Effects of soil organic matter molecular conformation and substrate additions on the formation and release of xenobiotics bound residues
Zusammenfassung der Projektergebnisse
The results have shown that the treatment of peat or soil with polyvalent cations increases its sorptive properties for the hydrophobic organic compound nonylphenol. The effects of the Na-treatment are less pronounced, but generally decrease the sorption of NP. From our first experiments with phenanthrene, this seems to be also true for this compound. At the same time, the analyses of contact angles and glass transition temperatures by the cooperating groups Bachmann and Schaumann confirm the hypothesis that the observed changes in sorption properties are accompanied and most likely caused by changes in SOM rigidity and hydrophobicity. The unexpected result of higher sorption-desorption hysteresis in the Na-treated soil does not agree with our hypothesis of less restricted diffusion in SOM matrices that lack cross-linking from polyvalent cations. But this only shows, that our model concepts may be too simplistic or that the Na-treatment only modified the surfaces of SOM and not the interior. Degradation of NP in the soils was initially not affected by the cation treatments. But the stimulation of NP mineralization by glucose and wood flour showed that degradation activity is partially limited by substrates and not only by the inaccessibility of the compounds. However, the wood flour induced stimulation of NP-mineralization was lowest in the Ca- and Al-treated soils, indicating that here degradation rate is diffusion limited due to slower release from the more rigid SOM matrix. Overall, this study has greatly profited from the close cooperations with the groups of Bachmann and Schaumann who have provided important data for the characterization of our treated peat and soil samples. The results from our joint storage experiment show that even short-term effects of temperature, storage time and cation treatment affect SOM structures and properties. We therefore expect that our ongoing long-term aging experiment with the treated Lakwiese soil spiked with 14C-NP or Phe will produce even more pronounced effects. This too will be accompanied by investigations of our cooperating partners.
Projektbezogene Publikationen (Auswahl)
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(2007): Effects of soil organic matter conformation and of substrate additions on the formation and release of bound residues. Jahrestagung der DBG, September 2007, Dresden
Marschner, B.; Shchegolikhina, A.
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(2008) Effects of soil organic matter conformation on the formation and release of bound residues of xenobiotics. EuroSoil, August 2008, Vienna, Austria
Shchegolikhina, A.; Marschner, B.
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(2008): Effects of soil organic matter conformation and substrates addition on the fate of xenobiotics in soils. 14th IHSS- Meeting, September 2008, Moscow-St. Petersburg, Russia
Shchegolikhina, A.; Stumpe, B.; Marschner, B.
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(2009): Effects of soil organic matter conformation and substrate additions on the formation and release of xenobiotic bound residues. SSSA International Annual Meeting, November 2009, Pittsburgh, USA
Shchegolikhina, A.; Marschner, B.
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(2009): Sorption and degradation of nonylphenol: effect of soil organic matter conformation and substrate additions in soil. In: Böden - eine endliche Ressource, September 2009, Bonn
Shchegolikhina, A.; Marschner, B.
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(2009): Sorption and degradation of nonylphenol: effect of soil organic matter conformation and substrate additions. DBG-IUSS- Symposium, October 2009, Dornburg, Germany
Shchegolikhina, A.; Marschner, B.
