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C OPPER AND N ICKEL TMDL D EVELOPMENT: L OWER S OUTH B AY

C OPPER AND N ICKEL TMDL D EVELOPMENT: L OWER S OUTH B AY. Presentation Overview. Scientifically Defensible Site Specific Objectives Key Elements of the TMDL Process Lessons Learned and Recommendations.

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C OPPER AND N ICKEL TMDL D EVELOPMENT: L OWER S OUTH B AY

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  1. COPPER AND NICKEL TMDLDEVELOPMENT:LOWER SOUTH BAY

  2. Presentation Overview • Scientifically Defensible Site Specific Objectives • Key Elements of the TMDL Process • Lessons Learned and Recommendations

  3. Proposed SSOs for Copper and Nickel for San Francisco Bay South of the Dumbarton Bridge • Chronic 6.9 mg/l dissolved copper 12 mg/l dissolved nickel • Acute 10.8 mg/l dissolved copper 62.4 mg/l dissolved nickel

  4. Key Elements of the TMDL Process • Stakeholder Involvement and City of San Jose Funding and Commitment • Source Characterization • Conceptual Model Development • Impairment Assessment • Copper and Nickel Action Plans

  5. Task 1Conceptual Model Report for Copper and Nickel in Lower South San Francisco Bay

  6. Role of the Conceptual Model in the TMDL Project • Summarize current understanding of Cu and Ni in Lower South San Francisco Bay • Communicate information to wide audience • Provide technical basis for project planning

  7. Conceptual Model for Copper Concentrations in the South Bay

  8. Average Total and Dissolved Copper Concentration (1993-1997 Data)

  9. Copper Inventories and Loadings in Lower South San Francisco Bay

  10. Copper Concentrations in Lower South San Francisco Bay

  11. Copper Mass Balance Model • Simplified but realistic: Hydrodynamics generated from 3D model • Calculates Internal Loadings • Calculates Loading – Concentration Response

  12. How Would Bay Respond to a 250 kg Loading Change During Wet Season? • 250 kg would be a Significant Change • Dissolved Concentrations:See bar chart • Conclude:Lower South Bay is Buffered for Cu

  13. Uncertainties and Recommendations for Additional Studies • Limited Understanding of Processes in South Bay • Sedimentation/Resuspension Dynamics • Adsorption/Desorption Kinetics • Biogeochemical processes influencing metal speciation • Effects of speciation and competing metals on phytoplankton uptake and toxicity • Biological cycling in sediments and water column • Direct Data Limitation • Limited Sediment Core Data • Nonpoint source tributary loads • Food web transfer • Resuspension fluxes and other sediment-water interactions

  14. Task 2Impairment Assessment Report for Copper and Nickel in Lower South San Francisco Bay

  15. Compile and evaluate data on ambient concentrations and toxicity information Identify, evaluate and select indicators of beneficial-use impairment Develop endpoints for the selected indicators Assess levels of uncertainty Recommend numeric values for site-specific objectives Purpose: To present new information and to re-evaluate the determination that the beneficial uses of the South Bay are impaired due to ambient concentrations of copper and nickel. Goals: Task 2: Impairment Assessment

  16. Strategy to Assess Impairment of Beneficial Uses

  17. Proposed Indicators • Individual Species Toxicity Tests • Aquatic Ecological Risk Assessment Protocol (AERAP) • Site-Specific Studies • Phytoplankton • Benthic Macroinvertebrates • Ratio of Simultaneously Extracted Metals to Acid Volatile Sulfides (SEM/AVS) • Charismatic Macrofuna: Harbor Seals and Birds

  18. Phytoplankton Toxicity • Phytoplankton in laboratory experiments are sensitive to concentrations of free ionic Cu that have been measured in the South Bay • Several site-specific water quality variables that must be taken into account to predict the toxicity of free ionic copper • Insufficient data to predict the effects of free ionic Cu in the South Bay • Several unanswered questions regarding the applicability of the test results to developing water quality objectives

  19. Conceptual Model for Copper Concentrations in the South Bay

  20. Copper Uptake and Toxicity in Phytoplankton

  21. Range of pM+ Values in Oceanic and Estuarine Environment

  22. Spatial and Temporal Variability in Picocyanobacteria in San Francisco Bay

  23. Lessons Learned • Substantial amount of data and information required to implement science-based approach • Additional technical information required to support regulatory decision making process • Comprehensive monitoring programs do not meet all the information requirements of the regulatory decision-making process

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