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Sediment contamination Sediment toxicity Benthic community structure

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 contamination Sediment toxicity Benthic community structure

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  1. 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tests are those recommended for the accepted statewide SQO methods for bays and estuaries, EXCEPT… Draft data - do not cite or quote

  2. 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of candidate sediment toxicity tests The SQO recommends the use of sediment water interface (SWI) samples Draft data - do not cite or quote

  3. Mussel embryo development 48-h exposure Sublethal endpoint Sediment elutriate VS. Sediment-water interface exposure Draft data - do not cite or quote

  4. 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 Draft data - do not cite or quote

  5. Issues Considered • Comparison to historic RMP/other programs • Interpretation (Ecological Relevance) • Cost Draft data - do not cite or quote

  6. 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 Draft data - do not cite or quote

  7. 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Yerba Buena Is Horseshoe Bay Alameda San Bruno Shoal San Jose (LEMP) Coyote Creek Redwood Creek South Bay Draft data - do not cite or quote

  8. Amphipod 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Davis Point Rivers Horseshoe Bay Yerba Buena Island Redwood Creek San Jose (BA21) Coyote Creek South Bay Draft data - do not cite or quote Pulse of the Estuary, 2003

  9. Interpretation • 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

  10. Current Status • 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

  11. Question for EEPS 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

  12. 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

  13. Cost Draft data - do not cite or quote

  14. Cost $20 more per sample Draft data - do not cite or quote

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