重金属在饱和-非饱和分层土壤中迁移过程的三维数值模拟

Three dimensional numerical simulation of migration process of heavy metal in saturated-unsaturated layered soil

为揭示重金属在层状土壤中的迁移规律,以某小型污染地块为例,建立三维饱和-非饱和分层土壤溶质运移模型,重点考察不同土体构型、边界水位和污水入渗通量条件下砷(As)的迁移规律和含量分布。结果表明:含As溶液定通量注入土壤20 a, As在砂土夹粉质黏土中的水平迁移距离远大于其在粉质黏土-砂壤土中的迁移距离;粉质黏土层能较好地阻滞As的迁移扩散,且边界水位和污水入渗通量的增加均可增强As的迁移。

To reveal the migration law of heavy metal in layered soil, a 3 D solute transport model of saturated-unsaturated layered soil is established based on the measurement data in a small-scale polluted plot. The migration law and spatial concentration distribution of arsenic(As) under different soil configurations, different boundary water levels and different sewage infiltration fluxes are explored. The results show that: after the constant flux of As solution is injected into the soil for 20 a, the horizontal migration distance of heavy metal arsenic insandy soil mixed with silty clay is faster than that insilty clay-sandy loam soil;silty clay layer can slow down the migration and diffusion of As, while the increase of boundary water level and sewage infiltration flux promotes the migration of As.