RUI: Systematic Analysis of the Photodegradation of Pesticides on Heterogeneous Surfaces: The Photolysis of Imidazolinone Herbicides on Two Midwest Crops

Gustavus Adolphus College, Saint Peter MN

Investigators

Abstract

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Amanda Nienow from Gustavus Adolphus College who will explore the heterogeneous chemistry of pesticides sorbed to the crop/plant surfaces to which they are applied with a focus on the photolysis mechanisms and photoproducts formed when one class of pesticides, the imidazaolinone herbicides, is applied to plants. The photochemistry of some imidazolinone herbicides has been examined in aqueous systems but not on plant surfaces; this examination will provide insight into the photodegradation mechanisms and photoproducts of these herbicides at crop surfaces, thereby enhancing current understanding of the environmental chemistry of the imidazolinone herbicides. In addition, the knowledge gained from this work will inform reconnaissance missions for measurement of organic pollutants in the environment, provide a molecular understanding of the chemistry occurring at the plant surface, and potentially influence regulation of pesticide application. This project will provide a more realistic picture of the environmental fate of pesticides by examining photolysis of pesticides sorbed to cuticular wax and plant foliage. The research has implications for environmental modeling and pesticide regulation. In addition, the methods and protocols developed under this project will be a model for studying a wide range of pesticides or other environmentally relevant organic molecules, and may be extended to study the photochemistry of organic molecules on other surfaces, (e.g., urban buildings). The undergraduates will participate in all aspects of this interdisciplinary project and will gain experience in a wide range of fields including spectroscopy, chromatography, microscopy, and statistical data analysis. The students' experiences will improve their ability to plan, analyze, synthesize and communicate scientific results. In addition, they will gain experience presenting at national meetings and co-authoring peer reviewed journal articles. All of these experiences will position them well for future graduate studies or professional careers. The principal investigator is a faculty member early in her career, so this project will benefit her by supporting foundational research and establishment of a sustainable research program. The results will be disseminated through publications and presentations at scientific conferences. Aspects of the project will also be used to enhance the Chemistry Department's established community outreach into local elementary schools.