New Emphasis on Sediment Quality Objectives

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New Emphasis on Sediment Quality Objectives
Water Board, SCCWRP, SFEI RMP Annual Meeting
2007
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Water Board Policy Development

• 1989 Legislature amended Water Code
• Sec 13392.6 Sediment Quality Objectives
• reasonable protection of beneficial uses
• November Water Board hearing
• Chemistry - Biology Toxicity
• Process driven by Scientific Steering Comm

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Conceptual FrameworkDirect Effects
Three lines of evidence (LOE) needed to assess
direct effects of sediment contamination
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Toxicity Line of Evidence
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Benthic Community LOE - Steps

• Compile Data
• Standardize taxonomy
• Calculate abundance and other metrics
• Calculate Benthic Indices
• Benthic Response Index (BRI)
• Index of Biotic Integrity (IBI)
• Relative Benthic Index (RBI)
• River Invertebrate Prediction and Classification
  System (RIVPACS)
• Combine Index Scores

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Benthic Community LOE - Steps

• Compile Data
• Standardize taxonomy
• Calculate abundance and other metrics
• Calculate Benthic Indices
• Benthic Response Index (BRI)
• Index of Biotic Integrity (IBI)
• Relative Benthic Index (RBI)
• River Invertebrate Prediction and Classification
  System (RIVPACS)
• Combine Index Scores

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Chemistry Line of Evidence
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Sediment Quality Lines of Evidence
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Direct Effects Station Assessment
Six assessment categories

• Unimpacted
• Likely Unimpacted
• Possibly Impacted
• Likely Impacted
• Clearly Impacted
• Inconclusive

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MLOE Conceptual FrameworkDirect Effects
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Severity of Effect
Toxicity
Benthos
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Potential Effects are Chemically Mediated
Toxicity
Chemistry
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MLOE Conceptual FrameworkDirect Effects
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Station Categories

• Unimpacted - no significant adverse impacts.
• Likely Unimpacted - some uncertainty from small
  disagreement among the LOE.
• Possibly Impacted - Small impacts or LOE
  disagreement cause substantial uncertainty.
• Likely Impacted - Evidence persuasive, some
  disagreement among LOE.
• Clearly Impacted - clear and severe adverse
  impacts
• Inconclusive - Large disagreement among the LOE

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Station Assessment
Severity of Effect
Potential that Effects are Chemically Mediated
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Sec 305 (b) Report Test
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Common Approach in Regions
Common Tools Eohaustorius, RBI, CA LRM CSI
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Results
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Results
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LOE Responses ( Area)
Affected Moderate or High response
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ChemistryToxicity Relationships
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Effect of Tool Differences on Area Estimates
Affected Benthos Moderate or High
responseAffected MLOE Possibly, Likely, or
Clearly Impacted
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RMP Response

• Implement Sediment Triad
• Regional Consensus on Indices
• Assessment of Toxicity Causes

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Sediment Chemistry Classification Steps

• Compile Data
• Calculate sums, estimate nondetects
• Calculate Chemistry Indicators (SQGs)
• Chem-Tox CA LRM (maximum probability of
  toxicity)
• Chem-Benthos CSI (weighted mean score)
• Combine Indicator Scores to Determine Chemistry
  LOE Category

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Toxicity Classification Steps

• Compile Data
• Normalize to control response
• Statistical significance tests
• Apply Toxicity Classification Criteria
• Amphipod survival (Eohaustorius estuarius)
• Determine Toxicity LOE Category

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Statewide Condition
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California Regions
Total 1295 km2
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Regional Condition
North 139 km2
South 135 km2
San Francisco Bay 1020 km2