太湖流域典型支沟生态环境调查研究——以新沟河为例

为应对太湖流域水污染问题,我国2005年开始实施了引江济太工程,提高了太湖湖区和引排干流的水体自净能力和水环境容量,而对于太湖流域众多分支河网水质的直接改善作用有限,该部分相关研究与关注也较少。以引江济太工程主要通道新沟河为例,选取典型支沟(湖)开展多种生态环境因子的调查与分析。研究结果表明:支沟(湖)均为Ⅳ类以下水质,其中大部分为劣Ⅴ类,主要特征污染因子为氮磷营养盐等;浮游植物Shannon-Wiener多样性指数和Pielou均匀度相对较高的河段出现在北阳湖、西横河西段等区域。总体上支沟(湖)生态环境情况空间分布特征明显,环境质量健康程度如水质级别、富营养化程度、生物物种多样化和均匀化等指标,均与不同区域的水体交换能力和环境容量表现出显著的相关性。从污染源的角度来看,支沟(湖)的生态环境威胁主要来自于生活污水排放与富营养化等陆源污染。

Eco-environment investigation on typical branches in Taihu Lake: case of Xingou River

To cope with the water pollution of Taihu Lake, water diversion project from Yangtze River to Taihu Lake has been started since 2005 and the project improved the self-purification capacity of the main water diversion channel and lake. However the direct improvement on numerous drainage branches of the lake network was limited, relative study were not too much. Taking the main diversion channel of the Xingou River as a case, this paper investigates multiple eco-factors in typical branches (or sub-lake) and analyzes the pollution conditions. The research results show that the water quality of branches (or sub-lake) was inferior to classification IV, most of which are inferior to classification V, with the main pollutant factors of N, P nutritive salt. The river reaches with higher Phytoplankton Shannon-Wiener diversity index and Pielou homogeneity index were located in Beiyang sub-lake, west part of Xiheng sub-lake. In general, the spatial distribution characteristic of eco-environment of drainage branch (or sub-lake) was distinct. The health degree of environment quality, such as water quality classification, eutrophication degree, biological diversity and homogeneity etc., have significant relation with water exchange capacity and environment capacity. In the view of pollution sources, land-based pollution of domestic sewage and eutrophication etc. are dominant to the drainage branch or sub-lake.