1 Richard Looker 2008 RMP Annual Meeting October 7, 2008 The Water Board’s Regulatory Approach and the RMP Mercury Strategy Hg

Conceptual Model for Mercury Sources System is complicated so we used a simple single box model. And we did mass balance only for total mercury.

Bacteria in wetlands, mudflats and sloughs Mercury in sediment Methylmercury available for bioaccumulation Conceptual Model for Mercury Fate: “All Mercury is Equally Bioavailable” Mercury Discharges (Elemental and Inorganic) Methylating Regions--

4 Loads and Allocations Reduce from 1220 to 700 kg/yr

SOURCEIMPLEMENTATION STRATEGY Bed Erosion What to do? Is source really that big? Central Valley Watershed Implement Central Valley TMDLs Urban Runoff Identify sources & implement controls Guadalupe River Implement Guadalupe River TMDL Atmospheric Deposition Study and seek ways to control significant local sources Rural Runoff Target already met Wastewater 40% load reduction & study local effects Dredging and Disposal Limit disposal to ambient mercury concentration Implementation Plan “One Liners”

Oh ! Improvement Takes Decades! Current Loads Proposed Allocations Sediment Target Richard retires to undisclosed location Total mercury in sediment reaches target

7 Key Assumptions of TMDL  All Bay mercury is equally bioavailable.  Reducing total mercury inputs will reduce concentrations in biota because… … reducing total mercury inputs will eventually reduce in-Bay total mercury sediment concentrations …… … and in-Bay sediment total mercury concentrations are proportional to food web mercury concentrations.

8 What We Need to Know to Adapt TMDL  Where are the hot spots for methylation and food web uptake?  Is mercury from some sources much more likely to enter the food web? Legacy, deposition, wastewater, urban runoff, other watershed inputs?  What can we do to control sources, manage methylation/uptake or otherwise hasten recovery?

9 Mercury Strategy Guiding Principles  Mercury Strategy Team formed in Summer  Focus on methylmercury production & uptake.  Conduct studies to find ways to reduce mercury accumulation in species of concern in a shorter time- frame than currently thought possible for total mercury reductions.  Information from studies is foundation for the next iteration of TMDL.

10 RMP Mercury Strategy – Priority Questions 1. Where is mercury entering the food web? 2. Which processes, sources, and pathways contribute disproportionately to food web accumulation? 3. What are the best opportunities for management intervention for the most important pollutant sources, pathways, and processes? 4. What are the effects of management actions? 5. Will total mercury reductions result in reduced food web accumulation?

11 RMP Mercury Strategy – Priority Questions 1. Where is mercury entering the food web? 2. Which processes, sources, and pathways contribute disproportionately to food web accumulation? 3. What are the best opportunities for management intervention for the most important pollutant sources, pathways, and processes? 4. What are the effects of management actions? 5. Will total mercury reductions result in reduced food web accumulation?

1) Where is mercury entering the food web? Does the pattern of food web uptake look like the pattern for total mercury in sediment?

…or like the pattern for methylmercury in water?

…or like the pattern for methylmercury in sediment or something else? How will we try to find out? Stay tuned!

Hg Where does the mercury in fish come from?

16 Possible Outcomes of Strategy  Home run – we identify hot spots and critical mercury sources.  Base Hit – some progress but uncertainties remain.  Strikeout – inconclusive results or bad news about our ability to speed recovery.

17 How might TMDL be adapted?  Allocations expressed as bioavailable Hg.  Discharge or embayment-specific control measures or allocations. To prevent discharge to sensitive area. To prevent discharge of type of Hg disproportionately found in fish.  Management/manipulation of methylation or uptake hot spots.

18 …but policy choices are tough!  “Virtue” of current approach is geographic equity Discharger not “penalized” for discharging into particular Bay location.  Will stakeholders accept an approach that singles out certain sources?  Are we willing to address hot spots despite local environmental impacts?  Remember: uncertainty will likely remain.