Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 102616, China; Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Department of Water Conservancy and Civil Engineering, Beijing Vocational College of Agriculture, Beijing 102442, China.
Sci Total Environ. 2022 Mar 20;813:152674. doi: 10.1016/j.scitotenv.2021.152674. Epub 2021 Dec 29.
As the demand for urban flood prevention and drainage increases, a large number of plastic rainwater facilities are in use. Microplastics will be released inevitably into stormwater systems during aging and hydraulic scouring processes, which could cause potential pollution risk. This study simulated the release behavior of microplastics from three typical plastic rainwater facilities including a rainwater inspection well, rainwater storage module, and rainwater pipe (mainly composed of high-density polyethylene, polypropylene, and polyvinyl chloride, respectively) under the effects of aging and hydraulic scouring. After 15-45 days of UV aging and 72 h of hydraulic scouring, the surfaces of the three facilities were found to exhibit increases in roughness, cracks, folds, and cavities, with the most pronounced changes occurring in the rainwater storage module. As the aging time increased, oxygen-containing functional groups formed and led to carbon chain scission. Fourier transform infrared spectroscopy (FTIR), two-dimensional correlation spectroscopy (2D-COS) and X-ray photoelectron spectroscopy (XPS) of facility surfaces showed that the formation of oxygen-containing functional groups was an important factor affecting the release of microplastics. The amount of microplastics released from the three facilities ranged from 160 to 1905 items/g (microplastics/facilities), following in the order of rainwater inspection well > rainwater storage module > rainwater pipe. The particle size of the released microplastics ranged from 3 to 1363 μm, with 10-30 μm accounting for the greatest proportion of particles, 50.10%. The size of microplastics released from the rainwater inspection well and rainwater storage module increased with the aging degree, while the release from the rainwater pipe decreased. The release behavior depends mainly on the composition of the materials and the aging time. Thus, microplastics can be released from plastic rainwater facilities under suitable conditions. The results can be used to further evaluate microplastic pollution caused by urban rainwater facilities.
随着城市防洪排涝需求的增加，大量塑料雨水设施正在使用。在老化和水力冲刷过程中，微塑料不可避免地会释放到雨水系统中，这可能会造成潜在的污染风险。本研究模拟了三种典型的塑料雨水设施（雨水检查井、雨水储存模块和雨水管）在老化和水力冲刷作用下微塑料的释放行为，这三种设施主要由高密度聚乙烯、聚丙烯和聚氯乙烯组成。经过 15-45 天的紫外线老化和 72 小时的水力冲刷后，发现三种设施的表面粗糙度、裂缝、褶皱和空腔都有所增加，其中雨水储存模块的变化最为明显。随着老化时间的增加，形成了含氧官能团并导致碳链断裂。设施表面的傅里叶变换红外光谱（FTIR）、二维相关光谱（2D-COS）和 X 射线光电子能谱（XPS）表明，含氧官能团的形成是影响微塑料释放的重要因素。三种设施释放的微塑料数量为 160-1905 个/g（微塑料/设施），依次为雨水检查井>雨水储存模块>雨水管。释放的微塑料粒径范围为 3-1363μm，其中 10-30μm粒径的颗粒占比最大，为 50.10%。雨水检查井和雨水储存模块释放的微塑料粒径随老化程度的增加而增加，而雨水管的释放则减少。释放行为主要取决于材料的组成和老化时间。因此，在适当的条件下，塑料雨水设施可能会释放微塑料。研究结果可用于进一步评估城市雨水设施造成的微塑料污染。
