Chemosphere 2014-07-01

Nonextractable residue formation of sulfonamide antimicrobials: new insights from soil incubation experiments.

Anna Gulkowska, Basilius Thalmann, Juliane Hollender, Martin Krauss

Index: Chemosphere 107 , 366-72, (2014)

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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. Copyright © 2014 Elsevier Ltd. All rights reserved.