Investigation of transformation of triazole fungicides using model systems


Ulrike Mülow-Stollin1, Christian Piechotta1, Ulrich Szewzyk2
Organization(s): 1: Federal Institute for Materials Testing and Research, 1.8 - Environmental Analysis; 2: TU Berlin, Institute of Environmental Micorbiology

In order to provide nutrition for a growing world population pesticides are a necessary tool. Crop protection agents may be considered safe, if handled correctly. Nevertheless, they are subject to transformation processes and metabolization in the environment and technical installations. Transformation products (TP) and metabolites may be more harmful than the mother substance and thereby pose a threat to environmental and human health.

With 19 % market share in 2014, triazole pesticides are the class of organic fungicides which are most commonly used in Germany. However, only little data is available concerning their TP and metabolites. In this study the fate of the triazole fungicides propiconazole and difenoconazole in soil and water using model reaction systems mimicking their pathway in the environment and the industrial water treatment is investigated.

During application the substances may directly contaminate soil as well as surface waters. In these compartments, transformation by global irradiation needs to be considered. Due to their moderate mobility both pesticides may also end up in ground water from which drinking water is produced. Owing to the vigorous conditions during drinking water production the formation of a variety of technical TP can be expected. Additionally, for all compartments the degradation by bacteria is a factor which needs to be taken into account. For this survey, the potential for metabolization by model organisms is investigated.

In this work degradation and transformation of the fungicides is monitored using quantitative target analysis. Major components in the reaction mixtures are identified by non-target analysis. GC-EI-MS-spectra, HR-MS-measurements, or the comparison with native standards are utilised for structural elucidation. For identification, products will be isolated and characterized by NMR. Toxicity assessment of these TP is essential to define threshold values in the environment.

The model reaction systems will be presented and possible TP will be shown.

Ulrike Mülow-Stollin

03/2014-current: phD student, Federal Institute for Materials Research and Testing, Division 1.8 – Environmental Analysis and Technische Universität Berlin, Department of Environmental Microbiology
10/2008-10/2013: Bachelor and Master in Chemistry, Freie Universität Berlin

Bundesanstalt für Materialforschung und –prüfung (BAM)
Fachbereich 1.8, Umweltanalytik – Chromatografische Verfahren
Richard-Willstätter-Str. 11
12489 Berlin

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