In the realm of soil science, the influence of solution chemistry on the mobility of trace metals in biosolids-amended soils has garnered significant attention. While several investigations have underscored the role of dissolved organic carbon (DOC) in this context, a comprehensive quantification of both DOC and metal concentrations remains relatively scarce. To address this gap, we conducted extensive laboratory leaching column studies, focusing on two distinct soil types: a dryland Platner loam (fine, smectitic, mesic Aridic Paleustoll) and an irrigated Osgood sand (loamy, mixed, mesic Arenic Ustollic Haplargid). Our meticulous examination of these soils…