Depositional history of micropastics in the Laurentian Great Lakes basin

北美劳伦特五大湖拥有世界淡水供应量的近20%，但这些湖泊不断受到历史和新兴污染物和污染物的威胁。这些污染物中全球分布最广的是塑料，塑料因其强度、重量轻、生产和运输成本低以及抗降解性而大规模生产。虽然塑料提高了生活质量，但其独特的化学性质导致其保存和全球积累。微塑料，即最长直径小于5毫米的颗粒，特别成问题，因为它们有可能被各种大小的生物体摄入。虽然生产的大多数塑料密度低于水，但如果含有矿物填料，被微生物结壳或在粪便中排出，微塑料可能会下沉。栖息在底栖沉积物中和/或以底栖沉积物为食的生物已被证明摄取微塑料纤维、珠粒和碎片。因此，沉积物可以作为湖泊和河流中微塑料污染的关键指标。拟议的研究计划将首次全面调查五大湖及其支流的底栖沉积物中的微塑料污染，未来的长期监测将建立在此基础上。短期目标包括：1）使用过时的沉积物岩心调查微塑料到湖底沉积物的沉积通量，2）确定当前沉积“汇”或关注的区域，其中底栖微塑料在五大湖及其支流中积累，3）确定支流和控制微塑料输入湖泊的相关因素，（4）确定底栖沉积物中主要微塑料的组成，以确定源产品和位置。

The Laurentian Great Lakes of North America contain almost 20% of the world's freshwater supply, but the lakes are constantly threatened by historic and emerging pollutants and contaminants. The most globally widespread of these contaminants is plastic, which is mass-produced for its strength, lightweight nature, low cost of production and transport, and resistance to degradation. Although plastics improve quality of life, their unique chemical properties result in their preservation and global accumulation. Microplastics, particles <5 mm in longest diameter, are particularly problematic because they have the potential to become ingested by organisms of all sizes. Although the majority of plastics produced are less dense than water, microplastics can sink if they contain mineral fillers, are encrusted by microorganisms, or are expelled in fecal matter. Organisms that dwell in and/or feed on benthic sediment have been shown to ingest microplastic fibres, beads and fragments. Sediment can therefore be used as a critical indicator of microplastics pollution in lakes and rivers. The proposed research program will provide the first comprehensive investigation of microplastics pollution in benthic sediment of the Great Lakes and their tributaries on which future long-term monitoring will build. The short-term objectives include: 1) Investigating the depositional flux of microplastics to lake bottom sediment using dated sediment cores, 2) Identifying the current depositional "sinks" or areas of concern where benthic microplastics accumulate in the Great Lakes and their tributaries, 3) Determining the tributaries and related factors controlling microplastic input into the lakes, and 4) Identifying the compositions of the predominant microplastics in benthic sediment in order to determine source products and locations.