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Spatial patterns in forage fish Hg: 2008 update. Ben Greenfield & Katie Harrold, SFEI Darell Slotton & Shaun Ayers, UC Davis. San Francisco Mercury Coordination Meeting February 5, 2009. RMP Mercury Strategy Questions. Where is mercury entering the Bay food web?
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Spatial patterns in forage fish Hg:2008 update Ben Greenfield & Katie Harrold, SFEI Darell Slotton & Shaun Ayers, UC Davis San Francisco Mercury Coordination Meeting February 5, 2009
RMP Mercury Strategy Questions • Where is mercury entering the Bay food web? • What processes, sources, and pathways contribute disproportionately to food web accumulation? Draft Data Do Not Cite
General approach Spatial analysis Stratified random design Identify hotspots based on conceptual model Seasonal trend evaluation Interannual trend detection Field sampling for Hg isotopes and for DGT study Draft Data Do Not Cite
Spatial survey: stratified random design • Probabilistic sampling of entire bay shoreline • Enclosed sites • Open-water sites • Potential Hg source sites • Wetlands • High elevation (high methylation) • Low elevation (low methylation) • Selected to correspond with other sampling in 2008 Draft Data Do Not Cite
Design – Source Site Selection • Mining sources • Creeks draining probable source mines • WWTP shallow water discharges • Creeks draining urban/industrial areas • High sediment Hg or MeHg Draft Data Do Not Cite
2008 Fish Sites Long term site Draft Data Do Not Cite
Previous data (2005 – 2007) Hg (ug/g) Draft Data Do Not Cite
Organized by species/habitat Bay margins Hg (ug/g) Open waters Draft Data Do Not Cite
Silverside Means of Comps ± SE Draft Data Do Not Cite
300 South Bay 280 Silverside Hg (mean SE) 260 240 220 200 San Pablo Bay Suisun Bay Central SF Bay 180 160 Hg (ng/g wet weight, whole body) 140 120 100 80 60 40 20 0 29BIR KIRKE ALVSL 4ALVS CHINA 06OTH 04OTH 66OTH 64OTH 62OTH 93OTH 01OTH 05OTH 03OTH COYSL EDENL 306WE BENPK NEWSL 18PAB-A WWTP-2 WWTP-3 Draft Data Do Not Cite
300 South Bay 280 Silverside Hg (mean SE) 260 Silverside Hg ( ± of Composites 240 ) SE 220 200 San Pablo Bay Suisun Bay Central SF Bay 180 160 Hg (ng/g wet weight, whole body) 140 120 100 80 60 40 20 0 29BIR KIRKE ALVSL 4ALVS CHINA 06OTH 04OTH 66OTH 64OTH 62OTH 93OTH 01OTH 05OTH 03OTH COYSL EDENL 306WE BENPK NEWSL 18PAB-A WWTP-2 WWTP-3 Not enclosed Enclosed Draft Data Do Not Cite
300 South Bay 280 Silverside Hg (mean SE) 260 240 220 San Pablo Bay Suisun Bay 200 Central SF Bay 180 160 Hg (ng/g wet weight, whole body) 140 120 100 80 60 40 20 0 29BIR KIRKE ALVSL 4ALVS CHINA 06OTH 04OTH 66OTH 64OTH 62OTH 93OTH 01OTH 05OTH 03OTH COYSL EDENL 306WE BENPK NEWSL 18PAB-A WWTP-2 WWTP-3 Wetland sites Draft Data Do Not Cite
300 South Bay 280 Silverside Hg (mean SE) 260 Silverside Hg ( ± of Composites 240 ) SE 220 200 San Pablo Bay Suisun Bay Central SF Bay 180 160 Hg (ng/g wet weight, whole body) 140 120 100 80 60 40 20 0 29BIR KIRKE ALVSL 4ALVS CHINA 06OTH 04OTH 66OTH 64OTH 62OTH 93OTH 01OTH 05OTH 03OTH COYSL EDENL 306WE BENPK NEWSL 18PAB-A WWTP-2 WWTP-3 Hg contaminated sediment Industrial watershed WWTP Draft Data Do Not Cite
Means of Comps ± SE (WWTP) Hg Mine (New Almaden) WWTP Silverside Draft Data Do Not Cite
Means of Comps ± SE (WWTP) Hg Mine (New Almaden) WWTP Silverside Draft Data Do Not Cite
Means of Comps ± SE (WWTP) Hg Mine (New Almaden) WWTP Silverside Draft Data Do Not Cite
Silverside Means of Comps ± SE WWTP Legacy, Industrial Legacy, Industrial WWTP Draft Data Do Not Cite
Prickly Sculpin Calif. Roach Golden Shiner Silverside Topsmelt Mosquitofish Means of Comps ± SE Hg mine (Bella Oaks) Napa river WWTP Hg Mine Legacy, Industrial Legacy, Industrial WWTP Draft Data Do Not Cite
Prickly Sculpin Regional Mercury Merced River Sac R. RM44 Clear Creek Tuolumne River Sac R. Hamilton City Draft Data Do Not Cite
Prickly Sculpin Regional Mercury Hg mine (Bella Oaks) Napa river Merced River Sac R. RM44 Clear Creek Tuolumne River Sac R. Hamilton City Draft Data Do Not Cite
Means of Comps ± SE Topsmelt Draft Data Do Not Cite
200 180 160 0.78 y = 1.43x 140 2 R = 0.67 120 Topsmelt Hg (ppb ww) 100 80 60 40 20 0 0 50 100 150 200 250 300 Silverside Hg (ppb ww) Draft Data Do Not Cite
300 280 Topsmelt Hg (mean SE) 260 Topsmelt Hg South Bay 240 Mean of ( 220 San Pablo Bay 200 Suisun Bay 180 Central SF Bay 160 Hg (ng/g wet weight, whole body) 140 120 100 80 60 40 20 0 29BIR KIRKE 4ALVS ALVSL CHINA 66OTH 62OTH 93OTH 06OTH 04OTH 64OTH COYSL 05OTH 01OTH 03OTH BENPK EDENL 306WE NEWSL 18PAB-A WWTP-2 WWTP-3 Draft Data Do Not Cite
Topsmelt Means of Comps ± SE Hg Mine (New Almaden) Draft Data Do Not Cite
Preliminary findings 2008 • Where is mercury entering the Bay food web? • A regional gradient • What processes, sources, and pathways contribute disproportionately to food web accumulation? • No evidence of wetlands • No evidence of industrial watersheds • Wastewater treatment plants apparent reduction • Evidence of mining Hg source signal Draft Data Do Not Cite
Next steps • Analyze data length corrected • Analyze with model including spatial covariance • Continue probabilistic study design in 2009 and 2010 Draft Data Do Not Cite
2009 Fish Sites Long term site Draft Data Do Not Cite