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Mercury Control in San Francisco Bay: Regulatory Updates and Implementation Strategies

This regulatory update covers the coordination meeting on February 22, 2007, focusing on mercury control in the San Francisco Bay area. Key topics include the Delta Methylmercury TMDL, scientific background, control programs, and MeHg linkage. The program aims to reduce mercury exposure in fish and wildlife, revise fish advisories, and control MeHg and total Hg sources in the region. Efforts include developing water quality objectives, implementing MeHg source reductions, and a pilot offset program. Learn about ongoing initiatives and future goals to manage mercury levels effectively.

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Mercury Control in San Francisco Bay: Regulatory Updates and Implementation Strategies

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  1. Regulatory UpdatePart 2 San Francisco Bay Mercury Coordination Meeting February 22, 2007 Michelle Wood (Central Valley Water Board) Carrie Austin (San Francisco Water Board)

  2. DeltaMethylmercuryTMDL

  3. Outline • Delta MeHg TMDL & BPA • Background • Key Questions • State Board’s Scoping Efforts • Hg Offset Policy for theBay-Delta System • Statewide Water Quality Objectives for Mercury

  4. Sacramento Region 5 Region 2 San Francisco Bay Antioch Stockton Brentwood Tracy The Delta >1100 mi waterways Drains ~1/3 of CA ReduceCentral Valley Mercury Outflows by 110 Kg

  5. Delta MeHg TMDL & BPA • TMDL draft staff report (August 2005, revised June 2006) • Scientific background • Basin Plan Amendment draft staff report (scientific peer review June-August 2006) • Control program

  6. Next Steps • Board Workshop in March 2006 • Release draft BPA staff report w/ formal comment period • Board Hearing later in 2006

  7. Delta MeHg Control Program: Reduce MeHg exposure to thefish-eating public & wildlife As stated by Jim Wiener and other researchers in their 2003 Mercury Strategy for the Bay-Delta Ecosystem: “The problem with mercury in the Delta’s aquatic ecosystems can be defined as biotic exposure to methylmercury.”

  8. 2. Reduce mercury levelsin Delta fish Delta MeHg Control Program • Revise fish advisories & expand education & outreach programs to reduce MeHg exposure to the fish-eating public

  9. California least tern PROPOSED Water Quality Objectives for Delta Fish 0.24 ppm mercury in large predator fish 1 meal/wk 0.03 ppm mercuryin prey fish

  10. Average MeHg Levelsin Large TL4 Fish(mg/kg)[Compare to Proposed WQO of 0.24 mg/kg] 0.56 na 0.92 0.32 0.26 na 0.50

  11. Control Program • Reduce MeHg exposure to the fish eating public & wildlife • Reduce mercury levels in Delta fish • Control MeHg sources • Control total Hg sources

  12. MeHg Linkage: 350 mm Largemouth Bass & Avg. Annual Water MeHg Mokelumne R. 1.0 y = 20.365x1.6374 R2 = 0.91 350 LMB Hg (mg/kg) 0.5 0.24 mg/kg Central Delta 0.066 ng/l 0.0 0.0 0.1 0.2 Aqueous MMHg (ng/l)

  13. Proposed MeHg Implementation Goal • 0.06 ng/l in unfiltered ambient water, annual average (~10% margin of safety) • Use goal to establish how much reduction from each source is needed to achieve WQOs

  14. Average AnnualAmbient MeHg Levelsin Water(ng/l) 0.11 0.27 0.17 0.08 0.06 0.22 0.16

  15. Delta TMDL: MeHg Sources Within-Delta Sources (~40%) • Wetlands (16%) • MeHg flux from open water sediments (15%) • Waste water treatment plants (4%) • Agricultural return flows (3%) • Urban runoff (½%) Tributary Watersheds (~60%)

  16. Methylmercury Allocations: Implement MeHg Source Reductions in the Delta & Yolo Bypass by 2030 • Cap MeHg loads from: Atmospheric, dredging, open channel* • Reduce MeHg loads from:Agricultural, WWTPs, stormwater, wetlands & tributaries with discharge > 0.06 ng/l MeHg • Minimize MeHg from new sources:(e.g., wetland restoration, water management changes, new WWTP discharges...)

  17. Phase 1 (2008-2015)Study Period: • Conduct characterization & control studies to evaluate existing sources’ MeHg & TotHg concentrations and loads • GOALS: • Address uncertainty in load estimates • Develop technically & economically feasible MeHg management practicesto reduce on-site MeHg production

  18. Control Program • Reduce MeHg exposure to the fish eating public & wildlife • Reduce mercury levels in Delta fish • Control MeHg sources • Control total Hg sources

  19. Delta TMDL: TotHg Sources Within-Delta Sources (~3%) • Waste water treatment plants (1%) • Urban runoff (1%) • Atmospheric deposition (1%) Tributary Watersheds (~97%)

  20. Inorganic Mercury Limits: Hg Sources in Delta & Tributaries Downstream of Major Dams • Cap Hg loads from: Local atmospheric emissions, dredging, flood conveyance, WWTPs, and urban stormwater • Reduce Hg loads by 110 kg from: Cache Creek Settling Basin, American & Feather Rivers & Putah Creek • Minimize Hg from new sources • Continue upstream MeHg & TotHg evaluations & implement control actions as part of future TMDLs

  21. Pilot Mercury Offset Program • Phase 1: allow pilot offset projects to promote early implementation of MeHg/TotHg reduction projects & to provide information for Phase 2 offset program. • Phase 2: Regional Board considers adoption of an offset program to allow dischargers to offset MeHg and/or TotHg in their discharges by implementing more feasible or cost effective projects elsewhere in the watershed. • The approved offset program must be consistent with any State Board offset policy.

  22. Outline • Delta MeHg TMDL & BPA • Background • Key Questions • Regional / Statewide Efforts • Hg Offset Program for the San Francisco Bay, Delta & Tributary Watersheds • Statewide Water Quality Objectives for Mercury

  23. Key Question***Highest Priority for Delta & upstreamMeHg control programs*** Can we develop MeHg control actions & management practicesfor wetlands, WWTPs& other sources?

  24. 26 < 0.05 ng/l Preliminary Municipal WWTP MeHg Monitoring Results

  25. Other Key Questions: • What types of wetlands are contributing MeHg to the Delta andits tributaries, and how much? • How much TotHg and MeHg does atmospheric deposition contribute to Delta loading? • How does sulfate affect open water MeHg levels in the Delta?

  26. Other Key Questions: • Is it possible to design or manage wetlands to reduce wildlife exposure to MeHg? • Which aquatic species do humans consume and how much?

  27. Other Key Questions: The proposed Delta MeHg control program applies to hydrologically connected waterways.We need a better understanding of the following for future phases of the control program: • What are the specific mercury effects on key wildlife species in the Delta & its trib watersheds? • What are the consumption habits of key wildlife species? • Where do they consume fish? [main channel versus isolated wetlands and Ag drains] • Which seasons are critical? • Which aquatic species are consumed?

  28. Outline • Delta MeHg TMDL & BPA • Background • Key Questions • Regional / Statewide Efforts by State Board • Hg Offset Program for the San Francisco Bay, Delta & Tributary Watersheds • Statewide Water Quality Objectives for Mercury

  29. Hg OffsetPolicy forthe SF Bay,Delta &Tributary Watersheds [“Bay-Delta System”] The red hatching represents the SFBay watershed and Delta source area downstream of major dams.

  30. Policy would provide “General Principles” for Regional Water Boards & dischargers to implement offset projects Policy would not give specific project offset ratios or address pollutant trading Proposed State BoardBay-Delta System Hg Offset Policy

  31. Statewide Water Quality Objectivesfor Mercury • Apply to California’s: • Inland waters • Enclosed bays • Estuaries

  32. State Water Board Considerations • Six Objective Alternatives: • MeHg in fish tissue • MeHg in water, TotHg in water • Fish / water combinations • Uses national average BAFs & MeHg/TotHg translator to convert from concentrations in fish to water • Alternatives vary by: • Consumption rates for humans (USEPA default vs. San Francisco Bay) • Species to which WQO would apply (average of trophic levels vs. top trophic level only)

  33. Public Scoping Meeting on Feb 20th CEQA Scoping comments due Feb 28th Contact: Tom Kimball or Joanne Cox http://www.waterboards.ca.gov/plnspols/index.html#policies State Board CEQA Scoping for Bay-Delta Offset Policy & Statewide WQOs:

  34. SacramentoRiver Feather R. American R. Clear Lake Cache Creek Bear Creek Harley Gulch Delta San Joaquin R. Central Valley Mercury TMDLs

  35. Lower Fish Hg Evaluate Monitor Adaptive Implementation Action

  36. Water Quality Improvement Assessment Evaluation Planning Implementation Water Quality Management Process Special Discharger Studies Monitoring CWA 303(d) Review - Monitoring Results - Mgmt. Plans • Basin Plan • Uses • Objectives • Impl. Program • TMDLs WDRs Waivers Prohibitions

  37. Delta Mercury Impairment • High mercury levels in fish • Fish consumption advisories • Federal CWA 303d list • TMDL Program to address impairment

  38. The Methylmercury Problem • Hg is a potent neurotoxicant - impairs nervous, reproductive, & immune systems in humans & wildlife • Sulfate-reducing bacteria convert mercury to MeHg, the most toxic form of Hg • >90% mercury in top trophic level fish is MeHg • Exposure to MeHg is through consumption of fish & shellfish because of the way MeHg bioaccumulates

  39. San Joaquin Subarea Methylmercury SourcesTotal Loading: ~478 g/yr Agri- Wastewater Other cultural 9% Tributaries Lands Inputs 77% 5% 23% Open Water Wetlands Urban 4% 4% 1%

  40. Yolo Bypass Subarea Methylmercury SourcesTotal Loading: ~1,000 g/yr Wetlands Other 39% Tributaries Inputs 51% 49% Open Water 8% Agricultural Lands 2%

  41. Methylation factors • Amount and type of inorganic Hg in sediment • Sulfate and pH concentration: Sulfate in Delta affected by EC and ratio of SJR to Sac R water • % organic matter in sediment • Creation of new impoundments increases MeHg in sediment, water and biota • Habitat type, particularly the amount of seasonally or permanently flooded wetland in a watershed

  42. Tributary TotHg Sources & Concerns about Reduction • Millions of kilograms released to waterways by historic mining • Much remains in channels & may be untreatable • Natural erosion will remove some mercury, but it may take centuries to wash the mercury from the waterways • TotHg:MeHg relationship varies by habitat, so how do we develop a safe level for TotHg that would protect the Delta without being overly stringent?

  43. Interrupt the Methylation Cycle • Control TotHg in watersheds that discharge the most Hg-contaminated sediment • Identify Delta & upstream MeHg sources: • Reduce on-site methylation, and/or • Reduce TotHg sources that supply the methylation sources • Shorten time to see fish tissue mercury improvements from centuries to decades

  44. Potential Timeline Years 1 to 7: Conduct characterization & control studies; begin TotHg control actions Year 8: Update MeHg source analyses & allocations, evaluate discharge control programs & offset program, amend Basin Plan as needed Year 9 to 2030: Implement MeHg control actions 2030 onward: Continued MeHg controls & natural erosion reduces contaminated in-channel sediments

  45. What is a Mercury Offset Program? Voluntary program that enables projects to proceed even if on-site mercury controls are not feasible. Dischargers could obtain offsets: • To help meet their allocations; • To allow an increase above their allocations as a result of expansion that would otherwise result in additional mercury loading to the Bay–Delta system; or • To initiate a new discharge that would otherwise result in new mercury loading to the Bay–Delta system.

  46. Mercury Water Quality Objective Alternatives

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