长沙水利枢纽工程蓄水前湘江长沙段水质评价

对湘江长沙段6个断面进行水质监测,用长沙水利枢纽工程施工前制定的水质标准评价后,发现其中大部分断面水质指标均符合相应标准,在平水期COD均超出标准,部分断面超标1.0～2.5倍,而丰水期TP质量浓度普遍较高,最高达到0.62mg/L,同时期铅、砷浓度均未超标,而枯水期镉在上游段超标1.15倍。研究表明,湘江长沙段仍存在污染问题,且该流域各污染物浓度与湘江水位关系密切,但整体水质未见恶化,工程建设对其影响不大,工程运营后该段水体富营养化污染的风险变大。

Water quality monitoring of Changsha section of Xiangjiang River before impoundment of Changsha Water Conservancy Project

The water quality in six reaches of the Changsha section of the Xiangjiang River was monitored. According to the water quality standards that were established before implementation of the Changsha Water Conservancy Project, it was found that the water quality indices in most of the sections met the requirements; the COD in the dry seasons exceeded the standard on average, and exceeded it one to 2.5 times in part of the sections; in the wet seasons, the concentration of TP was generally high, with its maximum value being 0.62 mg/L, and the concentrations of lead and arsenic did not exceed the standards; and the concentration of cadmium in the upstream section exceeded the standard 1.15 times in the dry seasons. This study shows that the water in the Changsha section of the Xiangjiang River has been polluted, and the concentrations of the pollutants in the basin have a close relationship with the water level of the Xiangjiang River. However, the overall water quality has not deteriorated, the project construction has had little impact on the water quality, and eutrophication is more likely to occur due to the implementation of the project.