title: Fe plaque-related aquatic uranium retention via rhizofiltration along a redox-state gradient in a natural Phragmites australis Trin ex Steud. wetland.
abstract: Studies have revealed that the rhizofiltration is a feasible plant-based technology for aquatic metal/metalloid removal. However, the performance of aquatic U retention via rhizofiltration has not been fully revealed yet. In this study, a field investigation was conducted in a Phragmites australis Trin ex Steud. dominated wetland to estimate the efficiency of Fe plaque (IP)-assisted U rhizofiltration, with redox-state gradient (-179 to 220 mV) and low aquatic U level (66.7 to 92.0 μg l-1). The U concentrations were determined in soil, root, and aboveground biomass of P. australis. The IP on root surface was extracted via DCB extraction procedure. The bio-concentration factor (BCF) was applied to evaluate the aquatic U transfer capacity from root to above ground biomass of P. australis. The result suggested that root of P. australis was highly effective for aquatic U uptake via rhizofiltration (BCF 1025 to 1556). It also benefited the real U accumulation in aboveground biomass of P. australis (up to 0.4 mg m-2) and related plant-water-soil U recycling. The IP and associated microbial community in rhizosphere was effective mediator for aquatic U retention on root surface (BCF 1162 to 847). The IP-assisted aquatic U rhizofiltration was significantly promoted in relatively reductive environment. It was benefited by the enhanced root uptake of Fe due to lower oxidizers (e.g., DO and NO3-) availability. On the other hand, the competitive adsorption effect from co-existing IP-affinitive elements (e.g., As) also possibly impaired the real capacity of IP-assisted aquatic U rhizofiltration via P. australis.
authors.affiliation: Institute of Plant and Wood Chemistry, Dresden University of Technology, Pienner Strasse 19, D-01737, Tharandt, Germany. wang.tud@hotmail.com.
authors.forename: Weiqing
authors.initials: W
authors.lastname: Wang
authors.affiliation: Institute of Plant and Wood Chemistry, Dresden University of Technology, Pienner Strasse 19, D-01737, Tharandt, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Gert Dudel
mesh_terms: D006109:Poaceae; D058441:Rhizosphere; D012987:Soil; D014501:Uranium; D053833:Wetlands
chemical_list: D012987:Soil; D014501:Uranium
keywords: Area-related removal rate; As; Competitive adsorption; Fe plaque; Plant biomass