Department of Chemistry, Rutgers Camden, 315 Penn St., Camden, NJ 08102, 856-225-6333, USA.
Civil & Environmental Engineering, Rutgers, The State University of New Jersey, 500 Bartholomew Rd, Piscataway, NJ 08854, 848-445-8416, USA.
Environ Sci Process Impacts. 2023 Aug 16;25(8):1374-1384. doi: 10.1039/d3em00172e.
Understanding not only microplastic (MP) concentration but also size distribution, morphology, and polymer profiles is desirable for stormwater, which is an important pathway of entry for MP into the aquatic environment. A challenge is that subsampling is often required for analysis of environmental samples and the impact of subsampling on the stormwater MP concentration determined and the polymer types identified is poorly characterized. To address this, MP were extracted from urban and suburban stormwater, including from green infrastructure. Fourier Transform Infrared microscopy was performed to characterize MP. In addition, particle dimensions and morphology were recorded. Varying the number of 63-250 μm particles subsampled per sample demonstrated the coefficient of variation for concentration (standard deviation/mean) for most samples was <0.3 when 20 particles (0.8-15% of total particles) or <0.2 when 30 particles (1.2-24% of total particles) per sample were analyzed. MP concentrations in the 63-250 μm size class ranged from 15 to 303 MP/L, one to two orders of magnitude greater than observed in previously reported paired samples from the 250-500 or 500-2000 μm size classes. A total of 25 plastic polymer types were observed across samples, more than observed in the large size classes. Spectral signatures of surface oxidation indicative of weathering were observed on most polyethylene, polypropylene, and polystyrene particles, which were the most abundant polymer types. Fragments were the dominant morphology with an average maximum length of 158 ± 92 μm. Overall, these results may help inform subsampling methods and be useful in future exposure assessments for aquatic organisms or design of MP removal technologies for urban and suburban stormwater.
了解暴雨中的微塑料（MP）浓度，以及尺寸分布、形态和聚合物分布，这一点很重要，因为它是 MP 进入水生态环境的重要途径之一。然而，环境样本分析通常需要进行亚采样，而亚采样对确定的暴雨 MP 浓度和识别的聚合物类型的影响还没有得到很好的描述，这是一个挑战。为了解决这个问题，从城市和郊区的暴雨中提取了微塑料，包括从绿色基础设施中提取。采用傅里叶变换红外显微镜对微塑料进行了表征。此外，还记录了颗粒尺寸和形态。通过改变每一样本中所取的 63-250 μm 颗粒的数量，证明对于大多数样本，当分析的颗粒数量为 20 个（占总颗粒数的 0.8-15%）或 30 个（占总颗粒数的 1.2-24%）时，浓度（标准偏差/平均值）的变异系数<0.3。63-250 μm 粒径范围内的微塑料浓度范围为 15-303 MP/L，比以前报道的 250-500 或 500-2000 μm 粒径范围内的配对样本观察到的浓度高出一到两个数量级。在所研究的样本中观察到了 25 种塑料聚合物类型，比在大粒径范围内观察到的类型更多。大多数聚乙烯、聚丙烯和聚苯乙烯颗粒上都观察到了表面氧化的光谱特征，这表明它们经历了风化，这些颗粒是最常见的聚合物类型。碎片是最主要的形态，平均最大长度为 158±92 μm。总的来说，这些结果可能有助于为水生生物的暴露评估或城市和郊区暴雨中微塑料去除技术的设计提供信息。
