1. Mercury in the Ohio River A Modeling and Field Data Approach Presentation to: ORSANCO Reed Harris, David Hutchinson and Don Beals RHE Ltd. February 12, 2013

2. Presentation Outline Objectives and approach Objectives and approach Model background and description Model background and description Field data Field data Initial model results Initial model results Next Steps Next Steps

3. Objectives Identify the primary sources of inorganic Hg and methylmercury to the Ohio River, and their relative importance, focusing on a single navigation pool (Robert C. Byrd Pool). Identify the primary sources of inorganic Hg and methylmercury to the Ohio River, and their relative importance, focusing on a single navigation pool (Robert C. Byrd Pool). Demonstrate the sensitivity of predicted biota mercury concentrations to various factors, including Hg loading. Demonstrate the sensitivity of predicted biota mercury concentrations to various factors, including Hg loading. Seek input from stakeholders (state and federal regulatory agencies, federal research agencies). Seek input from stakeholders (state and federal regulatory agencies, federal research agencies).

4. Dynamic Mercury Cycling Model D-MCM Version 4.0 EPRI 3412 Hillview Ave. Palo Alto, CA Copyright © 2012 Electric Power Research Institute Inc. All rights reserved Please wait while D-MCM loads….

5. What Does D-MCM do? Predicts Hg cycling & bioaccumulation in aquatic systems Predicts response to Hg loading and changes to environmental conditions. Includes water, sediments, and food web Methylmercury, inorganic Hg, elemental Hg Outputs through time

6. (a) Project (c) Group of cells (b) Wetland Cell One water compartment Four sediment compartments

7. Ohio River Application of D-MCM

9. Pennsylvania West Virginia Ohio R.C. Byrd Racine Belleville Hannibal Pike Island Willow Island Emsworth Dashields New Cumberland Montgomery Island Pittsburgh Kanawha River

10. Mercury in Fish in the Ohio River 2002-2012 – by River Mile Data from ORSANCO and AEP Not adjusted for size, includes composites Largemouth Bass Channel Catfish Sauger Hybrid Striped Bass

11. Sauger Hybrid Striper Channel Catfish Bluegill Benthic Invertebrates - Omnivores Algae Benthic Invertebrates - Herbivores Food web in D-MCM Ohio River simulations Emerald Shiner

12. Predicted and observed Hg in surface waters in Robert C. Byrd Pool

13. Predicted and Observed MeHg in Fish in Robert C. Byrd Pool Observations includes composites Bluegill Channel Catfish Sauger Hybrid Striped Bass

14. Where does the MeHg in fish in Robert C. Byrd pool originate? Atmosphere Inflow Terrestrial runoff Sediment methylation

15. Predicted Hg fluxes in Robert C. Byrd Pool - Inflows from upstream dominate Hg loads to water column MeHg Total Hg

16. MeHg sources to Robert C. Byrd Pool - Methylation in pool was small source to water column, but more important in sediments Water column Sediments Contribution of sediment methylation

17. MeHg is broken down and resupplied along rivers.. - How far upstream is the MeHg in Robert C. Byrd Pool formed?

18. Summary/Next Steps Fish Hg levels in the Ohio River are low to moderate. MeHg levels in water column are relatively low. Model reasonably reflects Hg and MeHg in water and food web. Most of the inorganic and MeHg load to Robert C. Byrd pool water column is from upstream. Methylation in R.C. Byrd Pool sediments is more important as a source of MeHg to sediments (and some biota?) How far upstream is MeHg load to Robert C. Byrd Pool produced? Role of fish growth rates and trophic structure? Effect of mussels?