20072008: Causes of Sediment Toxicity Study

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2007-2008 Causes of Sediment Toxicity Study
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• 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

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Prioritized Sites for Amphipod TIE Study
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Group 1 Group 2 Group 3
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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
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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

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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

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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 ST 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

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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
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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
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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

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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 TIEs 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 TIEs 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
Primary Objective Understand the Causes of
Ecological Effects in Sediments of the San
Francisco Estuary
Dose-response studies of both resident and lab
estuarine species using contaminant of concern MQ
4.1 SQ 1, 2, 3 5
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Five-Year WorkplanSummary, Cost Estimates, and
MQs
Table 4 of the draft workplan On Page 18
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Five-Year Workplan
Table 5 of the draft workplan On Page 19