Nassour Mohammad, Weiske Arndt, Schaller Jörg, Brackhage Carsten, Gert Dudel E
Institute of General Ecology and Environmental Protection, Technische Universität Dresden, 01062, Dresden, Germany.
Arch Environ Contam Toxicol. 2015 Feb;68(2):317-22. doi: 10.1007/s00244-014-0117-4. Epub 2014 Dec 30.
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.
铀矿开采可能对淡水生态系统构成重大威胁，这是由排水中金属/放射性核素浓度升高所致。此类水体的重要污染物是铀（U）和镭（Ra），因为它们兼具放射性和化学毒性。尽管对特定元素形态及固定过程已有全面了解，但对于铀和镭在更高复杂程度（在异源生态系统中，低阶溪流占主导）下的滞留情况了解较少。因此，我们研究了异源生态系统中铀和镭的分布及滞留潜力，以及铀/镭比值的变化。我们发现铀主要长距离迁移，而镭在到达地表后（即在泉域）立即主要沉淀下来。尽管在富含有机物的沉积物中发现了高铀积累，但仍检测到高迁移率。在以异源为主导的湿地中，铀的总体固定率较低，导致铀长距离迁移。因此，大面积区域受到铀矿开采活动及其开采后影响，与镭相比，铀的影响更为显著。
