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Updated: May 3, 2026

Assessment of Labile Organic Carbon in Soil Using Sequential Fumigation Incubation Procedures
Published on: October 29, 2016
Nonextractable residue formation of sulfonamide antimicrobials: new insights from soil incubation experiments
Anna Gulkowska1, Basilius Thalmann2, Juliane Hollender1
1Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland.
Abstract:
Soil incubation experiments using (14)C-labelled sulfamethazine were carried out to assess the factors governing its nonextractable residue (NER) formation via nucleophilic addition reactions. Circumstantial evidence on possible mechanisms of NER formation was derived from a selective manipulation of soil samples. The amount of quinones in soil available for nucleophilic addition was a limiting factor as indicated by (i) an (initial) increase of NER formation by adding quinone precursors or enhancing their formation by manganese oxide addition and (ii) a decrease of NER formation by limiting the formation of quinones under anaerobic conditions. A slow NER formation with time under aerobic conditions is likely caused by covalent bonding as well, because no slow NER formation phase was observed under anaerobic conditions.
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