富里酸对聚乙烯微塑料污染土壤水分入渗过程的影响

为研究富里酸对聚乙烯污染土壤水分入渗过程的影响，本研究通过土柱一维垂直入渗试验，分别在含有质量比为0.1%、1%和3%荧光染色聚乙烯污染的土壤中添加0.3%的富里酸进行探究。结果表明：与空白土壤相比，0.1%、1%聚乙烯均减少土壤表面孔状结构和粗糙度，抑制土壤水分入渗速率，减小土壤饱和导水率，3%聚乙烯增加土壤表面孔状结构和粗糙度，降低入渗速率和饱和导水率；施加0.3%富里酸后，0.1%、1%和3%聚乙烯污染土壤表面孔状结构增多，粗糙度增大，水分入渗速率降低，饱和导水率随聚乙烯含量增大而增大，但较不施加富里酸前的饱和导水率分别下降48.75%、32.01%和3.64%；添加0.3%富里酸，可使聚乙烯微塑料在土壤中垂直向下的迁移速度分别提高33.33%、37.50%和38.33%。研究表明，富里酸增加了聚乙烯污染土壤的孔状结构和粗糙度，降低了聚乙烯污染土壤的水分入渗速率和饱和导水率，同时提高了聚乙烯在土壤中垂直向下的迁移速度。

Effects of fulvic acid on the water infiltration of soil contaminated by polyethylene microplastics

To study the effect of fulvic acid on the water infiltration of polyethylene-contaminated soil, 0.3% fulvic acid was added to contaminated soil containing 0.1%, 1%, and 3% fluorescent-stained polyethylene and analyzed by one-dimensional vertical infiltration test of the soil column . The key results of the study were listed below： compared with the blank soil, 0.1% and 1% polyethylene reduced the pore structure and roughness of the soil surface（inhibiting soil water infiltration and reducing the soil saturated water conductivity）, whereas 3% polyethylene increased the soil surface pore structure and roughness（reducing the infiltration rate and saturated water conductivity）; after the application of 0.3% fulvic acid of on the soil surface of 0.1%, 1%, and 3% polyethylene pollution, the pore structure increased, the roughness increased, the water infiltration rate decreased, and the saturated water conductivity increased with the increase of polyethylene content; however, the saturated water conductivity decreased by 48.75%, 32.01%, and 3.64%, respectively; and the addition of 0.3% fulvic acid increased the vertical downward migration rate of polyethylene microplastics in the soil by 33.33%, 37.50%, and 38.33%, in the 0.1%, 1%, and 3% polyethylene samples, respectively. Thus, fulvic acid increases the pore structure and roughness of polyethylene-contaminated soil, which can reduce the water infiltration rate and saturated water conductivity and improve the vertical downward migration rate of polyethylene in the soil.