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The South Bay Salt Pond Restoration Project and Bay Water Quality SFEI Letitia Grenier, Jay Davis, Robin Grossinger South Bay Salt Pond Restoration Largest tidal wetland restoration project ever on the west coast Comprises 16,500 acres of salt ponds 15,100 acres in South Bay 1,400 acres in Napa River watershed Map from SBSPRP web site South Bay Salt Pond Restoration Extensive geographic scope Encompasses much of South Bay shoreline Certain to have tremendous benefits Concern about water quality Marshes and Bay Strongly Linked water Restored Marsh sediment Bay food web Potential for regional impacts Project Objectives Mix of wetland habitats for wildlife Flood management Protect or improve water and sediment quality Public access and recreation Water Quality Concerns Increased mercury in the food web www.cargillsalt.com Endangered California Clapper Rail Methylmercury (MeHg) Toxic to animals, including humans Accumulates in food webs Already a problem in Bay food web Humans Wildlife USGS Human Health Screening Value Data from Greenfield et al. (2003) Effects become apparent from 0.5 – 0.8 ppm Data from Schwarzbach and Adelsbach (2003) Clapper Rail Population Trends See Pulse 2005 for data sources Increased Food Web Mercury? Wetlands Known to produce methylmercury New wetlands may produce more MeHg Regional effects on MeHg accumulation SBSP Restoration Project Could increase MeHg in food web Potentially as important as all current sources Water Quality Concerns Increased mercury in the food web Legacy sediment pollution New Almaden Quicksilver Mine Legacy Sediment Pollution Legacy pollutants in Bay marshes, salt ponds, and their food webs PCBs, DDT, Hg South Bay sources Historic mercury mining ― New Almaden Urban and industrial runoff More information is needed Concentrations 10 times greater than Bay average Runoff from New Almaden mining district Beutel and Abu Saba 2004 Water Quality Concerns Increased mercury in the food web Legacy sediment pollution Erosion and recirculation of polluted Bay sediment Accelerated Erosion Restoration will likely increase erosion of Bay and marsh sediments in some areas Increased tidal prism Sediment sink Buried sediments from the 1950s and 1960s that contain high contaminant concentrations could be eroded and relocated Lower South Bay Model Prediction San Pablo Bay Core Water Quality Concerns Increased mercury in the food web Legacy sediment pollution Erosion and recirculation of polluted Bay sediment Ongoing inputs of pollutants Ongoing Inputs Contaminants Legacy pollutants (Hg, PCBs, etc.) Chemicals in current use (PBDEs, pyrethroids) Combustion emissions (PAHs) Pathways Runoff from adjacent watersheds Direct atmospheric deposition PBDEs Highest concentration ever observed in biota Forster’s Tern egg Hayward shoreline Near Baumberg salt ponds Pyrethroids Use increasing in urban areas Highly toxic to fish and aquatic arthropods Could cause breakdown of food web as prey species are affected How to Address Concerns Proceed with restoration Adaptive management Sound science Reduce risk © C. Benton 2004 Key Recommendations Hg monitoring and research should be an on-going component of the SBSPRP Hg poses the greatest contaminant threat to achieving project goals Coordination with other research and monitoring projects (RMP, CBDA) Further Information SBSP Restoration Project http://www.southbayrestoration.org/ Article in Pulse of the Estuary 2005 (p.72) Davis et al. 2003. San Francisco Estuary and Watershed Science: Volume 1, Article 4. For a longer paper on this topic written for the SBSPRP, contact me: [email protected] © C. Benton 2004 © C. Benton 2004