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Gewählte Master / Diploma Thesis:

Sascha Mohnke (2014): Combined Chemical Immobilization and Subsequent Re-mobilization of Metallic Pollutants in Enhanced Phytoextraction.
Master / Diploma Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 116. UB BOKU obvsg FullText

Data Source: ZID Abstracts
To improve phytoremediation (PR) efficiency, two common approaches have evolved in science: soil amendments are either used to immobilize pollutants thus decreasing the uptake by plants or to increase the pollutant availability for phytoextraction crops. Based on the previous work of Iqbal et al. (2012), we combined these two PR strategies by using vermicompost (VC), lignite (Lig) and biochar (BC) as immobilization agent (with rates of 45 and 90 g kg-1) and elemental sulfur (S) as mobilization agent. In contrast to Iqbal et al. (2012), S was not applied with the immobilization agents but after several weeks. For testing this new method, we used a highly Zn, Cd and Pb contaminated Gleyic Fluvisol in an incubation experiment with two S rates (0.5 and 1.5 g kg-1) and a pot experiment with a S rate of 0.5 g kg-1 and Zea mays. Metal (Zn, Cd, Pb, Mn, Fe), phosphorus and S concentrations in the soil solution, CaCl2 extraction and plant tissues were assessed and scans of the root systems were conducted. During the immobilization, the application of VC, BC and Lig significantly reduced the CaCl2-extractable Zn and Cd concentrations in both experiments. When S was applied during the incubation experiment, CaCl2-extractable concentrations of Zn increased by 8 to 41 times, those of Cd by 6 to 14 times and pH decreased significantly. However, S oxidation and mobilization of metals in the pot experiment were very limited: only in one Lig treatment CaCl2 concentrations of Zn, Pb, Cd, Mn and sulfate increased significantly after S addition. The heterogeneous application of S in the pots, oxygen depletion due to root and microbial respiration and the use of organic amendments may have inhibited S oxidation. The highest total Zn and Cd contents in the shoots of maize were measured in the VC treatments increasing PR efficiency by 100 % for Zn and 400 % for Cd compared to the control. However, rather the provision of nutrients than the oxidation of S caused this increase.

Beurteilende(r): Wenzel Walter

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