Xue Lian-Qing, Hao Zhen-Chun
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, College of Water Resources and Environment, Hohai University, Nanjing 210098, China.
J Environ Sci (China). 2006;18(3):591-5.
The sediment distributed and insolated under lake was collected for experiments. The nutrient layer distribution conditions of sampled sediment and its physical and chemical characteristics were analyzed to simulate and assess the influence degree to lake water quality. Based on the dynamic water exchanging experiments the nutrient release process in sediment and influence mechanism to substance exchanging on water-sediment interface was studied, and the correlation between the changing content of total phosphors and total nitrogen in sediment and covered water were analyzed for setting up a simulation model. At the same time the influence degree is explained in detail. The experimental results indicated that even if clean water without nutrient contents was used for water exchangement so as to decrease pollution or prevent eutrophication, however owing to the vertical nutrient distribution in lake sediment, it will lead to the increasing release amount greatly especially when the organic nutrient contained in sediment turns into inorganic status because of isolation. Besides the release process of total phosphate (TP) and total nitrogen (TN) were modeled and each nutrient's exchanging equation at interface caused by covered water nutrient concentration changing was set up. According to the simulating prediction, TP and TN content of cover water will also sustain a steady higher level in a long period. The nutrient release amount of sediment is not only affected by the covered water concentration but also connects with accumulative time. The experiments provide the fundamental theoretical and practical basis for taking ecological restoration project. And research is helpful to prevent or restore lake eutrophication.
采集湖泊底部分布并经暴晒的沉积物用于实验。分析采样沉积物的营养层分布状况及其理化特性，以模拟和评估其对湖泊水质的影响程度。基于动态水交换实验，研究沉积物中的营养释放过程以及水 - 沉积物界面物质交换的影响机制，分析沉积物和上覆水中总磷与总氮含量变化的相关性，建立模拟模型。同时详细阐释影响程度。实验结果表明，即便采用无营养成分的清水进行水交换以减少污染或防止富营养化，但由于湖泊沉积物中营养物质的垂直分布，尤其是沉积物中的有机营养物质因隔离转化为无机状态时，会导致释放量大幅增加。此外，对总磷（TP）和总氮（TN）的释放过程进行了建模，并建立了因上覆水营养浓度变化导致的各营养物质在界面处的交换方程。根据模拟预测，上覆水中的TP和TN含量在较长时期内也将维持在较高且稳定的水平。沉积物的营养释放量不仅受上覆水浓度影响，还与累积时间有关。这些实验为采取生态修复工程提供了基础理论和实践依据，有助于预防或修复湖泊富营养化。
