Contaminants entering the estuary attach to particles which may then be deposited as sediments

1. Summary of 10 years of sediment toxicity monitoring for the San Francisco Estuary Regional Monitoring Program Brian Anderson, Bryn Phillips, John Hunt, Patricia Nicely, Ron Tjeerdema University of California, Davis Bruce Thompson, Sarah Lowe, Jay Davis San Francisco Estuary Institute Karen Taberski California Regional Water Quality Control Board – San Francisco Bay Region

2. Contaminants entering the estuary attach to particles which may then be deposited as sediments Contaminants may impact benthic organisms or higher trophic level species

3. Laboratory Toxicity Testing (UC Davis – Marine Pollution Studies Lab) Amphipod 10-d survival test Measures acute effects

4. Mussel embryo development 48-h exposure Sublethal endpoint Sediment elutriate exposure Sediment-water interface exposure

5. Sediment Quality Triad Toxicity test data used in a weight-of-evidence Sediment contamination Sediment toxicity Benthic community structure Bioaccumulation Results used to identify and map areas of impaired or potentially impaired beneficial uses: Aquatic life Human health Wildlife

6. Napa River Legend: Grizzly Bay San Pablo Bay Rivers Horseshoe Bay Yerba Buena Island Redwood Creek San Jose Coyote Creek South Bay Some stations are consistently toxic, others exhibit seasonal toxicity

7. 1993-2000 100 % Stations toxic to amphipods 50 36% 10% 0 Winter Summer Change in RMP Experimental Design: 1993 –2001: Winter and Summer Sampling of Fixed Stations 2002-2003: Summer Sampling Using Probabilistic Sampling Design (7 fixed stations + 21 random stations) 2002 100 % Stations toxic to amphipods 50 18% 0 Summer

8. Amphipod response vs. contaminant mixtures 100 80 r = - 0.685 p = <0.0001 60 n = 118 Amphipod % survival 40 20 0 0.06 0.20 0.40 0.60 0.80 1.00 1.40 mERMQ Always Toxic Never Toxic toxic nontoxic Thompson et el. 1999

9. Amphipod response vs. contaminant mixtures toxic nontoxic 100 80 r = - 0.685 p = <0.0001 60 n = 118 Amphipod % survival 40 20 0 0.06 0.20 0.40 0.60 0.80 1.00 1.40 mERMQ Always Toxic Never Toxic Benthic impact 68% stations Benthic impact 100% stations Thompson et el. 1999 Thompson and Lowe in review

10. Toxicity Identification Evaluations (TIEs) Phase I – characterization: e.g., metals vs organics, ammonia, H2S Phase II – identification: specific metal or organic compound(s) responsible for toxicity Phase III – confirmation Consider confounding factors: grain size, ammonia, pH etc. Once identified, chemical responsible for toxicity are emphasized in later studies : Source identification and control

11. Grizzly Bay Bivalve TIE w/ 25% Elutriate Mortality (%) Phillips et al. in press

12. Sediment-Water Interface TIE w/ EDTA Mortality (%) Phillips et al. in press

13. Bivalve TIE Summary: Grizzly Bay • Copper is implicated as the primary cause of sediment toxicity to bivalves (elutriates, sediment-water interface) • u Other divalent metals may also contribute to elutriate toxicity • Amphipod TIE Summary: Grizzly Bay • Toxicity is probably not due to organic chemicals • Sediment is toxic, pore water is not • Toxicity is due to some acid-soluble compound

14. North Bay Rivers Napa River Petaluma River Coyote Creek Redwood Creek Guadalupe River

15. Future Work • Continued Status and Trends monitoring • Application of TIEs at consistently toxic stations Winter samples • Possible Special Studies • Winter sampling at the base of key tributary streams • Dose-response toxicity tests with resident and surrogate toxicity test species