Assessment of Sediment QualityAssessment of Sediment Qualityin San Francisco Estuaryin San Francisco Estuary

RMP EEWG MeetingSeptember 6, 2007

SCCWRP Team: Bay, Ranasinghe, Ritter, Barnett, WeisbergSFEI Team: Thompson, Lowe, Connor

• A new regulatory approach

• Methods development since 2004

• Scheduled implementation in 2008

CALIFORNIA SEDIMENT QUALITY OBJECTIVES (SQO)

FOR BAYS AND ESTUARIES

SQO IndicatorsSQO Indicators

1. Chemistry Indicators (SQGs)

– Chem-Tox: CA LRM (maximum probability of toxicity)

– Chem-Benthos: CSI (weighted mean score)

2. Sediment Toxicity

– Amphipod survival (Eohaustorius estuarius)

3. Benthic Indices

– Benthic Response Index (BRI)

– Index of Biotic Integrity (IBI)

– Relative Benthic Index (RBI)

– River Invertebrate Prediction and Classification System (RIVPACS)

Three Lines of Evidence for Direct Effects:

MLOE Conceptual FrameworkMLOE Conceptual FrameworkDirect EffectsDirect Effects

Severity of Effect

Potential for Chemically

Mediated Effect

Station Assessment

Benthos Toxicity Chemistry Toxicity

2. Overall SQO Assessment combines 3 Lines of Evidence into 6 categories:

1. Each line of evidence uses 4 categories of impact:

• No impact• Low • Moderate• High

SQO Site Classification ProcessSQO Site Classification Process

• Unimpacted• Likely unimpacted• Possibly impacted• Likely impacted• Clearly impacted• Inconclusive

STATEWIDE ASSESSMENT OF STATEWIDE ASSESSMENT OF SEDIMENT QUALITYSEDIMENT QUALITY

BAYSBAYS

Objectives:

Apply assessment framework and tools to available data

- “Test Drive”

Estimate area of state with unimpacted/impacted sediment quality

– EPA 305(b) Report

Compare waterbody condition with previous assessments (303(d)

DataData

Sample sizes Study Year North SFBay South

1998 0 0 113 SoCal Bight 2003 0 0 102 1999 19 0 24 2000 0 40 0

WEMAP

2005 8 0 15 Huntington

Harbor/ Anaheim Bay

2001 0 0 60

Total 27 40 314

Random sampling data was used in order to make assessments based on area

SF Estuary SQO % Area % Area Stratum n Category Estimate Confidence bounds

Bay 11 Poor 90.99 75.72 100.00Bay 1 Good 9.01 0.00 24.28

Estuary 20 Poor 99.21 97.81 100.00Estuary 1 Good 0.79 0.00 2.19

Marina 1 Poor NA NA NAMarina 0 Good NA NA NA

Port 6 Poor 100.00 100.00 100.00Port 0 Good NA NA NA

Summary of SQO Demonstration Assessment Results for San Francisco Estuary

ResultsResults

Regional EstimatesRegional Estimates

North SFB South

Category % Area % Area % Area

Unimpacted 58 0 43

Likely Unimpacted 18 4 19

Possibly Impacted 17 73 24

Likely Impacted 4 19 12

Clearly Impacted 0 4 2

Inconclusive 3 0 <1

Assessment of RMP and BPTCP SamplesAssessment of RMP and BPTCP SamplesRMP StudyRMP Study

Objectives:•Put statewide assessment into perspective•Facilitate interpretation of SFE SQO results

Data:•60 samples, 7 sites, 2 assemblages, 1994-2000.•NOT random

Location Sta. ID Habitat n % Impact DriversSouth Bay BA21 M 10 70 C TRedwood Creek BA41 P 8 100 B T San Bruno Shoal BB15 P 5 60 C B TAlameda BB70 P 10 60 TYerba Buena Is. BC11 P 10 70 THorseshoe Bay BC21 P 10 0San Leandro Bay SLB6 M 1 100 C B TSan Pablo Bay BD41 M 7 0 (B)

Total 61 52.5M 18 44.4P 43 55.8

Results of SQO Assessment for RMP and BPTCP Sites, 1994-2000 P=Central Bay, polyhaline; M=Estuary, mesohaline

SQO ASSESSMENT RMP ALAMEDA STATION BB70

0

1

2

3

4

1994-02 1995-02 1995-08 1996-02 1996-07 1997-01 1997-08 1998-02 1998-07 2000-07

Sampling Period

LO

E C

ateg

ory

Chemistry

Benthos

Toxicity

**

* * * *

Relationship between CA LRM and mean ERM quotientin San Francisco Estuary

CA LRM

mERMq

Spearman’s r = 0.714

p < 0.0001, n = 94

Summary Summary

SQO methods provide overall assessment of sediment condition using MLOEs

Most of state’s marine embayments have impacted sediments

San Francisco Estuary has more impacted area than other Bays

Difference in incidence of impacts between two sets of samples

Additional analyses and studies needed to refine and interpret results

– Particularly identification of causes of observed impacts, ‘stressor identification’