2009年太湖水域“湖泛”监测与分析

Monitoring and analysis on "Black Water Aggregation" in Lake Taihu,2009

"湖泛"是太湖水域近年来发生的重要环境灾害问题之一.根据2009年4-10月的太湖"湖泛"易发区巡测和跟踪监测资料,分析了2009年太湖水域"湖泛"发生情况.2009年太湖共发生11次小范围"湖泛",主要发生在太湖西岸、梅梁湾和贡湖湾局部水域.对比近年"湖泛"发生水域的水质指标,以及同期太湖蓝藻水华暴发、湖体水质及其变化情势,认为蓝藻水华强度、频次和面积与2007、2008年相比呈明显的下降趋势,从而可能降低了大面积"湖泛"暴发的机率;同时,2007年以来在太湖北部湖湾的生态清淤工程也降低了北部湖湾发生大面积"湖泛"的可能性.同期水质监测指标显示,2009年同期太湖水质综合评价为Ⅳ类、中富营养状态,而太湖湖西、竺山湖、梅梁湾水域仍为Ⅴ类或劣Ⅴ类,"湖泛"仍时有发生.蓝藻打捞、生态清淤、控源截污、"引江济太"调水是预防太湖"湖泛"的有效措施;同时,加强太湖"湖泛"巡查,建立太湖"湖泛"监测预警系统,及时发现太湖"湖泛",有序、妥善地处置黑臭水体,将对确保太湖饮用水水源地安全起到积极的作用.

＂ Black Water Aggregation＂ （BWA） is one of the most serious environmental hazards occulted in Lake Taihu. Based on the investigation in relevant areas during Apr. Oct. ,2009,the BWA status was analysed. 11 BWA were observed in western Lake Taihu, Meiliang Bay and Gonghu Bay. Comparison of blue-green algal blooms, water level, water-quality in recent years gave insight to the further understanding of BWA. The algal bloom was less serious in intensity,frequency and scale in 2009 than in 2007 and 2008, which reduced the possibility of BWA outbreak. In addition, the ecological dredging project undertaken in northern Lake Taihu since 2007 also functioned for the less serious BWA in 2009. Invertigations of water quality revealed that the lake was still under meso-eutrophic as a whole whereas the western Lake Taihu, Meiliang Bay and Lake Zhushan was hyper eutrophic. In order to mitigate and control the BWA, measures such as algae salvage, ecological dredging, source control and interception and water diversion from the Yangtze River to Lake Taihu. More efficient invertigation in relevent BWA-sensitive areas and setup of monitoring-warning system for BWA are favored for early assertainment and instant handling of BWA,which offers technical guarantee for water supply in Lake Taihu.