EAGER: CAS-MNP: Laboratory Radiation Chemistry Methods to Induce Rapid Aging of Microplastics in Water to Assess Fundamental Chemical Reactivity Changes

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The Division of Chemistry supports Professor Julie Peller at Valparaiso University and Professor Stephen Mezyk at the California State University at Long Beach with this award. They study microplastics, which are tiny fragments of plastic waste and can be found in our oceans, lakes, and other surface waters around the world. Since plastic materials are extremely stable, much of this pollution has resided in the water for many decades, where it undergoes changes very slowly. However, these changes are not well understood, and may be harmful to ecosystems and human health. This project studies the long-term changes of microplastics in water to determine the details of the chemical changes and the level of hazard created from their slow breakdown. This is done in the laboratory by using high energy radiation sources, which simulate similar weathering changes in nature but can be done in much shorter time. The project provides research opportunities for multiple undergraduate students at both institutions and the results are integrated into classes. Information on this topic is of high societal relevance and is being communicated to the public. The natural decomposition of microplastic in water is very slow, which makes it difficult to determine chemical reaction rates and mechanisms of the reactive radicals involved. To make such studies feasible, Professor Julie Peller and Professor Stephen Mezyk use ionizing radiation techniques to create reactive radicals in water rapidly (in hours) and reproducibly. This process mimics the impacts of long-term (years) natural, radical-based reactions occurring in marine and freshwater environments and allows the fundamental chemical reactivity of microplastics with these radicals to be determined quantitatively. They also study the surface and adsorption properties of transformed (aged) microplastics and compare to those of new materials. The data lead to a better understanding of the risks of microplastics in the natural environment.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.