Comparative Analysis of Loads of Mercury in Coyote Creek and Guadalupe River

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Comparative Analysis of Loads of Mercury in
Coyote Creek and Guadalupe River

• Lester McKee
• RMP SPLWG Chair
• San Francisco Estuary Institute
• lester_at_sfei.org

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Acknowledgements and Data Sources

• Coyote Creek
• USGS discharge
• WY 1999 2006 (ongoing)
• USGS suspended sediment
• WY 2005
• WY 2006
• Regional Board TMDL laboratory funding (10k)
• WY 2005 PCB, PBDE, HgT, SSC, organic carbon
• Data
• SFEI field team able to grab 7 samples during
  wading stage only during breaks from Guadalupe R.
  sampling

• Guadalupe River
• USGS discharge
• WY 1929 2006 (ongoing)
• USGS/SFEI suspended sediment
• WY 2003 2006 (ongoing)
• Funding
• WY 2003 CEP
• WY 2004 CEP / RMP
• WY 2005 RMP / SCVWD / USACE / SCVURPPP
• Data
• HgT, HgD, MeHgT, MeHgD, Bedload HgT

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Land Use Comparisons
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Field Locations
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Methods
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Results Coyote Creek
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Total Mercury v Suspended Sediment(All data)
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Total Mercury v Suspended Sediment(Runoff from
Upper and Lower Watershed)
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Loads Calculation Methods(WY 2005)

• USGS 15 minute discharge
• USGS 15 minute SSC estimates from GCLASS based on
  rating relationships between flow and about 100
  real measurements of SSC
• Regression between instantaneous SSC and Total
  Mercury concentrations
• All data
• Separate regressions for water derived from Lower
  and Upper watershed

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Maximum Daily and Flood Loads
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Why so little during the largest flood?
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Results Monthly Loads
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Estimated Average - Methods
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Estimated Average Coyote Loads

• Using the range in flow experienced from WY 1971
  to WY 2006 we estimate the following

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Coyote Creek versus Guadalupe River
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Particle ConcentrationsCoyote Ck, Guadalupe R.
and Sacramento R.
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Applicable Management Questions

• B. Loads of mercury and methylmercury
• Are current estimates about loading to San
  Francisco Bay from watersheds, wastewater
  treatment facilities, and atmosphere valid?
• What is the contribution of atmospheric
  deposition to urban storm water?

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Applicable Management Questions

• C. Processes of mercury methylation
• What is the relative bioavailability of mercury
  entering the Bay from various loading sources
  (e.g., wastewater treatment facilities,
  atmosphere, urban runoff, tributaries, newly
  eroded historic sediments, etc)?

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Applicable Management Questions

• D. Given what we currently understand about
  processes, loads, and impacts (Sections A, B, and
  C), what are the management implications?
• Given that rivers, creeks, and storm drains
  discharge methyl mercury, what can be done to
  manage production in the watershed and urban
  environments, and to manage downstream impacts as
  it passes through wetlands to the Bay margin and
  Bay?