GEOC 6 |
| Gunnar H. Meyenburg, Section Land use, soil protection, soil analysis, Federal Institute for Geosciences and Natural Resources, Stilleweg 2, 30655 Hannover, Germany and Heinz-Ulrich Neue, Department of Soil Sciences, UFZ-Center for Environmental Research, Theodor-Lieser Strasse 4, 06120 Halle, Germany. |
| Reoxidative alterations of fractions of Fe (hydr)oxides and associated Zn, Pb, As, and P in selected wetland soils were monitored in an aging experiment for 7 months by the use of common extraction procedures. Reoxidation of sulfidic Fe and transformation of Fe (hydr)oxides from mineral phases of lower crystallinity to those of higher crystallinity occurs within relatively short periods. The intensity of these alterations is high in the initial phase of reoxidation, followed by rather uniform changes at aging times > 1-3 mo, depending on pH and organic matter content. The fractionation patterns of Zn and Pb differ markedly from that of As and P, the latter being rather similar. Depending on pH and organic matter content, a shift between fractions for all elements occurs with increasing reoxidation time. With the exception of Pb, a simultaneous transformation to both, more labile fractions and fractions of higher crystallinity of Fe (hydr)oxides was observed. Though alterations of the binding form of Pb occur, it remains rather mobile. Organic matter is more important for binding Pb than for Zn and As. Alterations were related to transformations of Fe (hydr)oxide fractions. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
8:00 AM-11:25 AM, Sunday, March 28, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |