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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HCO_3-Ca型,HCO_3~-和Ca~(2+)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~+、Mg~(2+)、Cl~-、SO_4~(2-)、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_3~-和Ca~(2+)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。
Based on the sampling and analysis data of Gui Jiang Guilin Station from October 2013 to April 2015, this paper discusses the chemical composition of water and the main sources of river water in the upper reaches of the Guijiang River. The results show that the chemical type of river water is HCO_3-Ca, and HCO_3 ~ - and Ca_ (2) are the main cations and anions, mainly due to the weathering and dissolution of carbonates in the watershed, the main ion concentration Influenced by the change of flow, the trend of winter and summer and summer and low is presented. At the same time, sulfuric acid in the basin is also involved in the weathering of carbonate rocks. In addition, although the carbonate rocks in the catchment are only distributed in small quantities, the hydrochemical characteristics of the river water are still controlled jointly by carbonate and silicate rocks. The principal component analysis showed that the contribution rate of the first factor was 38.8%, which was highly correlated with K ~ +, Na ~ +, Mg ~ (2 +), Cl ~ -, SO4 2-, NO3 ~ In the present study, the effects of anthropogenic activities and atmospheric deposition on NO 3 - are mainly from non-point source pollution of agricultural activities in the basin. The contribution rate of the second factor is 28.2%, which is related to HCO 3 ~ - and Ca 2+ Large, representing the dissolution of carbonate rocks; the third factor has no obvious indication of high load.