Review of Study on Groundwater Contamination Risk Assessment in Vadose Zone-Aquifer

The vadose zone-aquifer is an important media for water circulation and solute transport in soil, surface water and groundwater. It is a research hotspot in the field of earth science. In this paper, we took the groundwater contamination risk assessment for the vadose zone-aquifers as the review object. The groundwater contamination status of vadose zone-aquifers was pointed out. The characterization of vadose zone-aquifers, the flow and solute transport as well as the key effect parameters were systematically analyzed and the research progresses were reviewed. Finally, the existing problems in the groundwater contaminant risk assessment under the condition of different scales of vadose zone-aquifers and future research direction were pointed out from the perspective of groundwater contaminant risk assessment. In particular, more attention should be paid to the groundwater contamination risk assessment based on percolation threshold.