Micro and Nanoplastic Aggregation and Deposition in Subsurface Environments

地下环境中微米和纳米塑料的聚集和沉积

• 批准号: RGPIN-2020-05524
• 负责人: Cheng, Tao
• 金额: $ 1.82万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751127
• 关键词: Micro; Nanoplastic; Aggregation; Deposition; Subsurface

The widespread production, use, and disposal of plastic products has led to the release of plastic wastes into the environment. Plastics are "aged" by weathering processes and break down to smaller pieces including microplastics (MPs) (100 nm-5 mm) and nanoplastics (NPs) (<100 nm). MPs/NPs are harmful to aquatic organisms, human health, and ecosystems due to their physical hazards and chemical toxicity. To evaluate the environmental impacts of MPs/NPs, understanding the fate and transport of these emerging contaminants is essential. Aggregation (particles attach to each other to form large aggregate) and deposition (particles attach to transport media) are among the most important processes influencing the fate and transport of MPs/NPs in subsurface environments. The properties of MPs/NPs, water chemistry, and mineral and organic composition of transport media are expected to significantly influence MPs/NPs aggregation and deposition. Yet, most studies have examined only pristine polystyrene MPs/NPs but not the polyethylene or polypropylene MPs/NPs that are more abundant in the environment. "Aging" alters MPs/NPs (e.g., shape and size) and how this may influence their environmental behaviour is largely unknown. Moreover, most investigations use artificial electrolyte solutions with simple composition as background solution, and clean quartz sand columns as transport media to study MPs/NPs aggregation and deposition. MPs/NPs behaviour in these model solutions may not fully represent that in natural water that contains multiple interacting components. Also quartz sand is not a good proxy for the complex composition of natural soils. The short-term objective of my research program is to fill these knowledge gaps by carrying out experiments to investigate MPs/NPs aggregation and deposition under environmentally relevant conditions. A variety of polyethylene, polypropylene, and polystyrene MPs/NPs with distinct properties will be prepared, "aged", and characterized. The aggregation of the MPs/NPs in artificial electrolyte solutions, and in soil solutions with complex compositions will be systematically investigated. MPs/NPs deposition will be examined using columns packed with natural soils or mineral mixtures to determine the effect of individual and multiple natural components. Regression methods, theoretical calculation, and mathematical modeling will be used to analyze the experimental results. The knowledge gained on MPs/NPs aggregation and deposition under environmentally relevant geochemical conditions will enable more accurate prediction of the environmental behaviour of MPs/NPs, which helps industries and governments establish proper practices and guidelines for tackling the negative environmental impacts of plastic wastes. Furthermore, the proposed research will provide well-rounded and high-quality training, which will contribute to the creation of a top-notch Canadian scientific workforce.

塑料产品的广泛生产，使用和处置已导致塑料废物释放到环境中。塑料是通过风化过程“老化”的，并分解为包括微塑料（MPS）（100 nm-5 mm）和纳米塑料（NPS）（<100 nm）的较小碎片。国会议员/NP由于身体危害和化学毒性而对水生生物，人类健康和生态系统有害。为了评估国会议员/NP的环境影响，了解这些新兴污染物的命运和运输至关重要。聚集（粒子相互附着以形成大骨料）和沉积（粒子附着在传输介质上）是影响地下环境中MPS/NP的命运和运输的最重要过程之一。 MP/NP，水化学和矿物质和有机成分的特性预计将显着影响MPS/NP的聚集和沉积。然而，大多数研究仅检查了原始的聚苯乙烯MPS/NP，而不是在环境中更丰富的聚乙烯或聚丙烯MP/NP。 “老化”改变了MPS/NP（例如形状和大小），以及这可能会影响其环境行为的情况很大程度上是未知的。此外，大多数研究都将人工电解质解决方案与简单组成作为背景溶液，而清洁石英砂柱则作为传输介质来研究MPS/NPS的聚集和沉积。这些模型解决方案中的MPS/NP行为可能无法完全表示包含多个相互作用组件的天然水。石英砂也不是天然土壤复杂组成的好代理。我的研究计划的短期目标是通过进行实验来研究MPS/NP的聚集和沉积在环境相关条件下，以填补这些知识差距。将制备各种具有不同特性的聚乙烯，聚丙烯和聚苯乙烯MPS/NP，并进行了表征。 MPS/NP在人造电解质溶液中的聚集以及具有复杂组成的土壤溶液中的聚集将被系统地研究。 MPS/NPS的沉积将使用装有天然土壤或矿物混合物的柱进行检查，以确定个体和多种天然成分的效果。回归方法，理论计算和数学建模将用于分析实验结果。在与环境相关的地球化学条件下获得的MPS/NP聚集和沉积所获得的知识将使MPS/NP的环境行为更加准确地预测，这有助于行业和政府建立适当的实践和准则，以解决塑料废物的负面环境影响。此外，拟议的研究将提供全面且高质量的培训，这将有助于创造一流的加拿大科学劳动力。