典型岩溶槽谷区降雨条件下地下河水质短时间尺度变化过程研究——以重庆南山老龙洞地下河为例  

Short Time-Scale Change of Underground River Water Quality in a Typical Karst Trough Valley Area Under Rainfall Conditions ——A Case Study of the Underground River in Nanshan Laolong Cave,Chongqing

作　　者：郑洁[1] 李林立[1,2] 曹敏[1] 罗健[1] 吴金权[1] 

机构地区：[1]西南大学地理科学学院,重庆400715 [2]西南大学岩溶环境与石漠化治理研究所,重庆400715

出　　处：《西南大学学报（自然科学版）》2012年第12期130-136,共7页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(41172331);国家自然科学基金资助项目(41040026);中央高校基本科研业务费支项资金资助项目(XDJK2011B3003);国土资源部地质调查项目(1212011087119);国土资源部公益性行业科研专项(201111022);国土资源部岩溶动力学重点实验室开放课题(KDL2011-01);西南大学博士基金资助项目(SWU109050)

摘　　要：采用CTDP300多参数水质自动记录仪对重庆市南山老龙洞地下河出口处的地下水在降雨条件下水位、水温、pH值和电导率进行监测,以及2h时间间隔的地下水水化学指标(HCO3-,Ca2+,Mg2+,NO3-,PO34-,SO24-,Fe2+,Mn2+,Ba2+)测定,根据监测数据进行分析对比,结果表明:监测期间南山老龙洞地下河水质变化与降雨、气温以及流量表现出良好的响应关系,降雨前后水质变化明显,这可能是因为降雨的稀释作用以及大流量、快流速使水体中CO2由于水体的扰动逸出,导致HCO3-质量浓度低.随后由于降雨停止,HCO3-质量浓度升高.可能与此时的水受到来自岩溶洼地水和来自裂隙水的补给有关,并且HCO3-与水温的关系为负相关.Ca2+与Mg2+质量浓度在降雨初期随降雨量的增多而减小,之后开始上升,与雨水的稀释有关,但是其最高值不在降雨量的最大值.NO3-,PO34-,SO42-的质量浓度随降雨的到来和流量的增加而升高.Fe2+,Mn2+,Ba2+质量浓度在降雨初期迅速上升,Mn2+在降雨过后,快速下降.降雨初期,各种离子的变化受雨水稀释作用控制,降雨停止后,表层岩溶带的高裂隙率和渗透性开始发挥作用,水动力条件和CO2效应占主导,进而影响水质的变化.The quality of groundwater under rainfall conditions at the outlet of the underground river in Nanshan Laolong Cave of Chongqing was monitored round the clock. Its water level, water temperature, pH, conductivity and various chemical indicators （HCO3 , Ca2＋ and Mg2＋ , NO3 , POa , SO24 and Fe2＋ , Mn2＋ and Ba2＋） were recorded at two-hour intervals with the multi-parameter CTDP300 automatic water quality logger. Analysis and comparison of the monitoring data showed a good response relationship be- tween water quality change, on the one hand, and rainfall, temperature and flow rate, on the other. Wa- ter quality obviously changed before and after the rainfall, probably because of the dilution effect of rain- fall. CO2 escape caused by flow disturbance resulted in a low mass-volume concentration of HCO3. When the rain stopped subsequently, the mass-volume concentration of HCOa increased. This might be related to the water supply from karst depressions and fissures at the time, and HCOa was negatively correlated with water temperature. The mass-volume concentrations of Ca2＋ and Mg2＋ decreased early in the process of rainfall, followed by a rise, a phenomenon associated with the dilution effect of the rainfall, but its maximum did not coincide with that of the rainfall. The concentrations of NO; , POa4 and SO4^2- increased with the arrival of the rainfall and with the increase in flow amount. Fe2＋ , Mn2＋ and Ba2＋ concentrations rose abruptly early in the rainfall process, and Mn2＋ concentration dropped sharply when it stopped. In conclusion, in the early period of the rainfall process the changes in various ions are main controlled by the dilution effect of rainwater, but when the rainfall has stopped, epikarst fissure rate and permeability begin to play a role, and hydrodynamic conditions and the CO2 effect become dominant, thereby affecting the changes in water quality.

关 键 词：南山老龙洞 岩溶地下水 降雨 短时间尺度 水质 

分 类 号：P641.25[天文地球—地质矿产勘探]