Groundwater from karst subterranean streams is among the world＇s most important sources of drinking water supplies, and the hydrochemical characteristics of karst water are impacted by both natural environment and people. Therefore, the study of hydrochemistry and its solutes＇ sources is very important to ensure the normal function of life support systems. In this paper, thirty-five representative karst groundwater samples were collected from different aquifers （limestone and dolomite） and various land use types in Chongqing to trace the sources of solutes and relative hydrochemical processes. Hydrogeochemical types of karst groundwater in Chongqing were mainly of the Ca-HCO3 type or Ca （Mg）-HCO3 type. However, some hydrochemical types of karst groundwater were the K＋Na＋Ca-SO4 type （G25 site） or Ca-HCO3＋SO4 type （G26 and G14 site）, indicating that the hydrochemistry of these sites might be strongly influenced by anthropogenic activities or unique geological characteristics. The dissolved Sr concentrations of the studied groundwater ranged from 0.57 to 15.06 ~tmmol/L, and the STSr/S6Sr varied from 0.70751 to 0.71627. The j34S-SO42- fell into a range of-6.8%o-21.5%o, with a mean value of 5.6%o. The variations of both 87Sr/S6Sr and Sr values of the groundwater samples indicated that the Sr element was controlled by the weathering of limestone, dolomite and silicate rock. However, the figure of STSr/S6Sr vs. Sr2＋/[K＋＋Na＋] showed that the anthropogenic inputs also obviously contributed to the Sr contents. For tracing the detailed anthropogenic effects, we traced the sources of solutes collected karst groundwater samples in Chongqing according to the j34S value of potential sulfate sources. The variations of both j34S and 1/ SO42- values of the groundwater samples indicated that the atmospheric acid deposition （AAD）, dissolution of gypsum （GD）, oxidation of sulfide mineral （OS） or anthropogenic inputs （SF： sewage or fertilizer） have contributed to solutes in karst gro
岩溶动力系统中微量元素及其同位素是指示岩溶动力系统运行过程及其环境意义的重要指标。本研究以我国南方亚热带地区典型岩溶动力系统为研究对象,利用高分辨率监测及采样方法研究了暴雨期昼夜尺度上岩溶泉水微量元素Sr及其同位素的变化特征,计算了暴雨条件下的岩溶作用速率。研究结果表明CO_2效应和稀释效应是降雨初期泉水水化学变化的主要控制机制,随后随着流量的持续上升,稀释效应占主导地位。降雨所导致的稀释效应对泉水Sr含量变化影响非常明显,但对岩溶泉水n(^(87)Sr)/n(^(86)Sr)同位素的影响非常有限。降雨期岩溶动力系统内持续的岩溶作用,维持了泉水相对稳定的n(^(87)Sr)/n(^(86)Sr)值特征。通过质量平衡方程计算表明暴雨期内补给的雨水溶蚀灰岩来源的n(^(87)Sr)/n(^(86)Sr)只占泉水总输出n(^(87)Sr)/n(^(86)Sr)的24.3%,当期补给的雨水所引发的CaCO_3净溶蚀速率为0.136 mg/(cm^2·d),其所产生的碳汇通量为1.01 t CO_2。这一结果初步确定了岩溶动力系统中"老水"和新近补给的雨水所导致的溶蚀速率差异和碳汇量差异,这为准确计算降雨诱发的岩溶溶蚀速率和碳汇量准确计算具有十分重要的意义。
