关键词: 湘江, 河流沉积物, 沉积物重金属, 形态类型, 形成因素, 江段, 河床沉积物, 可交换态, 微量金属, 水体沉积物

Abstract: In this article the metal forms of Xiangjiang aquatic sediment are discussed.The wet and hot climate of subtropical zone as well as the carbonate environment inupper and middle reaches of Xiangjiang rebuilt in some specific regional factors for themetal forms.1. The proportion of the exchangeable trace metal concentration in the sediments is low, generally not over 2%. The proportion of the major metals in the sediments is 10-30% for Ca, 2-6% for Mn and iron the lowest.2. Beside Cu, there is a higher proportion of content of the trace metals of carbonate forms than the hydrous Fe/Mn oxides forms metal, they amount to 30-81% for the total content.The two processes mentioned above suggest that the major mechanism of self-purifica-tion in the water for trace metals is effected by the human activities pollution.3. These processes might exist simultaneously as the proportion and distribution of the trace metals for hydrous Fe/Mn oxides-form, carbonate and organic substances forms, however the major trend is different, Cd and Zn were associated by carbonate and hydrous Fe/Mn oxides and carbonate for Pb, and organic substances for Cu.4. Except the content of Fe which is more than 90%, the normal concentration of other metals is about 35-50% in residual fraction.