富里酸对聚乙烯微塑料污染土壤水分入渗过程的影响

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

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。

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.