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Mercury Monitoring and Assessment in the South Baylands. Letitia Grenier, Joshua Collins, Jay Davis — SFEI Mark Marvin-DiPasquale — USGS David Drury — Santa Clara Valley Water District. Peter LaTourette. South Bay Salt Pond Restoration Hg Monitoring. Goals
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Mercury Monitoring and Assessment in the South Baylands Letitia Grenier, Joshua Collins, Jay Davis — SFEI Mark Marvin-DiPasquale — USGS David Drury — Santa Clara Valley Water District
Peter LaTourette South Bay Salt Pond Restoration Hg Monitoring • Goals • Identify areas where Hg is a problem or may become one for the South Bay Salt Pond Restoration Project • Study how Hg processes differ between problem areas and non-problem areas • Collaborative Project • SFEI – Letitia Grenier, Josh Collins, Jay Davis • USGS Menlo Park – Mark Marvin DiPasquale • SCVWD – Dave Drury
Sentinel Species Approach • Direct measurement of Hg problem • Methylmercury • Food web wildlife, people • Integrate over appropriate spatial and temporal scales • Measure the spatial and temporal variation of interest (not very fine-scale variation) • Link to water/sediment to understand processes
Sentinel Species Hg Monitoring • Habitat based • One sentinel species per habitat • Year-round residents • Small home range • Abundant and important role in food web • Spatially associated with abiotic measurements • Water and sediment measurements spatially mapped onto sentinel species sampling plan
Habitat-specific Sentinel Species Grenier 2004
Sentinel Species Monitoring Tidal Marsh Salt Pond
Geographically broad sampling to place each restoration site in context. Need to monitor and assess Baylands, not just salt ponds.
Results • Identify problem areas by geography • e.g., Hg is a greater problem in the Alviso area than near the Island Ponds • Identify problem areas by habitat • e.g., biota in tidal marsh pannes have higher Hg than in managed ponds • implications for restoration design • Increase understanding of Hg processes • e.g., higher Hg in biota is associated with habitats that undergo many wetting/drying cycles
Phased Approach • Phase 1 • Develop sentinel species indicators of Hg exposure; • Map the legacy Hg in Alviso Slough that might be mobilized by breaching Pond A8 (coring); • Use sentinel species coupled with water and sediment sampling to assess the mercury problem for dominant specific habitat types associated with Pond A8 and Alviso Slough; • Establish a baseline for tracking the effects of management actions on the Hg problem into the future.
Scott Haefner Scott Haefner Phased Approach • Phase 2 • Expand the survey of the mercury using the sentinel species to encompass more of the South Baylands; • Provide a picture of the spatial variability in mercury problem within and between bayland habitats throughout the South Bay.
Phased Approach • Phase 3 • Initiate focused research to better understand the linkages between Hg contamination in sentinel species and bio-geochemical indicators for specific habitat types in selected areas, based upon the results of Phase 2; • Help translate the scientific understanding of the Hg problem into habitat designs and management options that minimize the problem.
Timeline (Phase 1) • Fieldwork: May-Oct 2006 • Lab turn-around time: 3-6 months • Preliminary results: Early 2007 Gillichthys mirabilis Grenier 2001
Acknowledgements • Funding Sources • Santa Clara Valley Water District • State Coastal Commission • San Francisco Foundation Bay Fund • Regional Monitoring Program for Trace Substances • SBSP Project Management Team and Science Teams