Depositional history of micropastics in the Laurentian Great Lakes basin

北美的劳伦斯五大湖拥有世界上近20%的淡水供应，但这些湖泊不断受到历史上和新出现的污染物和污染物的威胁。在这些污染物中，全球分布最广泛的是塑料，它因其强度高、重量轻、生产和运输成本低以及耐降解而大规模生产。虽然塑料提高了生活质量，但其独特的化学性质导致了它们的保存和全球积累。最长直径为5毫米的微塑料特别有问题，因为它们有可能被各种大小的生物体摄取。尽管生产的大多数塑料的密度都低于水，但如果微塑料含有矿物填充物、被微生物结壳或从粪便中排出，它们可能会下沉。生活在海底沉积物中和/或以海底沉积物为食的生物已被证明摄取微塑料纤维、珠子和碎片。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。拟议的研究方案将对五大湖及其支流海底沉积物中的微塑料污染进行首次全面调查，今后将在此基础上进行长期监测。短期目标包括：1)利用测定日期的沉积物岩心调查微塑料向湖底沉积物的沉积通量；2)确定五大湖及其支流中目前沉积的“汇”或底栖生物微塑料聚积的令人关注的区域；3)确定支流和控制微塑料输入湖泊的相关因素；4)确定海底沉积物中主要微塑料的成分，以便确定来源产品和地点。

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.