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。海洋已经积累了高达2110万吨的塑料，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，当塑料在河流中向下游移动时，它可能会沉淀、破碎或与生物相互作用。大量的塑料可能储存在河流中，但塑料储存的时间和地点以及下游的移动仍然未知。该研究结合了现场测量和计算机建模，跨越了一系列的流大小，这在塑料研究领域是新颖的。这项研究需要更好地管理塑料污染，在哪里集中清理，以及饮用水源是否受到影响。一个多元化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。首要的研究问题是：“水文的时空变化如何控制河网中保留的塑料碎片与下游运输的比例？”该项目将确定流量变化、塑性特征和流域特征对塑性运动的作用。耦合场和建模方法将应用于三个大都市地区（芝加哥，伊利诺伊州；波士顿，马萨诸塞州；多伦多，安大略省）的流域。实地测量将在每个流域的多个地点进行。在每个站点，我们将测量基流和风暴流中的宏观和微塑料，以量化塑料浓度、类型、大小分布、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尺度的塑料积累、停留时间和滞留。该团队将与流域组织合作，确定塑料堆积的热点，优先清理塑料废物，并将出席海洋科学和饮用水会议，塑料污染管理是这些会议的主要兴趣所在。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。

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.