岩溶易旱区地下水水文地球化学特征及其控制因素——以兴仁县为例

地下水是岩溶易旱区极其重要的水资源,是当地生态环境和人类生存的基本保障。通过收集整理岩溶易旱区兴仁县地下水水化学数据,分析与研究,发现岩溶易旱区地下水的溶解组分主要来源于碳酸盐岩的溶蚀,水化学类型主要为HCO_3-Ca型和HCO_3-Ca·Mg型,部分地区由于受到岩层中石膏夹层溶解的影响,水化学类型为HCO_3·SO_4-Ca·Mg型。地下水中Ca~(2+)、Mg~(2+)、HCO_3~-等离子受流经区域地层岩性和水-岩相互作用的影响,表现出显著的区域性特征,属自然来源;K~+、Na~+、Cl~-、NO_3~-等指标与人类活动关系密切,SO_4~(2-)受水-岩相互作用和人类活动共同影响。岩溶易旱区地下水水文地球化学容易受到人为活动的干扰且日趋明显,降低人为活动对岩溶地下水的影响是确保岩溶易旱区地下水环境及饮水安全的关键。

Hydrogeochemical Characteristics of Groundwater of Arid Zone of Karst Region and Its Controlling Factors:Case for Xinren County

Groundwater is an extremely important resource and basic material for human life and natural ecosystems in arid zone of karst areas. Data for groundwater chemistry of Xingren County, Guizhou Province, China were collected to illustrate the characteristics of chemical components, spatial variations and controlling factors. Three chemical types of groundwater were recognized; Ca²⁺, Mg²⁺ and HCO₃^- are mainly derived from the dissolution of carbonate rocks and characterized by HCO₃-Ca type and HCO₃-Ca·Mg type; the SO₄^2- are predominated by both dissolution of sulfate evaporates(e.g.gypsum) in karst aquifer and anthropogenic in origin and characterized by HCO₃·SO₄-Ca·Mg type; the K⁺, Na⁺, Cl^- and NO₃^- are principally allochthonous origin. The hydrogeochemical characteristics of groundwater in arid zone of karstic areas are increasingly impacted by human activities. Decreasing human activities impacts on karstic groundwater is a key to protect drink water and groundwater environment.