Adsorption and migration of heavy metals between sediments and overlying water in the Xinhe River in central China

Long-term polluted rivers often lead to the accumulation of heavy metals in sediments. Anthropogenic activities or biological disturbances break the adsorption balance, causing them to return from the bottom mud to the overlying water and change the aquatic environment. In order to understand the variation of heavy metals between sediments and river water, we collected the riverbed sediments in the polluted Xinhe River and carried out static continuous infiltration and dynamic uninterrupted disturbance experiments. The leaching experiment shows that the absorbability of Cd and Pb is stronger than Cr in the sediment; at the same time, the properties of the medium have a great influence on the adsorption of heavy metals. The disturbance can prompt heavy metals in the sediment to resuspend into the overlying water. The impact is the greatest during the first 12 h, and the influence degree is stronger in the relatively static water than in the moving river. In addition, pH and other factors have different degrees of influence on the desorption of heavy metals. HIGHLIGHTS The static infiltration and dynamic agitation experiments were carried out.; The adsorption performances of Cd and Pb were better than that of Cr.; Disturbances greatly affect heavy metals in sediments especially at the first 12 h.; Disturbance has irregular effect on Fe and Cu in sediments.; Influence of disturbance in static water on heavy metals is greater than that in flowing water.