Cui Jia-Qi, Li Xian-Yue, Shi Hai-Bin, Sun Ya-Nan, An Hai-Jun, Xing Jin-Ping
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Administration of Yongji Irrigation Area of Hetao Irrigation District, Bayannur 015000, China.
Huan Jing Ke Xue. 2020 Sep 8;41(9):4011-4020. doi: 10.13227/j.hjkx.202003150.
Groundwater resources are important sources of water in the arid region of northwestern China, but their overexploitation and utilization has led to a series of ecological and environmental problems. Exploring the characteristics and mechanism of groundwater chemical evolution is important for the rational use of groundwater resources. The characteristics of groundwater chemical evolution were studied in the Yongji Irrigation Area of Hetao Irrigation District and the formation mechanism of the chemical compounds in groundwater were investigated using cluster analysis, factor analysis, and other statistical methods. The influence degree of different factors was calculated. The results showed that the major cations in groundwater in the study area were Na and K, and the major anions were Cl and HCO. Moreover, Na, K, and Cl showed high spatial variability and were the main factors contributing to groundwater salinization. The major chemical compounds in the groundwater in the study area were Cl-Na, HCO ·Cl ·SO-Na, and HCO-Na. Based on the cluster analysis results, the groundwater was divided into four categories (A, A, B, and B), of which A was highly mineralized by Cl-Na type water, while A, B, and B were mainly HCO ·Cl ·SO-Na and HCO-Na type water. Principal component analysis results suggest that groundwater chemistry was mainly affected by salinization, carbonate karstification, and human activities with the influence degrees of 45.976%, 23.853% and 16.678%, respectively. Evaporation, salt rock dissolution, and cation exchange were important sources of Na and Cl accumulation in the irrigation area. Agricultural irrigation (leaching of soil salts) and drought (intense transpiration) were the key drivers of groundwater salinization in the irrigation area.
地下水资源是中国西北干旱地区重要的水源，但对其过度开发利用已引发了一系列生态环境问题。探究地下水化学演化特征及机制对于合理利用地下水资源具有重要意义。本文以河套灌区永济灌域为例，研究了地下水化学演化特征，并运用聚类分析、因子分析等统计方法，探讨了地下水中化合物的形成机制，计算了不同因素的影响程度。结果表明，研究区地下水中主要阳离子为Na和K，主要阴离子为Cl和HCO。其中，Na、K、Cl空间变异性大，是导致地下水盐渍化的主要因素。研究区地下水中主要化合物类型为Cl-Na、HCO·Cl·SO-Na和HCO-Na。基于聚类分析结果，将研究区地下水划分为4类（A、A、B、B），其中A类为Cl-Na型高矿化水，A、B、B类主要为HCO·Cl·SO-Na和HCO-Na型水。主成分分析结果表明，研究区地下水化学主要受盐渍化、碳酸盐岩岩溶作用和人类活动影响，其影响程度分别为45.976%、23.853%和16.678%。蒸发、盐岩溶解及阳离子交换是灌区Na和Cl积累的重要来源；农业灌溉（土壤盐分淋洗）和干旱（强烈蒸腾作用）是灌区地下水盐渍化的关键驱动因素。
