Dong Jiao, Zhao Tingjie, Wang Yuemei, Zhao Shaoyan, Zhu Long, Li Huiqin, Wang Manxiang, An Lihui
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Baotou Branch of Inner Mongolia Autonomous Region Environmental Monitoring Station, Baotou 014060, China.
Sci Total Environ. 2024 Dec 15;956:177352. doi: 10.1016/j.scitotenv.2024.177352. Epub 2024 Nov 6.
Atmospheric precipitation is recognized as a significant source of environmental microplastics, especially in inland waters and remote areas. However, due to the limited availability of existing data, further information on microplastics in precipitation is essential. Therefore, this study aims to elucidate the contamination of microplastics in both snowfall and rainfall while identifying potential factors that may influence their presence during atmospheric deposition. Samples of snowfall and rainfall were collected from two representative cities in Northern China across winter and summer seasons. Subsequently, microplastics were identified and quantified automatically using laser-assisted direct infrared imaging techniques. The findings indicate that microplastic concentrations are higher in snowfall (City A: 182.30 ± 190.25 items/L; City B: 301.74 ± 325.81 items/L) compared to rainfall (City A: 58.90 ± 51.00 items/L; City B: 39.20 ± 30.31 items/L), revealing significant variations in the polymer composition of microplastics. Moreover, a greater diversity of polymers was identified in snowfall relative to rainfall, despite some commonalities among polymers; fragments measuring between 20 μm to 100 μm comprised the majority of detected microplastic particles across both types of precipitation. Crucially, the frequency of precipitation events (rainfall versus snowfall) appears to affect the concentration of atmospheric microplastics, resulting in notably higher levels within snowfalls. These findings offer valuable insights into wet deposition processes by underscoring the atmospheric origins contributing to environmental microplastic pollution.
大气降水被认为是环境微塑料的一个重要来源，尤其是在内陆水域和偏远地区。然而，由于现有数据有限，关于降水中微塑料的更多信息至关重要。因此，本研究旨在阐明降雪和降雨中微塑料的污染情况，同时确定在大气沉降过程中可能影响其存在的潜在因素。在冬季和夏季从中国北方两个具有代表性的城市收集了降雪和降雨样本。随后，使用激光辅助直接红外成像技术自动识别和量化微塑料。研究结果表明，与降雨（城市A：58.90±51.00个/升；城市B：39.20±30.31个/升）相比，降雪（城市A：182.30±190.25个/升；城市B：301.74±325.81个/升）中的微塑料浓度更高，这揭示了微塑料聚合物组成的显著差异。此外，尽管聚合物之间存在一些共性，但与降雨相比，降雪中共鉴定出更多种类的聚合物；在两种类型的降水中，20μm至100μm之间的碎片构成了检测到的微塑料颗粒的大部分。至关重要的是，降水事件（降雨与降雪）的频率似乎会影响大气微塑料的浓度，导致降雪中的微塑料浓度明显更高。这些发现通过强调导致环境微塑料污染的大气来源，为湿沉降过程提供了有价值的见解。
