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

化学系支持瓦尔帕莱索大学的Julie Peller教授和长滩加州州立大学的Stephen Mezyk教授获得此奖项。他们研究微塑料，这是塑料废物的微小碎片，可以在我们的海洋、湖泊和世界各地的其他地表水中找到。由于塑料材料非常稳定，许多污染已经在水中存在了几十年，在那里它经历了非常缓慢的变化。然而，这些变化尚未得到充分了解，可能对生态系统和人类健康有害。该项目研究水中微塑料的长期变化，以确定化学变化的细节以及它们缓慢分解所产生的危害程度。这是通过使用高能辐射源在实验室中完成的，它模拟了自然界中类似的风化变化，但可以在更短的时间内完成。该项目为两所大学的多名本科生提供了研究机会，研究结果将融入课堂。关于这一主题的信息具有高度的社会相关性，并正在向公众传播。微塑料在水中的自然分解非常缓慢，这使得很难确定所涉及的化学反应速率和反应自由基的机制。为了使这些研究可行，Julie Peller教授和Stephen Mezyk教授使用电离辐射技术在水中快速（在数小时内）产生可重复的活性自由基。这一过程模拟了在海洋和淡水环境中发生的长期（年）自然自由基反应的影响，并允许定量确定微塑料与这些自由基的基本化学反应性。他们还研究了转化（老化）微塑料的表面和吸附性能，并与新材料进行了比较。这些数据有助于更好地了解微塑料在自然环境中的风险。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.