Climate Adaptation, Swedish Geotechnical Institute, SE-412 96 Gothenburg, Sweden.
Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
Sci Total Environ. 2018 Nov 15;642:553-566. doi: 10.1016/j.scitotenv.2018.06.078. Epub 2018 Jun 14.
The potential catastrophic event of a landslide bringing contaminants to surface waters has been highlighted in public media, but there are still few scientific studies analyzing the risk of landslides with contaminated soil. The aim of this study is to present a method to estimate the risk of potential long-term ecological effects on water bodies due to contaminated soil released into a river through a landslide. The study constitutes further development of previous work focusing on the instantaneous (short-term) release of contaminants and associated effects. Risk is here defined as the probability of surface water failing to comply with environmental quality standards (EQS). The transport model formulation is kept simple enough to allow for a probabilistic analysis as a first assessment of the impact on the river water quality from a landslide runout deposit containing contaminated soil. The model is applied at a contaminated site located adjacent to the Göta Älv River that discharges into the Gothenburg estuary, in southwest Sweden. The results from the case study show that a contaminated runout deposit will likely cause contamination levels above EQSs in the near area for a long time and that it will take several years for the deposit to erode, with the greatest erosion at the beginning when water velocities are their highest above the deposit. A contaminated landslide runout deposit will thus act as a source of contamination to the downstream water system until all the contaminated deposit has been eroded away and the contaminants have been transported from the deposit to the river, and further to the river mouth - diluted but not necessarily negligible. Therefore, it is important to prevent landslides of contaminated soil or waste, and if such events were to occur, to remove the contaminated runout deposit as soon as possible.
山体滑坡将污染物带到地表水中的潜在灾难性事件已经在公共媒体上得到了强调，但仍有少数科学研究分析了受污染土壤的滑坡风险。本研究旨在提出一种方法，以评估由于滑坡导致受污染土壤释放到河流中对水体可能产生的长期生态影响的风险。本研究是对以前专注于污染物瞬时（短期）释放及其相关影响的研究的进一步发展。风险被定义为地表水不符合环境质量标准（EQS）的概率。传输模型的公式保持足够简单，以允许进行概率分析，作为对含有受污染土壤的滑坡流动沉积物对河流水质影响的初步评估。该模型应用于位于哥德堡河口的 Göta Älv 河附近的一个污染场地，瑞典西南部。案例研究的结果表明，受污染的流动沉积物很可能在很长一段时间内导致近岸地区的污染水平超过 EQS，并且需要数年时间才能侵蚀沉积物，在开始时水流速度最高，侵蚀最大在沉积物上方。因此，受污染的滑坡流动沉积物将成为下游水系统的污染源，直到所有受污染的沉积物被侵蚀，并且污染物从沉积物被输送到河流，并进一步输送到河口——被稀释但并非可以忽略不计。因此，防止受污染土壤或废物的滑坡是很重要的，如果发生此类事件，应尽快清除受污染的流动沉积物。
