五里湖综合整治对湖水水质的影响

Influences of comprehensive treatment on water quality in Wuli Bay of Taihu Lake

为探讨湖泊综合整治工程对城市湖泊水质的改善效果,利用国家野外科学观测研究站江苏太湖湖泊生态系统研究站1998—2009年的监测数据,结合湖体与环湖河道调查,分析了太湖五里湖综合整治工程对水质的改善效果.结果表明:综合整治之后,总氮、总磷及叶绿素a质量浓度平均值显著下降(P<0.01),分别由6.06mg/L,0.183mg/L和0.060mg/L降为3.48mg/L,0.133mg/L及0.024mg/L;而湖体透明度、悬浮颗粒物含量等感观指标无明显改善;退渔还湖区及其入湖河道水质明显优于更靠近城区的东出口区.营养盐含量环湖河道显著高于湖体,底泥中也较高,对湖体的生态恢复构成很大威胁.与太湖其他几个湖区相比,五里湖的营养盐含量仍然较高.研究表明,五里湖实施的综合整治措施在很大程度上改善了湖泊重污染的状况,但要获得稳定的高透明度景观水质,还需要实现湖泊水生态系统的深度调控,包括采取环湖河道的同步治理及湖体大面积沉水植被恢复等措施.

In order to evaluate the impacts of the comprehensive treatment project on the lake water quality,the effect of the comprehensive treatment project in the Wuli Bay of the Taihu Lake on the water quality was analyzed using the ten years of monitoring data from the Taihu Lake ecosystem research station.The results show that after the comprehensive treatment,the mass concentrations of total nitrogen（TN）,total phosphorus（TP）,and chlorophyll a（Chl-a） decrease significantly（P0.01）,from 6.06 mg/L,0.183 mg/L,and 0.060 mg/L to 3.48 mg/L,0.133 mg/L,and 0.024 mg/L,respectively.However,there were no obvious improvement in transparency and suspended solid content.The water quality improvement in the zone of transforming fishing to lake and rivers entering the lake was more effective than that in the east exit near the city zone.The nutrient content in the rivers around the WuliBay is significantly higher than that in the lake.It is also high in the sediment,which causes a threat to lake ecological restoration.The nutrient content in the Wuli Bay is higher than that in other lakes.The comprehensive treatment in the Wuli Bay improves the water pollution to a great extent.But it is necessary to implement the depth control of water ecosystem for high transparency,including comprehensive treatment of the rivers around the lake and restoration of submerged vegetation in the lake.