1. Impairment Assessment and Conceptual Model of Legacy Pesticides: DDT, Chlordane, and Dieldrin RMP Annual Meeting May 4, 2004 Jon Leatherbarrow, Chris Werme, Mike Connor, Jay Davis San Francisco Estuary Institute

2. Regulatory Status Restricted/Banned DDT in the 1960s/70s Chlordane and Dieldrin in the 1970s/80s San Pablo Bay Suisun Bay Central Bay South Bay Lower South Bay Delta CWA 303(d) List 1994 Fish Advisory (OEHHA) All segments of SF Bay listed as impaired Carquinez Strait

3. Impairment Indicator – Fish 2000 RMP Fish Monitoring Results Fish Screening Value POSSIBLE IMPAIRMENT POSSIBLE IMPAIRMENT UNLIKELY

4. Impairment Indicator – Water 2002 RMP Water Monitoring Results No 2002 samples exceeded CTR water quality criteria for: p,p-DDE p,p-DDD p,p-DDT Total Chlordane Dieldrin

5. DDT Forecast …and Historic Trends in Bivalves

12. Data Gaps and Potential Next Steps 1. Current trends in contamination? Sediment cores and continued fish monitoring 3. Pesticide loading & fate from tributaries? Central Valley; storms with Delta Outflow > 150,000 cfs Local Watersheds; clean-up, loading & BMP studies 4. Loading & fate of remobilized sediment in Bay? Further investigation; field studies, clean-up, bathymetry, modeling 2. Benefits from activities focused on reducing PCB contamination in the Bay?