GEOCHEMISTRY OF DISSERVED AND PARTICULATE ELEMENTS IN THE MAJOR RIVERS OF CHINA (THE HUANGHE, CHANGJIANG, AND ZHUNJIANG RIVERS)

The relationship between the geochemistry of dissolved and particulate materials and geographic conditions was investigated. Samples of wate r and suspended particulate matter were collected from five locations in three of the major rivers of China (the Huanghe, Changjiang, and Zh unjiang rivers). Because these rivers generally flow parallel to latit udes and flow through diverse geologic and climate zones, they provide excellent opportunities for comparisons of solute transport. The geoc hemistry of these rivers is influenced strongly by climate. The low di scharge of the Huanghe River influences the character of the major ion ic materials (Cl- + SO42- and Na+ + K+) as well as the high degree of mineralization within the system. Dissolved concentrations of both maj or ions and trace elements are lower in the southern reaches of the ri vers. The highly mobile ions, such as, Na+ and Ca2+, are depleted from the suspended particulate material in the southern regions, while the relatively immobile ions of Al, Fe, Ti, Mn, and trace metals are conc entrated within the suspended material. The relative mobility of some elements as measured by the Dissolved Transport Index (DTI) changes wi th climate. The geology of the area drained by the rivers has a major influence on the geochemistry in areas of similar climate. Lowest leac hing rates in the southern climates occur in areas dominated by granit e, which is resistant to weathering. The composition of both cations a nd anions among the three tributaries of the Zhujiang River are depend ent on the rocks that dominate each region. Some particulate forms of the rare earth elements are present in the highest concentrations in r egions dominated by granite. The DTI calculated for the major rivers i n China are much smaller than those computed for other major rivers of the world. The low concentration of heavy metals in the particulate m aterial suggests that pollution in the rivers of China is less serious than in rivers of other industrialized countries.