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Arsenic speciation in Soil and Sediment

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Arsenic speciation in Soil and Sediment Myron Georgiadis Florida International University TAG Meeting January 10, 2003 Backgrounds Leaching occurs from CCA-Treated ... – PowerPoint PPT presentation

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Title: Arsenic speciation in Soil and Sediment


1
Arsenic speciation in Soil and Sediment
  • Myron Georgiadis

Florida International University TAG Meeting
January 10, 2003
2
Backgrounds
  • Leaching occurs from CCA-Treated Wood into soil
    and sediments
  • Traditional methods for arsenic analysis in soil
    - Digestion
  • Develop an extraction method for Arsenic in soils
    and sediments while preserving the species.

3
Method Development
  • Reference Soil PACS2
  • PACS2 Marine Sediment Reference Material from
    National Research Council Canada
  • Extraction Solution pH, Buffer Capacity,
    Chemical Interactions
  • PACS2 was extracted with a phosphate buffer.
  • Analyzed by HPLC-HG-AFS.

4
Arsenic Concentration vs Time
- Conversion of As(III) to As(V). -
Reabsorption back into soil.
5
Approaches
  • Potential Effect of Fe and Mn
  • Extract with EDTA to remove metals from solution
    which may aid in the interconversion
  • Provide a reducing environment using
    hydroxylamine
  • Use of Complexing Reagent NaDDC and APDC

6
Potential Effect of Fe and Mn
7
Extraction with EDTA
8
Use of Hydroxylamine
9
Use of Hydroxylamine
As(III)
10
Complexing Reagents
  • Sodium diethyldithiocarbamate trihydrate (NaDDC)
  • Ammonium pyrrolidine dithiocarbamate (APDC)

11
Arsenic Concentrations in Marine Organisms
Attached to CCA-treated Wood
12
  • Organisms analyzed soft coral, hydroids, crabs,
    barnacles, orange sponge, yellow sponge, black
    sponge, oyster, tube worm, amphipods, starfish,
    unknown invertebrate (black outer layer, soft
    inner)
  • Hydroids and amphipods showed elevated arsenic
    concentration for those collected from on
    CCA-wood

13
As Speciation standards
1. AsB 2. As(III) 3. DMA 4. MMA 5. As(V)
14
As speciation Hydriods on Concrete Pilings
Unknown 1
AsB
Unknown 3 or MMA
Unknown 2
AsC
As(V)
As(III)
DMA
15
As speciation Barnacle on OLD RSMAS Pier
AsB
Unknown 1
Unknown 3 or MMA
Unknown 2
AsC
Unknown 2
AsC
As(V)
As(V)
As(III)
Unknown 4
As(III)
DMA
16
Acknowledgements
  • Dr. Helena Solo-Gabriele
  • Dr. Pat Walsh
  • Dr. Greg Mayer
  • Dr. John Barimo
  • Ms. Zhangrong Chen
  • Mr. Myron Georgiadis
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