娘子关泉群水化学特征及成因

娘子关泉群流量7.19m³·s^-1，提水量约1.7 m³·s^-1，其是阳泉市区和平定县城主要供水水源.查明其泉群水化学特征及成因，对合理利用水资源与污染防治具有重要意义.以娘子关泉域岩溶大泉为研究对象，通过样品采集和水化学同位素，以地球科学系统理论为指导综合运用地质构造、水化学监测和同位素方法分析娘子关泉群水化学特征及成因.娘子关泉群其pH值7.2~7.5.钙离子112.1~135.2 mg·L^-1.硫酸根离子185.6~271.8 mg·L^-1.水化学类型为HCO₃·SO₄-Ca·Mg.泉群水化学特征总体表现为高Ca²⁺、Mg²⁺和SO₄^2-，低Na⁺、K⁺和Cl^-.城西泉的补给路径较短，其次是五龙泉.其余5组泉补给路径较远.娘子关泉群水化学特征表现为：煤矿酸性排水的污染有加剧趋势，生活污水的污染有减缓趋势.环境同位素示踪显示城西泉的SO₄^2-主要来源于大气降水和石膏溶解.五龙泉的SO₄^2-值增加，其变化主要受煤矿酸性水污染量的影响.

Chemical Characteristics and Causes of Groups Water in Niangziguan Spring

Discharge in Niangziguan Spring is 7.19 m³·s^-1, which is the main water supply source for Yangquan City and Pingding County. Every year, Yangquan municipal government take water from the mouth of Niangziguan Spring to supply drinking water to urban residents at a rate of approximately 1.7 m³·s^-1. It is of great significance to determine the characteristics and causes of variations in spring water flow conditions for the appropriate utilization of water resources and pollution prevention. Here, sample collection and hydrochemical isotope analyses were undertaken for the Niangziguan Spring area to chemically characterize the water environment and genesis. The pH of the karst spring is 7.2-7.5 with an average of 7.36; the calcium content of the water is 112.1-135.2 mg·L^-1 with a mean value of 131.4 mg·L^-1; the concentration of magnesium ions is 34.8-42.3 mg·L^-1 with an average of 40.8 mg·L^-1; the concentration of K⁺+Na^- ions is 41.6-46.7 mg·L^-1 with an average of 45.2 mg·L^-1; and the sulfate ion concentration is 185.6-271.8 mg·L^-1 with a mean value of 255.4 mg·L^-1. The hydrochemical type of the aquifer is classified as HCO₃·SO₄-Ca·Mg. The spring water is characterized by high Ca²⁺, Mg²⁺, and SO₄^2- concentrations, and low Na⁺, K⁺, and Cl^- concentrations. The supply path of Chengxi Spring is shortest followed by Wulong Spring. The supply paths of the remaining five spring are much longer. The Niangziguan Spring water environment is characterized by increasing pollution from coal mine acid drainage alongside decreasing inputs from domestic sewage. Environmental isotope tracing shows that sulfate in Chengxi Spring mainly derives from precipitation and gypsum dissolution, and the concentrations of sulfate in Wulong Spring are increasing. These changes are mainly driven by the amount of coal mine acid water pollution in the area.