草海流域水质时空分布特征及污染评价

为揭示草海流域水质的空间分布特征,对草海不同断面空间水体进行布点采样,参照《地表水环境质量标准》(GB 3838—2002)对水体主要污染指标进行检测,采用单因子污染指数法对草海水质进行了评价,探究草海水体污染物源以及变化规律。结果表明:草海丰水期DO、COD_Mn、COD_Cr、TP较枯水期高,其余的污染指标也表现为枯水期较好;水质指标总体上在码头通往湖中心方向的这段水域表现最差;COD_Mn和TP对草海水质产生的影响较大,超标指标主要为COD_Mn和COD_Cr;草海码头和草海出口处的水域的水质污染较重,其余水质相对较好。草海各断面空间的水质类别总体上在Ⅳ—Ⅴ类之间。草海流域应着力Ⅳ类水域治理,扩大Ⅲ类水域占比,从而缩减Ⅴ类水域,这对改善草海流域水质具有重要意义。研究成果可为草海流域污染防治及合理开发提供理论依据。

Spatial and Temporal Features and Pollution Evaluation of Water Quality in Caohai Lake

The purpose of this study is to reveal the spatial distribution of water quality in Caohai Lake watershed, and to provide a theoretical basis for pollution prevention and rational development in Caohai Lake watershed. Water samples were collected from different sections of the lake and were tested to identify major pollutants in line with Environmental Quality Standards for Surface Water (GB 3838-2002). Furthermore the water quality of Caohai Lake was evaluated. Results showed that the concentrations of DO, COD_Mn, COD_Cr and TP of Caohai Lake in wet season are higher than those in dry season, and other pollutants are also lower in dry season. COD_Mn, COD_Cr and TP have greatest impact on water quality, among which COD_Mn and COD_Cr are two major standard-exceeding indexes. In general, the water quality in the area between pier and lake center is the worst, and the water quality at the outlet of the lake is also inferior. The water quality of Caohai Lake is generally between Ⅳ-class and Ⅴ-class. Treating Ⅳ-class water, expanding Ⅲ-class waters, and reducing Ⅴ-class water area is of great significance for improving the water quality of Caohai watershed.