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Sediment Quality Assessment. Toxicity test data used in a weight-of-evidence:. Sediment contamination Sediment toxicity Benthic community structure Results used to identify and map areas of unimpacted to clearly impacted sediments

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Sediment Quality Assessment

Toxicity test data used in a weight-of-evidence:

Sediment contamination

Sediment toxicity

Benthic community structure

Results used to identify and map areas of unimpacted to clearly impacted sediments

Current RMP toxicity tests are those recommended for the accepted statewide SQO methods for bays and estuaries, EXCEPT…

Draft data - do not cite or quote


Excerpt from SQO Staff Report - Table 5.2

List of candidate sediment toxicity tests

The SQO recommends the use of sediment water interface (SWI) samples

Draft data - do not cite or quote


Mussel embryo development

48-h exposure

Sublethal endpoint

Sediment elutriate VS. Sediment-water interface exposure

Draft data - do not cite or quote


In April-08 the TRC decided that the

RMP S&T will adopt the

sediment-water interface (SWI)

bivalve test in 2008

using intact sediment cores.

Draft data - do not cite or quote


Issues considered
Issues Considered

  • Comparison to historic RMP/other programs

  • Interpretation (Ecological Relevance)

  • Cost

Draft data - do not cite or quote


Comparison to historic rmp data
Comparison to historic RMP data

1999 - 2001 Bivalve Methods Study

  • 48-hr. sublethal development test

  • Elutriate (1:4 dil. VS. SWI intact cores)

  • 14 stations (52 samples).

Draft data - do not cite or quote


RMP 1999-2001 Elutriate & SWI bivalve development tests (N=52)

Rivers

Davis Point

Napa River

Grizzly Bay

Red Rock

Yerba Buena Is

Horseshoe Bay

Alameda

San Bruno Shoal

San Jose (LEMP)

Coyote Creek

Redwood Creek

South Bay

Draft data - do not cite or quote


Amphipod (N=52) and Bivalve Sediment Toxicity Results 1993-2001

Legend:

(BF21)

Grizzly Bay

Napa River

Davis Point

Rivers

Horseshoe Bay

Yerba Buena Island

Redwood Creek

San Jose

(BA21)

Coyote Creek

South Bay

Draft data - do not cite or quote

Pulse of the Estuary, 2003


Interpretation
Interpretation (N=52)

  • SWI tests are thought to be more ecologically relevant

  • However, not much in known about contaminant flux and exposure

  • SCCWRP study (4 samples) to determine if homogenized sediments can be left to equilibrate and used in the SWI test.

Draft data - do not cite or quote


Current status
Current Status (N=52)

  • RMP S&T 2008 will switch to collecting intact cores for the SWI bivalve development test to be comparable to recommended SQO methods that have been endorsed by a panel of national experts

    This will result in a NEW toxicity measure and will not be comparable with historic RMP data (largely an issue in Suisun Bay & Lower South Bay Regions)

Draft data - do not cite or quote


Question for eeps
Question for EEPS (N=52)

Should the RMP continue the bivalve elutriate tests in Suisun Bay and Lower South Bay Regions?

+ evaluate chemistry in the overlying water of both tests to begin to understand differences in contaminant exposure between intact cores and homogenized sediment elutriates

Draft data - do not cite or quote


RMP 1999-2001 Elutriate & SWI bivalve development tests (N=52)

Rivers

Davis Point

Napa River

Grizzly Bay

Red Rock

Yerba Buena Is

Horseshoe Bay

Alameda

San Bruno Shoal

San Jose (LEMP)

Coyote Creek

Redwood Creek

South Bay

Draft data - do not cite or quote


Cost (N=52)

Draft data - do not cite or quote


Cost (N=52)

$20 more per sample

Draft data - do not cite or quote


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