[锡林河流域地表水主要离子化学及其可能的控制因素]

Tang Xi-Wen, Wu Jin-Kui

Huan Jing Ke Xue. 2014 Jan;35(1):131-42.

Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in the steppe region in Inner Mongolia is urgently needed. Major ions are widely used to identify the hydrological processes in a river basin. Based on the analysis results of 239 river water samples collected in 13 sections along the Xilin River system during 2006 to 2008, combined with data from groundwater and precipitation samples collected in the same period and the meteorological and hydrological data in the Xilin River Basin, hydrochemical characteristics and the chemistry of major ions of the Xilin River water have been studied by means of Piper triangle plots and Gibbs diagrams. The results showed that: (1) the total dissolved solid (TDS) in river water mainly ranged between 136.7 mg x L(-1) and 376.5 mg x L(-1), and (2) it had an increasing trend along the river flow path. (3) The major cations and anions of river water were Ca2+ and HCO3-, respectively, and the chemical type of the river water varied from HCO3- -Ca2+ in the headwater area to HCO(3-)-Ca2+ Mg2+ in the lower part. (4) The variation in the concentration of major irons in surface water was not significant at the temporal scale. Usually, the concentration values of major irons were much higher in May than those in other months during the runoff season, while the values were a bit lower in 2007 than those in 2006 and 2008. Except for SO4(2-), the concentrations of other ions such as Ca2+, Na+, Mg2+, K+, Cl- and HCO3- showed a upward trend along the river flow path. Comparing major ion concentrations of the river water with those of local groundwater and precipitation, the concentration in river water was between those of precipitation and groundwater but was much closer to the concentration of groundwater. This indicated that the surface water was recharged by a mixture of precipitation and groundwater, and groundwater showed a larger impact. The Gibbs plot revealed that the chemical compositions of the river water were mainly affected by rock weathering in the drainage area.

在水资源短缺和草原退化压力不断增加的情况下，内蒙古草原地区水文循环的信息亟待获取。主要离子被广泛用于识别流域内的水文过程。基于2006年至2008年期间在锡林河水系13个断面采集的239个河水样本的分析结果，结合同期采集的地下水和降水样本数据以及锡林河流域的气象和水文数据，利用派珀三角图和吉布斯图对锡林河河水的水化学特征和主要离子化学组成进行了研究。结果表明：（1）河水中总溶解固体（TDS）主要在136.7mg·L⁻¹至376.5mg·L⁻¹之间，（2）沿河流流程呈增加趋势。（3）河水的主要阳离子和阴离子分别为Ca²⁺和HCO₃⁻，河水化学类型从源头地区的HCO₃⁻ -Ca²⁺变化为下游的HCO₃⁻ -Ca²⁺ Mg²⁺。（4）地表水主要离子浓度在时间尺度上变化不显著。通常，径流季节5月主要离子浓度值远高于其他月份，而2007年的值略低于2006年和2008年。除SO₄²⁻外，Ca²⁺、Na⁺、Mg²⁺、K⁺、Cl⁻和HCO₃⁻等其他离子浓度沿河流流程呈上升趋势。将河水主要离子浓度与当地地下水和降水的浓度进行比较，河水中的浓度介于降水和地下水之间，但更接近地下水浓度。这表明地表水由降水和地下水混合补给，且地下水影响更大。吉布斯图显示，河水的化学成分主要受流域内岩石风化的影响。