Depositional history of micropastics in the Laurentian Great Lakes basin

北美的劳伦森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和新出现的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，塑料因其强度大、重量轻、生产和运输成本低、不易降解而被大量生产。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。微塑料，即最长直径小于5毫米的颗粒，问题尤其严重，因为它们有可能被各种大小的生物吸收。尽管大多数塑料制品的密度比水小，但如果含有矿物填料、被微生物包裹或随粪便排出，微塑料就会下沉。生活在底栖沉积物中和/或以底栖沉积物为食的生物已被证明会摄入微塑料纤维、微珠和碎片。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底栖生物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)利用年代测定的沉积物岩心研究微塑料在湖底沉积物中的沉积通量；2)确定目前底栖微塑料在大湖及其支流中积聚的沉积“汇”或关注区域；3)确定支流和控制微塑料进入湖泊的相关因素；4)确定底栖沉积物中主要微塑料的成分，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.