Spatial distribution and driving factors of molybdenum in soil in the Pearl river delta, China

As a critical element for ecosystem functioning, the spatial distribution patterns and influencing mechanisms of molybdenum (Mo) remain poorly understood. The Pearl river delta (PRD), a heavily industrialized and densely populated region in China, faces significant ecological risks. This study utilizing soil geochemical survey data to identify the primary drivers of soil Mo distribution on PRD combining random forest and geodetector model. Mo concentrations in surface and deep soils range from 0.15 to 109.76 mg/kg and 0.14-43.68 mg/kg, with median values of 1.16 mg/kg and 1.31 mg/kg, respectively. Key factors influencing surface soil Mo include Si/Al, CoD (coastline distance), and TFe2O3, whereas deep soil Mo is primarily affected by Si/Al, Mn, and TFe2O3. There are varying degrees of synergy between the different driving factors. The study concludes that soil Mo in the PRD predominantly originates from natural sources, with parent material weathering and seawater erosion shaping its spatial distribution.