Revealing Influencing Mechanisms and Spatial Pattern of Soil Cadmium Through Geodetector and Spatial Analysis

Elucidating the dominant factors governing heavy metal accumulation and their spatial heterogeneity in soils is fundamental to implementing science-based environmental management protocols. In this study, a Geodetector model, spatial interpolation, bivariate local Moran’s I (BLMI), and hotspot analysis were adopted to reveal the spatial pattern and driving mechanisms of soil cadmium (Cd) across six townships in southern Shimen County, Hunan Province. Results showed that Cd accumulation in the study area was predominantly controlled by natural factors, though anthropogenic contributions were also significant. Strata (q = 0.068), soil type (q = 0.045), and atmospheric deposition (q = 0.046) emerged as the most influential factors. The interaction between different driving factors exhibited a synergistic enhancing effect. Spatial interpolation revealed elevated Cd concentrations primarily clustered in central and western regions, particularly concentrated in Jiashan Town. BLMI analysis confirmed significant spatial correlations between Cd distribution and driving factors, and hotspot areas showing strong spatial coherence with strata and soil type. This study provides valuable insights for understanding the driving mechanisms of soil heavy metal pollution and informs targeted contamination control strategies.