洞庭湖湿地枯水期地表水体微塑料的赋存特征及风险评估

Occurrence Characteristics and Risk Assessment of Microplastics in Surface Water of Dongting Lake Wetland during the Dry Season

  • 摘要: 湿地作为陆地-水域过渡带的关键生态系统,其微塑料污染研究长期滞后于其他水生系统。本文以中国长江中游典型湿地洞庭湖为研究对象,在“四水三口”入湖段及城陵矶出湖段8个采样点采集枯水期地表水,通过显微镜观察与傅里叶变换红外光谱分析微塑料丰度、尺寸、形状、颜色及聚合物类型,并采用污染负荷指数法(PLI)、聚合物风险指数法(PHI)以及潜在生态风险指数法(RI)开展多维风险评价。结果显示:洞庭湖湿地微塑料丰度为4~28.5n/L,处于国内湿地中等污染水平,以透明色(66.9%)碎片和纤维状(84.8%)、小于200μm(83.9%)为主,主要聚合物为聚对苯二甲酸乙二醇酯(PET,27.7%)、聚丙烯(PP,16.5%)、聚氯乙烯(PVC,14.9%)和聚乙烯(PE,11.2%)。风险评估结果表明,环境风险呈“丰度低负荷、毒性高风险”特征。62.5%的样点检出氨基甲酸乙酯(PU)、聚氯乙烯(PVC)、丙烯腈-丁二烯-苯乙烯(ABS)和聚碳酸酯(PC)等高毒性聚合物,其风险指数达高风险或极高风险等级。

     

    Abstract: As a key ecosystem in the land-water transition zone, microplastic pollution research in wetlands has long lagged behind other aquatic systems. This study focused on Dongting Lake, a typical wetland in the middle reaches of the Yangtze River, China. Surface water samples were collected during the dry season from eight sampling sites along the “Four Rivers and Three Outlets” inflow sections and the Chenglingji outflow section. Microplastics were analyzed for abundance, size, shape, color and polymer types through microscopic observation and FTIR. Multidimensional risk assessments were conducted using the pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk index (RI). Results showed that microplastic abundance in the Dongting Lake wetland ranged from 4 to 28.5n/L, representing a moderate pollution level compared to other domestic wetlands. The microplastics were predominantly transparent (66.9%) fragments and fibers (84.8%), with sizes mainly below 200μm (83.9%). The dominant polymers were polyethylene terephthalate (PET, 27.7%), polypropylene (PP, 16.5%), polyvinyl chloride (PVC, 14.9%), and polyethylene (PE, 11.2%). The results of the risk assessment showed that environmental risks were characterized by “low abundance and load, but high toxicity and risk”. Polyurethane (PU), PVC, acrylonitrile butadiene styrene (ABS), polycarbonate (PC) and other highly toxic polymers were detected in 62.5% of the sampling points, and their risk indices reached high-risk or extremely high-risk levels. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202504030078.

     

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