EVALUATION OF THE BINDING MECHANISM OF ANILAZINE AND ITS METABOLITES IN SOIL ORGANIC-MATTER

Soil bound residues of organic xenobiotics or their metabolites can be partly extracted by diluted NaOH together with the humic and fulvic a cids or remain in the humin. These residues, however, are only detecte d by their radioactivity after using C-14- or H-3-labeled xenobiotics. A more detailed analysis of the binding character of xenobiotics was conducted with the fungicide Dyrene(R) which contains anilazine as an active ingredient. This compound forms up to 80% of unextractable resi dues after a short incubation period in soil. C-13 NMR-spectroscopic a nalysis of the bound residues in the humic matrix of a soil could be s ignificantly improved by application of the C-13-enriched ingredient. Further improvement was gained by incubation of the fungicide in an ar tificial soil, obtained by humification from corn stalk material of pl ants previously grown in a (CO2)-C-12 atmosphere. The results revealed that the binding of anilazine metabolites occurs in the form of ether s or possibly also of esters with various functional OH-groups of the humic molecules. Derivatization of the humus matrix by silylating reag ents also provided additional information.