School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
Water Res. 2023 Sep 1;243:120322. doi: 10.1016/j.watres.2023.120322. Epub 2023 Jul 7.
Microplastics (MPs) pollution in the Yangtze River Basin (YRB) of China has grown to be a serious issue, yet there is a lack of understanding of the environmental risks of MPs in the sediment of the entire basin. This work revealed the spatial distribution characteristics of MPs in YRB sediments, and it methodically assessed the ecological risks of MPs by taking into consideration their abundance, toxic effects, and polymer types. The results showed a high heterogeneity in the abundance of MPs in YRB sediments, with an average of 611 particles/kg dry weight (DW) sediment. Small-sized MPs (<1 mm), fibrous, transparent-colored and polypropylene (PP) accounted for the majority with 71.6%, 68%, 37% and 30.8%, respectively. Correlation analysis indicated significant influences of human activities such as population, industrial structure, and urban wastewater discharge on the abundance and morphological types of MPs in sediments. Based on chronic toxicity data exposed to sediments, a predicted no-effect concentration (PNEC) of 539 particles/kg DW was calculated using the species susceptibility distribution (SSD). Multiple deterministic risk assessment indices indicated that MPs in YRB sediments exhibited primarily low pollution load levels, moderate-to-low potential ecological risk levels, and high levels of polymer pollution. However, probabilistic risk assessment revealed an overall low risk of MPs in YRB sediments. Monte Carlo simulation results demonstrated that polyvinyl chloride (PVC) and polycarbonate (PC) made a great contribution to ecological risk and should be considered as priority control pollutants in MPs. In addition, various assessments showed that the ecological risk of MPs in river sediments was higher than that in lake reservoir sediments. This is the first study to comprehensively assess the ecological risk of MPs in sediments of the YRB, which improves the understanding of the basin-wide occurrence characteristics and environmental risks of MPs in freshwater systems.
中国长江流域（YRB）的微塑料（MPs）污染已经变得非常严重，但对于整个流域沉积物中 MPs 的环境风险还缺乏了解。本研究揭示了 YRB 沉积物中 MPs 的空间分布特征，并系统地评估了 MPs 的丰度、毒性效应和聚合物类型等因素所带来的生态风险。结果表明，YRB 沉积物中 MPs 的丰度存在高度异质性，平均为 611 个/千克干重（DW）沉积物。小粒径（<1 毫米）、纤维状、透明色和聚丙烯（PP）的 MPs 分别占 71.6%、68%、37%和 30.8%。相关性分析表明，人口、产业结构和城市污水排放等人类活动对沉积物中 MPs 的丰度和形态类型有显著影响。基于暴露于沉积物的慢性毒性数据，使用物种敏感性分布（SSD）计算得出预测无效应浓度（PNEC）为 539 个/千克 DW。多种确定性风险评估指数表明，YRB 沉积物中的 MPs 主要表现为低污染负荷水平、中低潜在生态风险水平和高聚合物污染水平。然而，概率风险评估显示 YRB 沉积物中的 MPs 总体风险较低。蒙特卡罗模拟结果表明，聚氯乙烯（PVC）和聚碳酸酯（PC）对生态风险的贡献较大，应将其视为 MPs 优先控制的污染物。此外，各种评估表明，河流沉积物中 MPs 的生态风险高于湖泊水库沉积物。这是首次全面评估 YRB 沉积物中 MPs 的生态风险，提高了对淡水系统中 MPs 全流域发生特征和环境风险的认识。
