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2007-2008: Causes of Sediment Toxicity Study

This study aims to identify and characterize potentially toxic intertidal sites in San Francisco Bay through a phased Toxicity Identification Evaluation (TIE) approach. The study will analyze sediment quality and chemistry to determine the causes of observed toxicity.

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2007-2008: Causes of Sediment Toxicity Study

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  1. 2007-2008: Causes of Sediment Toxicity Study w • Identify 12 potentially toxic inter-tidal sites • Sample four sites at a time to find two suitable sites for amphipod TIE development - Perform phased TIE to characterize, identify, and confirm causes of observed toxicity - Analyze sediment quality and chemistry at the TIE sites to help with TIE interpretation w w w w Prioritized Sites for Amphipod TIE Study w w Group 1 Group 2 Group 3 w w w w w

  2. Sediment Effects in San Francisco Bay Management Context Current Status Important Work to Date Sediment Toxicity Benthic Pilot Study/SQO RMP Objectives and Management Questions Addressed Five-Year Plan EEPS WG Sep. 2007

  3. Management Context • Sediment toxicity is persistent in the Estuary and we need to investigate the causes • Narrative toxicity objectives outlined in the Basin Plan are employed by the Water Board to list water bodies • Sediment Quality Objectives for bays and estuaries are proposed and will be promulgated soon

  4. Current Status • Persistent toxicity in Estuary sediments • Toxicity in higher in the winter than the summer • Toxicity in more prevalent in the margins than channels • Benthic indices have been developed for some benthic assemblages, and some benthic community impacts are seen based on contamination (However salinity and TOC were strong correlates as well) • Benthic impacts are more prevalent in margins than channels

  5. Important Work to Date • RMP Status and Trends continues to characterized sediment toxicity conditions in the Estuary • Complex mixtures and specific contaminant groups have been correlated to sediment toxicity observed in the S&T program • Bivalve and Amphipod TIEs are useful tools to separate contaminant causes of toxicity • Benthic Assemblages have been characterized for the Estuary • Benthic Indices developed within some of these assemblages are employed by the SQO for bays and estuaries

  6. RMP Management Objectives Addressed • Objective 4. Characterize ecological and human health risk due to pollution of the Estuary ecosystem • Objective 5. Use monitoring information to compare to relevant regulatory guidelines (and to establish new guidelines) Page 8 of the draft workplan

  7. Specific Questions to be Addressed in Next Five-Years In order of priority: • What are the causes of sediment toxicity? • Are Estuary sediments toxic? • Are the benthos impacted by pollutants? • Is the SQO method a valid way evaluate ecological condition in this Estuary? • What are the causes of benthic impacts? Page 8 of the draft workplan

  8. Toxicity Workgroup Recommendations: • Evaluate toxicity during Winter near potential sources • Follow the most relevant matrix (sediment) • Investigate causes of persistent sediment toxicity • Develop LC50s for estuarine species • Integrate this study with Benthic work and other SQO work that is planned

  9. We have begun to address these questions Causes of Sediment Toxicity Causes of Benthic Impacts ID Benthic Assemblages MQs 4.2,5.1, 5.2 SQ 3 & 4 Bivalve TIE’s MQ 4.1 SQ 1 & 2 Multivariate analyses to ID stressors MQs 4.2,5.1, 5.2 SQ 1, 2, 3 & 5 Amphipod Dose Response Experiments MQ 4.1 SQ 1, 2, 3 & 5 Multi-metric Benthic Response Indices MQs 4.2,5.1, 5.2 SQ 3, 4 & 5 SQO for bays and estuaries MQs 4.2, 4.4, 5.1, 5.2 MQs = Management Questions addressed by the study SQ = Specific Question Addressed by the Sediment Effects Studies See Page 8 of the draft workplan Graphic is a modified version of Figure 1 on Page 21 Amphipod TIE’s MQ 4.1 SQ 1 & 2 Intensive triad studies at gradient sites to investigate stressors MQs 4.1, 4.2 SQ 1,2,4 & 5 Experimental studies to understand benthic community effects MQs 4.1, 4.2 SQ 3 & 5 Develop TIE “toolbox” to address causes MQ 4.1 SQ 1 & 2 Dose-response studies of both resident and lab estuarine species using contaminant of concern MQ 4.1 SQ 1, 2, 3 & 5 Primary Objective Understand the Causes of Ecological Effects in Sediments of the San Francisco Estuary

  10. Table 4 of the draft workplan On Page 18 Five-Year WorkplanSummary, Cost Estimates, and MQs

  11. Table 5 of the draft workplan On Page 19 Five-Year Workplan

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