title: Distribution and relationship of uranium and radium along an allochthonously dominated wetland gradient.
abstract: Uranium mining may pose a large threat for freshwater ecosystems, caused by elevated concentrations of metals/radionuclides in drainage water. Important pollutants of such waters are uranium (U) and radium (Ra), because of their impact due to both radio- as well as chemo-toxicity. Despite the comprehensive knowledge about specific element speciation as well as fixation processes, less is known about the retention of U and Ra at a higher level of complexity (within allochthonous ecosystems as predominant for low order streams). Consequently, we investigated the distribution and retention potential of allochthonous ecosystems regarding U and Ra as well as changing U/Ra ratios. We found U predominantly transported over long distances, whereas Ra mainly precipitates immediately after reaching the surface, i.e. in the spring area. Although high U accumulation in organic rich sediments is found, still high transport rates are detected. Low overall fixation of U within the allochthonously dominated wetland results in an U transport over long distances. Consequently, large areas are affected by U mining activities and its post-mining impact, with U being more relevant compared to Ra.
authors.affiliation: Institute of General Ecology and Environmental Protection, Technische Universität Dresden, 01062, Dresden, Germany.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nassour
authors.forename: Arndt
authors.initials: A
authors.lastname: Weiske
authors.forename: Jörg
authors.initials: J
authors.lastname: Schaller
authors.forename: Carsten
authors.initials: C
authors.lastname: Brackhage
authors.forename: E
authors.initials: E
authors.lastname: Gert Dudel
mesh_terms: D008906:Mining; D011834:Radiation Monitoring; D011883:Radium / Q000032:analysis*; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D053833:Wetlands
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium; D011883:Radium