Abstract:

As emerging contaminants, microplastics have garnered considerable attention because of their potential risks to both ecosystems and human health. In October 2022, the Ministry of Water Resources issued a list of nationally important drinking water sources in the Yangtze River Basin, imposing higher standards for their protection and safety. However, there is currently limited research specifically focusing on microplastics in drinking water sources, and knowledge of their ecological risks in critical environments remains insufficient. This study focused on 12 important drinking water sources located in the upper, middle, and lower reaches of the Yangtze River Basin in China. The occurrence characteristics of microplastics in these water bodies were analyzed using Fourier-transform infrared (FTIR) imaging microscopy and optical microscopy. Furthermore, the ecological risk of microplastics in water bodies was assessed using a potential ecological risk index. The results revealed that the abundance of microplastics in the water of all water sources ranged from 0 to 4 pieces∙L⁻¹, with an average abundance of 1.8 pieces∙L⁻¹, which was lower than the average level of microplastics in water of the Yangtze River Basin. The microplastics detected in the drinking water source were predominantly fibrous in shape (57.1%), transparent in color (42.9%), and mainly composed of polyethylene (PE, 47.6%) and polypropylene (PP, 28.6%) in terms of polymer composition. The ecological risk assessment of microplastics in drinking water sources indicated that among the nine water sources detected with microplastics, two belonged to risk zone IV, primarily due to polyvinyl chloride (PVC) pollution, one belonged to risk zone II, and six belonged to risk zone I, with low ecological risk. This study contributes to the understanding of current state of microplastic pollution in important drinking water sources in the Yangtze River Basin and provides a scientific basis for ensuring drinking water safety and ecological protection.

Key words: microplastics, Yangtze River Basin, source of drinking water, emerging contaminants, occurrence characteristics, ecological risk assessment

摘要：

微塑料作为一种新型污染物，因其对生态系统以及人体健康的潜在风险而被广泛关注。2022年10月，水利部发布了长江流域国家重要饮用水水源地名录，对饮用水水源地保护与饮用水安全提出了更高的要求，但目前少有针对水源地微塑料的调查研究，对微塑料在水源地的生态风险缺乏认知。本研究选取了长江流域上中下游12个重要饮用水水源地，通过傅里叶变换红外成像显微镜以及光学显微镜，分析水源地微塑料赋存特征并评估其生态风险。结果表明，各水源地水体微塑料丰度为0－4 piece∙L⁻¹，平均丰度为1.8 piece∙L⁻¹，低于长江流域水体微塑料丰度的平均水平，这与对饮用水水源地的严格管控密不可分。水源地微塑料形状主要为纤维状，占比为57.1%；微塑料颜色主要为透明，占比为42.9%；微塑料化学类型以聚乙烯（PE）和聚丙烯（PP）为主，占比分别为47.6%和28.6%。水源地微塑料生态风险评估表明，在9个检出微塑料的水源地中，2个水源地属于IV级风险区，主要与聚氯乙烯（PVC）污染有关；1个水源地属于II级风险区，6个水源地属于Ⅰ级风险区，整体生态风险较低。上述研究成果有助于了解长江流域重要水源地的微塑料污染现状，为饮用水安全保障以及水生态保护提供科学依据。

关键词: 微塑料, 长江流域, 饮用水水源地, 新型污染物, 赋存特征, 生态风险评估