Quantifying Drivers and Their Interactions in Heavily Contaminated Farmland Soil in an Industrial‐Agricultural Region

ABSTRACT Heavy metal contamination in farmland soils poses serious risks to food safety, human health, and ecosystems. Elucidating the complex interactions between heavy metal contamination and its driving factors is crucial for advancing soil health management in industrial–agricultural transition areas. This study investigated the contamination characteristics, ecological and health risks of As, Cd, Pb, Hg, and Cr in farmland soils of Zhangjiagang City, China. A combination of a Random Forest model interpreted using SHapley Additive exPlanations (SHAP) and an improved Generalized Additive Model (i‐GAM) was employed to identify the key driving factors and their interactions affecting heavy metal concentrations. The results showed that heavy metal average concentrations in farmland soils ranked as Cr (79.91 mg kg −1 ) > As (34.34 mg kg −1 ) > Pb (25.69 mg kg −1 ) > Cd (0.08 mg kg −1 ) > Hg (0.04 mg kg −1 ). The Nemerow pollution index exceeded the warning threshold in most areas, with elevated geo‐accumulation index values for As, whereas the overall ecological risk remained mild. The total carcinogenic risk for both adults and children was mainly driven by As. Soil organic carbon, normalized difference vegetation index, nitrogen fertilizer use, pesticide application, slope, gross domestic product, population density, cation exchange capacity, and manufacturing‐related factors were identified as the key drivers of As contamination. The i‐GAM demonstrated that land use (F = 3.892), agricultural practices (F = 2.794), soil properties (F = 1.993), and topography (F = 1.152) strongly influenced As ( p < 0.05), through both near‐linear and nonlinear effects. Notably, the interactive effects of land use with socioeconomic activities and agricultural practices mitigated As contamination to varying extents. This study provides valuable insights for improving farmland soil management and informing policies for healthy and sustainable development.