奥陶系灰岩地下水硬度和硫酸盐超标成因分析

Cause Analysis of Hardness and Sulfate Exceeding Standard of Ordovician Limestone Groundwater

河北省峰峰矿区装备A区水源地为奥陶系灰岩地下水,作为研究区主要供水水源,其地下水水质将影响周围居民生活、生产用水安全。根据水质检测结果,研究区奥陶系灰岩地下水总硬度及硫酸盐含量大幅超标。为探究该地区地下水的水质成因,在收集区域水环境资料、实地调查和地质勘探的基础上,开展研究区及其周边水源井水质分析,以pH值、溶解性总固体、总硬度和硫酸盐为主要研究因子,从地表水、煤系地层、特定岩相古地理条件和水文地质条件4个方面分析其水质成因,结果表明:研究区地下水总硬度、硫酸盐含量偏高与地表水和煤系地层无关;膏溶角砾状灰岩的存在是研究区总硬度和硫酸盐含量偏高的内因,属原生水环境因素影响;研究区受滞留区和断层影响导致水动力条件滞缓,形成相对封闭的滞留环境使得离子富集,独特的地质构造是区域总硬度和硫酸盐含量偏高的外因。

The water source of equipment area A in Fengfeng mining area of Hebei Province is Ordovician limestone groundwater.As the main water source for the study area,its groundwater quality issues will seriously affect the lives and production safety of the surrounding residents.According to the water quality test results,it can be seen that the total hardness and sulfate concentration of the groundwater in the Ordovi⁃cian limestone in the study area have been seriously exceeded.Therefore,in order to explore the cause of the special water quality of ground⁃water in this area,on the basis of collecting regional water environment data,field investigation and geological exploration,this paper carried out the water quality test of the well in the study area and its surrounding water sources.Taking pH value,total dissolved solids,total hard⁃ness and sulfate as the main research factors,the special water quality genesis was analyzed from four angles of surface water,coal formation,specific lithofacies palaeogeographic conditions and hydrogeological conditions.The results show that the total hardness of groundwater and high sulfate in the study area have nothing to do with surface water and coal strata;The presence of gypsum breccia limestone is the internal cause of the high total hardness and high sulfate concentration,which is influenced by the original water environment;The study area is af⁃fected by the retention zone and faults,which leads to the stagnation of hydrodynamic conditions.Therefore,the closed retention environment makes the ions enrich.The unique geological structure is the external cause of the high total hardness and sulfate concentration.