Adsorption And Transfer Regulation Of Heavy Metals In Biofilms Grown On Rocks And Inert Carries In Tidal Rivers

Heavy metals existing in the surface of sediments of the tidal river could be transferred into the surrounding natural and artificial biofilms, through physical, chemical, biological or their combination processes. This paper studied on the adsorption and transfer regulation of heavy metals in biofilms grown on river rocks and inert carriers in tidal rivers. The natural and artificial biofilms, and the surrounding sediments nearby were taken, among of which the heavy metals (Mn, Zn, Cu, Pb, Ni and Cd) contents were measured using ICP-AES method. The absorption of heavy metals in the biofilms and the migration characteristics of heavy metals into the biofilms were measured and analyzed. Our results showed that the contents of heavy metal in the biofilms were similar to those in the surrounding surface sediments nearby in the tidal rivers, which was probably attributed to the dynamic equilibrium between the biofilms and its surrounding surface sediment and water. The migration of heavy metals between biofilms and surface sediment through water movement in tidal river showed certain limitations for biofilms adsorption to remove heavy metals. The contents of heavy metals in biofilms were impacted by many factors, such as the biofilms characteristics, the types and forms of existing heavy metals, the contents of heavy metals in the adjacent surface sediment, the hydrological conditions, and the formation time of biofilms. This study can provide important references for the remediation of the polluted tidal rivers by using biofilms method.