亚高山旅游景区岩溶地下水水化学动态变化及其影响因素

岩溶地下水是岩溶区重要的水资源，因岩溶水文系统具有敏感性和脆弱性，其一旦遭受污染便很难再恢复。以重庆亚高山金佛山水房泉为例，通过计算2008年和2016年各水化学参数的浓度增降幅度和地球化学敏感性指数，对比分析各水化学参数及其地球化学敏感性变化特征。结果表明：水房泉水化学类型为Ca-HCO₃型，受水 岩作用控制。旅游活动产生的生活污水自2013年起被分成两条管道，住宿排污经过泉域内化粪池的沉淀降解后排入地下，使得2016年水房泉中K⁺、Na⁺、PO₄^3-浓度较2008年降低，显示化粪池对污染物具有有效的调节作用；而餐饮排污未经处理仍直接排入地下，导致流域出口水房泉中Cl^-、NO₃^-浓度呈翻倍增长，水质恶化。污水还加剧了碳酸盐岩的溶蚀，地下水中HCO₃^-、Ca²⁺、Mg²⁺浓度上升。由于旅游高峰期与非高峰期的游客量差距逐渐缩小，2016年各化学组分的敏感性指数多低于2008年，地下水受旅游活动影响的时间变长；分别对比不同水文年各主量组分的敏感性指数大小和离子当量浓度大小，发现2008年两者排序基本一致，而2016年较为混乱，这可能表明研究区地下水系统逐渐从有序转向无序的状态，稳定性被破坏，熵值增大。

Geochemical Variation and Its Influence Factors in A Karst Tourist Attraction of Subalpine Area of Chongqing

Karst groundwater is one of the crucial water resources to karst area. Because of its sensitivity and vulnerability, the karst hydrology system is difficult to recover once it is polluted. In this study, by taking the Shuifang spring of Jinfo Moutanin in Chongqing as an example, the variation of hydro chemical parameters and its geochemical sensitivity in 2008 and 2016 were compared and analyzed. Results indicated that groundwater in study area was controlled by water rock interaction and characterized by Ca-HCO₃ type. The sewage from tourism activities has been divided into accommodation and kitchen sewage since 2013. The former was discharged into underground after precipitation and degradation of septic tank, which made concentrations of K⁺, Na⁺, PO₄^3-reduced in 2016 compared with 2008. This reveals the effective regulation role of septic tank to contaminant. However, unprocessed sewage from accommodation was directly recharged the karst aquifer, increasing the concentrations of Cl^- , NO₃^-and deteriorating the groundwater quality. Meanwhile, the concentrations of HCO₃^-, Ca²⁺, Mg²⁺ elevated due to the dissolution of carbonate rock. In addition, because the tourist numbers in peak and off peak was narrowing, the geochemical susceptivity indices of chemical parameters in 2016 were generally lower than 2008, and the time of groundwater influenced by tourism activities was longer. The geochemical susceptivity index of chemical parameters was largely consistent with normal concentration in 2008, but was disorderly in 2016. It maybe indicates that the groundwater system in study area gradually turned from order to disorder, with a destroyed stability and elevated entropy.