乌梁素海低密度微塑料聚合物沉降规律

沉降是低密度微塑料聚合物在湖泊中的主要迁移过程.为探究乌梁素海中低密度微塑料聚合物的沉降规律，基于微塑料和悬浮微粒的相似和不同之处设计微塑料捕获器和沉降试验方法，定量描述不同形状和不同大小的低密度微塑料聚合物在乌梁素海的沉降过程.结果表明，各类型低密度微塑料聚合物沉降通量随风速变快而增大，其中形状为纤维状，各种尺寸（0.05～0.5、 0.5～2和2～5 mm）的低密度微塑料聚合物沉降通量与风速的相关性较好，相关系数变化范围为0.218～0.836.在不同点位处，不同风速下，形状为纤维状、碎片状、块状和薄膜状，各种尺寸（0.05～0.5、 0.5～2和2～5 mm）的低密度微塑料聚合物沉降通量变化范围分别为0～（1 458±284）、 0～（368±144）、 0～（71±37）和0～（85±65）n·（m²·d）^-1.在形状相同的情况下，大尺寸的低密度微塑料聚合物更容易沉积，而小尺寸的低密度微塑料聚合物更容易随水流迁移.在尺寸相同的情况下，纤维状和薄膜状的低密度微塑料聚合物更容易随水流迁移，而碎片状的低密度微塑料聚合物更容易沉积.

Deposition Law of Low-Density Microplastics Aggregation in Wuliangsu Lake

Deposition is the main migration process of low-density microplastic aggregation in lakes. In order to explore the deposition law of low-density microplastic aggregation in Wuliangsu Lake, a microplastic trap was designed and applied to examine the deposition process based on the similarities and differences between microplastics and naturally occurring suspended solids. The deposition processes of different sizes and shapes of low-density microplastic aggregation were quantified in Wuliangsu Lake. The results showed that the deposition fluxes of all types of low-density microplastic aggregation increased with wind speed. The deposition of flux of low-density microplastic aggregations with a similar shape of fiber and with a size ranging from 0.05-0.5, 0.5-2, and 2-5 mm had better correlation with wind speed. The correlation coefficient changed from 0.218 to 0.836. The deposition of flux of low-density microplastic aggregations with a similar shape of fiber, fragment, grain, and film and with size ranging from 0.05-0.5, 0.5-2, and 2-5 mm under different wind speeds at different experiment sites changed from 0-(1458±284), 0-(368±144), 0-(71±37), and 0-(85±65)n·(m²·d)^-1, respectively. Furthermore, we found that, when shape was held constant, larger low-density microplastic aggregations were more likely to be deposited, whereas smaller low-density microplastic aggregations were more likely to be transported. When size was held constant, fragmentary low-density microplastic aggregations were more likely to be deposited than fibrous and film microplastic.