Identification of dominating factors affecting vadose zone vulnerability by a simulation method.

Area of Science:

• Environmental Science
• Hydrogeology
• Geochemistry

Background:

• Vadose zone vulnerability is crucial for understanding contaminant migration to groundwater.
• Contaminant transport is influenced by hydrogeological profiles and physicochemical reactions.
• Accurate assessment of groundwater vulnerability is essential for environmental protection.

Purpose of the Study:

• To identify and rank vadose zone vulnerability dominating factors (VDFs).
• To develop a method for assessing groundwater vulnerability considering pollution source location and contaminant properties.
• To improve the reliability of groundwater vulnerability predictions.

Main Methods:

• Analysis of vadose zone hydrogeological profiles (single, double, multi-lithologic).
• Classification of media permeabilities (clay-layer vs. non-clay-layer) and introduction of maximum pollution thickness.
• Incorporation of soil adsorption and soil degradability to represent contaminant physicochemical reactions.
• Identification and sequencing of VDFs using simulations and sensitivity analysis.

Main Results:

• The study successfully identified and sequenced VDFs impacting groundwater vulnerability.
• The proposed method improved factor weighting in groundwater vulnerability assessments.
• Application to three Chinese polluted sites demonstrated increased reliability in predicting groundwater vulnerability.

Conclusions:

• The characterization of VDFs is critical for understanding contaminant migration in the vadose zone.
• The developed methodology provides a more accurate assessment of groundwater vulnerability to contamination.
• This approach enhances the reliability of predictions for polluted sites.