Mercury in the Delta Where does it come from and what can we do - - PowerPoint PPT Presentation

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Mercury in the Delta Where does it come from and what can we do - - PowerPoint PPT Presentation

Jan 27, 2023 567 likes •803 views

Mercury in the Delta Where does it come from and what can we do about it? Laura McLellan , Environmental Scientist, Central Valley Water Board Laura.McLellan@waterboards.ca.gov; 916-464-4646 Janis Cooke , Environmental Scientist, Central Valley

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Mercury in the Delta

Where does it come from and what can we do about it?

Laura McLellan, Environmental Scientist, Central Valley Water Board Laura.McLellan@waterboards.ca.gov; 916-464-4646 Janis Cooke, Environmental Scientist, Central Valley Water Board Janis.Cooke@waterboards.ca.gov; 916-464-4672

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Outline

  • What is mercury?
  • Where does it come from?
  • What can we do to clean it up in the Delta?

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Mercury (Hg)

http://spock.fcs.uga.edu/ext/housing/images/mercury2.jpg

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Where mercury comes from

http://bellona.org/assets/sites/6/Coal-Fired-Power-Plant.jpg Oakland Museum of California

Atmosphere Mercury-rich soils Legacy mining

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Source: USGS Fact Sheet 2005-3014

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21 April 2009 Delta Mercury Control Program Stakeholder Meeting Slide 6

bacterial methylation

Hg MeHg

Methylmercury (MeHg)

MeHg

  • Byproduct of the metabolism of sulfate- and iron-

reducing bacteria

  • Typically produced in sediment

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  • Reduce inorganic Hg in Delta sediment
  • Control activities that affect MeHg production and loss

In other words, How can we reduce MeHg in Delta fish & waters?

What can we do to clean up mercury in the Delta?

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Reducing inorganic mercury in sediment

In-Delta Sources (~3%):

  • Wastewater treatment

plants

  • Atmospheric deposition
  • Urban runoff

Watershed Sources (~97%):

  • Wastewater treatment

plants

  • Atmospheric deposition
  • Urban runoff
  • Historic mining activities
  • Naturally mercury-

enriched soils

  • Geothermal springs

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Upstream Mercury Control Programs are being developed

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Cache Creek Settling Basin in Yolo Bypass

  • A source and solution to mercury inputs

Image: Dept. Water Resources

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In other words, How can we reduce MeHg in Delta fish & waters?

  • Reduce inorganic Hg in Delta sediment
  • Control activities that affect MeHg production and loss

What can we do to clean up mercury in the Delta?

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Tributary Inputs

Urban

Open Water Wetlands

Wastewater

Ag

Control activities that enhance methylmercury production and loss

Methylmercury Sources to the Delta

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Managed Wetlands

  • Polishing pond pilot

test

  • Vegetation removal

(baling, disking, grazing)

Test wetland

Graphic credit : USGS

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Tributary Inputs

Urban

Open Water Wetlands

Wastewater

Ag

Methylmercury Sources to the Delta

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Multi- Layered System

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Layer 1: Tributary Watersheds to the Delta

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Layer 2: Wetlands and Open Water

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Layer 3: Wastewater Treatment plants

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Layer 4: Agricultural Areas

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Layer 5: Urban Areas in the Delta Region

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Layer 6: It is dynamic!

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Video provided by Moss Landing Marine Laboratories

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Thank you. Questions?

Laura McLellan, Environmental Scientist, Central Valley Water Board Laura.McLellan@waterboards.ca.gov; 916-464-4646 Janis Cooke, Environmental Scientist, Central Valley Water Board Janis.Cooke@waterboards.ca.gov; 916-464-4672