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The South Bay Salt The South Bay Salt Pond Restoration Pond Restoration Project and Bay Project and Bay Water QualityWater QualitySFEISFEI
Letitia Grenier, Jay Davis, Robin Letitia Grenier, Jay Davis, Robin GrossingerGrossinger
South Bay Salt Pond South Bay Salt Pond RestorationRestoration
Largest tidal wetland restoration Largest tidal wetland restoration project ever on the west coastproject ever on the west coast
Comprises 16,500 acres of salt pondsComprises 16,500 acres of salt ponds 15,100 acres in South Bay15,100 acres in South Bay 1,400 acres in Napa River watershed1,400 acres in Napa River watershed
Map from SBSPRP web site
South Bay Salt Pond South Bay Salt Pond RestorationRestoration
Extensive geographic scopeExtensive geographic scope
Encompasses much of South Bay Encompasses much of South Bay shorelineshoreline
Certain to have tremendous benefitsCertain to have tremendous benefits
Concern about water qualityConcern about water quality
Marshes and Bay Strongly Marshes and Bay Strongly LinkedLinked
RestoredMarsh
Bay sediment
food web
water
Potential for regional impactsPotential for regional impacts
Project ObjectivesProject Objectives
Mix of wetland habitats for wildlifeMix of wetland habitats for wildlife
Flood managementFlood management
Protect or improve water and Protect or improve water and sediment qualitysediment quality
Public access and recreationPublic access and recreation
Water Quality ConcernsWater Quality Concerns
Increased mercury in the food webIncreased mercury in the food web
www.cargillsalt.com
Endangered California Clapper Rail
Methylmercury (MeHg)Methylmercury (MeHg)
Toxic to animals, including humansToxic to animals, including humans
Accumulates in food websAccumulates in food webs
Already a problem in Bay food webAlready a problem in Bay food web HumansHumans WildlifeWildlife
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)
See Pulse 2005 for data sources
Clapper Rail Population Trends
Increased Food Web Increased Food Web Mercury?Mercury?
WetlandsWetlands Known to produce methylmercuryKnown to produce methylmercury New wetlands may produce more MeHgNew wetlands may produce more MeHg Regional effects on MeHg accumulationRegional effects on MeHg accumulation
SBSP Restoration ProjectSBSP Restoration Project Could increase MeHg in food webCould increase MeHg in food web Potentially as important as all current Potentially as important as all current
sourcessources
Water Quality ConcernsWater Quality Concerns
Increased mercury in the food webIncreased mercury in the food web
Legacy sediment pollutionLegacy sediment pollutionNew Almaden Quicksilver Mine
Legacy Sediment PollutionLegacy Sediment Pollution
Legacy pollutants in Bay marshes, Legacy pollutants in Bay marshes, salt ponds, and their food webssalt ponds, and their food webs PCBs, DDT, HgPCBs, DDT, Hg
South Bay sourcesSouth Bay sources Historic mercury mining ― New AlmadenHistoric mercury mining ― New Almaden Urban and industrial runoffUrban and industrial runoff
More information is needed More information is needed
Concentrations 10 times greater than Bay averageRunoff from New Almaden mining district
Beutel and Abu Saba 2004
Water Quality ConcernsWater Quality Concerns
Increased mercury in the food webIncreased mercury in the food web
Legacy sediment pollutionLegacy sediment pollution
Erosion and recirculation of polluted Erosion and recirculation of polluted Bay sedimentBay sediment
Accelerated ErosionAccelerated Erosion
Restoration will likely increase Restoration will likely increase erosion of Bay and marsh sediments erosion of Bay and marsh sediments in some areas in some areas Increased tidal prismIncreased tidal prism Sediment sinkSediment sink
Buried sediments from the 1950s Buried sediments from the 1950s and 1960s that contain high and 1960s that contain high contaminant concentrations could be contaminant concentrations could be eroded and relocatederoded and relocated
San Pablo Bay Core
Lower South Bay Model Prediction
San Pablo Bay
Model Prediction
Water Quality ConcernsWater Quality Concerns
Increased mercury in the food webIncreased mercury in the food web
Legacy sediment pollutionLegacy sediment pollution
Erosion and recirculation of polluted Erosion and recirculation of polluted Bay sedimentBay sediment
Ongoing inputs of pollutantsOngoing inputs of pollutants
Ongoing InputsOngoing Inputs
ContaminantsContaminants Legacy pollutants (Hg, PCBs, etc.)Legacy pollutants (Hg, PCBs, etc.) Chemicals in current use (PBDEs, Chemicals in current use (PBDEs,
pyrethroids)pyrethroids) Combustion emissions (PAHs)Combustion emissions (PAHs)
PathwaysPathways Runoff from adjacent watershedsRunoff from adjacent watersheds Direct atmospheric depositionDirect atmospheric deposition
PBDEsPBDEs
Highest concentration ever observed in Highest concentration ever observed in biotabiota Forster’s Tern eggForster’s Tern egg
Hayward shorelineHayward shoreline
Near Baumberg Near Baumberg salt pondssalt ponds
PyrethroidsPyrethroids
Use increasing in urban areasUse increasing in urban areas
Highly toxic to fish and aquatic Highly toxic to fish and aquatic arthropodsarthropods
Could cause breakdown of food web Could cause breakdown of food web as prey species are affectedas prey species are affected
How to Address How to Address ConcernsConcerns
Proceed with restorationProceed with restoration
Adaptive managementAdaptive management Sound scienceSound science Reduce riskReduce risk
© C. Benton 2004
Key RecommendationsKey Recommendations
Hg monitoring and research should Hg monitoring and research should be an on-going component of the be an on-going component of the SBSPRPSBSPRP
Hg poses the greatest contaminant Hg poses the greatest contaminant threat to achieving project goals threat to achieving project goals
Coordination with other research and Coordination with other research and monitoring projects (RMP, CBDA)monitoring projects (RMP, CBDA)
Further InformationFurther Information SBSP Restoration Project SBSP Restoration Project
http://www.southbayrestoration.org/http://www.southbayrestoration.org/
Article in Article in Pulse of the Estuary 2005 Pulse of the Estuary 2005 (p.72)(p.72)
Davis et al. 2003. San Francisco Estuary and Davis et al. 2003. San Francisco Estuary and Watershed Science: Volume 1, Article 4.Watershed Science: Volume 1, Article 4.
For a longer paper on this topic written for For a longer paper on this topic written for the SBSPRP, contact me: the SBSPRP, contact me: [email protected]@sfei.org
© C. Benton 2004
© C. Benton 2004