怒江源区那曲河水化学特征的多元统计分析

Multivariate Statistical Analysis of the Hydrochemical Characteristics of the Naqu River in the Source Region of the Nujiang River

探讨自然背景条件下河流水化学特征对于流域管理和保护具有重要意义。那曲河流域是怒江源区,受到人类活动的影响较小,以2018年8月采集的那曲河干流及主要支流的河水样品为例,应用描述性统计、聚类分析、因子分析等多元统计分析方法,研究了那曲河流域河流的水化学特征及主离子来源。结果表明:①那曲河流域河水呈弱碱性,河水TDS含量的变化范围为120.00~512.00 mg/L,平均值为232.92 mg/L。②那曲河流域河水阳离子浓度均值由大到小的顺序为Ca 2+、Na+、Mg 2+、K+,阴离子浓度均值由大到小的顺序为HCO-3、SO4^2-、Cl-。③那曲河干流中游的水化学类型为重碳酸盐类-镁组,龚曲干流的水化学类型为硫酸盐类-钙组,那曲河干流的上游与下游以及其他支流的水化学类型为重碳酸盐类-钙组。④那曲河流域河流的水化学特征控制机制以岩石风化为主。⑤那曲河干流上游与那曲河干流中下游以及那曲河支流的水化学特征差异较大。

It is of great significance for watershed management and protection to explore the characteristics of river hydrochemistry under natural background conditions.Naqu River basin is the source region of Nujiang River,which is less affected by human activities.Taking the water samples of the main stream and main tributaries of Naqu River collected in August 2018 as an example,with the application of different multivariate statistical techniques such as descriptive statistics,cluster analysis and factor analysis,the hydrochemical characteristics and main ion sources of Naqu River basin were studied.The results are as follows.Firstly,the river water of Naqu River basin was mildly alkaline.TDS values varied from 120.00 to 512.00 mg/L with an average value of 232.92 mg/L.Secondly,the order of the average cation concentration from large to small is Ca 2+,Na+,Mg 2+,K+,and the order of the average anion concentration from large to small is HCO-3,SO4^2-,Cl-.Thirdly,the hydrochemistry type in the middle reaches of Naqu River is HCO-3-Mg 2+group,and the hydrochemistry type in the Gongqu River is SO4^2--Ca 2+group,as well as the hydrochemistry types in the upper,lower reaches of Naqu River and its other tributaries are HCO-3-Ca 2+group.Fourthly,the control mechanism of hydrochemistry characteristics of rivers in the Naqu River basin is mainly rock weathering.Finally,the hydrochemistry characteristics of the upper reaches of Naqu River are quite different from those of the middle and lower reaches of Naqu River and its tributaries.