Photochemical Fate of Dissolved Amino Acids in Natural Aquatic Environment

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This award from the Environmental Chemical Sciences Program in the Division of Chemistry supports Profs. Daisuke Minakata and Paul Doskey from Michigan Technological University. They study the reactions of free amino acids in natural freshwater with light. Understanding and predicting these processes is important because nitrogen-containing free amino acids and their degradation products are involved in global nitrogen-cycling. They also affect biological activity in natural aquatic environments. The effluent of wastewater contains amino acids as one of the major components. The findings from this study address the impact of nitrogen-containing contaminants to aquatic systems that receive treated municipal wastewater. The project includes outreach activities to K-12 high school students in the Detroit region through a summer youth intern program. This program promotes the participation and retention of underrepresented groups in the environmental science field. A webinar is being developed based on the findings of this study to raise public awareness of water safety and security in freshwater systems and the importance of protecting ecosystems from contaminants. This award supports computational and experimental research and education to predict the photolytic and elementary reaction pathways of free amino acid transformation. This transformation is induced by direct photolysis and indirect oxidation by photochemically produced reactive intermediates. The researchers use computational chemistry tools to identify the fundamental elementary reaction pathways of representative free amino acids transformation. The research team then predicts the kinetics information of each identified elementary reaction pathway. Finally, a kinetic model based on elementary reactions is developed to predict the time-dependent concentration profiles of free amino acids and their transformation products in environmentally relevant conditions. The predicted concentration profiles are compared to laboratory-scale experimental observations to validate the kinetic model.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.