Slide 1 Scientific Studies Reveal Causes of Biological Mercury Hotspots January 9, 2007 Findings from two new papers in the journal BioScience www.hubbardbrookfoundation.org A project of the Hubbard Brook Research Foundation Science Links program Papers available here with complete list of authors HBRF is a non-profit organization dedicated to… If you are joining by phone please note that we will be referring to specific slides and the power point presentation can be found at: www.hubbardbrookfoundation.org

11 Authors Slide 2 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

New BioScience Studies Slide 3 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

Outline of Today’s Presentation Slide 4 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 We will each present 5 slides then open it up for questions…

Key Findings Slide 5 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.

What is Mercury and Why is it a Problem? Slide 6 What is Mercury and Why is it a Problem? Advisories are useful, but they are somewhat blunt and don’t identify areas particularly high in mercury 44 states have one or more fish advisories

Where Does Mercury in Fish and Wildlife Come From? Slide 7 Where Does Mercury in Fish and Wildlife Come From? Dominant source of mercury to most watersheds is atmospheric emissions and deposition. Mercury deposited is either near or far from source depending on its form Then converted to methyl mercury in the watershed - more readily absorbed by people and animals Methyl mercury strongly bioaccumulates in food chain, increasing in concentration up to 10 million times from water to loons Exposure through the aquatic food web is largely from fish consumption

Where Does Mercury Pollution Come From? Slide 8 Where Does Mercury Pollution Come From? Globally, Asia is the largest source. Leads some to believe that US sources are not as important to US deposition Total: 2076 short tons Total: 2496 short tons

Northeast Sediment Trends Reflect US Emissions Pattern Slide 9 Northeast Sediment Trends Reflect US Emissions Pattern Location of emission sources matter – not all mercury transported globally Seepage Pond – reflects direct atmospheric inputs Recent declines are consistent with declines in US emisions whereas global emissions have remained the same or gone up slightly Decrease in recent years These patterns have been observed widely across eastern North America Pirrone et al. 1998, Lorey and Driscoll 1999.

What is the Current Mercury Policy Context? Slide 10 What is the Current Mercury 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 Viability cap and trade program if many states opt out

What Are Biological Mercury Hotspots and Where Do They Occur? Slide 11 What Are Biological Mercury Hotspots and Where Do They Occur? David C. Evers, PhD BioDiversity Research Institute

Biological Mercury Hotspot Definition Slide 12 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.” 1. Analyzing data for hotspots allows us to locate areas that stand out from general fish consumption advisories 2. Includes fish and wildlife Evers et al. 2007.

Biological Mercury Hotspots Slide 13 Biological Mercury Hotspots Upper Ken. and Andro. Rivers Nova Scotia Upper Connecticut River Lower Merrimack watershed 5 confirmed 9 suspected Five confirmed, nine suspected from Nova Scotia to NY 2. Highest mercury levels in yellow perch = Merrimack River where average is 0.78 and maximum values are more than 10 times higher than EPA human health criterion. 3. Highest levels in common loon blood – Keji, NS. Average = 5.5 ppm, 93% exceed 3.0 ppm 4. Primary mechanisms – atmospheric deposition amplified by water sensitivity, reservoir fluctuation, and large local sources 5. The important role of atmospheric emissions and deposition has implications for policy and the advisability of mercury trading 6. Point sources from contaminated sites do occur and may be responsible for some of the suspected hotspots = former Holterchem site Adirondacks Evers et al. 2007.

Methods 1. Based on 7,311 observations 2. Human health analysis Slide 14 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

How Does Our Approach Differ From EPA’s? Slide 15 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.

What are the Causes of Biological Mercury Hotspots? Slide 16 What are the Causes of Biological Mercury Hotspots? Charles T. Driscoll, PhD Syracuse University

New Results: Causes of Biological Mercury Hotspots Slide 17 New Results: Causes of Biological Mercury Hotspots Global and Regional Atmospheric Emissions and Deposition Reservoir Fluctuations Local Emissions Landscape Sensitivity Evers et al. 2007.

Sensitive Watersheds: Abundant forest cover and wetlands Slide 18 We Found that Some Biological Hotspots Are Caused by Moderate Mercury Deposition to Sensitive Watersheds Sensitive Watersheds: Abundant forest cover and wetlands Impacted by acid rain Shallow groundwater flow paths For example, the Adirondacks have been hit by acid rain and are now more sensitive to mercury pollution. Areas like the Adirondacks receive double-whammy of acid rain and mercury. Driscoll et al. 2007.

Slide 19 New Finding: Biological Hotspots Detected in Reservoirs Manipulated for Power Production Evers et al. 2007.

Mercury Levels Higher in Reservoirs With Large Fluctuations Slide 20 Mercury Levels Higher in Reservoirs With Large Fluctuations

Slide 21 New Model Results: Major Biological Hotspot Caused by High Mercury Deposition from Local Sources If sources are not controlled, could perpetuate the existence of these hotspots Maximum deposition = 76 µg/m2-yr Evers et al. 2007.

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

U.S. Total Mercury Emissions Slide 23 U.S. Total Mercury Emissions 1. As you’ve heard from previous speakers, local and regional emission sources in the US are important to deposition in the US. 2. The largest emission source in the US is coal-fired power plants. 3. Some sources such as incinerators have made dramatic reductions in emissions, but coal-fired power plants have not changed substantially. After EPA National Trends Inventory, 2006.

New Results Differ From EPA’s Slide 24 New Results Differ From EPA’s We used a case study approach to determine mercury deposition near a biological hotspot in southern NH and northeastern MA and estimate the contribution of coal-fired power plants to emissions in near that hotspot. 2. Maps show results from two different studies that have different objectives – national approach versus local scale 3. Map on left shows that mercury deposition in NH tends to be moderate or low (6-10 µg/m2-yr), but there is an area of particularly high deposition near several large emission sources in the southern part of the study region (76 µg/m2-yr) 4. Different approach gives different results – national approach estimates deposition in same area as 15-20 µg/m2-yr 5,. Should point out that even though are numbers are higher, we do not account for deposition from sources beyond ^ km whereas EPA model does.

How & Why Do These Results Differ? Slide 25 How & Why Do These Results Differ? Deposition Our 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. Implications Suggests finer resolution modeling is needed to characterize deposition patterns near large sources – even outside heavily industrialized regions.

Slide 26 New Model Results Highlight the Role of Coal-fired Power Plants in Hotspots Evers et al. 2007. Scenario: 90% emissions reductions from 4 coal-fired power plants EPA estimates the utilities contribute 5 to 10 percent of total mercury deposition in southern NH Deposition After Evers et al. 2007.

Results Supported by Other Studies J. Keeler and Colleagues Slide 27 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.

Adverse effect threshold Slide 28 Good News: Fish and Wildlife Can Respond Rapidly to Emissions Reductions Mercury air emissions from local upwind sources declined 45% from 1997 – 2002. 64% decline Adverse effect threshold Findings further corroborate connection between local emissions and biological mercury hotspots. Substantial local contribution corroborated by biological data The loon data are consistent with fish (largemouth bass and yellow) and zooplankton trends After Evers et al. 2007.

Key Findings Slide 29 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.