Post on 11-Jan-2016
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
Slide 11
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
Slide 13
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
Slide 14
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
Slide 19
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
Slide 21
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
Slide 22
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
Slide 23
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