The Geochimcal Character And Environmental Effect Of Rare Earth Elements In Lakes, Upper And Lower Reaches Of Yangtze River, China

With the rapid increase of population and increasingly speeding up of industrialization and urbanization, the environmental problems of surface waters were paid close attention and became a globally concerned problem. As we know, more than 90% of the fresh water that can be used by human being stores in lakes. The natural characters of lakes make them easily contaminated. Once the water is polluted, it will be a really time-consuming, very complicated and difficult work to recover and remedy it. Although people have paid much attention to this problem, the concerned research is still falling behind. Up to now, people are still not clear on many problems, such as how does the contamination move and scavenge itself in lakes, and under what conditions will the pollutant that has been scavenged pollutes the water body again. But people have gradually realized that the suspended particles matter (SPM) plays essential role in pollutant generation, migration and precipitation. Thus, the water-particle interaction processes have become the key point for the study of the environmental behavior of contaminant in lakes.The rare earth elements (REEs) are a series of elements including lanthanides with atomic number from 57 to 71 , as well as Y with atomic number 39. The REEs are commonly used as geochemical tracers in the study of many geologic processes because of their unique and chemically coherent behavior. The REEs are better tracers than other single trace elements, because it is continually changing with the increasing of atomic numbers in geochemical processes. Since colloids are major carriers of REEs in water and sorption/desorption can occur easily, the REEs are sensitive to water-particle interaction processes. Fractionation between LREE and HREE appears during this process due to the different behavior of adsorb and complex properties, so the REEs have distinct process character in the surface water and can be used to trace the interacting process at the water-particle interface.The main purpose of this research is to provide a scientific basis for making decisions on the remedy of the aquatic environment through case studies on geochemical behavior of the REE in lakes as well as comparison of the distinct geochemical process of the REE in lakes with different characteristics and to have an understanding of the water-particle interaction process and the distribution and forms of the REE in water. Based on the study of the extract method for the REE, aquatic chemistry and REE from Taihu, Chaohu, Longgan, Hongfeng and Aha lakes and the...