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Contaminants at the Estuary Interface. Jon Leatherbarrow 1 Rainer Hoenicke 2 Lester McKee 1 1 San Francisco Estuary Institute 2 California Resources Agency. Estuary Interface Pilot Study History. EIP study 1996-1999
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Contaminants at the Estuary Interface Jon Leatherbarrow1 Rainer Hoenicke2 Lester McKee1 1San Francisco Estuary Institute 2California Resources Agency
Estuary Interface Pilot Study History • EIP study 1996-1999 initiated with the goal of describing how surface runoff from local watersheds might influence water quality in the Bay. • Final report – Available soon
Objectives • Relate patterns of contamination near the bottom of the watersheds to patterns in the receiving waters of the Lower South Bay • Explore what kinds of water quality parameters and watershed characteristics should be measured or described to improve tributary monitoring methodology
Sampling Design • Water - three samples per year • Sediment - two samples per year Parameters • Trace Elements • Organics – PCBs, PAHs, Pesticides • Water and sediment quality parameters
Conclusions • Concentrations of PCBs, PAHs, mercury, selenium, DDTs, and chlordanes were high in water and/or sediment collected from one or both of the EIP stations relative to several other Bay segments. • High wet-season concentrations in EIP water samples suggest that the tributaries were a likely pathway for all of these contaminants to the Lower South Bay. • Mercury concentrations in Guadalupe River (BW15) water and sediment were most likely influenced by the historic mining activities in the New Almaden district. • Several independent factors, such as TSS in the water column and grain size effects in sediment, account to some extent for variability in contaminant concentrations.
RMP Five-Year Review • New RMP Objective “Describe general sources and loadings of contamination to the Estuary” • RMP Sources Pathways and Loadings Workgroup
Further Questions • How do contaminant concentrations vary during conditions of peak streamflow and sediment transport? • What is the magnitude of contaminant loading from the local watersheds? • How does loading from the tributaries compare to other pathways of contamination? • What are the specific sources of contamination in the local watersheds? • What are the most effective management actions?
Next Steps • Develop network of tributary monitoring locations in the fresh water reaches of selected watersheds. • Prioritize locations based on conceptual models, recent and historic contaminant data, and watershed characteristics. • Design monitoring to capture contaminant response to peak flow and sediment transport and quantify loading from the watersheds. • Explore and develop indicators for determining sources and temporal trends in contaminant concentrations and loading. • Compare watershed loading with other pathways of contamination in the context of refined mass budgets for contaminants of concern.
Acknowledgments • City of San Jose and Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP) • RMP Principal Investigators and Contractors Applied Marine Sciences Brooks Rand Laboratories City and County of San Francisco East Bay MUD Texas A&M – Geochem. and Environ. Research Group UC Santa Cruz – Dept. of Environmental Toxicology University of Utah – Energy and Geoscience Institute • Jay Davis, Don Yee, and members of the RMP Sources, Pathways, and Loadings Workgroup • All reviewers of the EIP Study report