向家坝、溪洛渡水库蓄水前后长江上游珍稀、特有鱼类国家级自然保护区水环境质量比较

Comparative study on water quality of National Nature Reserve of Rare and Endemic Fishes in the Upper Yangtze River before and after impoundment of Xiangjiaba and Xiluodu reservoirs

为掌握向家坝和溪洛渡水库蓄水前后,长江上游珍稀、特有鱼类国家级自然保护区水质变化情况,基于2011年12月-2013年保护区渔业环境水质监测数据,对保护区该两阶段水质总体特征进行分析评价,并就水质指标变化做出分析。结果表明,蓄水前后保护区多数水质指标特征总体平稳,变异不大,仅悬浮物及重金属Zn、Cd和Pb变异较大。评价显示蓄水前后保护区水质总体良好,但总氮和总磷均超标,表明保护区存在有机污染的较高风险。蓄水后保护区水温、总氮和硝酸盐氮显著高于蓄水前,p H、悬浮物、氨氮、镁和重金属Cu、Pb、Cd和As显著低于蓄水前,说明蓄水对保护区水质指标可造成不同影响。

To understand the changes of water quality of National Nature Reserve for Rare and Endemic Fishes in the Upper Yangtze River, the general characteristics of water quality before and after impoundment of Xiangjiaba and Xiluodu reservoirs were assessed and the variations were also analyzed based on fishery environmental routine monitoring data from December of 2011 to 2013. The results showed that there was few variations in most of water quality parameters, but suspended solids and heavy metals Zn, Cd and Pb varied greatly. The nevertheless assessment showed that the water quality in the reserve was good on the whole before and after impoundment, the values of total nitrogen （TN） and total phosphorus （TP） were beyond the water quality assessment standard indicating a high risk of organic pollution in the reserve. Compared water quality parameters with those before impoundment, water temperature, total nitrogen and nitrate nitrogen were significantly higher, but pH, suspended solids, ammonia nitrogen, magnesium and heavy metals including Cu, Pb, Cd and As were lower. This result indicated that the water quality parameters would be affected by impoundment in different ways.