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Richard Looker2008 RMP Annual Meeting October 7, 2008

The Water Board’s Regulatory The Water Board’s Regulatory Approach and the RMP Approach and the RMP

Mercury StrategyMercury 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--

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Loads and Allocations

0

200

400

600

800

1,000

Current Load Allocation

BE = Bed Erosion

CV = Central Valley

G = Guadalupe

G

BE

cv

G

cv

BE

(kilograms per year)

Reduce from 1220 to 700 kg/yr

SOURCE IMPLEMENTATION 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!

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0 50 100 150 200 250 300

Year After Beginning Implementation

Sediment Mercury Concen-

tration (ppm)

Current Loads

Proposed Allocations

Sediment Target (0.2 ppm)

Current Loads

Proposed Allocations

Sediment Target

Richard retires to undisclosed location

Total mercury in sediment reaches target

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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.

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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?

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Mercury Strategy Guiding Principles

Mercury Strategy Team formed in Summer 2007.

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.

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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?

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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?

deposition

wastewater

industry

legacy

runoff

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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.

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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.

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…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.