湘江流域若干重金属元素在岩石、残坡积物及水中的背景值研究

本文从湘江流域环境地球化学特征出发,在大面积采样调查基础上,用地球化学和数理统计方法计算了湘江流域Pb、Cu、As、Hg、Cd和Ti等元素在岩石、土壤及湘江水体中的背景值,并用地球化学方法勾绘出湘江干流流域岩石中Pb、Cu、As、Hg、Cd、Ti和pH值等含量图和趋势面图以及浅层地下水中Pb、Hg和pH值趋势面图。阐明了整个流域中上述元素含量均在区域背景范围内。高含量区是局部的。流域中的浅层地下水水质是良好的。此外,还用地球化学、地下水渗透模拟试验等方法论证了金属元素从岩石(或矿石)—土壤—地下水中溶出迁移机理,得出天然地质体中金属元素直接溶于水中的量甚微、湘江重金属污染主要来自工厂的结论。

BACKGROUND VALUES OF SOME METALS IN ROCKS, SOIL AND WATER IN XIANG JIANG BASIN

In view of geochemical characteristics of the environment in Xiang Jiang basin, background values of Pb, Cu, As, Hg, Cd and Ti in rocks, soil and water were determined with geochemical and statistical methods, based on large scale sampling. Isograms and trend analysis figures of the elements in rocks and trend analysis figures of Pb, Hg and pH in underground water near surface of the major valley of Xiang Jiang river were drawn. It has shown that contents of the elements are close to the background values, that regions of high content of the elements are local and that quality of the underground water is essentially pure. A conclusion may be drawn that quantity of dissolved metals in natural geological body is very small and heavy metals pollution is caused by factories, by using geochemical and modelling methods.