摘要:
本文根据2013年10月至2015年4月桂江桂林站的采样分析数据,讨论桂江上游的水化学组成及河水离子的主要来源.结果表明,研究区河水水化学类型为HCO3-Ca型,HCO3和Ca2+是主要的阴阳离子,主要来源于流域内碳酸对碳酸盐岩的风化溶解,河水主要离子浓度受流量变化的影响,呈现出冬高夏低的趋势.同时,流域内硫酸也参与了碳酸盐岩的风化.此外,虽然流域内碳酸盐岩仅少量分布,但河水水化学特征仍受碳酸盐岩和硅酸盐岩的共同控制.主成分分析结果表明,第一因子贡献率为38.8%,与K+、Na+、Mg2+、Cl、SO24-、NO-3相关性较大,在本研究中代表人类活动及大气沉降的影响,其中NO-3主要来源于流域内农业活动的面源污染;第二因子贡献率为28.2%,与HCO;-和Ca2相关性大,代表碳酸盐岩的溶解;第三因子没有明显具有高载荷的指标.
Abstract:
In order to discuss the hydrochemical composition variation and the source of dissolved ions in the upper stream Guijiang river,observations and sampling were undertaken in October 2013 to April 2015.The results show that the hydrochemistry type of Guilin section is of HCO3-Ca type.Ca2+ and HCO3 are the main cations and anions,which are mainly from the weathering of carbonate rocks in the basin.The concentration of ions is controlled by the river flow,which is higher in the winter while low in the summer.Meanwhile,the sulfate also takes part in the carbonate weathering in the basin.The hydrochemistry of Guijiang upstream is controlled by carbonate as well as silicate rocks,even though there is much limited carbonate rocks occur in the basin.Analysis of principal compositions shows that the contribution ratio of the first factor is 38.8%,well correlated with K+,Na+,Mg2+,Cl,SO24-and NO-3,representing the influence of human activity and precipitation on the water.And the contribution ratio of the second factor is 28.2%,including HCO3 and Ca2-,which indicates the solution of carbonate rocks.In addition,there is no significantly effective load indicator of the third factor.
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