Fig. 1. Schematic design of the experimental procedure. Fig. 2. Box diagram illustrating descriptive statistics for RMAs from 22 soil columns. The box extends from the 25th to the 75th percentile of the data, with the horizontal line inside the box indicating the median value. Fig. 3. Performance of RF regression model trained on the entire dataset. Fig. 4. Dependence plots between soil property and its SHAP values. a) D30 particle size, b) Fe content, c) OM content, d) bulk density (ρb), and e) coefficient of uniformity (Cu). SHAP values for the bulk density showed no discernible trend, so no fitting line is included. Fig. 5. Dependence plots illustrating the inter-related effects of D30 and Fe content on their SHAP values. SHAP values for a) D30 and b) Fe content, with the counterparts indicated by colored dots. Fig. 6. Dependence plots illustrating the relationship between bulk density and its SHAP values, alongside the coupled effect with OM content. Fig. 7. (a) SHAP summary plot illustrating the impact of soil properties on As remobilization, (b) Mean Absolute SHAP (MAS) values indicate the relative importance of each soil property on As remobilization. | 
