白洋淀上覆水及沉积物中微塑料赋存特征

为探究我国白洋淀淡水环境中微塑料的赋存特征，于2021年10月通过野外采样、实验室预处理、显微镜观察和激光红外光谱测定等方法鉴定了淀区10份上覆水及10份沉积物样品中微塑料的丰度分布、形状、粒径和聚合物类型，并通过Stokes沉降公式研究了微塑料在上覆水-沉积物界面的沉降规律，对其污染特征及潜在来源进行分析.结果表明，淀区上覆水及沉积物中微塑料丰度范围分别为474～19 382 n·m^-3和95.3～29 542.5 n·kg^-1,平均值为6 255.4 n·m^-3和11 088 n·kg^-1.上覆水中的微塑料主要聚合物为聚对苯二甲酸乙二醇酯PET,(17.20±0.26)%],沉积物中微塑料以氯化聚乙烯CPE,(46.11±1.30)%]为主.淀区内微塑料的沉降速度从0.079 3～111.754 7 mm·s^-1不等，粒径大的颗粒沉降速度较高，易沉降并保留在沉积物中.研究区微塑料污染主要来源为洗涤废水产生的纺织纤维排放，船舶漆、船舶橡胶和建筑材料磨损等过程.

Occurrence Characteristics of Microplastics in Baiyangdian Lake Water and Sediments

In order to explore the occurrence characteristics of microplastics in the freshwater environment of Baiyangdian Lake in China, ten overlying water samples and ten sediment samples were collected in Baiyangdian Lake of Hebei Province in October 2021, and the abundance distribution, shape, particle size, and polymer type of microplastics in the samples were identified using laboratory pretreatment, microscope observation, and laser infrared spectroscopy. The sedimentation law of microplastics at the overlying water-sediment interface was studied using the Stokes sedimentation formula, and their pollution characteristics and potential sources were analyzed. The abundances of microplastics in the overlying water and sediments in Baiyangdian Lake ranged from 474-19382 n·m^-3 and 95.3-29542.5 n·kg^-1, respectively, with an average value of 6255.4 n·m^-3 and 11088 n·kg^-1. The main polymer of the microplastics in the overlying water was polyethylene terephthalatePET, (17.20±0.26)%], and the microplastics in the sediments were mainly chlorinated polyethyleneCPE, (46.11±1.30)%]. The sedimentation velocities of microplastics in the sedimentation zone ranged from 0.0793-111.7547 mm·s^-1. The particles with larger particle size had higher sedimentation velocity and easily settled and remained in the sediments. The main sources of microplastic pollution in the study area were the discharge of textile fibers from washing wastewater and the wear and tear of ship paint, ship rubber, and building materials.