Correlation of Dissolved Organic Matter Fluorescence Properties and Photoproduction of Reactive Oxygen Species

Dissolved Organic Matter (DOM) is prevalent in natural waters and is the byproduct of natural decay processes. Prior work shows that DOM properties depend on the sources, and in many cases, two main types of DOM exist, which are microbial and terrestrial. The former comes from biological activity of microscopic organisms in the water, while the latter is from decayed terrestrial plant material. When DOM absorbs sunlight, it has the capability to produce Reactive Oxygen Species (ROS). Several types of ROS exist, but the types studied for this project are molecular singlet oxygen and the triplet state of DOM. Each of these ROS potentially provides a “pathway” for the decomposition of pollutants, which can be beneficial and/or harmful due to the possibility of oxidizing pollutants into less or more harmful substances. Prior evidence suggests a correlation between the DOM source properties and the relative amounts of the different ROS produced. Knowledge of the specific ROS that will be produced in a natural water sample will allow more accurate predictions about this pollutant decomposition. For this project, correlations between optical characterization of the DOM (using UV-Visible and fluorescence spectroscopy with PARAFAC analysis) and the relative amounts of ROS that are produced by a DOM sample were performed. Preliminary results suggest that the probe molecules (furfuryl alcohol and methylated phenols) react with the photogenerated reactive species and provide a measure of the differences within DOM samples