Simulation of Contaminant Transport Processes in a Semiarid Deep Vadose Zone

The maximum infiltration amounts,the migration time and processes of contaminants are important parameters for groundwater pollution control and monitoring.The simulation of vadose zone moisture and solutes can provide valuable information on the maximum infiltration rate and time,and is the basis to achieve the whole process of solutes transport when combing the vadose zone and saturated zone together.In this paper,a loess plain with deep vadose zone(80m)is chosen to study the related issues.A 62-m vadose zone is sampled at intervals of 25 cm.Under a near saturated condition for the upper boundary,the soil moisture and solute transportation are simulated.The results show the infiltration rate can reach 10 m/year.After 1.59 years,the contaminant can reach water table.This value can be used as the basis of groundwater modeling for prediction.It is suggested that the vadose zone sampling and simulation should be paid more attention in the groundwater environmental impact assessment.