EAGER: CAS-MNP: Effect of Sunlight on Fate and Transport of Nanoplastics and Associated Organic Pollutants in Aquatic Systems

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With support from the NSF Division of Chemistry and the NSF 2026 Fund Program in the NSF Office of Integrated Activities, Professor Matthew Tarr and Professor Phoebe Zito at the University of New Orleans study nanoplastics. Very small plastic particles (microplastics and nanoplastics) have been found in increasing amounts in oceans and may be a threat to the health of aquatic organisms. Rivers, lakes, and oceans are essential to human life. These systems contain a complex web of organisms that can be severely impacted by pollutants. Combinations of pollutants often have more damaging impacts than one pollutant alone. Nanoplastics (which have sizes from a nanometer up to about a micron) form in the breakdown of used plastic drink bottles, clothing fibers from laundry, and other sources of plastic. This project studies how sunlight changes nanoplastics and their impact on aquatic organisms. The energy in sunlight can break down nanoplastics, but very little is known about the resulting materials. The data from this project give new information on how and how fast sunlight helps eliminate nanoplastics or causes them to be more dangerous to aquatic organisms. The project also directly addresses one of the top thirty-three Idea Machine entries: "Imagine a Life with Clean Oceans." The project provides research opportunities for graduate, undergraduate and high school students.Model nanoplastics are exposed to simulated sunlight. Experiments assess both physical and chemical changes that occur. Photochemical degradation products are determined using high resolution mass spectrometry and infrared spectroscopy. Simple toxicity screenings monitor potential impacts of the photoproducts. Physical changes are assessed using dynamic light scattering and electron microscopy. Photoproduction of reactant transients is observed using well-established chemical probe methods. Studies in the presence of dissolved natural organic matter evaluate the impacts of nanoplastics as free radical scavengers that alter indirect photodegradation, which normally occurs in natural waters. The impact of nanoplastics on the photochemistry of important molecular pollutants is evaluated through irradiation of model pollutants with and without nanoplastics.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.