混合作用下地表水的水文地球化学效应研究

Study on Hydro-geochemical Effects of Surface Water under Mixed Effect

分析黄陵县境内混合前沮河、建庄川河和混合后沮河水化学组分特征的基础上,采用Cl^-质量守恒法对沮河与建庄川河的混合比例进行了计算,并结合Gibbs图和矿物饱和指数对地表水混合过程中发生的水文地球化学作用进行了阐释。研究结果表明:受混合作用的影响,汇入建庄川河后的沮河水中TDS、K^+、Na^+、Ca^(2+)、Mg^(2+)、Cl^-含量相对于汇入前沮河水明显上升,SO_4^(2-)含量明显下降,水质变差。混合河水中建庄川河水与沮河水的混合比例分别为69.26%和30.74%。Gibbs图显示混合前沮河、建庄川河和混合后沮河的水化学组分主要受岩石风化和人类活动的共同影响。在沮河水与建庄川河水混合过程中,由于方解石沉淀和石膏溶解及其影响下的去白云石化等水文地球化学作用形成了低Ca^(2+)、Mg^(2+),高SO_4^(2-)的Na-Mg-Cl型水。

By analyzing the characteristics of chemical composition of Juhe river, Jianzhuangchuanhe river and mixing river, this paper used the mass balance of Cl^- to calculate the mixing proportion of Juhe river and Jianzhuangchuanhe river. Combined with the Gibbs figure and saturation index(SI) of mineral,this paper analyzed the hydrogeochemical action in the mixing process of surface water. Results showed that, compared with Juhe river, the contents of TDS, K^+, Na^+, Ca^(2+), Mg^(2+), Cl^- of mixing river increased significantly, but the content of SO_4^(2-) decreased significantly. The mixing proportion of Jianzhuangchuanhe river was calculated to be 69. 26%.Gibbs figure showed the major chemical composition of Juhe river, Jianzhuangchuanhe river and mixing river were controlled by rock weathering and human activities. In the mixing process of Juhe river and Jianzhuangchuanhe river, the Na-Mg-Cl type water with low-content Ca^(2+), Mg^(2+)and high-content SO_4^(2-) were formed by the hydrogeochemical actions including calcite precipitation, gypsum dissolution and dolomitization.