CAREER: Multiphase Oxidation and Fate of Pesticides in Dry and Wet Deposition

College Of Wooster, Wooster OH

Investigators

Abstract

Pesticides are introduced into the environment deliberately through their application to cops. Once applied, pesticides can enter the atmosphere where they react on aerosol particles and eventually deposit back to surfaces that may be far removed from their point of application. Little is known, however, about the chemical reactions that pesticides undergo on these particles while suspended and how these processes impact their spatial distribution. In this CAREER award, the PI intends to integrate laboratory and field studies to increase understanding of pesticide oxidation reactions on particles and their deposition. State-of-the-art instrumentation is used to characterize reactants and products as well as components in field samples. Numerous undergraduate students will be involved at every level of this research and play a significant role in mentoring students from diverse high schools thus contributing to the development of a well-prepared STEM workforce. Objectives of the research focus on increasing current understanding of the atmospheric fate of pesticides, specifically through processes of (i) heterogeneous oxidation of pesticides adsorbed on aerosol particles and (ii) regional atmospheric transport and deposition. Rates and products of heterogeneous oxidation of pesticide films will be determined under controlled laboratory conditions, using advanced instrumentation, including Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QToF-MS). Regional transport and deposition will be determined through measurements performed at 4 sites in a regional network in Ohio, where herbicides are regularly used on corn and soybean fields. Air mass back trajectories and statistical testing of pesticide levels in samples across sites and seasons will aid in assessing whether local or regional sources dominate pesticide deposition. Findings will provide insight into whether pesticides and their degradation products cause poor air quality, health risks to humans and ecosystems, and crop damage in regions distant from pesticide application. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.