引水工程絮凝剂余铝对杭州西湖水体、底泥铝盐分布的影响

摘要

Aluminum salt content in the water body and sediment of Hangzhou West Lake was investigated to study the effects of residual aluminum flocculant on aluminum salt content of water,sediment and attachments on submerged macrophyte.The results show that:(1) Aluminum ion content of water inlets is higher than that of the central lake,which caused by residual aluminum flocculants from Diversion Project,while Al2O3 content of sediment tend to be distributed evenly across the lake and is not affected by the Diversion Project;(2) With the flow velocity of about 0.04 to 0.20 m/s,submerged macrophyte can easily become attachment receptors to residual aluminum flocculate,but is slightly weaker than sediment in the ability of attaching Al2O3 content;(3)Aluminum ion content of water is high in autumn and winter,which may potentially cause greater biological harm to aquatic organism in the lake.Therefore,it is important to restore submerged macrophyte in autumn and winter seasons.Effect of Diversion Project on the West Lake water body is essential but unpredictable.It should be possible to reduce the negative impact of Diversion Pmject.The use of flocculant can be reduced or environmentally friendly flocculant can be chosen instead,and appropriate aquatic plants may be cultivated near water inlets.%通过对杭州西湖综合保护工程钱塘江引水范围内多个湖区水体和底泥中铝盐含量的调查分析,研究了工程絮凝剂余铝对西湖水体、底泥铝盐及沉水植物附着物的影响.结果表明:(1)引水工程输入的絮凝剂残余铝盐导致各湖区入水口水中铝离子含量普遍高于湖心,高出7.86％～ 288.55％不等,但底泥中Al2O3含量在整个湖区分布较为均匀;(2)约0.04～0.20 m/s流速下,沉水植物很容易成为残余铝盐絮凝物的附着受体;(3)秋、冬季水体中铝离子浓度较高,对西湖水生生物存在更大的生物潜在危害,有必要重视秋、冬季的沉水植物恢复工作.引水工程对西湖水体的影响是长久且难以预见的,在引水的同时应尽量减少其负面影响,可减少絮凝剂的使用或选择环保型絮凝剂,并选择合适的水生植物.