative reactivity of old vs. new mercury

and anthropogenic vs. natural mercury?

Unlike many other high-visibility environmental pollutant problems, mercury is

an element, and as such, all mercury originated as ‘‘natural’’ mercury. The reactivity

and mobility of mercury is controlled by the details of its chemical form (speciation)

in the environment. It is in affecting this chemical form that man has had the greatest impact. For example, the principal ore of mercury is the mineral Cinnabar,

which is relatively insoluble and stable, and was used as a red pigment long before

the process for refining mercury ore to recover elemental mercury was discovered.

Converting cinnabar to liquid elemental mercury, which was the specific conversion

process of placer miners during the Gold Rush, greatly increases its propensity to

vaporize to the atmosphere. Similarly, most of the mercury found in coal deposits

is found as traces in the mineral pyrite, which is also relatively stable if left undisturbed. However, upon combustion a substantial amount of the mercury in coal is

converted to gaseous elemental mercury, and thereby increasing its post emission

transport distance.

There are important natural processes that also serve to increase the reactivity

of mercury, regardless of whether it originates from natural or anthropogenic

sources. For example, researchers recently discovered that natural processes lead to

formation of high levels of bromine near the surface of the Arctic and Antarctic regions at the time of the first sunrise, following the extended dark, polar winter. This

process serves to oxidize (chemically change) large quantities of gaseous elemental

mercury in the atmosphere over the polar regions, thereby converting it to particulate or reactive gaseous mercury and substantially increasing the deposition rate of

a highly reactive form of mercury to the landscape there. In summary, there are

no known differences between the chemical reactivity of mercury from anthropogenic or natural sources, but what does matter is what controls or alters the chemical form of the mercury.

Recently, researchers have begun to investigate whether there is any difference

between ‘‘new’’ versus ‘‘old’’ mercury in the environment. The terms ‘‘new’’ and ‘‘old’’

do not refer to the source, but simply how long the mercury has been deposited on

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the landscape. This question has been posed because of vast pools of mercury that

currently reside in soils and sediments from over a century of enhanced mercury

deposition. Scientists wondered if this relic mercury pool might not sustain the

present mercury problem for very long periods of time.

In order to address this question, scientists have initiated dosing studies, in which

mercury is delivered to test sites ranging in size from about a cubic meter, to whole

watershed scale. When conducting these studies, scientists are using traceable forms

of mercury that behave the same as the existing mercury, but that are distinguishable using advanced analytical procedures. This experimental approach has been applied thus far in two distinctly different ecosystems: the Everglades of Florida, and

a boreal forest ecosystem in western Ontario. Results from these two studies have

shown remarkable agreement in many ways, despite their different ecological settings. First, the results have clearly shown that the experimentally administered

mercury (‘‘new mercury’’) is much more apt to become methylated (about 5 to 10

fold) than previously existing ‘‘old mercury.’’ The precise physical and/or chemical

reasons for these observations are still being researched, but at this point we do not

have a definitive explanation.

3. What does research tell us about the extent to which reducing mercury

deposition will reduce mercury levels in fish?

Recent and historic research results tell us that fish mercury levels generally follow changes in mercury loading rates, both for increasing and decreasing rates. The

timing of the recovery, however, can vary substantially, and in some cases can take

many decades. For example, at industrially polluted Clay Lake, Ontario, mercury

concentrations in fish have declined from peak levels but remained substantially

above the Canadian mercury advisory level (0.5 mg/g) nearly three decades after operations ceased at a nearby chlor-alkali plant source. Mercury concentrations in fish

from Clay Lake decreased rapidly after the plant ceased operations—from about 15

micrograms per gram wet weight in 1970 to about 7.5 micrograms per gram in

1972—and then declined gradually to about 3.5 micrograms per gram in 1983. However, concentrations apparently declined little during the next 15 years (mercury in

fish tissues averaged 2.7 micrograms per gram in a sample of 14 walleyes taken

from Clay Lake in 1997 and 1998). It should be noted however, that the cause of

persistent problems with methylmercury contamination of aquatic biota at historically contaminated sites may result from:

• continuing, unintended emissions of mercury from the local point source,

• recycling and methylation of the mercury present in contaminated sediments,

• temporal increases in the reactivity of mercury from highly contaminated

zones,

• current atmospheric deposition of mercury from other sources, or from a combination of these factors.

More recently, researchers conducting mercury-loading studies have observed that

there is a direct relationship between the amount of mercury added to an ecosystem,

and the amount that is observed in fish. The time frame for a response depends on

the ecosystem in which the study was conducted. In the Everglades, the response

was very fast (within the season of the experiment or about 30–90 days). In a deeper, colder lake in Canada, the response was about a year, but the magnitude of the

response there was still growing after two years. Although it stands to reason that

the reverse observation would also be true (that reduced levels of loading would lead

to lower levels in fish), researchers need more time to monitor the experimental

sites when they transition from mercury loading studies to mercury reduction or recovery studies.

4. What are the future research needs with respect to understanding how

mercury cycles in the environment?

There are several areas of research needed to reduce the uncertainties relating

the linkages between mercury sources, cycling in the environment, and bioaccumulation in fish.

• Although scientists have made substantial advances in our understanding of

the importance of detailed information on the chemical form of mercury in the

environment and important chemical reactions, an incomplete understanding

still exits. At the present time, relatively few detailed studies of atmospheric

mercury transport have been conducted near specific sources, such as: combustion facilities, urban settings, or near known natural mercury sources.

Without this information, it is difficult to predict how much mercury in a particular location is derived from local, regional, or global sources.

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• Better definition of the relative contributions of natural versus anthropogenic

sources. Current estimates of mercury emissions from these two broadly defined source categories range substantially, and presently hinder our ability

to anticipate the level of benefit that might be derived from proposed emission

reductions. Natural mercury source emissions are particularly poorly understood.

• Better understanding of what factors control the observed far-ranging differences among ecosystem types, in terms of sensitivity to mercury loading

and bioaccumulation. The literature holds that some ecosystems are very sensitive to mercury inputs and can yield substantial levels of methylmercury,

while others are not. A better understanding of what controls this sensitivity

to mercury inputs and production of methylmercury will greatly aid our ability to predict the level and timing of potential benefits received from changes

to mercury loads.

• At the present time, very little understanding from the scientific literature

can be derived for resolving where marine fish get their mercury. This is particularly important in light of the fact that most of the fish consumed in the

United States and elsewhere are marine fish, yet a preponderance of the literature is based on freshwater studies. It is difficult to use the conceptual

models developed for shallow, freshwater systems and apply them to deep,

oceanic settings. Integrated, multi-disciplinary studies that link terrestrial

mercury sources, near-coastal and estuarine cycling, and bioaccumulation of

mercury in important commercial and sport fish are needed.

• Lastly, questions that require additional attention to ensure effective environmental protection are: how and to what extent will decreases in anthropogenic mercury emissions decrease the amount of mercury cycling in the environment, in what magnitude will those decreases reduce mercury bioaccumulation in aquatic ecosystems, and what will be the timing of such a recovery.

Mr. Chairman, this concludes my remarks. I would be happy to respond to questions Members of the Subcommittee may have.

Chairman EHLERS. Thank you.

Dr. Offen.

STATEMENT OF DR. GEORGE R. OFFEN, SENIOR TECHNICAL

LEADER, AIR EMISSION AND BYPRODUCT MANAGEMENT,

ELECTRIC POWER RESEARCH INSTITUTE

Dr. OFFEN. Thank you, Chairman Ehlers, for the opportunity to

speak before you on the important subject of mercury control. You

have kindly introduced EPRI so I don’t need to do that except to

mention that we do, in our work, collaborate quite a bit with suppliers, equipment suppliers, and government agencies. And particularly in the case of mercury, we have strong collaborations with the

Department of Energy and the EPA.

In that area, you asked us to talk about five questions in three

areas. The first one is on existing controls and what mercury reductions can one expect from those controls. On the average in the

U.S., current power plants with their emission controls for particulates, NOΧ, and SO2 are achieving a 40 percent reduction. However, that varies from 10 percent at some power plants to 90 percent at other power plants. And we see the primary differences

being a function of the coal that is burned and the air pollution

controls that are already in place at those power plants. Furthermore, those numbers are actually what we call snapshots in time.

They are derived from three tests taken for two-hour periods, and

we do know that mercury emissions vary widely over time. Over

a week’s period, they can vary by a factor of five to one, even when

the same coal is burned.

There is, beyond the 40 percent number I mentioned, a fraction

of the coal, particularly a portion of the eastern bituminous coal,

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that is washed, and the washing process is used for removing ash

and sulfur. And that process also does remove some mercury, on

the average 25 to 35 percent.

You asked what determines the effectiveness of the mercury reductions, and I have, more or less, answered that. The coal, and especially the chlorine content and its reactivity, its ability to burn

completely, and, of course, the air pollution control devices. And the

reason these two relate is that mercury, as Dr. Krabbenhoft mentioned, is released in two different gaseous forms. Any mercury

that is particulate is captured by the particulate control. But it can

be, as he said, either an elemental mercury or an oxidized form

when it is combined with other chemicals. And the other pollution

controls, like particulate and SO2 controls, really capture the

oxidized fraction and not the elemental fraction.

You asked about controls that are under development today. The

industry, and that includes EPRI, the suppliers, the power industry

themselves, DOE, EPA, are really following four parallel paths on

that. One is to try to better understand the interactions between

selective catalytic reduction for NOΧ control and scrubbers for SO2

control with regard to the mercury impact, what is called the cobenefits in all of the discussions that you have had. We see it in

some cases and don’t see it in some cases.

The next area is the area of sorbent injection, which is the technology where you blow a dust, a material like activated carbon,

into the gas and that absorbs the mercury, and then the activated

carbon with the mercury is captured by the particulate control. We

are doing quite a bit of work in that area as industry. That seems

to be the nearest-term mercury-specific control that is on people’s

agenda. We are trying to reduce the costs. We are trying to develop

sorbents that are more effective for more different coals. The—and

also trying to understand what the negative impacts may be and

mitigating those and overcoming those.

The third area is to develop and demonstrate new technologies.

These are falling into a couple of categories. One, again, is to help

capture mercury and scrubbers, so we are looking at catalysts that

will make more oxidized mercury. We are looking at chemical addition to boilers that will make more oxidized mercury. And the other

is trying materials that you can put in the very back end of your

power plant that sit there and that capture mercury and that you

occasionally regenerate, pull out and regenerate.

And then finally, we are looking at multi-pollutant controls and

seeing what role they could play in the picture of mercury.

You asked about the inferences of the full-scale tests of these

controls on what we know about effectiveness and cost. I need to

mention that the only full-scale tests that have been done today

have been short-term, about one week. Each test has been on a different fuel. And you have a figure in your package that shows the

removal is a function of the amount of carbon that is injected. And

you will see a separate line for each test that has been done. Again,

one test for each fuel. We don’t know if those lines are representative of each of those fuels or whether they are unique situations.

They are also short-term, so we don’t have any sense of what the

long-term impact might be.

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Fortunately, this is where the DOE is stepping up to the plate

right now. They have just released eight contracts that will be testing all of these technologies or many of these technologies for multiple month periods, one- or two-month periods, so we should have

a better handle on that after the tests are done. That will be in the

’04, ’05, and possibly ’06 time frame.

With that said, just to give you a flavor of the numbers, we are

seeing right now on these, with the caveats, 60 to 70 percent capture with sorbent injection in plants firing Powder River Basin

coal, which is now used by about 40 percent of the plants, and

going up to 90 percent in the low-sulfur eastern bituminous case,

which is the one case we are getting that much reduction. As I

mentioned, we don’t understand the sustainability and long-term

impacts of that. So we are very much looking forward to and very

supportive of the DOE program to extend our tests and our knowledge on that base.

Thank you, Mr. Chairman.

[The prepared statement of Dr. Offen follows:]

PREPARED STATEMENT OF GEORGE R. OFFEN

Mr. Chairman and Members of the Subcommittee:

Thank you for inviting EPRI to address the House Committee on Science’s Subcommittee on Environment, Technology, and Standards on the important subject of

mercury reductions from power plants. I am George Offen, and I manage our programs in air emission reductions and the beneficial use of combustion products.

EPRI was established 30 years ago as a non-profit, collaborative R&D organization

to carry out electricity-related supply, delivery, end-use, and environmental R&D in

the public interest. Our funders include electric power companies responsible for

over 90 percent of the electricity sold in the U.S., as well as over 60 companies

worldwide. We also cooperate closely with (and for some projects receive funding

from) government agencies in our research programs, particularly DOE and EPA,

as well as equipment suppliers and engineering firms. This is especially true in the

case of mercury.

For well over a decade, EPRI has been conducting research on all aspects of mercury sources, movement and chemical transformation in the environment, health effects, and methods to reduce emissions. My remarks today will respond to five questions in three topical areas that this subcommittee asked EPRI to address on the

subject of mercury control technologies.

1. Existing controls

A. To what extent do control technologies in use today at utilities reduce mercury

pollution?

On average across the domestic coal-fired population of power plants, current

technologies used to reduce particulate, NOΧ and SO2 emissions capture about 40

percent of the mercury that enters these boilers with the coal. However, these removals vary from less than 10 percent to over 90 percent, depending on the coal

and air pollution controls used. Further, the data that underlie these generalizations are snapshots in time at each plant in many cases just a few tests over a 1–

2 day period—while we now know that emissions can vary by a factor of five or

more over a week’s period. I should note that the removal efficiencies cited above

are additive to the mercury removed by coal washing for the many supplies of eastern bituminous coal that are washed; cleaning these coals often provides an average

mercury reduction of 25–35 percent before the coal arrives at the power plant.

B. What determines the effectiveness of these technologies in reducing mercury emissions?

The primary factors that affect the capture of mercury by existing air pollution

controls are the coal burned and the type of air pollution (NOΧ, SO2, particulate)

controls used at the plant. Mercury in the flue gas appears as a mix of elemental

(or metallic, non-water soluble) and oxidized (water soluble) mercury, depending priVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00029 Fmt 6633 Sfmt 6621 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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marily on the coal and to a lesser extent on the design of the boiler. Some controls,

such as scrubbers for SO2 reduction, capture only oxidized mercury. In some cases,

selective catalytic reduction (SCR) for NOΧ control may increase the percent of the

mercury that is in the oxidized form, enabling a downstream scrubber (if present

at the power plant) to capture more of the mercury. Coals and boilers that result

in increased levels of carbon leaving the boiler unburned tend to produce a fly ash

that may adsorb some of the mercury. The amount that would be adsorbed and subsequently captured by the particulate control depends on the technology used—electrostatic precipitators or baghouses—due to the difference in how the fly ash and

flue gases contact each other in these devices. All these interactions depend on complex chemical reactions between various species in the flue gas, especially chlorine,

but we do not yet totally understand this chemistry.

2. New controls

A. What are the major technologies under development today to control mercury

emissions from power plants?

The technical community is following four parallel paths to seek cost-effective,

sustainable mercury controls for the domestic boiler population—(1) trying to understand and improve the performance of existing controls, especially the combination

of SCR and scrubbers; (2) developing and lowering the cost of sorbent injection (such

as activated carbon), the nearest-term mercury-specific technology; (3) developing

and demonstrating new technologies; and (4) developing multi-pollutant controls to

capture NOΧ, SO2, mercury, and particulate in an integrated fashion. With sorbent

injection, a powder such as activated carbon is injected into the flue gas ahead of

the particulate collector, where it captures the mercury by adsorption and is then,

itself, collected along with the fly ash in the particulate collector. The technical community is looking at variants of this process aimed at reducing costs, avoiding contamination of the ash by using non-carbon sorbents, and developing sorbents that

work for all coals and particulate/SO2 controls. New technologies include catalysts

designed specifically to oxidize mercury that would be placed at the clean end of the

particulate collector for plants with downstream SO2 control; attempts to make flue

gas from Powder River Basin and other low-chlorine western coals behave like Eastern bituminous coal by adding chemicals to the coal or boiler; and fixed structures

that sit in the flue gas ducts and adsorb mercury until they need to be regenerated.

B. What do full-scale demonstrations tell us about the likely costs and effectiveness

of these technologies?

To date we only have full-scale data on activated carbon injection, and those data

are limited to one week tests at just one site for each of the coals tested. Mercury

removals were different at each of the sites (see Figure, which also shows the broad

range of pilot-scale results), and we do not know if this was due to the different

fuels or other reasons. The short-term removals ranged from a maximum of 60–70

percent at the site burning Powder River Basin coal to as much as 90 percent at

the plant firing Eastern low-sulfur bituminous coal site. Because these tests were

demonstrations, we do not have commercial cost data for the installations. Furthermore, having no long-term operational experience with these systems, we know neither their ability to sustain these levels of performance nor their potential impacts

on plant operations and maintenance. Assuming sustainable operation and no unexpected impacts—both big assumptions at this point in time—we have estimated

costs of $2 MWh to $3 MWh for activated carbon injection, including sorbent, operation and maintenance, and amortized capital.

3. What are the major barriers to development of technologies to control

mercury emissions from power plants?

The biggest barrier is the complexity of mercury chemistry in flue gases, and the

underlying lack of fundamental data on the chemical reactions in this kind of environment. This prevents us from (1) extrapolating tests on one power plant to other

plants with apparently similar features, and (2) carrying out most of the development of new technologies in the lab, where the costs should be less and turnaround

time quicker. Consequently, most of our development work occurs via full-scale

trials at power plants, and we need data from enough plants to allow us to develop

correlations we can use to predict mercury control performance across the population of U.S. boilers. The other main barrier is the absence of any long-term experience with mercury controls to address the questions I have raised on sustainable

operation and potential impacts on boiler operation and maintenance.

27

DOE’s Phase II field test program, which EPRI strongly supports, is an important

step to address both these needs. We believe that additional tests, possibly of shorter duration, are still needed to provide greater confidence in the representativeness

of the data we will obtain under the DOE Phase 11 program, and they are needed

on an accelerated schedule so that the power companies can use the results to meet

their upcoming regulatory obligations. We would also recommend that DOE conduct

similar field test evaluations of integrated pollution controls for those that show

promise at smaller scale.

Summary

Over the past decade, the technical community has made substantial progress in

understanding mercury emissions and developing mercury reduction options for a

wide range of coals and power plant air pollution control configurations. Coal washing and existing emission controls already reduce some of the mercury emitted from

coal-fired power plants, although this varies widely. The ability to remove mercury

from power plant flue gas is determined largely by the coal properties—especially

chlorine content and coal reactivity—the degree to which the boiler can combust the

coal completely, and the controls in existence at each individual plant. Correspondingly, suppliers, DOE, EPRI, and others are developing a variety of mercury controls

to provide cost-effective solutions for these various fuel/equipment configurations.

Accelerated research on mercury flue gas chemistry in parallel with expansion of

the current DOE field test program are needed to determine performance and cost

with confidence.

Thank you, again, for giving EPRI the opportunity to provide these comments.

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STATEMENT OF MR. KENNETH A. COLBURN, EXECUTIVE DIRECTOR, NORTHEAST STATES FOR COORDINATED AIR USE

MANAGEMENT

Mr. COLBURN. Thank you, Mr. Chairman.

NESCAUM appreciates the chance to address the Subcommittee

regarding the technological feasibility of controlling mercury from

power plants. Your timing is particularly opportune, as NESCAUM

has just completed a major report on mercury and control technologies to reduce its emissions.

Concern over the adverse health impacts of mercury has led the

Northeast States to adopt aggressive mercury-reduction initiatives.

In 1998, the New England States set a goal of reducing mercury

to 50 percent by 2003, 75 percent by 2010, and then to virtually

eliminate mercury emissions over time after that. We have met the

2003 goal with a reduction of 55 percent.

We did this by conducting a careful scientific analysis of our mercury sources and the technological feasibility of controlling their

emissions. This study allowed states to adopt standards mainly for

municipal waste combustors, in most states the largest sources,

that were almost three times more stringent than federal standards. Our 75 percent goal will require equally aggressive controls

on the part of power plants. And several states have already moved

to implement stringent mercury limits on power plants. Due to

deposition, however, a strong national program through the mercury MACT is crucial to our ability to protect the public.

This afternoon, I would like to comment just briefly on mercury

controls currently in use at power plants, emerging mercury-specific control technologies, and barriers to deploying those controls

all in the context of EPA’s mercury MACT proposal.

Under the Act, MACT can not be less stringent than the average

achieved by the best performing 12 percent of power plants for

which EPA has information. This is known as the ‘‘MACT floor.’’

And based on EPA’s current data, that would be a 91 percent reduction in mercury found in the coal. At present, mercury reductions from power plants are mostly co-benefits, as Dr. Offen mentioned, resulting from controls for other pollutants, such as NOΧ

and sulfur dioxide in particular.

Nearly all coal-fired power plants have at least some air pollution control devices, and a number of them already achieve impressive mercury reductions. In EPA’s tests, for example, four bituminous plants caught 95 percent of the mercury in the coal. And

some subbituminous plants captured 74 to 86 percent of the mercury in the coal. While these co-benefits are substantial, they don’t

include any attempt to optimize the controls for mercury removal.

Remember, they are for other pollutants. So the potential exists for

even greater mercury reductions from existing controls.

Many new mercury-specific control technologies are also well on

their way to commercialization. Activated carbon injection, for example, is being successfully demonstrated in full-scale applications,

showing that a 90 percent reduction is feasible for power plants at

costs comparable to those for NOΧ reductions. A recent American

Coal Council article, for example, said that activated carbon injection ‘‘requires minimal new capital equipment, can be retrofit without long outages, and is effective on both bituminous and subbituVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00033 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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minous coals,’’ and thus, ‘‘it appears unlikely that compliance with

pending mercury reduction regulations will result in significant

fuel switching.’’ Recognizing this, a permit issued in June 2003 for

a new power plant in Iowa burning western subbituminous coal requires mercury reductions of over 80 percent using activated carbon injection.

Other promising technologies include enhanced wet scrubbing to

help with oxidization of the mercury, as Dr. Offen mentioned, KFuel (r), a processed coal, and Powerspan’s Electrocatalytic Oxidation technology. I will hopefully have more time to go into these

during the question and answer session.

While these mercury-specific technologies are closest to commercialization, the Subcommittee should also be aware that several additional mercury control technologies have also emerged from the

laboratory and are now being tested. These include EPRI’s ‘‘Toxicon’’ process, the use of flyash as a sorbent at GE Power Systems and CONSOL Energy, promising chemical versus the usual

physical sorbents at Amended Silicates, and various metal amalgamation approaches. The fact that several of these approaches

were not even in existence when we looked at technologies two and

three years ago illustrates the technology creation benefits that

even the prospect of a good mercury MACT rule is having.

The only real barrier to controlling mercury emissions from

power plants is the current absence of a regulatory driver to create

a market for mercury control technologies. Coal-fired power plants

are not installing aggressive mercury-specific control technologies

today not because they can’t, but because there is simply no requirement for them to do so.

In September of 2000, NESCAUM issued a report that looked at

a history of sulfur dioxide controls, NOΧ controls, and auto emissions, and we found that regulations with well defined targets and

compliance deadlines drive innovation and control technology, resulting in dramatically lower implementation costs than initially

anticipated.

In short, we need to expose the commercial availability argument

for the red herring that it is. And I would caution the Committee

that there are several other red herrings in the wings, those being:

the technologies don’t work all of the time, the cost is too high, and

they can’t be installed in time. We all had those with sulfur and

nitrogen controls as well. History shows that market forces will capably address each of these concerns. Technology rapidly gets the

kinks out and becomes reliable. Costs drop dramatically, and the

market gets the job done on time. But it won’t happen until there

is a market, and there won’t be a market until there is a regulatory

driver, the mercury MACT rule.

In conclusion, one of my favorite sayings is: ‘‘Ask an engineer to

do something and you get nothing but problems. Tell an engineer

to do something and you get nothing but solutions.’’ Today, we are

getting significant mercury reductions as co-benefits from non-optimized controls for other pollutants. We have full-scale tests on new,

cost-effective control technologies that reduce mercury substantially from a variety of coals. And we have new, even more promising mercury control technologies coming out of the labs. Let us

tell our power sector engineers that it is time to reduce mercury

31

1 NESCAUM, Mercury Emissions from Coal-Fired Power Plants: The Case for Regulatory Action, October 2003. See www.nescaum.org.

emissions by 90 percent and begin to reap the public health and

environmental technology benefits that the resulting market will

bring forth.

Thank you.

[The prepared statement of Mr. Colburn follows:]

PREPARED STATEMENT OF KENNETH A. COLBURN

Thank you Mr. Chairman. My name is Ken Colburn. I am the Executive Director

of the Northeast States for Coordinated Air Use Management (NESCAUM).

NESCAUM is an association of state air pollution control agencies representing

Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode

Island and Vermont. We provide technical assistance and policy guidance to our

member states on regional air pollution issues of concern to the Northeast. On behalf of our eight member states, I would like to express our appreciation for this

opportunity to address the Committee regarding the technological feasibility of controlling mercury from electric generating facilities. The timing is particularly opportune, as NESCAUM has just completed a thorough review and assessment of mercury emissions from power plants and control technologies to reduce these emissions.1 This report, Mercury Emissions from Coal-Fired Power Plants: The Case for

Regulatory Action, has been made available to the Subcommittee.

Concern over the adverse public health impacts associated with exposure to

methylmercury has prompted all of the Northeast states to issue fish consumption

advisories and to adopt and implement aggressive mercury reduction initiatives. In

1998, the New England Governors and Eastern Canadian Premiers (NEG/ECP)

adopted a regional Mercury Action Plan that established a science-based, integrated

regional strategy intended to reduce in-region emissions by: 50 percent by 2003; 75

percent in 2010; and virtually eliminate anthropogenic releases over the long-term.

As of 2003, the region has achieved a 55 percent reduction in mercury emissions.

The success of the NEG/ECP effort is largely a function of the fact that the states

and provinces conducted a careful analysis of the sources of mercury emissions in

our region and technological feasibility of measures available to control these emissions. For example, based on our technology assessment, states where able to adopt

standards for municipal waste combustors (MWCs)—the largest source of mercury

in many Northeast States—nearly three times more stringent than the federal

standards, and MWCs have routinely achieved compliance with even the most stringent state standards. Achieving our next goal of a 75 percent reduction will require

equally aggressive controls on power plants which are now the largest source of

mercury emissions in the region. To address this need, several states in the Northeast have already moved to include stringent mercury emission limits as part of

multi-pollutant requirements for power plants. However, since about one-third of

the mercury deposition in the Northeast is attributable to out-of-region sources, primarily power plants, a strong national mercury MACT standard is critical to our

ability to protect the public from the harmful health effects associated with exposure

to methylmercury.

In my testimony this afternoon, I will: (1) provide an overview of in-use mercury

pollution control technology for power plants; (2) discuss emerging mercury-specific

control technologies; and (3) consider barriers to the development and deployment

of mercury emission controls for power plants. Given the pending proposal of a Maximum Achievable Control Technology (MACT) standard by the U.S. Environmental

Protection Agency (USEPA), I will relate my comments on technological feasibility

to that process.

In-Use ‘‘Co-Benefit’’ Mercury Control Technologies

For existing sources, MACT cannot be less stringent than the average emission

limitation achieved by the best performing 12 percent of the existing sources for

which the Administrator has emissions information. This is known as the ‘‘MACT

floor.’’ The USEPA has collected data from emission tests on 80 coal-fired boilers.

If the boilers are ranked according to the percent reduction achieved, the average

of the top 12 percent is a 91 percent reduction from the mercury in the combusted

coal.

At this point in time, in-use reductions from power plants accrue primarily as ‘‘cobenefits’’ associated with technologies designed to control pollutants other than mercury such as oxides of nitrogen (NOΧ), sulfur dioxide (SO2) and particulate matter

32

2Durham, Michael, Tools for Planning and Implementing Mercury Control Technology, American Coal Council, 2003.

(PM). All coal-fired power plants have at least some air pollution control devices,

such as electrostatic precipitators or baghouses (also known as fabric filters) for particulate control; wet or dry scrubbers for SO2 control; and low-NOΧ burners, selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) for NOΧ

control. Most of these controls can have impacts on mercury emissions and speciation. Electrostatic precipitators, fabric filters and wet and dry scrubbers all have

demonstrated particular promise in this regard.

A number of power plants already achieve impressive mercury reductions with

technologies that are designed to control other pollutants. For example, four bituminous coal-fired plants with dry scrubbers and fabric filters each captured more

than 95 percent of the mercury contained in the combusted coal during emission

tests. Some plants burning subbituminous coal that are equipped with fabric filters

and other stack controls achieved capture of 74 to 86 percent of the mercury in the

combusted coal during emission tests. For example: an 86 percent mercury reduction

was measured at a boiler equipped with a fabric filter and low NOΧ burner; a 74

percent mercury reduction was measured at a boiler using limestone injection and

a fabric filter; and an 84 percent mercury reduction was measured at Intermountain

at a plant which burns subbituminous and bituminous coal in a boiler equipped

with a low NOΧ burner, a wet scrubber, and a fabric filter.

As these examples illustrate, mercury co-benefits from existing air pollution control technologies have already proven to be quite substantial. Moreover, at the time

of these emissions tests, there was no attempt to optimize controls for mercury removal. Thus, the potential exists to increase mercury removal significantly using

various optimization strategies on existing controls.

Emerging Mercury-Specific Control Technologies

Mercury-specific control technologies are well on their way to commercial availability. For example, activated carbon injection technology is being successfully demonstrated in both pilot and full-scale applications. The results indicate that mercury

control efficiency of over 90 percent is feasible for power plants, with costs that are

comparable to the costs of NOΧ removal required under the federal program to

achieve national ambient air quality standards for ozone (i.e., in the range of two

mills per kilowatt hour). According to an article in a recent American Coal Council

publication, activated carbon injection ‘‘requires minimal new capital equipment,

can be retrofit without long outages, and is effective on both bituminous and subbituminous coals,’’ and ‘‘it appears unlikely that compliance with pending mercury

reduction regulations will result in significant fuel switching.’’ 2 Recognizing this opportunity, a permit issued in June 2003 for a new power plant in Iowa burning

western subbituminous coal requires mercury reductions of over 80 percent using

activated carbon injection.

Other promising technologies include enhanced wet scrubbing, K–Fuel, and

Powerspan-ECOΤΜ. Enhanced wet scrubbing technology promotes the oxidation of

elemental mercury in the flue gas prior to entering the scrubber, such that as high

a fraction as possible of the total mercury is in the oxidized state and hence more

easily removed in the scrubber vessel. Many approaches are under development to

accomplish this goal, including those using chemical reagents, fixed catalysts, and

high-energy oxidation.

KFX’s K–Fuel is a processed coal derived from western subbituminous coals. It

is lower in ash, higher in BTU value, and produces lower pollutant emissions than

the parent coals. K–Fuel is processed in two-steps—physical separation and thermal processing—to produce a fuel that is higher value and ‘‘cleaner’’ than the original coal. The process involves elevated temperature and pressure, greatly reducing

the moisture content of the coal. The mercury is volatilized and subsequently captured in a carbon-bed reactor.

Powerspan-ECOΤΜ is a post-combustion multi-pollutant control technology. It consists of a high-energy oxidation reactor followed by an ammonia-based scrubber and

a wet electrostatic precipitator, which captures the products of oxidation. Fertilizer

byproducts are generated (ammonia nitrate and sulfate), which should contribute to

the overall economics of the technology.

While NESCAUM’s new report focused on the above four mercury-specific control

technologies as those closest to commercialization, the Subcommittee should be

aware that several additional mercury control technologies have also emerged from

the laboratory and are now being tested, including EPRI’s ‘‘Toxecon’’ process, the

use of flyash as a sorbent at GE Power Systems and CONSOL Energy, promising

chemical (vs. physical) sorbents at Amended Silicates/ADA Technologies, and varVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00036 Fmt 6633 Sfmt 6621 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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3 NESCAUM, Environmental Regulation and Technology Innovation: Controlling Mercury

Emissions from Coal-Fired Boilers, September 2000. See www.nescaum.org. 4Worldwatch Institute, Working for the Environment, Paper #152. See www.worldwatch.org. 5Monroe, L., Southern Company, from Mercury Rising, UtiliPoint IssueAlert, July 15, 2003.

See www.utilipoint.com/issuealert/print.asp?id=1749.

ious metal amalgamation approaches. The fact that several of the above approaches

were not even in existence 2–3 years ago illustrates the rapid pace of research in

the area of mercury controls.

Barriers to the Development of Mercury Controls for Power Plants

Due to the pace of technology development, the only real remaining barrier to controlling mercury emissions from power plants is not a question of technology; it is

a question of will: it is the current absence of the regulatory driver needed to create

the opportunity—the demand—for mercury control technologies to come to market.

At this point, coal-fired power plants are not installing aggressive mercury control

technologies because they cannot do so; they aren’t simply because there is no re- quirement for them to do so.

In September 2000, NESCAUM issued a report summarizing an in-depth study

of the technology-forcing effects of environmental regulatory requirements.3 This

study looked at the regulation of nitrogen oxide (NOΧ) emissions from coal-fired boilers, sulfur dioxide from coal-fired boilers, and automobile emissions. It concluded

that regulations with well-defined targets and compliance deadlines drive innovation in control technology, resulting in dramatically lower implementation costs

than initially projected. Similar analyses of approximately a dozen major regulatory

initiatives ranging from CFCs to landfill leachate show that initial cost estimates

were at least double the actual costs and often far higher.4

Simply put, the principal barrier to the development of cost-effective controls for

mercury emissions from power plants has been EPA’s failure to date to establish

an appropriate MACT standard for this sector, and we have no doubt that the documented history of regulatory-driven technology innovation and cost reduction will

repeat itself if and when EPA does establish an appropriately stringent mercury

MACT standard.

Coal-fired boiler operators suggest that EPA proceed only gingerly—if at all—with

mercury reduction requirements because, they claim, there are no ‘‘commercially

available’’ mercury control technologies. This suggestion dovetails closely with the

above discussion of barriers. When does an ‘‘available’’ technology become ‘‘commercially available’’? When it provides competitive advantage to the buyer, or when the

buyer is required to modify its practices to meet a larger societal need, e.g., through

regulation. ‘‘Commercial availability,’’ then, resembles a ‘‘chicken or egg’’ scenario.

Which comes first, ‘‘commercial availability’’ or regulatory obligation? Per the above

discussion concerning barriers, history shows that well-designed regulatory requirements with appropriate lead times result in the commercialization of technological

innovation, not vice versa.

Let’s also consider precisely what industry opponents mean by ‘‘commercial availability.’’ Southern Company recently indicated that ‘‘There are currently no commercial technologies that are available for controlling mercury from coal-fired power

plants. There are no vendors that are offering process systems that are supported

by guarantees from the vendor for mercury control performance under all the conditions that an ordinary power plant is expected to encounter over the course of normal operating conditions and timelines’’ [emphasis added].5 These caveats suggest

that industry seeks zero risk regarding mercury control performance, which leads

me to wonder if it would accept a corresponding zero percent return on any mercury

control investments made under such caveats.

In sum, we need to expose the ‘‘commercial availability’’ argument for the red herring that it is. Other red herrings lie in the wings, including (a) the technologies

don’t deliver good results all the time, (b) the cost is too high, and (c) the technologies can’t be installed in time. History shows that market forces will capably

address each of these concerns. Technology rapidly gets the kinks out and becomes

reliable, costs drop dramatically, and the market gets the job done on time. But that

won’t happen until there is a market, and there won’t be a market until there is

a driver—a stringent mercury MACT.

In conclusion, I am reminded of an aphorism that arose during earlier NOΧ negotiations with the power sector, but seems no less applicable to mercury emissions:

‘‘Ask an engineer to do something, and you get nothing but problems. Tell an engineer to do something, and you get nothing but solutions.’’ Today, we are getting significant mercury reductions as co-benefits from non-optimized controls for other pollutants. We have full scale tests on new, cost-effective control technologies that reVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00037 Fmt 6633 Sfmt 6621 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
34

duce mercury substantially from a variety of coals. And we have new, even more

promising mercury control technologies coming out of the labs. Let’s tell our power

sector engineers that it’s time to reduce mercury emissions by 90 percent and begin

to reap the public health and environmental technology benefits that the resulting

market will bring forth.

DISCUSSION

Chairman EHLERS. Thank you all very much. In response to your

last comment, I should defend engineers, but I won’t. But I would

mention the way to get a physicist to solve a problem is to tell

them that there is no solution possible, and you will soon have ten

different solutions.

LESSONS LEARNED FROM THE STATE OF FLORIDA RESEARCH

Very good testimony. And a number of questions that I have, I

think we are going to need a second round just to accommodate my

questions. But I am trying to—well, Dr. Krabbenhoft, first, were

you involved in the work in the Everglades, and can you tell us

what we learned from the experiment there following the regulation of the incinerators in Florida? And I should mention, even

though most of the discussion has been about power plants burning

coal, the first regulations were on medical incinerators, which tend

to have a lot of mercury in them because of the medical products.

So that has been regulated for some time. Can you enlighten us on

what has been learned so far with that?

Dr. KRABBENHOFT. Yes, Mr. Chairman. I have been working on

the mercury issue in south Florida since 1995. Over that period of

time, we have learned a lot about what controls mercury cycling in

the environment.

In short, over the past five or six years, there has been a notable

decline in fish mercury concentrations observed in sport fish particulate gas and it is to the level of about a 60 or 70 percent reduction

in fish tissue concentrations. Over that same period of time, the

State of Florida has concluded that this reduction in fish tissue

concentration is related to the rules that were implemented around

1990 that had an effect on municipal and medical waste incineration in south Florida to reduce mercury emissions in the southern

peninsula of Florida. This corresponding reduction in fish mercury

concentrations has been linked to that. They have done modeling

exercises to see if that level of reduction in air emission sources

could result in those fish mercury concentration declines, and the

answer was, in short, yes.

That is one of the rare examples, here in the U.S., where you can

look at an air emission reduction and infer what happened ecologically.

THE DIFFERENCE BETWEEN METHYLMERCURY AND

ELEMENTAL MERCURY

Chairman EHLERS. Let me just ask a few questions to improve

my understanding. My understanding is that the only real risk is

from methylmercury, that the elemental mercury that is out there,

the mercury oxides, chlorides, and so forth don’t really seem to

pose a health risk, but just the methylmercury. Is that correct?

35

And that is because it is absorbed by living organisms and then

concentrated on the food chain. Is that a correct statement?

Dr. KRABBENHOFT. Yes, the fraction of mercury in the environment that is methylated typically, say, in sedimented water, is less

than one percent to a few percent, a very small fraction of the total

pool. But it is that small fraction that by the time you get into the

part of the food web where you would consume, say, a top predator

fish, it essentially comprises all of the mercury in those fish tissues. So that inorganic fraction, the oxides of the elemental mercury, does not bioaccumulate to the top levels of the food web. So

it is that fraction of the mercury that humans and other top carnivores or predators are exposed to.

HUMAN RESPONSE TO METHYLMERCURY EXPOSURE

There are also biochemical reasons in our bodies as well as other

vertebrate organisms that allow methylated mercury to get into

parts of our bodies that the inorganic fraction does not. So that is

in addition to not only bioaccumulation aspects, but also biochemically. It behaves differently once in our bodies.

Chairman EHLERS. The Mad Hatters became ill simply because

they had such a huge concentration of elemental mercury they

were working on.

Dr. KRABBENHOFT. That was a case of just gross exposure to the

inorganic mercury, correct.

Chairman EHLERS. Yeah. All right.

FRESH WATER VS. MARINE WATER

You made the comment about marine—you know a lot more

about fresh fish consumption and pollution than marine. What is

the likely difference? Is it the minerals in the water in the ocean

that make the difference or you don’t know whether the mercury

is distributed worldwide. What is the difference?

Dr. KRABBENHOFT. The key difference is that in most freshwater

systems, because they are much shallower than the ocean, scientists call upon mercury methylation to occur at the sediment

water interface. Therefore, the likelihood of that methylmercury

production zone being linked to the food web is not hard to imagine

at all. However, in the ocean where you have thousands and tens

of thousands of feet of separation from where the harvestable fish

are swimming. From the bottom of the ocean where it may be

methylated, it is very difficult to come up with a reasonable or

plausible link between a sedimentary-based methylation site and

fish swimming near the surface of the ocean. That is the problem

that we just can’t come up with a conceptual model that is reasonable based on our freshwater experience. Therefore, several of us

are proposing links to coastal margins, actually, food web links of

those marine fisheries to coastal margins.

Chairman EHLERS. To what extent are the ocean fish contaminated with mercury compared to the freshwater fish?

Dr. KRABBENHOFT. Some of the highest levels of mercury in fish,

on average, in fact, are from the marine fish.

Chairman EHLERS. Really?

Dr. KRABBENHOFT. Yes.

36

Chairman EHLERS. And what is the concentration of

methylmercury in the ocean water compared to freshwater?

Dr. KRABBENHOFT. We can use the example that if we use our

standard procedure, which is the best going right now, we would

take a freshwater sample and analyze methylmercury from it and

we apply that procedure to ocean water, we can not detect

methylmercury. If we use adapted procedures with much higher

volumes and stripping methylmercury out of a larger volume, we

can measure it. But the methylmercury in any case in ocean water

is extraordinarily low. And that is part of the conundrum. How can

we get such high levels in these marine fish when the levels are

so extraordinarily low?

Chairman EHLERS. Unless they eat an extremely greater amount

of fish, of smaller fish.

All right. My time has expired. I will recognize the Ranking

Member, Mr. Udall.

DEVELOPMENT OF SPECIFIC TECHNOLOGIES FOR MERCURY

ABATEMENT

Mr. UDALL. Thank you, Mr. Chairman. I, too, want to thank the

panel. And your testimony has been very educational.

If I could, I would start with Mr. Colburn. In your written testimony, you state that current technologies can achieve an impressive, I think, 95 percent reduction of mercury in power plants. I

think what is remarkable about it is in part because this is shown

even in the absence of specific controls for mercury. Since 95 percent of mercury can be removed as a co-benefit, is there a need for

the development of specific mercury control technologies?

Mr. COLBURN. I think, Congressman, that that is really a function of letting the market pick the best solution.

Mr. UDALL. Uh-huh.

Mr. COLBURN. We should require a mercury reduction result, and

then if individual plants in their market conditions can achieve

that through co-benefits, more power to them. If they need mercury-specific control technologies to achieve that, then market options should be there for them to do so. The principle reason, as

I see it, that most of those plants performed as well as they did

is because they have a fine particulate matter control technology

called a baghouse or a fabric filter. There is carbon in the gas. That

allows absorption with mercury. The baghouse provides greater

coverage, greater residence time, a greater exposure to the carbon

by the mercury, and thus, more is removed. Baghouses aren’t rocket science, and they could be installed on other plants, if the plants

chose that as their route. But that is being done today.

The oxidation opportunities that Dr. Offen mentioned are also

significant and I suspect that several of those plants also had SCR

before the baghouse, but those technologies exist. The reason other

plants have done less well is many of those plants don’t have

baghouses. Does that answer your question?

Mr. UDALL. That is helpful. Yes.

Dr. Offen, would you like to comment on that particular question

or add your comments?

Dr. OFFEN. Yes. There were a number of comments that were

made. What Mr. Colburn said was correct about the plants that

37

have very high removals. They do have, typically, spray dryers and

baghouse combinations, the particular set of controls that work

very well on low-sulfur coals. They have to be eastern low-sulfur

coal so they have enough chlorine in there to make all three work

together.

What Mr. Colburn said about unburned carbon is also correct.

For those plants that aren’t able to burn the coal out totally and

have some residue carbon left in there, that will help as long as

the temperature where the particulate collection device is low

enough. All of these are site-specific factors, so depending upon the

plant situation, you would have to add other controls to get to any

increased levels, especially those plants that are in the 10, 20, 30,

and 50 percent range.

FEDERAL REGULATION’S EFFECT ON MERCURY REDUCTION

Mr. UDALL. Back to you, Mr. Colburn, again. You had some remarkable results, as we were mentioning, in the Northeastern

States. And from what I understand, you did this in part because

these municipal waste combustors had higher standards, three

times as high as the federal standard. How important is it that federal mercury regulations allow States to institute more stringent

controls than federal law prescribes? If the Northeastern States

had not been able to increase control standards, in other words,

preempt federal laws, could the Northeast have been successful in

achieving this 55 percent in regional reduction?

Mr. COLBURN. We certainly would not have been able to achieve

it, Congressman. If we had been limited, if the States did not have

the opportunity to provide further protection to their citizens, it

couldn’t have been done. I should add, Congressman, that the

sources have actually controlled about three times better than even

the States required. We have been here and have done that as far

as mercury controls on municipal waste combustors go. No, we just

need to give the power plant sector the same motives to move forward with both the information needs that Dr. Offen mentioned

and the control technology installations.

Mr. UDALL. So you are saying the combustors went three times

beyond what the States were requiring which was three times beyond from the federal standards?

Mr. COLBURN. Yes. The federal standard is typically 80

micrograms per cubic meter. The States typically did a standard of

28. And the municipal waste combustors are operating in the 5 to

10 area.

RELATIONSHIP BETWEEN GOVERNMENT REGULATION AND

TECHNOLOGY DEVELOPMENT

Mr. UDALL. Dr. Offen and Mr. Colburn, one of my worries is that

we lag behind if we don’t put these new standards in place, lag behind other countries in the development of their technologies. Do

you foresee a point in which if we don’t make it clear what our

standards are that, when we do, because I think this is a matter

of not whether but when and how, that we will actually be buying

that equipment and generating that technology from other counVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00041 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
38

tries as opposed to within our own environmental technology sector?

Mr. COLBURN. Congressman, I think that is not only a perceptive

point, I think that is an accurate one. I had one technology vendor

recently say to me that the showstopper for their technology creation and development would be if there is not a good mercury

MACT rule. And I think that is representative of the other technology developers out there.

An interesting calculation, I certainly don’t have it at the tip of

my tongue, would be how many jobs are there in the control development manufacture and installation side of the coin versus the

power plant operation and extraction industries? I wouldn’t be surprised if the delta between those two is smaller than any expect.

Mr. UDALL. I see my time has expired, but I did want to mention

and show the Chairman as well, that on the coal consumption, a

million ton basis, China and the U.S. add up to about 50 percent.

And I am curious if the Chinese are developing any of this kind

of technology. And if they are not, then, of course, we are in a race

with the EU countries, I would imagine, and perhaps Japan in

fighting this technology with the Chinese, which would be an enormous market for us. Would that be correct from what you understand?

Mr. COLBURN. I don’t have direct knowledge of that, but I have

no reason to dispute the conclusion that they must be looking at

that.

Mr. UDALL. Thank you, Mr. Chairman.

Chairman EHLERS. The gentleman’s time has expired.

Next, we recognize the gentleman from Minnesota, Mr. Gutknecht.

HOW FEDERAL AGENCIES ARE RESPONDING

Mr. GUTKNECHT. Thank you, Mr. Chairman. And I was deadly

serious, I have become incredibly interested in this subject. And

the more I learn about it, sometimes, it is more disturbing what

I learn is out there.

First of all, I guess I would ask all four of you maybe to just respond as briefly as you can. Do you think that the EPA, the CDC,

the FDA, and the other agencies that are involved in this are taking this issue as seriously as they should? Dr. Burke.

Dr. BURKE. Great question. I think they are taking it very seriously. They interacted very actively with the National Academy.

They have active research at CDC, surveillance of the population

at EPA, the development of regulatory approaches as well as research, and the FDA has been doing a lot of fact-finding. Unfortunately, they take three different directions sometimes, and we have

not had a unified approach to really look from source to exposure

to health endpoint, but I think that is beginning to take shape.

Yes, they are taking it seriously.

Dr. KRABBENHOFT. I interact with agency members from most of

the agencies that you listed there, and my conclusion is they take

it very seriously. They don’t necessarily agree, but my conclusion

is they take it very seriously.

Dr. OFFEN. Of course, I will switch to the control technology portion of what they are doing. And as I mentioned in my discussion,

39

we work very closely with the Department of Energy but also with

the EPA. We co-fund projects, and they were participants in all of

the field tests that led to the graph that is at the end of your package, for example. So the answer is definitely yes.

Mr. COLBURN. Congressman, I would basically agree with the

other three witnesses. I would also include the private sector, because they are taking it very seriously in terms of technology development. I guess the only equivocation I would have is that one does

have to recall that EPA needed to be compelled through Court

Order to issue the MACT rule at the end of this year and then to

finalize it at the end of next year.

Mr. GUTKNECHT. That is part of the reason I raised the question.

And I think you all eluded to it that, even in the consumption of

fish, we have different agencies essentially saying different things.

Now I am not sure that that is necessarily a bad thing, but I am

also concerned, and this is a parochial interest, and part of the reason that has gotten me interested in this and I can’t remember

which one of you mentioned this, about the lack of setting clear

standards. For example—I would assume some of you are familiar

with the process of retorting and that actually, at one time, there

were ten firms involved in that and now we have two, in part because the EPA has not promulgated the rules, which I think everyone assumed that they would.

Dr. Krabbenhoft, I see you were shaking your head. Is that okay?

Dr. BURKE. Let me try and sort out the question there. There has

been a lot of uncertainty about the science, but clearly there are

different missions for the agencies involved, which has led to different approaches to how they have gone about their efforts to limit

mercury exposure and the health effects. I think EPA has been a

leader in the research and pushing forward with the evaluation of

the epidemiology. But clearly, there have been different points of

view from CDC and FDA. I think this has led to some confusion

and ultimately to the National Academy study, which we feel has

unified the database, has looked across the endpoints of animal

and human data and really tried to put an end to the different interpretations and come up with some definitive recommendations

about the effects seen in the human epidemiology, provides a

strong basis for EPA to move forward with the RFD, and that the

scientific basis of the actions, although they might have different

responsibilities, should be uniform across the agencies.

THIMEROSAL

Mr. GUTKNECHT. Let me just ask one last question, and I see the

yellow light has already come on.

One of the other things, Dr. Burke, you mentioned unborn children. And what about small children and the use of—I believe it

is called thimerosal. And I understand have been studies and some

back stepping and so forth on that whole issue. What is your view?

Dr. BURKE. Well, I understand today there was a—the American

Academy of Pediatrics came out with some new evidence that thimerosal in vaccines was not related to adverse effects. I have only

heard that through the press. I think there is a lot of uncertainty,

particularly at the very low doses that we are talking about. And

there are questions about when is the most vulnerable period of deVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00043 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
40

velopment? Is it in utero? Is it small children? We know the brain

is very busy developing in small children. We also know that mercury is a strong neurotoxic agent, but we don’t have all of the answers. I think that is why we depend upon the epidemiology from

the most sensitive, the children exposed in utero. But frankly,

there are effects throughout the life span, including cardiovascular

effects on middle-aged men that we are just beginning to understand and sort out.

Mr. GUTKNECHT. I see my time has expired, and I might come

back to that, because when you have small, underweight children

and you give them three booster shots all in the same day, they

are getting upwards of 75, is it microliters, or whatever the term

is. I mean, it seems to me that is a pretty good jolt to anybody’s

system.

Dr. BURKE. There was concern, particularly about the premature

infants and the regime of vaccination and a movement toward

phasing out thimerosal as a preservative. It has important benefits.

Vaccinations have been a tremendous public health breakthrough,

but we have to balance those. And right now, the news appears to

be good.

Mr. GUTKNECHT. All right. Thank you.

Chairman EHLERS. The gentleman’s time has expired.

Next we call on the gentleman from Maryland, Mr. Gilchrest.

WHAT HAPPENS TO MERCURY WHEN IT ENTERS THE

NATURAL ENVIRONMENT

Mr. GILCHREST. Thank you, Chairman.

Just to, maybe, Mr. Burke and Dr. Krabbenhoft. I was looking

at it to make sure I pronounced your name right.

Three forms of mercury, or the three that were mentioned here,

at least, oxidized, elemental, and methylmercury, are they all persistent in the environment, or do any of them biodegrade in the

natural environment?

Dr. KRABBENHOFT. Those forms of mercury all interconvert, some

on a very rapid basis. So if we go out and take a sample and have

a certain percentage, say and a sample has methylmercury, we can

come back a few months later and see a very different signal, because there are—— Mr. GILCHREST. So it might go from methyl to elemental to

oxidized?

Dr. KRABBENHOFT. Yes. There is a constant interconversion. Now

is there any——

Mr. GILCHREST. Is there a difference in freshwater in estuary or

the marine environment? Would that change?

Dr. KRABBENHOFT. I have—certainly for the marine system there

is not enough information to give you an answer.

Mr. GILCHREST. Could it change inside the fatty tissue of a fish

from methyl to elemental to oxidized?

Dr. KRABBENHOFT. Certainly methylmercury could be

demethylated to the oxidized inorganic mercury in our bodies, and

that is one of the things that does happen, yes. But it is very

slow——

Mr. GILCHREST. So it is not likely to change while it is in the

fatty tissue of a fish?

41

Dr. KRABBENHOFT. It actually doesn’t go to the fatty tissue. It

goes to the muscle.

Mr. GILCHREST. Oh.

Dr. KRABBENHOFT. That is the difference between mercury and

most other contaminants of concern. And that is why you can’t filet

it out or cook it out.

Mr. GILCHREST. But methylmercury is the dangerous form of

mercury that could cause health effects as opposed to elemental

and oxidized mercury?

Dr. KRABBENHOFT. None of them are good for us——

Mr. GILCHREST. Okay.

Dr. KRABBENHOFT [continuing]. That is for sure. Methylmercury

is more toxic gram per gram than the others for a variety of reasons that probably Dr. Burke is more qualified to answer.

SCIENTIFIC BASIS FOR EPA STANDARD

Mr. GILCHREST. Is it—Dr. Burke, you mentioned that the National Academy of Science has tried to find some uniform, I guess,

system to determine is it safe levels of mercury in humans and

have they come up with a unified statement or policy on that?

Dr. BURKE. The National Academy report reviewed the body of

evidence and make recommendations to EPA. It reviewed the basis

for the EPA standard, which at that time, was based upon a poisoning episode in Iraq. And we are most concerned about dietary,

consumption of fish that have mercury. So we recommended they

change the basis for their standard and use the human epidemiology and provided a presentation of that information, yes.

Mr. GILCHREST. So NAS made a recommendation to EPA for EPA

to change the standard they had been using?

Dr. KRABBENHOFT. Change the scientific basis for it.

Mr. GILCHREST. Oh, I see.

Dr. KRABBENHOFT. In fact, what we did was reaffirm the standard that they were using, because within that range, that appears

to be a range with levels of uncertainty that would be

protective——

Mr. GILCHREST. So you are saying EPA pretty much had it right

already?

Dr. KRABBENHOFT. EPA had it right, but we refined the basis for

that being maternal exposure, through diet, through fish.

MERCURY IN THE CHESAPEAKE BAY

Mr. GILCHREST. So in an estuary like the Chesapeake Bay, what

would be the prime source of mercury, methylmercury in particular? Would it be coal-fired power plants?

Dr. KRABBENHOFT. The knowledge I have of the Chesapeake, and

there are research projects that are going on right now, and I believe I have them accurately that the majority of the

methylmercury is made in the sediments of the Chesapeake itself,

but it is—— Mr. GILCHREST. When you say it is made in the sediments of the

Chesapeake itself, what do you mean?

Dr. KRABBENHOFT. The mercury that comes into the Chesapeake

is overwhelmingly the inorganic, oxidized form both from air depoVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00045 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
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sition and from runoff. And the runoff gets contributions from a

wide variety of sources.

Mr. GILCHREST. From as far away as Ohio?

Dr. KRABBENHOFT. Those would have to be air deposition, but

certainly that is not implausible at all. But once in the ecosystem,

that mercury that deposits either on streams that drain into the

Chesapeake or directly on the Chesapeake itself quickly descend to

the sediments. And there, a fraction of that mercury gets

methylated. So it is converted in the environment to

methylmercury. And so the majority of the methylmercury in the

Chesapeake——

Mr. GILCHREST. How long does it take to go from the oxidized

form to methylmercury while it is in the Bay?

[No response.]

Mr. GILCHREST. That will vary depending on the circumstances?

Dr. KRABBENHOFT. It varies depending upon the circumstances,

but in short, what we have seen in our environment studies is this

transformation is very fast.

Mr. GILCHREST. So the main source, whether it is the drainage

from the land to the streams to the Bay or from air deposition,

what would be the main source of that mercury, oxidized, elemental, or methyl? Is that—I mean, other than human activities,

is it automobiles, incinerators for medical waste, coal-fired power

plants?

Dr. KRABBENHOFT. I have not seen a mass balance, if you will,

for Chesapeake Bay itself. Researchers who I know are doing that

have done the calculations to suggest that most of the mercury, I

believe, comes in through the sky——

Mr. GILCHREST. I see.

Dr. KRABBENHOFT [continuing]. And rains directly on the Chesapeake that way. And that is generally the calculation results that

direct deposition is most important.

Mr. GILCHREST. Would you recommend that every fishing hole in

the Chesapeake Bay and its tributaries have a sign talking about

the contamination of methylmercury or is that not a problem to

fish?

Dr. KRABBENHOFT. Go ahead.

Dr. BURKE. If I may help with this, the inland waterways, the

rivers throughout Maryland actually have fishing advisories. The

Bay itself——

Mr. GILCHREST. Well, I live there, and I don’t see a lot of signs

posted——

Dr. BURKE. No, the signs aren’t there, but the advisories are

there.

Mr. GILCHREST. Should the signs be there? The advisories are in

the newspaper every once in a while.

Dr. BURKE. They should be there. They should be on the licenses,

and we should have, as best we can, the best information we can

have out there on the levels in inland waterways, not just in Maryland but throughout this country. In 44 of the States we have this

problem. They are elevated. The levels from outside in the Bay appear to be lower, though.

43

THE BASIS FOR NATIONAL ACADEMY OF SCIENCE’S

RECOMMENDATION

Chairman EHLERS. The gentleman’s time has expired. We will

start a second round of questioning.

And Dr. Burke, I would like to ask you a few questions about the

studies on which your work was based. First of all, I am interested

in the Seychelles study, which I understand, initially was just regarded as not having appropriate technique and so forth. So when

the National Academy did their work, they basically disregarded

that in setting their number. Now I gather from your testimony

that with additional work down there, the Seychelles study has

achieved some respectability. Now are they showing an effect at

this point? Are they still showing very little epidemiological evidence of disease from——

Dr. BURKE. Right.

Chairman EHLERS [continuing]. Eating the fish?

Dr. BURKE. First of all, the National Academy did not disregard

the Seychelles study. In fact, they very carefully evaluated that as

well.

Chairman EHLERS. Well, I am sorry.

Dr. BURKE. Yeah.

Chairman EHLERS. That was a strong word to use.

Dr. BURKE. Okay.

Chairman EHLERS. You didn’t incorporate that——

Dr. BURKE. But we didn’t use it for the basis of our recommendation, you are correct.

Chairman EHLERS. Yeah.

Dr. BURKE. But we have always felt it is a well-conducted longitudinal study. And the update also sheds new light on the potential

impacts. What we recommended, though, that for public health protection, when there are two positive studies, there really isn’t a

sound justification for using the negative study as the public health

basis for moving forward. This update, I might add, did address

one of the questions that we had, and that was that perhaps the

children were young when they were evaluated and it was hard to

get reliable test data. And now that the kids are a little bit older,

we feel that they really validate and continue to improve their observations and move forward.

But it is a well-conducted, sound study.

Chairman EHLERS. Is that—is it coming into agreement, then,

with the other studies or is it too early?

Dr. BURKE. No, it is not showing positive effects. The other ones

do show detrimental impacts on neurodevelopment. Seychelles does

not.

Chairman EHLERS. How do you explain that, and why would you

pick the ones that show positive effects and not the one that shows

negative effects or null effects, I should say?

Dr. BURKE. That is an important question. Our fundamental goal

is to protect public health. And with two well-conducted studies

that do show an effect, a public health based standard, the longstanding protocol to go about this is to select a critical study and

a critical effect and use that to go forward, informed by the other

studies as well. So the uncertainties introduced by the Seychelles

44

were important, however, the data from the other two studies and

the overall weight of the animal testing really provided, we think,

a sound, scientific basis.

Chairman EHLERS. So it was a combination of the animal studies

plus——

Dr. BURKE. A wide variety of human observational studies

throughout time, including poisoning episodes, as well as these

three very important epidemiological studies.

Chairman EHLERS. Did you determine anything about the type

of mercury that was involved in the study? Was it all

methylmercury that basically did the damage?

Dr. BURKE. Yes, by measuring both maternal hair and cord

blood, we feel that the primary source was fish consumption and

therefore it would be the methylmercury form.

THE EFFECT OF REGULATION ON INNOVATION

Chairman EHLERS. Okay. I am becoming thankful that I don’t

particularly enjoy eating fish. But that is not true of most people

in my State.

Dr. Offen, I want to ask you about the testimony of Mr. Colburn

in which he indicated that if we have the requirement, then there

will be more innovation. It is another way of saying, you know, necessity is the mother of invention, that once we set a standard,

there will be a scramble to produce cost-effective methods of controlling mercury emissions. Is that something that you would agree

with?

Dr. OFFEN. There is no doubt that if a standard—when the

standard is set, the industry will meet it as they are going to abide

by the law. I think the only question that I would raise is at what

level and how fast. I would also like to point out that even in the

absence of a standard, but yet in the expectation of standards, the

industry has been spending quite a bit of money on mercury. Our

program, as I made mention, has been going on for 15 years. And

right now, at EPRI, within the programs that deal with power generation, EPRI also covers, you know, transmission distribution, nuclear, et cetera, but within fossil power generation, the mercury

control research work is the largest effort that we have. So there

is some substantial amount of work that is going on right now.

I would hark back to the experience we had with scrubbers in

the early ’70’s as sort of a guiding principle, maybe an experiencebased principle. Those were mandated and because of the building

boom and the economic growth we had at that time, a lot of the

power plants were built and therefore a lot of scrubbers were built

in a very short period of time. About a year or two or three later,

most of them—or many of them had quite a bit of serious trouble.

And from a researcher’s perspective, that was good, because that

gave us a $10 million a year for 10- or 15-year program, but for

the economy, it maybe wasn’t so good. I think that is where the

concern is with statements that if you just mandate it, the solution

will be there no matter what the time schedule is and what the

level is.

Chairman EHLERS. So you are saying mandate it and then give

some time for the research and development to take place?

45

Dr. OFFEN. For the research to be completed that is already well

underway.

DEPARTMENT OF ENERGY EFFORT TO CREATE NEW

TECHNOLOGIES

Chairman EHLERS. Yeah. All right. You have mentioned the DOE

program that they were doing. Is this to develop new control technology, or is there——

Dr. OFFEN. I am obviously speaking secondhand here, since I am

not from DOE, sir.

Chairman EHLERS. Yes.

Dr. OFFEN. But in the work that we are doing with them and

that we are familiar with, they are doing both development and

evaluation. And the field tests program that I mentioned where we

will be testing for one to two months at 16 different sites I would

categorize as evaluation. But they have quite a few programs

where they are also developing work. They have two processes they

have developed themselves that they have also promoted, for example. These go along in parallel, because you just never know which

process is going to be successful. And secondly, you don’t know

which is going to be the most cost-effective. And the paradigm, if

I could say so, in the power industry, has been that the power industry needs options, because every plant is so different from every

other plant. That is why we see 10 to 90 percent reductions right

now.

Chairman EHLERS. Yeah. And every lump of coal is different

from every other lump of coal.

When do you expect the DOE work and your work to be able to

give some definitive answers as to what is the best and what are

the most cost-effective control technologies?

Dr. OFFEN. That is a difficult question to answer, because it depends on the success we have. If the current programs are successful and we get good results, we will know a lot more in 2006 than

we do now when the programs are over. If we continue to have a

different line for every power plant and can’t understand why, it

will be longer.

Chairman EHLERS. I see.

Dr. OFFEN. As my written testimony said, what we see as the

biggest uncertainty is our understanding of mercury chemistry.

Chairman EHLERS. Well, I have kept going on because we didn’t

have any more Members. But my time is expired. Mr. Gilchrest, do

you have additional questions?

Mr. GILCHREST. Just a couple.

Chairman EHLERS. Go ahead.

Mr. GILCHREST. I was interested in your line of questioning,

though.

THE CAUSE OF THE DECLINE OF MERCURY IN THE FLORIDA

STUDY

I understand that mercury is not biodegradable. Just stop me if

I am wrong with any of this. But it accumulates in the environment. It never goes away. It might change from one form or anVerDate 11-MAY-2000 16:16 Apr 08, 2004 Jkt 090163 PO 00000 Frm 00049 Fmt 6633 Sfmt 6601 C:\WORKD\ETS03\110503\90163 SCIENCE1 PsN: SCIENCE1
46

other, depending on the conditions, but it basically, for all intents

and purposes, is persistent.

Dr. Krabbenhoft, when you made a comment about reducing the

source of mercury in Florida, you saw a corresponding decline of

mercury in the environment. Does that mean that the mercury in

the environment was decreasing or just not increasing?

Dr. KRABBENHOFT. First of all, your question about the

biodegradability of mercury, that is absolutely right. Mercury is

one of the elements, and as such, it can neither be created or destroyed. It is there. That separates it from many of the contaminants of concern.

Mr. GILCHREST. And can a physicist, maybe believing in the

string theory, corroborate that comment or—— Chairman EHLERS. Well, I would have to disagree with the statement, of course, because physicists can’t create or destroy mercury.

But that is beside the point for this when you are talking about it

as part of the biological system. He is absolutely correct.

Dr. KRABBENHOFT. With regard to the specific question about

Florida, the waste streams in south Florida and the combustion

systems in south Florida were heavily dominated, unlike many of

the other areas of the country, by medical and municipal waste incineration. They do not burn, essentially, any coal for power production in south Florida. It is different than many other places.

But because they burn a disproportionately high amount of medical

and municipal waste in south Florida, the rules that were in place

around 1990 to eliminate or reduce mercury into those waste

streams had a, probably, larger effect in south Florida than other

parts of the country. And so the State of Florida has estimated reductions in mercury emissions from their local emitters on the

order of 70 or 80 percent.

Mr. GILCHREST. But the mercury that was there prior to 1990,

is it still there?

Dr. KRABBENHOFT. Is the mercury there by and large, yes. Now

mercury does re-emit as well, so if mercury rains down from the

atmosphere onto water or land, it is fully capable of being reduced

largely from photochemical reactions from the sunlight, UV reactions, back to gaseous mercury, and then it goes back to the sky.

Mr. GILCHREST. What percentage of mercury does that, then,

would you say?

Dr. KRABBENHOFT. It is generally not big, on the order annually

of, say—our dosing experiments in the field suggested somewhere

around the order of, say, five or 10 percent or so.

ELIMINATING MERCURY EMISSIONS

Mr. GILCHREST. Mr. Colburn spoke about his success in scrubbing out mercury in maybe somewhere around 2015 actually eliminating all of the mercury that is being emitted by fossil fuel power

plants. Is that a fairly accurate statement?

Mr. COLBURN. The entire elimination, Representative, the Governors didn’t put a date on that. They wanted 70 percent—75 percent by 2010 and then just to keep working beyond that.

Mr. GILCHREST. I see.

Mr. Offen, is that an achievable goal for the rest of the country

what New England seems to be doing?

47

Dr. OFFEN. We have not seen 100 percent elimination of a pollutant any place.

Mr. GILCHREST. Well, I am not talking about 100 percent, but do

you think that what New England has done for a projection of 75

percent elimination of mercury from these power plants by 2010,

is that a goal in any other area of the country, that you are aware

of?

Dr. OFFEN. Again, I will return to my answer to Chairman

Ehlers. I can’t predict how successful we will be in the next set of

tests. We continue to see quite big differences depending upon fuel

and the power plant. We see some successes, and we see some failures. And it continues that way.

Mr. GILCHREST. Sure.

Dr. OFFEN. Then the other question always is cost. You could create a scenario where every plant burned low sulfur eastern bituminous coal and had added to their current pollution controls a

spray dryer and a baghouse and you would get down there. I don’t

know that that is the policy that you want to make.

Mr. GILCHREST. Mr. Colburn, have you benefited from the kind

of coal that emits less sulfur and less mercury and you had other

conditions that are different from, let us say, Maryland or Texas

or California?

Mr. COLBURN. Okay. I think that most of our coal is bituminous,

and so we, no doubt, have benefited from that as opposed to other

coals. But today, Representative, most of our reductions have been

through hazardous waste and municipal waste combustors as well.

The reductions that we have had from coal plants, because that

commitment, that 50 percent by 2003 and 75 percent by 2010, is

economy-wide. It is not a power plant control. It is an overall mercury emissions goal. And as I said, we have met the 2003 one. So

while we may have some advantages when a mercury control regime is adopted for power plants, the only benefits we are getting

at this point are purely the co-benefits that we all spoke of before.

Mr. GILCHREST. Thank you.

TRACKING MERCURY ONCE IT HAS BEEN EMITTED FROM A

PLANT

Chairman EHLERS. The gentleman’s time has expired.

Dr. Krabbenhoft, how well can we keep track of the mercury or

how well do we keep track of the mercury once it goes up the

stack? And I am really getting at the local, regional, global question. Are we in the process of cleaning up to protect the people

downwind from the power plant or is this because it is a global

matter and every nation should be doing it? What insight can you

give me on that and how well can you measure the deposition in

the local environment, you know, say 40, 50, or 60 miles from the

plant?

Dr. KRABBENHOFT. The technologies to do that are relatively

new. By that, I mean probably within the last five years, the instruments that can actually be deployed in the field and distinguish those forms of mercury. So that has been a hindrance that

we have only had an instrument capable of doing that for a relatively short period of time. If you deploy those instruments in the

field, you can do a pretty good job of, A, measuring what is coming

48

out and few, but some studies have actually gone and followed

through to watch the interconversions that happen post-release.

Those are all very recent studies. But yes, you can do it. Yes, you

can keep track of it. Yes, you can then apply models to predict how

far it is raining out.

Chairman EHLERS. And what sort of—how many parts per million or parts per billion are we talking about when you are detecting this?

Dr. KRABBENHOFT. That we are detecting?

Chairman EHLERS. Yeah.

Dr. KRABBENHOFT. The instruments that are used in the field

presently can see picogram quality—picogram per meter cube

quantities, so extraordinarily low.

Chairman EHLERS. Um-hum.

Dr. KRABBENHOFT. So sensitive that you can’t apply it near the

source, because it overwhelms the detectors.

Chairman EHLERS. Yeah. Just as a matter of curiosity, what

methodology do you use?

Dr. KRABBENHOFT. Detection is always done by atomic fluorescence. It is a wonderfully sensitive, ancient measurement, but it is

wonderfully sensitive for mercury. The real work is done on the

front end for separating out the forms using a variety of deneuters

and columns and traps, et cetera.

Chairman EHLERS. Okay. Okay. So you look at the green lines,

the famous green lines of mercury?

Dr. KRABBENHOFT. Yes.

GLOBAL, LOCAL, AND REGIONAL SOURCES OF MERCURY

Chairman EHLERS. What do we know about the quantity of mercury emissions from utilities that deposit in the local environment?

How does that compare to the global load that an area may already

have?

Dr. KRABBENHOFT. That is an area that, quite frankly, is underexposed in terms of our understanding. A vast majority of the studies to date have been done in truly remote settings. And I really

believe the reason for that is just curiosity. How could you possibly

get this much mercury in the wildlife in a setting that is so remote? And because of that, our understanding of the near field— near source field is underappreciated or underevaluated at this

point. But certainly where researchers have gone into near field

source field environments, you see much higher concentrations. So

to use the example, we have recently collected data in East St.

Louis, Missouri where we see levels of reactive gaseous mercury

and particulate mercury on the order of 20,000 to 25,000 picograms

per cubic meter whereas if we go to a remote location, you will see

a number of about three. So there is tremendous gradient.

Now how do those gradients transition? We don’t know. We

need—we definitely need to do more work in those near source field

areas.

Chairman EHLERS. And just one other question on that. We have

largely talked about power plants as being the source or incinerators. Are there other sources of this? You mentioned the high

readings within the urban area. Are there other sources that we

have around?

49

Dr. KRABBENHOFT. Other sources of mercury, other than the ones

that we have discussed today, the power plants——

Chairman EHLERS. Right.

Dr. KRABBENHOFT. Yes. Certainly other facilities like

chloralcolyte plants are still a source of mercury today to the environment. Another one is metals melting. In fact, the high concentrations that I was speaking of in St. Louis, we don’t believe

that is contributed to any substantial degree—by coal combustion

at all. We believe, in fact, that it is coppers melting. So yes, there

are other sources that, I guess, haven’t seen their day yet.

Chairman EHLERS. Yes. Okay.

Oh, the staff just reminded me. I haven’t gotten to the global

part here yet of the local, regional, global. Are you able to track

mercury coming in from other countries and some way differentiate

it? And how much of the load, on average, across the United States

is from our own sources and how much is from global sources, including our own?

Dr. KRABBENHOFT. Well, if you look at the amount of mercury

being released to the global environment from the U.S. versus the

world, it is not a big proportion, five or 10 percent. But the real

question is how much mercury raining out——

Chairman EHLERS. Yeah.

Dr. KRABBENHOFT [continuing]. In the U.S. is coming from our

sources versus global sources.

Chairman EHLERS. Yeah. And that is my question.

Dr. KRABBENHOFT. That, I personally do not believe we have an

answer for. The way you have to go about looking at that is looking

at our own stacks and studies on our stacks, the mass account. You

do all of the Lagrangian following of that plume and watch it

through time to see how much of that mass and that plume drops

out over what distance and understand what the footprint of that

particular source is. Those kinds of things, quite frankly, have not

been done, or if they have been done, they haven’t been done

enough.

Can I or anybody else distinguish Asian mercury coming in from

European or California mercury by the time you get to New England? No.

Chairman EHLERS. There are ways you could determine it, if you

wanted to do the experiment. I mean, you could use radioactive

mercury and track it and see how far it goes.

Dr. KRABBENHOFT. Or even better yet, stable isotopes of mercury.

We use those all of the time. That is how we do our new mercury

versus old mercury source, so we wouldn’t have to release a radioactive form. But yes.

Chairman EHLERS. Yeah.

Dr. KRABBENHOFT. You can do that. We proposed that once to the

DOE. It didn’t get very far.

Chairman EHLERS. Well, that is interesting.

Okay. Yes, Dr. Offen.

Dr. OFFEN. Mr. Chairman, I know that some of my colleagues at

EPRI have looked at that. I am not capable of discussing it at any

great depth, but with your permission, I would like to submit a response to your question, for the record.

50

Chairman EHLERS. I would very much appreciate that and—I

was just going to close, but we will see if Mr. Gilchrest has any

other questions.

Mr. GILCHREST. Just a quick question, Mr. Chairman. Thank you

very much.

FISH CONSUMPTION IN THE SEYCHELLE ISLAND STUDIES

Dr. Burke, in, I guess it is the Faroe Islands, New Zealand, the

Seychelles Islands, you did studies on the vulnerable population of

unborn children looking at the amount of mercury in their system

based on fish consumption.

Dr. BURKE. We looked at mercury exposure to the mother——

Mr. GILCHREST. Okay. And was that——

Dr. BURKE [continuing]. And related that to developmental outcomes in the children.

Mr. GILCHREST. Was that based on fish consumption?

Dr. BURKE. Yes.

Mr. GILCHREST. On the level of mercury contamination in the

fish in these areas, were they all fairly high, pretty similar in those

three places——

Dr. BURKE. Well, actually——

Mr. GILCHREST [continuing]. Which is why you chose them?

Dr. BURKE. Well, actually, in the Seychelles, for instance, they

consumed ocean fish, and they are similar to the levels we see in

this country. But they consume a very high diet of fish with 12

meals a week, which would be very unusual——

Mr. GILCHREST. Right.

Dr. BURKE [continuing]. Here in the U.S. They were chosen,

though, because of——

Mr. GILCHREST. They seem to have——

Dr. BURKE [continuing]. Their dietary patterns.

Mr. GILCHREST. Yes.

Dr. BURKE. Yes.

EFFECTS ON WILDLIFE

Mr. GILCHREST. So you could say—I mean, I don’t want to put

words in your mouth, but if you evaluated the amount of mercury

in fish in the Chesapeake Bay, whether they were minnows or catfish or rockfish or whatever, would there be similar concentrations

of mercury in the Chesapeake Bay fish as there were in Seychelles?

Dr. BURKE. Well, that is an important question. Actually, there

is a wide range, like a 20-fold difference in the concentrations of

mercury, depending upon the species.

Mr. GILCHREST. Oh, gee.

Dr. BURKE. And the fish we are most concerned about for the average consumer are the large——

Mr. GILCHREST. Right.

Dr. BURKE [continuing]. Predator fish.

Mr. GILCHREST. So striped bass would be a concern?

Dr. BURKE. Actually, striped bass is—does not have——

Mr. GILCHREST. Really?

Dr. BURKE. And I might add that crab cakes don’t have mercury

issues as well.

51

Mr. GILCHREST. How about oysters? We are pretty safe with oysters?

Dr. BURKE. I actually don’t——

Mr. GILCHREST. So which fish in the Chesapeake Bay, then,

would have high concentration——

Dr. BURKE. The Chesapeake Bay, in general, the—for the main

body of the Bay, the levels are low.

Mr. GILCHREST. Fairly minuscule?

Dr. BURKE. It is—right. It is the inland rivers where, because of

localized sources——

Mr. GILCHREST. Now when you say inland rivers, are you talking—is that——

Dr. BURKE. Like the Back River, where the advisories are. It is

the inland waterways.

Mr. GILCHREST. Like the Sassafras River versus the Back River?

Dr. BURKE. Yes.

Mr. GILCHREST. The Back River would be worse than the Sassafras?

Dr. BURKE. I am not quite sure of that specific comparison.

Mr. GILCHREST. But it would be those tidal basins——

Dr. BURKE. Yes.

Mr. GILCHREST [continuing]. That would be of more concern than

the main focus of the Bay?

Dr. BURKE. Yes, because of the biology of the Bay and the nature

of the food chain of the fish.

Mr. GILCHREST. Since fish consumption is part of the, I would assume, main criteria for determining how dangerous this is, and

since probably people in Kent County, Maryland or Anne Arundel

County don’t eat as much as they do in the Seychelles, would not

be put at that same risk. Have there been studies done to evaluate

the neurological development of things like eagles and osprey and

blue heron, those kinds of things?

Dr. BURKE. I am not aware of ecological studies that way. That

was a little bit beyond the scope of the National Academy work.

Mr. GILCHREST. Could you assume that there would be potential

mercury poisoning in those animals that do eat fish everyday?

Dr. BURKE. Absolutely. I think that we would see the same kind

of bioaccumulation and high level exposure to the nervous system.

Mr. GILCHREST. Are you aware of any type of study that would

look at that?

Dr. BURKE. I can get back to you on that, but——

Mr. GILCHREST. Thank you. Thank you.

Yes, sir?

Dr. KRABBENHOFT. There are some studies in USGS of the Patuxent National Wildlife Testing Center where they are looking at

methylmercury exposure and the toxicological effects to

methylmercury exposure at the egg level of several of the species

that you have just named. And the short answer to your question

is yes, there are effects. It does have an appreciable affect on the

successful hatching rate of those birds.

Mr. GILCHREST. Thank you.

Mr. Colburn.

52

Mr. COLBURN. I was just going to reinforce that, Representative.

There has been some work done on loon, which of course, eat fish,

along the lines mentioned by Dr. Krabbenhoft in the Northeast.

Mr. GILCHREST. Thank you very much. Thank you, Mr. Chairman.

CLOSING COMMENTS

Chairman EHLERS. Well, thank you very much for your questions. They have contributed to this hearing.

With no further questions, I would like to conclude the hearing

with several comments. I think it is clear from today’s hearing that

there is compelling evidence that consumption of fish contaminated

with mercury is a serious health threat. I also think we learned

that there is a local effect from emissions from utility sources as

well as a global effect and that reducing emissions from these

sources will likely lead to reduced loading in the environment.

On the technology side, it also seems clear to me that while current technologies do achieve significant mercury reductions as a cobenefit, we have much to do to develop the technologies specific to

mercury control. It appears that it may take regulation before we

create a sufficient market that will drive innovation and commercialization of these technologies. Past experience, as Mr. Colburn

has said, has certainly demonstrated that major advances in technology development follow regulation in many fields and often at

much lower costs than initially projected. But we will see how this

plays out. I assume that the EPA is likely to set a standard some

time in the next month or two. And we will as Dr. Offen has pointed out, the time allotted to solve the problem could have a direct

impact on the cost to the economy generally.

I certainly want to thank all of you for your participation at the

hearing today. It has been a good cross-section of expertise. I,

frankly, think we couldn’t have had a better panel broadly representative of the issue from the Government, industry, and academia. And so I appreciate not only your testimony but your wisdom and your willingness to sit through all of these questions we

have thrown at you.

If there is no objection, the record will remain open for additional

statements from the Members. And also, Members may request answers from you, and we ask that you be kind enough to respond

to any follow-up questions that the Subcommittee Members may

send you. Without objection, so ordered.

Thank you, again, for your service, for your testimony, and keep

up the good work. It is my pleasure to declare the hearing adjourned.

[Whereupon, at 3:44 p.m., the Subcommittee was adjourned.]

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Appendix 1:

BIOGRAPHIES AND FINANCIAL DISCLOSURES

54

BIOGRAPHY FOR THOMAS A. BURKE

Thomas A. Burke is a Professor and Associate Chair at the Johns Hopkins

Bloomberg School of Public Health, Department of Health Policy and Management,

with joint appointments in the Department of Environmental Health Sciences and

the School of Medicine, Department of Oncology. Currently he is Director of the

School’s newly formed task force, Scientist Working to Address Terrorism (SWAT).

The goals of the task force are to provide: 1) scientific basis for rational action; 2)

accurate advise for public agencies and profession and 3) develop short training for

targeted groups via web, CD–Roms, etc. He is also Co-Director of the Johns Hopkins

Risk Sciences and Public Policy Institute. His research interests include environmental epidemiology, the evaluation of community exposures to environmental pollutants, the assessment and communication of environmental risks, and the application of epidemiology and health risk assessment to public policy. He was Principal

Investigator for the Pew Environmental Health Commission aimed at revitalizing

the national infrastructure for environmental health. He is particularly interested

in health and environment in the cities.

Prior to his appointment at Johns Hopkins, Dr. Burke was Deputy Commissioner

of Health for the State of New Jersey. He has also served as Assistant Commissioner for Occupational and Environmental Health at the New Jersey Department

of Health, and as Director of the Office of Science and Research in the New Jersey

Department of Environmental Protection. During his tenure with the State of New

Jersey, Dr. Burke established a number of exposure research efforts and environmental risk assessment programs at both the Departments of Environmental Protection and Health. He served as the scientific coordinator for many of the State’s

major investigations, including investigations of toxic contaminants in drinking

water, the evaluation of dioxin contamination from industrial sources, and the investigation of chromium exposure in urban areas from industrial waste used as

landfill.

Dr. Burke is the Chair of the Advisory Committee to the National Center for Environmental Health of the Centers for Disease Control. He also serves as a member

of the Executive Committee of the EPA Board of Scientific Counselors. An editor of

the book, Regulating Risk: The Science and Politics of Risk, he served on the National Academy of Sciences Committee on Risk Characterization. He has been a

member of the Council of the Society for Risk Analysis and has served on the Office

of Technology Assessment Advisory panels on Research on Risk Assessment of

Chemical Carcinogens, and Managing Nuclear Materials from Warheads. He was

also a member of National Academy of Sciences Committee an Risk Characterization, Panel on Separations Technology and Transmutation Systems, and Committee

on Remediation of Buried and Tank Wastes, evaluating nuclear waste management

options. He has served on EPA Science Advisory Board subcommittees, including reviews of the Clean Air Act Residual Risk Report to Congress and the Superfund

Hazard Ranking System. He was also a member of the General Accounting Office

expert panel to review the Superfund public health assessment process.

Dr. Burke received his Ph.D. in epidemiology from the University of Pennsylvania, his M.P.H. from the University of Texas, and his B.S. from Saint Peter’s College.

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BIOGRAPHY FOR DAVID P. KRABBENHOFT

Education:

Ph.D. Geochemistry/Hydrogeology–1988

University of Wisconsin-Madison

M.S. Geochemistry–1984

University of Wisconsin-Madison

B.S. Geology–1982

North Dakota St. University

David Krabbenhoft is a research scientist with the U.S. Geological Survey

(USGS). He has general research interests in geochemistry and hydrogeology of

aquatic ecosystems. Dave began working on environmental mercury cycling, transformations, and fluxes in aquatic ecosystems after completing his Ph.D. in 1988; and

the topic has consumed him since. His work on mercury started with the Mercury

in Temperate Lakes project in 1988, which served as the springboard for other environmental mercury research in the United States and around the world since. In

1994, Dave established the USGS’s Mercury Research Laboratory, and since has assembled a team of multi-disciplinary mercury investigators in Wisconsin. The laboratory is a state-of-the-art, analytical facility strictly dedicated to the analysis of

mercury, with low-level speciation. In 1995, he initiated the multi-agency Aquatic

Cycling of mercury in the Everglades (ACME) project, and in 1998 organize and conducted a national synoptic sampling of mercury in sport fish, sediment and water

from 122 sites across the United States for the USGS. More recently, Dave has been

a Primary Investigator on the internationally conducted Mercury Experiment To Assess Atmospheric Loading in Canada and the United States (METAALICUS)

project, which is a novel effort to examine the ecosystem-level response to loading

an entire watershed with mercury. The Wisconsin Mercury Research Team is currently active on projects from Alaska to Florida, and from California to New England. Since 1990, he has authored or co-authored over 50 papers on mercury in the

environment. In 2006, Dave will serve as the co-host for the 8th International Conference on Mercury as a Global Pollutant in Madison, Wisconsin.

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BIOGRAPHY FOR GEORGE R. OFFEN

Manager, Air Emissions and Coal Combustion Product Management

Education: B.S., Mech. Engr., Stanford University; M.S., Mech. Engr., MIT; Ph.D.,

Mech. Engr., Stanford University

Experience

EPRI (1985–present). Dr. Offen manages EPRI’s R&D program to cost-effectively reduce NOΧ, SO2, particulate, and air toxic emissions from utility boilers, as well as

to increase the use of coal combustion products. He started EPRI’s program on mercury control technology R&D in the late 1980’s, and recently expanded it into the

Integrated Environmental Control program. He has presented EPRI’s air pollution

control research results at numerous public meetings as well as to regulatory agencies, and coordinates EPRI’s collaborations with DOE and EPA in air emission control technology. Currently, he is directing a study to obtain an understanding of

mercury chemistry in the cooler temperature regions of a boiler and across catalysts

used for NOΧ reduction. Earlier projects included dry sorbent furnace injection for

SO2 control, fundamental research in combustion NOΧ formation/destruction, and

analyses of NOΧ control combustion and post-combustion options in search of the

least-cost combinations for any given site and NOΧ limits.

Acurex Corporation, California (1974–1985). Manager, Energy Engineering. Responsible for projects in combustion testing and performance/environmental impact analysis of alternate fuels.

Earlier. Acting Assistant Professor and Teaching Assistant in Mechanical Engineering; Research Engineer in petroleum industry, and Test Engineer for conventional

munitions in U.S. Air Force.

Associations. Air & Waste Management Association; American Society of Mechanical

Engineers.

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BIOGRAPHY FOR KENNETH A. COLBURN

Kenneth A. (Ken) Colburn is Executive Director of the Northeast States for Coordinated Air Use Management (NESCAUM), a 36-year-old policy research and

analysis organization representing state air quality agencies from New England,

New Jersey, and New York. NESCAUM and its sister organization—the Northeast

States Center for a Clean Air Future (NESCCAF)—provide technical assistance, research, and policy analysis to help the Northeast states develop and promote costeffective clean air solutions necessary to enhance the quality of life of their citizens.

Prior to joining NESCAUM in May 2002, Ken served as New Hampshire’s air director, helping to make New Hampshire a national leader in reducing air pollution, including the first ‘‘4–Pollutant’’ bill for power plants and the first Greenhouse Gas

Emissions Reduction Registry. Ken also served as a member of the U.S. Delegation

negotiating an Ozone Annex to the U.S.–Canada Air Quality Agreement and during

G8 environmental negotiations in Japan, and testified before Congress on several

air quality issues.

Before joining the New Hampshire Department of Environmental Services

(NHDES) in 1995, Ken was Vice President of the Business & Industry Association

of New Hampshire (BIA), representing the State’s business community on environmental, energy, and telecommunications matters in legislative and regulatory forums. Ken holds a B.S. in Mathematics from MIT and MBA and M.Ed. degrees from

the University of New Hampshire. Ken and his family reside in Meredith, New

Hampshire.

Kenneth A. Colburn, Executive Director, NESCAUM, 129 Portland Street, Boston,

MA 02114; (617) 367–8540 x216; Fax: (617) 742–9162; E-mail:

kcolburn@nescaum.org

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ADDITIONAL MATERIAL FOR THE RECORD

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