【作者】 蔡景波；

【导师】 杨肖娥；

【作者基本信息】 浙江大学 ， 环境修复与资源再生， 2006， 硕士

【摘要】 水体富营养是当今世界面临的一个严重环境问题。造成富营养化的限制因子主要是N和P,尤其是P。对于大多数外源磷得到控制的水体来说,底泥磷的释放对长期维持藻类生长,促进湖泊富营养化的发展具有举足轻重的作用。但是,底泥对磷的释放与吸收是有条件的,它受到多种因素的影响,包括底泥本身的理化性质和其它环境条件,如氧化还原状况、pH值、温度等。本课题以富营养化的华家池水体为例,以底泥内的磷为主要研究对象,揭示富营养化水体中底泥的特点、释磷规律以及沉水植物在控制底泥磷释放中的作用,并为防止湖泊富营养化提供参考。本文研究取得的主要研究结果如下: 1.实验中采用“SMT Protocol”磷分级分离方法,将底泥内磷分为无机磷(Inorganic phosphorus,IP),有机磷(Organic phosphorus,OP),非磷灰石无机磷(Non-apatite Inorganic phosphorus,NAIP),磷灰石磷(Apatite phosphorus,AP)四个部分,其中具备较大释磷潜力的主要形态是OP和NAIP。通过对底泥的分析,华家池底泥中磷的主要存在形式是无机磷(IP),占总磷的80-95%,IP的主要成分是磷灰石磷(AP),占总磷的75-90%。 2.室内模拟实验表明,溶解氧、pH、温度、扰动、上覆水深度、覆盖等对底泥磷向上覆水体释放都有一定影响。在中性条件下,磷释放速率最小,而在酸性条件下,磷释放速率比中性条件下的释放率增加;特别是在碱性条件下,磷的释放速率最大。缺氧加速底泥内磷释放,好氧可抑制其释放,两者数值差一个数量级。温度升高,扰动和上覆水深度都会影响底泥磷释放。底泥覆盖虽然在短时间内会减缓底泥中磷的释放,但对生态系统的破坏是巨大的。pH值和溶解氧是影响底泥内磷释放的最主要的环境因子。更多还原

【Abstract】 Eutrophcation of surface water system is a serious environmental problem in the world. The major factors causing water eutrophication include load of nitrogen (N) and phosphors (P), particularly P. Phosphorus release in sediment plays important roles in supporting algae growth and promote lake eutrophication. However, release and sorption of phosphorus by the sediment are controlled by many factors, including physico-chemical characteristics of sediment and other environmental conditions, such as redox potential, pH, temperature and so on. With the selected Huajia Pool as the representative of the eutrophicated lakes, the objectives of this study were to examine the characteristic of sediment, P release as affected by environmental conditions, and effect of growing submerged plant on P release from the sediment. The results of this study could provide scientific bases for controlling the lake eutrophication. The main results obtained are summarized as follows:1. Phosphorus fractions in sediments are investigated mainly by using the method named "SMT (the Standards Measurements and Testing Program of the European Commission) Protocol", the newest international current classification method of phosphorus. The results showed that major P fractions in the sediment included inorganic phosphorus (IP), organic phosphorus (OP), non-apatite inorganic phosphorus (NAIP) and apatite phosphorus (AP). Two fractions of OP and NAIP exhibited greater potentials of phosphorus release than others. The inorganic phosphorus accounted for 80-95% of the total P content in Huajia pool sediment, and the apatite phosphorus (AP) is the main form of the IP, which accounted for 75-90% of the total P in the sediment,2. A pilot experimental study showed that the dissolved oxygen(DO), pH, temperatures, disturbance, height of overlying water and coverage of the container affected P release rates from the sediment. Phosphorus release rate from the sediment washighest at high pH and smallest at neutral pH conditions. Anoxic condition (oxygen deficiency) stimulated P release, while the aerobic condition could inhibit the P release from the sediment. The increase in temperature, disturbance of the water and increasing height of overlying water influenced P release from the sediment. Covering sediments decreased P release from the sediment, but it will threaten the ecosystem. The pH and DO are the most important factors affecting P release from the sediment.3. Submerged plants play a key role on the control of nutrient release from the sediment, especially phosphorus. The results showed that planting Elodea canadensis L., Myriophyllum spicatum L. and Vallisneria gigantean L. decreased P release from the sediment and nutrient concentration in the water. Among the three plant species, Myriophyllum spicatum L. showed greater effectiveness in inhibiting P release from the sediment than Elodea canadensis L.and Vallisneria gigantean L.. In the shallow lakes, it is of practical value to revive submerged plants like Myriophyllum spicatum L. in the sediment under the conditions with greater disturbances in lake, for the control of phosphate release from the sediment. As floating aquatic plants can’t grow in winter at low temperature, planting submerged plants play a key role in stabilizing the water quality.4. Physical measures alone can not control the release of nutrients from the sediment, whereas aquatic plants especially submerged plants can absorb nutrients and control the nutrients release from the sediment and reduce nutrient concentration in water body. The results from this study indicate that phyoremediation with submerged plants is likely to be a promising technology of solving internal pollution of the lake sediment.更多还原