Content And Distribution Of Trace Elements In The Soil Surface Yeyahu Wetlands

With the development of agricultural research, agricultural research of trace elements in soils is very active, especially the application of trace rare earth fertilizer has been rapid development, and become a hot research of environmental geochemistry of trace elements. Research shows that, REEs can promote the growth of microorganisms in the soil and enhance its biological activity in a certain range of concentration, improve soil fertility, improves components and circulation capacity of soil ecological system, to promote the crop growth and development. China’s rare earth source is abundant, the amount are accounted for almost80%of global reserves, and they obtain the latest information. In recent years, the effects of rare earth in soil environment gets more and more concerned, in order to be re-used, further comprehensive and systematic study of rare earth and its behavior in soils essential.Yeya lake wetland protection area is the most typical and the largest land-wetland system in Beijing, selected typical soil region as the research object in the Yeya lake wetland, and get a large number of sampling, using advanced testing technique, research on the chemical behavior of rare earth elements and trace elements, a comprehensive and systematic study of rare earth element’s content, distribution, distribution pattern and the content of trace elements, distribution and the correlation of rare earth elements, in order to better carry out reasonable improvement on land, compared with other areas of rare earth elements in soil background value, in order to ensure the harmonious development of ecology and agriculture, can be targeted to the rare earth fertilizer application, with the important practical significance. For understand the geochemical characteristics between the REE and the trace elements in the typical area of Yeya lake wetland area, using the ICP-MS(plasma mass spectrometry)method to determination of REE and trace element content of52surface soil samples in the Yeya Lake Wetland Soil, analyses the distribution of level characteristics of REE and trace elements and they content, differentiation, Ce, Eu anomaly in the surface soil of the Yeya lake wet land area. The results show that:(1)∑REE in the typical region of the surface soil of ranged froml31.81mg/kg-217.49mg/kg, the average content is173.87mg/kg, standard deviation is19.85,the variation coefficient was0.11.Light rare earth elements(LREEs)ranged from106.49mg/kg-167.06mg/kg, the average content is133.87mg/kg, standard deviation is16.03,the variation coefficient was0.12.The content of heavy rare earth elements (HREEs) between14.63mg/kg-30.23mg/kg, the average content is24.57mg/kg, the standard deviation was3.15,coefficient of variation was0.13. TheREEratio of total between LREE/HREE ranged from4.7-7.28,average is5.49,far greater than1,indicating that light, heavy rare earth elements were difference in the surface soil of the study area, has the typical characteristics of enrichment of light rare earth.(2)REE distribution characteristics and ecological effects of52surface soil samples collected from the wetlands of Yeya Lake was studied. The8Eu value ranged from0.64to0.78in the study area, meaning negative anomalies. The δCe value ranged0.95to0.99, meaning without anomalies, matched the soil in the region which is a reducing environment. Correlation between δCe and8Eu,8Ce andEE showed that the diagenesis of the impact was notobvious.(3)There are differences between the content of trace elements in agricultural industry land and in the sediments from the Yeya lake wetland area. But the content of trace elements in the degree of curve trend is consistent. In the trace element analysis, numerical partial elements as high as0.95or more, reflect the trace elements have similar environmental geochemical properties in weathering, transport and deposition process--has homology.(4)For the chondrite normalized to the measured data, the REE chondrite normalized patterns generally light rare earth(La-Nd) and enrichment of heavy REE(Er-Lu) of losses, the curve is right oblique. And the rare earth elements on surface soil and the average data were compared, the content of LREE was higher than the national average and the MREE content is lower than the national average, showed the typical characteristics of continental crust REEs, show that the material source is the main terrestrial.(5)In different vegetation areas, the average content of∑REE, LREE and HREE was in order of common cultivated land> woodland> reed> grassland>sediment. However, fractionation was in order of cultivated land>woodland>grassland> sediment> reed. The author thus consider that the wet land environment and artificial have a larger influence on REE distribution and fractionation. In the wetland environment, the REE might have taken a more important part in geochemical cycle.The study not only help to better grasp the Yeya lake wetland’s geochemical study of elements and soil pollution status, but also can reveal the elements of physical erosion and chemical weathering processes about the elements distribution characteristics and transportation condition in the wild duck lake wetland and the surrounding soil. At the same time, provide scientific basis and decision-making research for the wetland and the Guanting reservoir about the present status of water environment, water pollution control, ecological environment protection and management, has a very important theoretical and practical significance.