COLL 593 |
| At a military installation in Oklahoma, elevated chromium concentrations were found in monitoring wells located away from obvious industrial sources. Two reports, contracted from an environmental firm, indicate that chromium is present in suspended particles found in the well water. Adsorption of chromium onto these particles from external sources were ruled out. To identify the source, well water was collected from 12 monitoring wells with and without chromium contamination. The suspended particles were separated from the water by submicron filtration. The particles were studied using X-ray photoelectron spectroscopy, X-ray powder diffraction spectroscopy and atomic absorption spectroscopy. The elemental composition of these particles are inconstant with that expected if the source was from bio-well corrosion of the well head. In addition, inspection of the dedicated well pumps indicates little corrosion. Although X-ray photoelectron spectroscopy found CrVI on the surfaces of these particles, the bulk of the chromium is CrIII and is primarily located within the particles. X-ray diffraction measurements indicate the presence of goethite, an iron oxide hydroxide. The most probable explanation for the observed chromium is the dissolution of the clay soil to form the observed goethite. In Oklahoma, the soil is known to contain chromium which is expected to be concentrated in the goethite particles by the dissolution process. Analysis of the core soil obtained from four drill sites also contains trace amounts of naturally occurring chromium. |
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Surface Chemistry Symposium in Honor of Gabor Somorjai
2:00 PM-5:20 PM, Thursday, 14 September 2006 Sir Francis Drake -- Franciscan Room, Oral
Division of Colloid & Surface Chemistry |