Haag I, Kern U, Westrich B
Institut für Wasserbau, University of Stuttgart, Germany.
Sci Total Environ. 2001 Feb 5;266(1-3):249-57. doi: 10.1016/s0048-9697(00)00753-1.
In this paper, an assessment strategy is introduced which allows one to evaluate the ecological hazard of contaminated sediments in connection with the risk of in-stream erosion. Special techniques for sediment sampling, non-intrusive density profiling, and depth related measurement of erosion are presented, which, in combination with ecological aspects, lead to a comprehensive risk assessment of fluvial sediments. The strategy was applied to a lock-regulated reach of the River Neckar in Germany. The spatial pattern of contamination in the river reservoir was found to be remarkably heterogeneous. At some sites, very high heavy metal concentrations were detected at the sediment surface. A sudden increase in contamination with depth at other sites could be attributed to an erosional unconformity. The critical shear stress of erosion for old contaminated sediments is higher than for recently deposited material. Nevertheless, during major flood events, bottom shear stress in the river exceeds the critical shear stresses of erosion of all sediments. Accordingly, there is a substantial risk that old contaminated sediment can be mobilised from the reservoir and transported downstream.
本文介绍了一种评估策略，该策略可使人们结合河道侵蚀风险评估受污染沉积物的生态危害。文中介绍了沉积物采样、非侵入式密度剖面分析以及与深度相关的侵蚀测量等特殊技术，这些技术与生态因素相结合，可对河流沉积物进行全面的风险评估。该策略应用于德国内卡河的一个船闸调节河段。发现河流水库中的污染空间格局显著不均一。在一些地点，沉积物表面检测到非常高的重金属浓度。其他地点污染随深度的突然增加可归因于侵蚀不整合面。老的受污染沉积物的临界侵蚀剪应力高于新沉积物质。然而，在大洪水事件期间，河流底部剪应力超过了所有沉积物的临界侵蚀剪应力。因此，存在老的受污染沉积物从水库中被冲走并向下游输送的重大风险。
