u Linda Russio: Organizer u Patricia Chambers: Pulse, photos u Todd Featherston and Mike May: IT u Mike Connor: AM Session u Bruce Thompson: PM Chair u Sheila Tucker: Press liaison u Jennifer Hunt: Timekeeper u Jon Leatherbarrow: Video u Lawrence Hall of Science u All our speakers Meeting Credits

Choosing a Future Bay: The Long Term Fate of PCBs and Other Organics Jay Davis Ben Greenfield Jon Leatherbarrow Nicole David San Francisco Estuary Institute

One Box Mass Budgets OUTPUTS Outflow Burial Volatilization Degradation INPUTS Discharges Runoff Atmosphere Hotspot erosion

PCBs u Present concentrations about 10 times higher than threshold for concern u Slow decline in the Bay in last 20 years u New sources minimal – restricted in 1979 u Residual loading from watershed and atmosphere u Degradation is negligible u Associate with sediment particles u Somewhat volatile u One-box final report in press, multi-box draft by January 2004

Year % of present 25% of present 10% of present 0 kg Predicted Long Term Trends in PCB Mass (kg) with Varying Loads

Year % of present 25% of present 10% of present 20 kg 10 kg 0 kg Predicted Long Term Trends in PCB Mass (kg) with Varying Loads

PAHs u Present concentrations at threshold for concern u No clear trend in the Bay in last 20 years u Masses are large u Degradation is significant u Significant continuing inputs u Associate with sediment particles u Somewhat volatile u One-box final report in prep

Year % of present 0 kg 7500 kg kg Predicted Long Term Trends in PAH Mass (BBF, kg) with Varying Loads

Organochlorine Pesticides u Present concentrations at threshold for concern u Decline in the Bay in last 20 years u New sources minimal – cancelled in 1972 u Residual loading from watershed and atmosphere u Degradation is faster than PCBs u Associate with sediment particles u Somewhat volatile u One-box draft report out soon

Year % of present Predicted Long Term Trends in DDT Mass (kg) with Varying Loads 0 kg 20 kg 40 kg

PBDEs u Threshold for concern not well known u Concentrations exponentially increasing u Use is increasing u Loading up the “blenders” in the Bay and the watershed u Degradation probably minimal u Associate with sediment particles u Less volatile than PCBs u No full analysis yet

u PBDEs have NOT been thoroughly reviewed yet u Model can be used to get a preliminary peek at the how the Bay would generally respond to this TYPE of scenario Increasing Loading Scenario

Year Exponential IncreaseEI for 10 yr, then 40 kg/yrEI for 10 yr, then 0 kg/yr PBDE-like Loading Scenarios

Year EI for 10 yr, then 0 kg/yrEI for 20 yr, then 0 kg/yr PBDE-like Loading Scenarios

Next Steps for Modeling in the RMP u Contaminant Fate Workgroup meets tomorrow u Local scientists and invited members Joel Baker and Tom McKone u Multiple boxes

A Multi-box Model

Next Steps for Modeling in the RMP (cont) u Quantify uncertainty u Extend food web model u Better input data –Sediment dynamics –Degradation rates –Outflow –Average concentrations –Historic long term trends

Closing Remarks