Scientific Studies Reveal Causes of Biological Mercury Hotspots January 9, 2007 Findings from two new papers in the journal BioScience A project of the Hubbard Brook Research Foundation Science Links program Slide 1

11 Authors Charles 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 BioScience 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 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 Findings 1. 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 5

What is Mercury and Why is it a Problem? Slide 6 44 states have one or more fish advisories

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

Where Does Mercury Pollution Come From? Total: 2076 short tonsTotal: 2496 short tons Slide 8

Northeast Sediment Trends Reflect US Emissions Pattern Slide 9 Pirrone et al. 1998, Lorey and Driscoll 1999.

What is the Current Mercury Policy Context? US EPA Clean Air Mercury Rule Two-phase program for coal-fired power plants 20% reduction by % 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 Hotspots and Where Do They Occur? David C. Evers, PhD BioDiversity Research Institute Slide 11

Biological Mercury Hotspot Definition “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 Slide 12

Biological Mercury Hotspots 5 confirmed 9 suspected Slide 13 Nova Scotia Upper Ken. and Andro. Rivers Adirondacks Upper Connecticut River Lower Merrimack watershed Evers et al

Methods 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? 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 Biological Mercury Hotspots? Charles T. Driscoll, PhD Syracuse University Slide 16

New Results: Causes of Biological Mercury Hotspots Global and Regional Atmospheric Emissions and Deposition Landscape Sensitivity Reservoir Fluctuations Local Emissions Slide 17 Evers et al

Sensitive Watersheds: Abundant forest cover and wetlands Impacted by acid rain 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

New Finding: Biological Hotspots Detected in Reservoirs Manipulated for Power Production Slide 19 Evers et al

Slide 20 Mercury Levels Higher in Reservoirs With Large Fluctuations

New Model Results: Major Biological Hotspot Caused by High Mercury Deposition from Local Sources Maximum deposition = 76 µg/m 2 -yr Slide 21 Evers et al

How Significant are Local Emission Sources and What Role Do Coal-fired Power Plants Play? Tom Holsen, PhD Clarkson University Slide 22

U.S. Total Mercury Emissions Slide 23 After EPA National Trends Inventory, 2006.

Slide 24 New Results Differ From EPA’s

How & Why Do These Results Differ? Deposition Our estimate = µg/m 2 -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. Implications Suggests 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 Coal-fired Power Plants in Hotspots Slide 26 Scenario: 90% emissions reductions from 4 coal-fired power plants Deposition Evers et al After Evers et al

Results Supported by Other Studies J. 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 27

Good News: Fish and Wildlife Can Respond Rapidly to Emissions Reductions Slide 28 After Evers et al % decline Mercury air emissions from local upwind sources declined 45% from 1997 – Adverse effect threshold

Key Findings 1. 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 29