Study On Characteristics Of Soil Microbe In Exogenous Rare Earths Accumulation Area Of Baogang Tailings Dam

With the large number of rare earth resources development and application, this caused a great deal accumulation of rare earth in the soil and affected soil environment. Baogang tailings dam is the place where Baotou Steel Group deposited tailings. The area of downwind of tailings dam accumulated exogenous rare earth elements seriously, which had effect on the local ecological environment seriously. This study determined the physical and chemical properties of soil, soil microbial quantity, microbial biomass and soil enzyme activities about accumulation area of exogenous rare earth of Baogang tailings dam.We also analyzed soil bacterial diversity in the Rare Earth accumulation area by PCR-RFLP technique.The results are as follows:1. The test of different plot rare earth content in rare earth accumulation area of Tailings dam showed that the highest rare earth content in C plots. The other plots have shown the farther away from the dam, the lower rare earth content. (A, B, C, D, E, F, G, H, and CK is nine plots from near to far of the tailings dam)Soil moisture of different plot in tailings dam is H>CK>G> E>B>D>F>C>A. Determination of pH showed that tailing dam soil is alkaline and different plots have distinction. Soil organic matter, total nitrogen, and total phosphorus, total potassium content between the plots also has some differences, but the difference is not significant. 2. Soil bacteria,fungi, actinomycetes, azotobacter and nitrobacteria quantity of different plot in rare earth accumulation area of Tailings dam are trends the closer away from the dam, the lower microbe quantity. Varieties of microbe are remarkably relative. The accumulation of rare earth has effect on microbial quantity.Denitrirying bacteria is apparently different from other species.3. MBC content are H>G>F>CK>D>E>B>C>A, MBN content are H>G>CK>F>D>E>A>B>C. MBC and MBN of A, B, C plots are evidently lower than other plots. Because the A, B, C plot rare earth elements accumulated seriously, the microbial biomass has been restrained.4. The study of soil enzyme activity in rare earth area accumulation of tailings dam indicates that different soil enzymes activity (protease, invertase, urease, catalase, polyphenol oxidase) have different law in different plots. The accumulation of Rare earth does not particularly influence soil enzyme activity. Polyphenol oxidase and the other four enzymes showed significant negative correlation.5. The study of bacterial diversity indicates that bacterial H', D, Hmax, dMa index of C and CK plots are CK>C. The bacterial diversity of CK plot is higher than C plot. Species of CK plot are more abundant. Pielou evenness index JSW of CK plot is also higher than C plot, which indicates that the accumulation of rare earth lead to emerge dominant species in the C plots.6. Soil bacteria of Baogang tailings dam attach to Acidobacteria, Proteobacteria, Bacteroidetes and Firmicutes. The others are uncultured bacterium.24 sequences in the 25 sequences measured are highly similar to the environmental uncultured bacteria and is 96% of the total. Only one sequence is similar to Bacillus of firmicutes. This study indicates that the vast majority of bacteria are uncultured.