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

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Presentation on theme: "C OPPER AND N ICKEL TMDL D EVELOPMENT: L OWER S OUTH B AY."— Presentation transcript:

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

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

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

4 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 1 Conceptual Model Report for Copper and Nickel in Lower South San Francisco Bay

6 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 ( 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 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 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 2 Impairment Assessment Report for Copper and Nickel in Lower South San Francisco Bay

15 15 Task 2: Impairment Assessment 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:

16 Strategy to Assess Impairment of Beneficial Uses

17 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 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

23 Spatial and Temporal Variability in Picocyanobacteria in San Francisco Bay

24 24 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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