中文摘要：

控制河流水化学组成的因素包括岩石类型、气候变化以及土地利用方式,河流溶解性物质主要来源于岩石溶解、大气干湿沉降以及人为输入。选取黄河小浪底水库以下干流及支流河水为主要研究对象,讨论自然过程和人为活动影响下的河流水化学演变过程。结果表明：（1）水-岩作用是控制河水化学组成重要因素,沁河流经碳酸盐岩地层,水化学类型为HCO3-Ca-Mg型。黄河河水水化学类型为HCO3-Cl-Na-K型,主要受上游碎屑岩、变质岩以及黄土溶解影响。伊洛河河水水化学类型为HCO3-Ca-Mg,与下游碳酸盐岩地层出露有关;（2）化学肥料、生活污水以及人畜粪肥等对沁河以及伊洛河河水均有影响,黄河河水受人为活动影响不大;（3）硫酸分别参与沁河和伊洛河流域碳酸盐岩溶解反应,硫酸可能分别来自于含煤地层硫化物氧化以及金属矿床硫化物氧化。研究区黄河河水受上游溶解盐蒸发浓缩影响较大,硫酸参与碳酸盐岩溶解反应不明显。

英文摘要：

Controlling factors on river hydrochemical composition include lithology,climate and land use.Dissolved constituents in river are mainly derived from lithologic dissolution,atmospheric dry/wet deposition and anthropogenic inputs.Mainstream and tributaries of Yellow River from Xiaolangdi Reservoir,including Qin River and Yiluo River,were selected to elucidate the hydrochemical evolution controlled by natural and anthropogenic activities.The results showed that：（1） Water-rock interaction is the important factor controlling river water hydrochemical composition.HCO3-Ca-Mg is the hydrochemical type of Qin River because of flowing through stratum dominated by carbonate rock.HCO3-Cl-Na-K is the hydrochemical type of Yellow River because of the dissolution of clastic rocks,metamorphic rocks and loess.HCO3-Ca-Mg is the hydrochemical type of Yiluo River because of flowing through stratum dominated by carbonate rocks in lower reaches;（2） Qin River and Yiluo River have been affected by anthropogenic activities,such as chemical fertilizers,sewage and human-animal waste.But Yellow River got little influence from those activities;（3） Carbonate dissolution by sulfur acid was found in Qin River and Yiluo River respectively.The sulfur acid is possibly derived from sulfide minerals of coal stratum in Qin River and from sulfide minerals of metal sulfides in Yiluo River,respectively.It is not obvious that carbonate rocks are dissolved by sulfur acid in Yellow River which more affected by dissolved salts undergoing evaporating and concentrating.