Arsenic speciation in Soil and Sediment Myron Georgiadis Florida International University TAG Meeting January 10, 2003

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.

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.

Arsenic Concentration vs Time - Conversion of As(III) to As(V). - Reabsorption back into soil.

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

Potential Effect of Fe and Mn

Extraction with EDTA

Use of Hydroxylamine

As(III)

Complexing Reagents Sodium diethyldithiocarbamate trihydrate (NaDDC) Ammonium pyrrolidine dithiocarbamate (APDC)

Arsenic Concentrations in Marine Organisms Attached to CCA-treated Wood

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

As Speciation: standards 10 ppb standards AsB; 2. As(III); 3. DMA; 4. MMA; 5. As(V)

As speciation: Hydriods on Concrete Pilings AsB Unknown 1 AsC As(III) DMA Unknown 2 Unknown 3 or MMA As(V)

As speciation: Barnacle on OLD RSMAS Pier AsC As(III) DMA Unknown 2 Unknown 3 or MMA As(V) AsB Unknown 1 AsC As(III) Unknown 2 Unknown 4 As(V)

Acknowledgements Dr. Helena Solo-Gabriele Dr. Pat Walsh Dr. Greg Mayer Dr. John Barimo Ms. Zhangrong Chen Mr. Myron Georgiadis