GEOC 197 |
| We evaluated the geochemical behavior of arsenic in soils from a contaminated terrain of 62.5 ha located at the geographical center of the city of Monterrey, Mexico, where a lead smelter operated for more than a hundred years. Soils in this area are alkaline, rich in calcium carbonate, and arsenic was identified as the most mobile trace element from the wastes dispersed by the smelter. The main results of the investigation lead to the successful clean-up of the terrain and its remediation for current urban land use. Surface soils in 462 points were sampled, together with 80 samples at 12 and 40 m depth, and 34 groundwater wells both inside and outside of the contaminated land. The following analyses were performed: pH, electrical conductivity, total carbonate, sulfate, and total and water-soluble trace elements (As, Ba, Ca, Cd, Cr, Cu, Ni, Pb, Fe, Zn). Additionally, selected samples were analyzed by X-ray diffraction, X-ray fluorescence, Scanning Electron Microscopy coupled with elemental analysis, and X-ray absorption spectroscopy. Natural attenuation processes of arsenic were identified related to the formation of chemical species where arsenic binds to cationic trace elements. |
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Speciation of Arsenic and Other Trace Elements in Soils and Sediments
8:35 AM-11:40 AM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 211, Oral
Division of Geochemistry |