南方岩溶区地下河主要离子浓度变化趋势分析

Change of major ions concentration in subterranean river in karst areas in South China

对我国南方岩溶区典型地下河——官村地下河的降雨量、流量和钾、钠、钙、镁、氯、重碳酸根、硫酸根以及硝酸根离子的浓度进行了两年多的监测和分析。结果显示:地下河的水化学类型为Ca-HCO3型;硝酸根和硫酸根的浓度在雨季大于旱季;钠离子、钙离子、镁离子、重碳酸根离子在雨季浓度降低;钾离子和氯离子浓度的变化没有规律,这些离子浓度的变化受到稀释作用、淋滤作用或岩溶作用和人类活动的控制。与20世纪80年代的离子浓度相比,只有硝酸根和硫酸根的浓度有明显的升高。地下河的水质虽然未超标,但探讨地下河主要离子浓度变化趋势及原因对保护岩溶含水层是非常必要的。

Rainfall and discharge of the subterranean river in Guancun, a typical subterranean river in karst areas in South China were monitored and analyzed for more than two years as well as the concentrations of major ions, including potassium, sodium, calcium, magnesium, chloride, bicarbonate, sulfate and nitrate. Results indicated that the chemical type of the subterranean river was Ca-HCO3. The concentration of sulfate and nitrate was higher in the rainy season than that in the dry season, while the concentration of sodium, calcium, magnesium and bicarbonate was lower. The concentration of potassium and chloride, which was influenced by dilution, eluviation and anthropogenic activity, changed randomly throughout the year. Only the concentration of nitrate and sulfate obviously increased during the past two decades. Though water quality in the subterranean river is not beyond the water quality standard, it is important for us to discuss the tendency of water quality variation and the reason in order to protect karst aquifer.