中文摘要：

2003年4月到5月对长江干流及主要支流河水中常量元素(Ca2+,K+,Na+,Mg2+,Cl-,SO42-及碱度)进行了测定,并对常量元素的含量及影响因素进行了研究。结果表明,长江阳离子以钙为主,占阳离子总量的40%~80%;而阴离子主要为HCO3-,占阴离子总量的60%~90%;阴阳离子含量顺序为HCO3->SO42->Cl-,Ca2+>Na+>Mg2+>K+。长江干流及主要支流河水的常量离子主要来自于岩石的风化,主要受碳酸盐类溶解的控制,硅酸盐类的风化过程较弱。而大气沉降的影响很小,只有SO42-受大气沉降影响较大。长江干流的Na+、Mg2+、Ca2+、HCO3-和Cl-主要来自于上游,下游只是对上游的简单稀释,而没有额外来源。与世界上其它大河相比,长江的常量离子浓度处于较高的水平;温带地区的河流河水中常量离子的含量常处于较高的水平;热带地区的河流河水中常量离子的含量相对较低。

英文摘要：

The chemistry of major elements(Ca,K,Na,Mg,Cl-,SO2-4 and alkalinity) from the Changjiang River was examined with data obtained from the main stream and its main tributaries in April 2003.HCO-3 was the most abundant anion of the Changjiang River and account for 60%~90% of total anion,concentrations of anions follows the order HCO-3>SO2-4>Cl-.Among the cations,Ca2+ was predominant and account for 40%~80% of total cation.Concentrations of cations vary in the order Ca2+>Na+>Mg2+>K+.Weathering and...