Untersuchungen zum ökotoxikologischen Schädigungspotenzial und Erosionsrisiko von kontaminierten Sedimenten in staugeregelten Flüssen

Particle-bound pollutants accumulate in river-bottom sediments, a process which results in a significant decrease in the ecotoxicological availability of toxicants for the majority of aquatic organisms. Under normal hydrologic conditions, the release of contaminants from bottom sediments is usually of minor importance. In contrast, flood events may remobilize highly contaminated sediments via in-stream erosion. The objective of this study was to develop a combined ecotoxicological and hydraulic approach to elucidate the ecotoxicological implications associated with the risk of erosion of contaminated sediments. This integrated strategy was applied to the lock-regulated Neckar river in Southern Germany. Both the bottom-sediment cores and suspended matter from two intensive flood events were investigated. Sediment samples below an erosional unconformity showed a sharp increase in the ecotoxicological load. Moreover, it was found that major flood events (HQ₅ and higher) could possibly erode even very old, well-consolidated and highlycontaminated sediments. The suspended matter of the high discharge events investigated (return periods of 15 to 20 years) exerted significantly higher cytotoxicity and mutagenicity than a moderate flood with a 1-year return period. These findings support the conclusion that the observed ecotoxicological effects during major floods may at least in part be due to the in-stream erosion of highly contaminated bottom sediments.     

进入大规模养殖贻贝的滨海地带:障碍和可能性

瑞典西海岸北部沿岸水域中的富营养化正在造成沿岸生态系统结构和功能的变化.为了在10～20年的过渡期内降低沿岸水域中营养物质,改善水质,按照欧洲水框架指令的要求,在措施计划中建议开展大规模的贻贝养殖.所有权、土地划拨、利益冲突及沿岸水体的保护正在阻挠着人们进入建立贻贝养殖场的合适水域.本文研究了关乎进入大规模贻贝养殖的沿岸水域这一领域的相关法律和法规中的障碍和可能性.在规划与建筑法、环境指令及与土地划拨和财产有关的法律框架中,给出了解决这个问题的一些可选择的方法并进行了讨论.适当地运用规划与建筑法,可以为进入沿岸水域进行以改善水的生态状况为目的的贻贝养殖提供有益的手段.