Fe plaque-related aquatic uranium retention via rhizofiltration along a redox-state gradient in a natural Phragmites australis Trin ex Steud. wetland

• Published in: Environmental science and pollution research international Vol. 24; no. 13; pp. 12185 - 12194
• Main Authors: Wang, Weiqing, Gert Dudel, E.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2017; Springer Nature B.V
• Subjects: Adsorption; Aquatic plants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biomass; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Hypotheses; Laboratories; Leachates; Metals; Phragmites australis; Poaceae; Research Article; Retention; Rhizosphere; Soil; Surface water; Uranium; Waste Water Technology; Water Management; Water Pollution Control; Wetlands; Germany; As; Competitive adsorption; Area-related removal rate; Plant biomass; Fe plaque
• DOI: 10.1007/s11356-017-8889-5
• ISSN: 0944-1344

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 NO 3 − ) 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 .