2017—2019年祁连山国家公园水库水质特征及综合评价

2017—2019 Qilian Mountain typical reservoir water pollution characteristics and water quality evaluation

本文以祁连山公园内水库为研究对象,选取祁连山6座水库2017—2019年的pH、氨氮(NH_(3)-N)、高锰酸盐指数(COD_(Mn))、总氮(TN)、总磷(TP)、粪大肠菌群数等监测年平均数据作为水质评价指标,分析了不同水库水质污染特征,分别采用单因子评价法、综合污染指数法、主成分分析法对水质进行综合评价.结果表明:各水库pH波动较小,水体整体呈中性偏弱碱性;各水库TN波动较大,浓度较高.单因子评价结果表明在2017年至2019年间,不考虑TN浓度时,水库评价结果基本为Ⅰ类、Ⅱ类与Ⅲ类水体,且Ⅰ类水体占比最高,水库水质评价结果较好.综合污染评价法显示,6座水库中大靖峡水库水质最差,主要污染物为有机物与总氮.主成分分析法得出各水库不同年份水质理化性质存在一定差异,与第一第二主成分高度相关的指标因子是TN与NH_(3)-N,2017年主成分得分最高,水质最差,2018年、2019年主成分得分减小.3种评价结果均显示,自2017至2019年祁连山水库水环境质量好转.通过3种方法定性定量的有机结合,得出祁连山国家公园水质主要限制因子为有机物、氮、磷及微生物指标,探明污染源并进行有效治理可以显著提高祁连山水环境质量,对祁连山国家公园内环境修复具有一定指导意义.

This paper takes the reservoirs in the Qilian Mountain Park as the research object,and selects the pH,ammonia nitrogen(NH3-N),permanganate index(COD_(Mn)),total nitrogen(TN),total phosphorus(TP),The annual average monitoring data such as the number of fecal coliforms are used as water quality evaluation indicators.The water quality pollution characteristics of different reservoirs are analyzed,and the single factor evaluation method,comprehensive pollution index method,and principal component analysis method are used to comprehensively evaluate the water quality.The results showed that the pH fluctuation of each reservoir was small,and the water body was neutral and weakly alkaline as a whole;the TN of each reservoir fluctuated greatly,and the concentration was high.The single-factor evaluation results show that from 2017 to 2019,without considering the TN concentration,the reservoir evaluation results are basically type Ⅰ,Ⅱ and Ⅲ water bodies,and the water bodies of type Ⅰ account for the highest proportion,and the water quality evaluation results of the reservoir are better.The comprehensive pollution evaluation method shows that the Dajingxia Reservoir has the worst water quality among the 6 reservoirs,and the main pollutants are organic matter and total nitrogen.The principal component analysis method shows that there are certain differences in the physical and chemical properties of the water quality of each reservoir in different years.The index factors that are highly related to the first and second principal components are TN and NH_(3)-N.The principal component score was the highest in 2017 and the water quality was the worst,2018—2019.The annual principal component score decreases.The three evaluation results all show that the water environment quality of Qilianshan Reservoir has improved from 2017 to 2019.Through the qualitative and quantitative organic combination of the three methods,it is concluded that the main limiting factors for the water quality of Qilian Mountain National Park are organic matter,nitrogen,phosphorus and microbial indicators.The identification of pollution sources and effective treatment can significantly improve the water environmental quality of Qilian Mountain,which has a significant impact on the environment in Qilian Mountain National Park.Repair has certain guiding significance.