Scientific Studies RevealScientific Studies Reveal Causes ofCauses of

Biological Mercury Hotspots Biological Mercury Hotspots

January 9, 2007January 9, 2007

Findings from two new papers in the journal Findings from two new papers in the journal BioScienceBioScience

www.hubbardbrookfoundation.orgwww.hubbardbrookfoundation.org

A project of the Hubbard Brook Research FoundationA project of the Hubbard Brook Research FoundationScience Links programScience Links program

Slide 1Slide 1

11 Authors11 AuthorsCharles T. Driscoll, PhD – Syracuse University

David Evers, PhD - BioDiversity Research Institute

Thomas Butler, PhD – Cornell University

Celia Y. Chen, PhD – Dartmouth College

Thomas A. Clair, PhD – Environment Canada

M. Wing Goodale – BioDiversity Research Institute

Young-Ji Han, PhD – HBRF

Thomas M. Holsen, PhD – Clarkson University

Neil C. Kamman – Vermont DEC

Kathy Lambert – Hubbard Brook Research Foundation

Ron Munson, PhD – Tetra Tech

Present today for comment – Gerald Keeler, PhD – University of Michigan

Slide 2

New New BioScienceBioScience Studies Studies

Mercury Contamination in Forest and Freshwater Ecosystems in the Northeastern United States: Sources, Transformations, and Management Options

Biological Mercury Hotspots in the Northeastern U.S. and Southeastern Canada

Mercury Matters: Linking Mercury Science with Public Policy in the Northeastern United States

Slide 3

Outline of Today’s PresentationOutline of Today’s Presentation

1. Background – Kathy Fallon Lambert

2. What are Biological Mercury Hotspots? – David Evers

3. What are the Causes? – Charles Driscoll

4. How Significant are U.S. Coal-fired Power Plants? – Thomas Holsen

5. Conclusions – Charles Driscoll

Slide 4

Key FindingsKey Findings1. Biological mercury hotspots do exist.

2. Specific hotspots linked to causes for the first time.

3. Airborne mercury emissions are the dominant source.

4. They produce a double-whammy in watersheds hit by decades of acid rain.

5. And cause ripple effects in reservoirs that are manipulated for power production.

6. New Hampshire case study demonstrates we’ve reached tipping point: coal-fired power plants have significant local impacts that are under-estimated by EPA.

7. Good news – document for first time in the Northeast that rapid recovery in fish and loons can occur if local emissions reduced.

8. Findings validate state concerns about mercury trading and need for new draft Federal legislation.

Slide 5Slide 5

What is Mercury and Why is it a Problem?What is Mercury and Why is it a Problem?Slide 6

44 states have one or more fish advisories44 states have one or more fish advisories

Where Does Mercury in Fish and Wildlife Come From?Where Does Mercury in Fish and Wildlife Come From?Slide 7

Where Does Mercury Pollution Come From?Where Does Mercury Pollution Come From?

Total: 2076 short tons Total: 2496 short tons

Slide 8

Northeast Sediment Trends Reflect US Northeast Sediment Trends Reflect US Emissions PatternEmissions Pattern

Slide 9

Pirrone et al. 1998, Lorey and Driscoll 1999.

What is the Current Mercury What is the Current Mercury Policy Context?Policy Context?

US EPA Clean Air Mercury Rule

Two-phase program for coal-fired power plants

20% reduction by 2010

70% reduction by 2025

Cap-and-trade approach

State Implementation Plans

Approx. 24 of 30 states filed more stringent plans

21 = deeper cuts

18 = faster cuts

17 = no trading

Slide 10

What Are Biological Mercury What Are Biological Mercury Hotspots and Where Do They Hotspots and Where Do They

Occur?Occur?

David C. Evers, PhD

BioDiversity Research Institute

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Biological Mercury Hotspot Biological Mercury Hotspot DefinitionDefinition

“A location on the landscape that, compared to the surrounding landscape, is characterized by elevated concentrations of mercury in fish and wildlife that exceed established human or wildlife health criteria as determined by a statistically adequate sample size.”

Evers et al. 2007.

Slide 12

Biological Mercury HotspotsBiological Mercury Hotspots

5 confirmed

9 suspected

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Nova ScotiaUpper Ken. and Andro. Rivers

Adirondacks

Upper Connecticut River

Lower Merrimack watershed

Evers et al. 2007.

MethodsMethods

1. Based on 7,311 observations

2. Human health analysis - Indicator = yellow perch- Threshold = 0.3 ppm (EPA criterion)

3. Ecological health analysis - Indicator = Common loon blood - Threshold = 3.0 ppm

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How Does Our Approach Differ From EPA’s?How Does Our Approach Differ From EPA’s?

1. We used a more inclusive definition of hotspot.

- Not limited to “consumable fish” with methyl mercury concentrations “attributable solely to utilities” above EPA criterion of 0.3 ppm

2. By focusing regionally and on more species, we used a larger biological database.

- Not limited to select sites and species from the National Fish Tissue Survey and Advisory Listing.

Slide 15

What are the Causes of What are the Causes of Biological Mercury Hotspots?Biological Mercury Hotspots?

Charles T. Driscoll, PhD

Syracuse University

Slide 16

New Results: Causes of Biological New Results: Causes of Biological Mercury HotspotsMercury Hotspots

Global and Regional Atmospheric Emissions and Deposition

Landscape Sensitivity

Reservoir Fluctuations

Local Emissions

Slide 17

Evers et al. 2007.

Sensitive Watersheds:

1. Abundant forest cover and wetlands

2. Impacted by acid rain

3. Shallow groundwater flow paths

We Found that Some Biological Hotspots Are Caused by Moderate Mercury Deposition to Sensitive Watersheds

Areas like the Adirondacks receive double-whammy of acid rain and mercury.

Slide 18

Driscoll et al. 2007.Driscoll et al. 2007.

New Finding: Biological Hotspots Detected in New Finding: Biological Hotspots Detected in Reservoirs Manipulated for Power ProductionReservoirs Manipulated for Power Production

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Evers et al. 2007.Evers et al. 2007.

Slide 20Mercury Levels Higher in Reservoirs Mercury Levels Higher in Reservoirs

With Large FluctuationsWith Large Fluctuations

New Model Results: Major Biological New Model Results: Major Biological Hotspot Caused by High Mercury Hotspot Caused by High Mercury

Deposition from Local SourcesDeposition from Local Sources

Maximum deposition = 76 µg/m2-yr

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Evers et al. 2007.Evers et al. 2007.

How Significant are Local How Significant are Local Emission Sources and What Role Emission Sources and What Role Do Coal-fired Power Plants Play?Do Coal-fired Power Plants Play?

Tom Holsen, PhD

Clarkson University

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U.S. Total Mercury EmissionsU.S. Total Mercury EmissionsM

ercu

ry E

mis

sio

ns

(to

n/y

r)

0

50

100

150

200

250

Utility Coal BoilersMedical Waste IncineratorsMunicipal Waste CombustorsInd./Com./Inst. Boilers and Process HeatersOther Sources

1990 1996 20021999

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After EPA National Trends Inventory, 2006.After EPA National Trends Inventory, 2006.

Slide 24 New Results Differ From EPA’sNew Results Differ From EPA’s

How & Why Do These Results Differ?How & Why Do These Results Differ?

DepositionOur estimate = 13 - 76 µg/m2-yr (local and regional)4-5 times higher than EPA estimates (all sources)

Why?We used a local scale plume model and detailed Northeast

emissions inventory.EPA used a larger scale grid model and coarse national

emissions inventory.

ImplicationsSuggests finer resolution modeling is needed to characterize

deposition patterns near large sources – even outside heavily industrialized regions.

Slide 25

New Model Results Highlight the Role of New Model Results Highlight the Role of Coal-fired Power Plants in HotspotsCoal-fired Power Plants in Hotspots

Slide 26

Scenario:

90% emissions reductions from 4 coal-fired power plants

Deposition

Evers et al. 2007.Evers et al. 2007.

After Evers et al. 2007.After Evers et al. 2007.

Results Supported by Other Studies Results Supported by Other Studies J. Keeler and ColleaguesJ. Keeler and Colleagues

1. Results in MI, OH, and VT show that EPA

estimates of wet mercury deposition are 34-56%

lower than measured values.

2. Steubenville, Ohio Study (Keeler et al. 2006)

~ 80% of wet mercury deposition is attributable

to local/regional anthropogenic sources.

~ 70% is attributable to coal combustion.

Slide 27Slide 27

Good News: Fish and Wildlife Can Respond Good News: Fish and Wildlife Can Respond Rapidly to Emissions ReductionsRapidly to Emissions Reductions

Southeast NH adult loon blood Hg equivalents

Year

1998 1999 2000 2001 2002 2003 2004 2005 2006

Ad

ult

Co

mm

on

Lo

on

Blo

od

H

g E

qu

ival

ent

(ug

/g, w

w)

0

1

2

3

4

5

Slide 28

After Evers et al. 2007.After Evers et al. 2007.

64% decline64% decline

Mercury air emissions from local upwind sources declined 45% from 1997 – 2002.

Adverse effect threshold

Key FindingsKey Findings1. Biological mercury hotspots do exist.

2. Specific hotspots linked to causes for the first time.

3. Airborne mercury emissions are the dominant source.

4. They produce a double-whammy in watersheds hit by decades of acid rain.

5. And cause ripple effects in reservoirs that are manipulated for power production.

6. New Hampshire case study demonstrates we’ve reached tipping point: coal-fired power plants have significant local impacts that are under-estimated by EPA.

7. Good news – document for first time in the Northeast that rapid recovery in fish and loons can occur if local emissions reduced.

8. Findings validate state concerns about mercury trading and need for new draft Federal legislation.

Slide 29Slide 29