Figure 4

Pearson correlation coefficient of soil heavy metal elements and impact factors. Elevation (X1), slope (X2), aspect (X3), soil parent materials (X4), soil types (X5), soil erosion degree (X6), distance from railway (X7), distance from national highway G109 (X8), distance from county road (X9), distance from pastoral point (X11), distance from rural area (X12), distance from lake (X13), distance from river (X14).