Association and migration behavior of trace metals with humus colloidal particles in aquatic subsurface medium

In this study, we investigate the influence of humic acid on the migration of trace metals (Fe, Ca, Mg, Cu, Sr, Zn) in the saturated subsurface medium. Migration study was carried out in a specially fabricated soil column. The results of this study demonstrate that presence of humic acid in the colloidal form play a key role in mobility of trace metals in aquatic subsurface medium. Migration of elements like Fe, Ca, Mg, Cu were facilitated by the presence of the humus colloids whereas presence of Zn, Sr in the hydrated form was evident from the experimental results. The observation was explained based on the linear attenuation coefficient (LAC). (author)