Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, 45221, USA.
ORISE, USEPA, Cincinnati, OH, 45220, USA.
Talanta. 2021 Mar 1;224:121743. doi: 10.1016/j.talanta.2020.121743. Epub 2020 Oct 15.
Micro- and nano-scale plastic particles in the environment result from their direct release and degradation of larger plastic debris. Relative to macro-sized plastics, these small particles are of special concern due to their potential impact on marine, freshwater, and terrestrial systems. While microplastic (MP) pollution has been widely studied in geographic regions globally, many questions remain about its origins. It is assumed that urban environments are the main contributors but systematic studies are lacking. The absence of standard methods to characterize and quantify MPs and smaller particles in environmental and biological matrices has hindered progress in understanding their geographic origins and sources, distribution, and impact. Hence, the development and standardization of methods is needed to establish the potential environmental and human health risks. In this study, we investigated stable carbon isotope ratio mass spectrometry (IRMS), attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy, and micro-Raman spectroscopy (μ-Raman) as complementary techniques for characterization of common plastics. Plastic items selected for comparative analysis included food packaging, containers, straws, and polymer pellets. The ability of IRMS to distinguish weathered samples was also investigated using the simulated weathering conditions of ultraviolet (UV) light and heat. Our IRMS results show a difference between the δC values for plant-derived and petroleum-based polymers. We also found differences between plastic items composed of the same polymer but from different countries, and between some recycled and nonrecycled plastics. Furthermore, increasing δC values were observed after exposure to UV light. The results of the three techniques, and their advantages and limitations, are discussed.
环境中的微纳米塑料颗粒源自其直接释放和较大塑料碎片的降解。相对于宏观塑料，这些小颗粒由于其对海洋、淡水和陆地系统的潜在影响而受到特别关注。虽然微塑料 (MP) 污染已在全球地理区域得到广泛研究，但关于其来源仍存在许多问题。据推测，城市环境是主要贡献者，但缺乏系统研究。缺乏用于表征和量化环境和生物基质中 MPs 和较小颗粒的标准方法，阻碍了对其地理起源和来源、分布和影响的理解。因此，需要开发和标准化方法以确定潜在的环境和人类健康风险。在这项研究中，我们调查了稳定碳同位素比质谱 (IRMS)、衰减全反射-傅里叶变换红外 (ATR-FTIR) 光谱和微拉曼光谱 (μ-Raman) 作为表征常见塑料的补充技术。用于比较分析的塑料物品包括食品包装、容器、吸管和聚合物颗粒。还研究了使用紫外线 (UV) 光和热的模拟风化条件来区分风化样品的 IRMS 能力。我们的 IRMS 结果显示，植物衍生和石油基聚合物的 δC 值存在差异。我们还发现了由相同聚合物但来自不同国家的塑料物品之间以及一些回收和不可回收塑料之间的差异。此外，在暴露于 UV 光后观察到 δC 值增加。讨论了三种技术的结果及其优缺点。
