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: letitia@sfei.orgletitia@sfei.org

© C. Benton 2004

© C. Benton 2004