The study investigated the distributions of heavy metals (Cd, Cr, Cu, Mn, and Pb) between dissolved fraction (<0.7 μm) and particles (>0.7 μm) during the adsorption process. The dissolved fraction was further separated into truly dissolved (<3kDa) and colloidal (3 kDa-0.7 μm) fractions. Significant metal adsorption occurred on the colloids, resulting in their aggregation into particles, which in turn influenced the particle adsorption kinetics. Colloids could either accelerate or inhibit the transformation of metal ions into particulates, depending on their stability. Competitive metals for colloids (Pb and Cr) were more susceptible to the effects of colloids than other elements. DOM was the predominant environmental factor influencing colloid behavior. The XDLVO theory showed that DOM enhanced the negative charge of colloids and made the colloid surface more hydrophilic, inhibiting the aggregation of colloids. DOM resulted in substantial increases in the concentrations of colloidal Pb and Cr from 0.31μg/L and 4.58μg/L to 20.52μg/L and 43.51μg/L, respectively, whereas the increment for less competitive metals (Cd and Mn) was smaller. These findings suggest that the distribution of heavy metals is influenced not only by adsorption from particles and ions but also by the complex dynamics of colloids. Environmental implicationHeavy metals are hazardous aquatic pollutants. This study explored the impact of colloids on metal adsorption and the distribution between the dissolved and particulate states. After metal adsorption, colloids may aggregate into particles or disperse in solution, affecting metal distribution and particle adsorption kinetics. Thus, the transformation of metals is influenced not only by adsorption but also by the aggregation of colloids. Colloids can either accelerate or inhibit the transformation of metal ions, depending on their stability and interactions with metals. This discovery enriches our understanding of adsorption processes and contributes to the heavy metal removal and control methods.