CEPRMP Sediment Coring Study Update

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CEP/RMP Sediment Coring Study Update

• RMP CFWG, May 2007

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Objectives (this Study)

• Better constrain future loads from eroding buried
  contaminants
• Estimate historic loadings of contaminants
  (especially recent decades)
• Characterize contamination with depth to assess
  current status and likely future changes
• Provide data for parameterization and/or
  evaluation of the multi-box model

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Core Sampling Strategy

• 17 Cores budgeted
• Hybrid (random deterministic)
• 6 samples specifically to understand loading
  history (wetland deposition zones)
• 11 sites to begin representative characterization
  of Bay sediments
• Bay sites vibracore manual push core, wetlands
  manually cored (Livingstone)

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Distribution of Sites

• 3 sites Central Bay, 2 sites each other segments
• Preference to RMP repeat stations
• CB001S, CB002S, CB006S,
• LSB001S, LSB002S,
• SB001S, SB002S,
• SPB001S, SPB002S,
• SU001S, SU002S

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Analyses to date

• 10 sections/core for 1 core per segment
• Sections from 30 60cm in other core each segment

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Results Suisun

• Eroded? no Cs or Pb profile

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Results San Pablo

• Eroding? Pb and Cs max at top 10cm

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Results Central

• Cs and Pb well mixed top 5-10cm
• Pb 4x diff (40 yrs) in 30cm, Cs 0 gt40cm

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Results South

• DepositionErosion? Well mixed top 10cm
• Pb 4x in 20cm, CS 0 gt20cm
• Pb decay and Cs surface max disagree?

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Results Lower South

• Deposition? Pb Cs well mixed top 10cm
• Pb 4x decrease 30cm, Cs subsurface mixed

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Summary

• Lead and cesium signals more or less agree for
  most sites so far
• 40-60 years 30 cm horizon
• Top layers highest in Cs many sites
• Expect 1960s highest, surface max static or
  eroded Bay surface at these sites
• Redistributed Cs from eroding sites?

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