College of Biology and Food Engineering, Chongqing Three Gorges University, Wanzhou, Chongqing, China.
Key Laboratory of Water Environment Evolution and Pollution Control in Three Gorges Reservoir, Chongqing Three Gorges University, Wanzhou, Chongqing, China.
Environ Sci Pollut Res Int. 2023 May;30(25):67854-67864. doi: 10.1007/s11356-023-27185-w. Epub 2023 Apr 29.
The pollution of freshwater environments with microplastics (MPs) has attracted increasing attention owing to their threats to aquatic ecosystems and human health. Here, we sampled and analyzed MPs from mainstream, tributary, and backwater areas in the Wanzhou section of the Three Gorges Reservoir (TGR) in impoundment and flood periods. Microplastic pollution was the most severe in the backwater areas. The average abundance of MPs reached the highest value in the flood period (5.27±3.47×10 items km), which was 3-5 times that in the impoundment period. In the 0.3-5 mm size class, the 1-5 mm fraction was the most abundant, accounting for more than 81% in the flood period and 68% of the total MP particle abundance in the impoundment period in the mainstream and backwater areas. However, 0.3-1 mm MPs contributed more than 50% in the tributaries during the impoundment period. Polystyrene, polypropylene, and polyethylene MPs were detected in foam, fragment, sheet, and line-shaped MP particles. White, opaque, foamed polystyrene MPs contributed 32-81% to total MP particle abundance in the watershed. Microplastic particle surfaces showed signs of damage and oxidation, and ten different elements were found. Oxygen was clustered on the surface of foam and fragment MPs. Microplastic pollution was severe in the Wanzhou watershed. Especially in the backwater areas, oxidized MPs of variable shapes derived mainly from surface runoff in the flood period and sewage discharge in the impoundment period were abundant. The results of this study contribute to understanding seasonal pollution patterns and surface characteristics of MPs in the TGR and similar watersheds.
淡水环境中的微塑料（MPs）污染因其对水生生态系统和人类健康的威胁而引起了越来越多的关注。在这里，我们在蓄水期和洪水期采集并分析了三峡水库万州段干流、支流和回水区的 MPs。回水区的微塑料污染最为严重。洪水期 MPs 的平均丰度达到最高值（5.27±3.47×10 个 km），是蓄水期的 3-5 倍。在 0.3-5mm 粒径范围内，1-5mm 粒径段最为丰富，占洪水期总 MPs 粒径的 81%以上，占蓄水期干流和回水区总 MPs 粒径的 68%。然而，在蓄水期，支流中 0.3-1mm MPs 占比超过 50%。泡沫、碎片、薄片和线状 MPs 中均检测到了聚苯乙烯、聚丙烯和聚乙烯 MPs。白色、不透明、泡沫状聚苯乙烯 MPs 占流域总 MPs 粒径丰度的 32-81%。MP 颗粒表面显示出损伤和氧化的迹象，发现了十种不同的元素。泡沫和碎片 MPs 的表面聚集了氧。万州流域的微塑料污染很严重。特别是在回水区，洪水期主要来源于地表径流的形态各异的氧化 MPs 和蓄水期的污水排放，含量丰富。本研究结果有助于了解三峡水库及类似流域 MPs 的季节性污染模式和表面特征。
