Department of Architecture and Civil Engineering, Chalmers University of Technology, Sven Hultins gata 6, SE-412 96, Gothenburg, Sweden.
Sustainable Waste and Water, City of Gothenburg, Box 123, SE-424 23, Angered, Sweden.
Environ Sci Pollut Res Int. 2020 Jul;27(19):24218-24230. doi: 10.1007/s11356-020-08637-z. Epub 2020 Apr 18.
Microplastics (MP) are transported from land-based sources from rivers to marine waters. However, there is currently little knowledge about MP fate from land sources to marine waters. Traffic is estimated to be one of the largest sources of MP; hence, stormwater is expected to be an important transportation route of MP to marine waters. The aim of this study was to investigate the effect of the size and density of tyre wear particles in road run-off on their fate in the Göta River in Sweden using hydrodynamic modelling. The model of the stretch of Göta River, Sweden's largest river, passing through Gothenburg (Sweden's second largest city) and out to the sea, was set up using MIKE 3 FM software. Literature data were used to define the MP characteristics: concentrations in stormwater, prevalent particle sizes, density of MP commonly occurring in road run-off and settling velocities. Results show that higher concentrations of MP are found on the south side of the river, compared with the north side, due to higher annual average daily traffic loads along the south side of the river. The mixing processes in the river and the MP concentrations were generally influenced by the vertical water density gradient caused by saline water from the Kattegat strait. While most MP with higher density and larger size settle in the river, smaller MP with density close to 1.0 g/cm do not settle in the river and therefore reach the Kattegat strait and the marine environments. Further research is needed to describe the fate and transport of microplastics in the stormwater system, including treatment facilities, i.e. biofouling, aggregation, degradation and/or further fragmentation and settling.
微塑料（MP）从河流等陆地源经由运输进入海洋水域。然而，目前人们对陆地源向海洋水域传输微塑料的情况知之甚少。交通被认为是微塑料的最大来源之一；因此，雨水被认为是微塑料向海洋水域运输的重要途径。本研究旨在利用水动力模型调查轮胎磨损颗粒在公路径流中的大小和密度对其在瑞典哥塔河命运的影响。使用 MIKE 3 FM 软件建立了流经瑞典第二大城市哥德堡的瑞典最大河流哥塔河的河段模型。文献数据用于定义微塑料的特征：雨水中的浓度、常见的颗粒大小、公路径流中常见的微塑料密度和沉降速度。结果表明，由于河流南侧的年平均日交通量较高，与河流北侧相比，南侧河流的微塑料浓度更高。河流中的混合过程和微塑料浓度通常受卡特加特海峡咸水引起的垂直水密度梯度的影响。虽然密度较高、尺寸较大的微塑料大部分会在河流中沉降，但密度接近 1.0 g/cm³的较小微塑料不会在河流中沉降，因此会进入卡特加特海峡和海洋环境。需要进一步研究以描述雨水系统中微塑料的命运和传输，包括处理设施，如生物污垢、聚集、降解和/或进一步碎裂和沉降。
