Wednesday, 8 October 2008: 2:30 PM

George R. Brown Convention Center, 360C

Todd Luxton, National Risk Management and Research Laboratory, US EPA, ORD, 5995 Center Hill Ave, Cincinnati, OH 45224, Kirk Scheckel, US-EPA(Environ. Protection Agency), US EPA, 5995 Center Hill Avenue, Cincinnati, OH 45224-1702 and Robert Ford, US-EPA(Environ. Protection Agency), Kerr Environmental Res. Ctr., PO Box 1198, Ada, OK 74820

The speciation and mineralogy of sediments contaminated with arsenic at the ground water/surface water interface of the Ft. Devens Super Fund Site in Ft. Devens, MA were determined using X-ray absorption fine structure and X-ray diffraction spectroscopy. Speciation and mineralogical results indicate arsenic is predominately present in the reduced form of arsenite. Spatial patterns in the distribution and concentration of arsenic in the study location combined with major element ground water chemistry indicate discharge of contaminated ground water as the primary source for arsenic. Adsorption of arsenic onto ferrihydrite derived from the oxidation and precipitation of ferrous iron from groundwater, by dissolved oxygen the surface water column, appears to be the primary mechanism by which arsenic is sequestered. Reducing environments capable of iron reduction at the ground water/surface water interface indicate a potential instability of arsenic contaminated sediments over and extended time periods.

See more of: Oxyanions in Soil Environments: II
See more of: S02 Soil Chemistry

2008 Joint Annual Meeting (5-9 Oct. 2008): Field Evaluation of Arsenic Speciation in Sediments at the Ground Water/Surface Water Interface.

742-5 Field Evaluation of Arsenic Speciation in Sediments at the Ground Water/Surface Water Interface.