The background values of rare-earth and radioactive elements in water system of source area of the Changjiang River

Abstract

Using neutron activation analysis method we determined contents of rare-earth and radioactive elements (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Cs, Rb, Sb, Sc, Sr, Ba, U, Th) in source water system of the Changjiang (Yangtze) River, which is mainly composed of the Tuotuo River, the Chumaer River, and the Buqu River. The contents of these elements in the unfiltered water have a great variation and a close correlation with the water turbidity. The contents of these elements in filtered water only have a little variation and are lower than those in the unfiltered water. The variations in contents of these elements in sediments are also very little. These elements in the unifiltered water are in geometric distribution, except Sc. Most of the elements in sediments are in arithmetic distribution, but Cs, Sb, Th, are in deviation distribution. The contents of most of these elements in the river source area correspond to the contents of fresh water of the earth. Most of these elements have a little variation in their contents in sediments. The variation coefficients of most of these elements are less than 30%. There are remarkable correlations between the contents of rare elements in sediments.