The Study Of Assessment Of Microbes In Uranium-contaminated Soil

With the rapid development of atomic energy industry, a large amount of radioactive waste was produced. The Uranium and its compounds are the important raw materials of nuclear industry, and the constant adoption and use of Uranium has also created large Uranium tailings, which has serious threat on human and ecological environment. For the assessment of related environmental risks of Uranium-contaminated soil, biological diagnosis has been an important analysis means of detection, which becomes the focus of research in recent years. Adding Uranium to the soil was the method in this study. BIOLOG-ECO fingerprint analysis technology and Illumina Miseq sequencing technology were used to study the impact of different concentrations of Uranium pollution on soil microbial communities. Combined with the other study in our group, the response to Uranium of microbial communities of different soils was comparative analysis. Considering the changes of microbial communities at the same time, the environment micro-biological testing system was constructed at the same time, which with a view to provide a theoretical basis and technical means for early warning of soil uranium contamination. The main results are as follows:(1) By using BIOLOG-ECO fingerprint analysis technology, respectively, the impact of soil microbial communities with immediate and a long-time Uranium processing were studied in this research. The results showed that the impact of immediate Uranium processing was more obviously than long time Uranium processing. The soil microbial abundance, community advantage and evenness were significantly inhibited in immediate Uranium process, and the carbon source utilization ability was significantly suppressed. The group of 10 mg·L-1 and 20 mg·L-1 Uranium treatment were most inhibited. Except for 100 mg·kg-1 Uranium treatment group in long-time Uranium processing, other groups were barely affected with long time Uranium process, indicating soil micro-organisms in a long period of time with Uranium processing might have been adaptive to the contaminated environment. To analysis the capacity of using carbon source, amine and amino acid carbon sources were utilized mostly by soil microbial both with immediate Uranium processing and a long time Uranium processing. The carbon sources utilization capability of two approaches of various types was coherence, it is possible to deduce that the different types of soil micro-organisms was not significant under Uranium processing.(2) Through Illumina Miseq sequencing Technology, the diversity impact of soil bacteria, fungi, anti-nitrifying bacteria and nitrogen fixing bacterial under different Uranium concentrations were studied. Results showed that light and moderate Uranium contamination have a catalytic role for various types of microbial diversity. After the Uranium processing, the advantages of bacteria was increased in a certain degree, of which the number of Paucimonas, Nitrosomonadaceae, Lysobacter and Thermincola, Basidiomycota and Staphylotrichum, Betaproteobacteria, Rhizobiales was increased significantly after Uranium processing, it can infer that which microbes were tolerance or resistance types to Uranium pollution. Anaerolineaceae, Alphaproteobacteria, Mortierella are significantly reduced after Uranium processing, it can infer that which microbes were sensitive organisms to Uranium pollution.(3) The Illlumina Miseq sequencing were used to study the different response of microbes' diversity to Uranium comtamination between uncontaminated soil and Uranium tailings. The results of the study revealed that advantage bacteria was different significant in different levels of contamination soil. The main micro-organisms was Anaerolineaceae in uncontaminated soil, and the main micro-organisms are nitrifying bacteria in Uranium tailings areas, which including Nitrosomonadaceae and Nitrospira. After Uranium processing, the nitrifying bacteria becomes advantage bacteria in uncontaminated soil and Uranium tailings soil, which indicated that Uranium contamination promote the microbes used nitrogen and contribute to soil nitrogen cycle.(4) According to traditional plate culture, the sensitive and resistant bacterial species to Uranium pollution was separated and screened from soil. The suitable ratio of microorganisms was selected to build the detection system to soil Uranium contamination. Two strains of microorganisms were screened in this research, after the 16 S rDNA identification, which respectively were Serratia marcescens strain and Kocuria rosea. Serratia marcescens strain was sensitive micro-organisms to Uranium, with a clear red features. Kocuria rosea was resistant bacteria to Uranium, with pink features, which the two strains both grow quickly. The detect system was composed by Serratia marcescens strain and Kocuria rosea, the ratio of which is 1:2. Through testing, the concentration of 10 mg·L-1 of Uranium contamination can be detected with the f detect system, which indicated that the detect system is effective for the testing of soil uranium contamination.To sum up, the dominat microbes is different in soils from different sources, and the response of which microbes is different to Uranium. The results showed that the inhibitory effect on soil microbes of the instant Uranium processing was more obvious than of the long time processing. While the species and quantity of the dominant microorganisms were greatly changed with Uranium treatment. After Uranium contanmination, the microbes used nitrogen was increased in different soils. In addition, the sensitive bacteria(Serratia marcescens strain) and the resistant bacteria(Kocuria rosea) were screened out to build the detection system, which the ratio of the two bacteria was 1:2, and 10 mg·L-1 of Uranium contamination can be detected with the f detect system.