Collaborative Proposal: Plastic Spiraling In River Networks (Plastic-SIReN): Determining the controls of watershed plastic fluxes using a field and modeling approach

塑料垃圾是一个普遍存在的问题。海洋已经积累了多达2110万吨塑料，其中大部分是通过河流进入的。但河流不仅仅是向海洋输送塑料的管道。相反，当塑料在河流中顺流流动时，它可能会沉淀、破碎或与有机体相互作用。大量的塑料可能储存在河流中，但塑料何时何地储存以及向下游转移仍是未知之数。这项研究结合了各种水流大小的现场测量和计算机建模，这在塑料研究领域是新的。这项研究是为了更好地管理塑料污染，将清理工作的重点放在哪里，以及饮用水水源是否受到影响。一个不同的学生团队将学习如何测量三个不同流域的溪流中的塑料。最重要的研究问题是：“水文学的时空变化如何控制河网中塑料碎屑与下游运输塑料碎屑的比例？”该项目将确定流动变化、塑性特征和分水岭特征对塑性运动的作用。将在三个大城市地区(伊利诺伊州芝加哥、马萨诸塞州波士顿和多伦多)的流域中应用场和建模耦合的方法。实地测量将在每个流域的多个地点进行。在每个地点，我们将测量底部和风暴流中的宏观和微观塑料，以量化塑料的浓度、类型、尺寸分布、沉积物中的储存和通量。应用于三个流域的水文模型将量化河网规模的塑料堆积、停留时间和滞留。该团队将与分水岭组织合作，确定塑料堆积的热点，以优先清理塑料垃圾，并将出席海洋科学和饮用水会议，在这些会议上，塑料污染的管理是一个主要利益。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Plastic litter is a widespread problem. Oceans have accumulated up to 21.1 million tons of plastic, the majority of which enters via rivers. But rivers are not just pipes delivering plastic to oceans. Instead, as plastic moves downstream in rivers it may settle, break into pieces, or interact with organisms. A substantial amount of plastic is likely stored in rivers, but when and where plastic is stored vs. moved downstream remains unknown. The research combines field measurements and computer modeling across a range of stream sizes, which is novel in the field of plastic research. This research is needed to better manage plastic pollution, where to focus cleanups, and whether drinking water sources are affected. A diverse team of students will learn how to measure plastics in streams in three different watersheds. The overarching research question is: “How does spatial and temporal variation in hydrology control the proportion of plastic debris that is retained within river networks vs. transported downstream?” The project will identify the role of flow variation, plastic characteristics, and watershed characteristics on plastic movement. A coupled field and modeling approach will be applied in the watersheds of three metropolitan regions (Chicago, IL; Boston, MA; Toronto, ON). Field measurements will take place at multiple sites in each watershed. At each site we will measure macro- and microplastic at base and storm flows to quantify plastic concentrations, types, size distribution, storage in sediments, and fluxes. A hydrologic model applied to each of the three watersheds will quantify river network-scale plastic accumulation, residence time, and retention. The team will work with watershed groups to identify hotspots of plastic accumulation to prioritize plastic waste cleanups and will present at ocean science and drinking water meetings, where management of plastic pollution is a major interest.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.