长沙水利枢纽工程蓄水后的湘江长沙段重金属污染评价

Assessment of Heavy Metal Pollution of Changsha Section of Xiangjiang River After Water Storage of the Water Hub Project

2014年8月～2015年5月对工程蓄水后的湘江长沙段水体中砷、汞、铅、镉4种主要重金属的污染状况进行了水质监测，并运用改进后的内梅罗指数法进行水体中的重金属污染综合评价。评价计算结果显示，同为饮用水源一级保护水域的黑石铺和杜甫江阁断面水体中汞含量超标率均达到100％，所有断面总超标率为66．7％。多个断面重金属镉监测浓度超过1μg／L，最高浓度为1．469μg／L。工程蓄水前后，水体重金属镉含量基本持平，砷、汞、铅含量均出现不同程度的上升，汞为湘江长沙段污染最严重的重金属。在各个监测断面中，坪塘、黑石铺和杜甫阁断面水质重金属污染严重，其余断面分时段出现轻度污染。

The pollution status of four kinds of main heavy metals As, Hg, Pb and Cd in the Changsha section of Xiangjiang River the after water Hub project during August 2014 to May 2015 was monitored and analyzed. Comprehensively evaluated the heavy metal pollution in water by improved Nemerow index method. The evaluation results showed that at HeiShipu and DuFuge section, which were both in the first - grade protection drinking water source protection areas, Hg content exceeded rates were 100% and 66. 7% of the sections were out of limit. The concentration of Cd in several sections was more than 1μg/L, and the highest concentration was 1. 469μg/L. Before and after the water control project, the Cd content in the water remain unchanged, the content of As Hg and Pb increased in different degrees. Water quality assessment results showed that the heaviest heavy metal pollutant is Hg in Changsha Xiangjiang section. In all monitoring sections, the water quality of section Ping Tang, HeiShipu and Dingzi town was heavily polluted by heavy metals, other sections were mild polluted in some period.