放射性污染对铀矿区土壤微生物群落结构的影响

Effects of Radioactive Contamination on Soil Microbial Community Structure in Uranium Mine Area

为探究放射性及其伴生污染对铀矿区附近土壤微生物群落功能多样性的影响,采集退役铀矿冶周围不同辐射值的土壤为研究对象,通过测定其土壤理化性质、土壤可培养微生物计数及Biolog-ECO微孔板培养,分析土壤放射性污染程度及理化性质对土壤微生物群落功能多样性和数量的影响。结果表明,矿区放射性污染土壤中重金属含量普遍较高,尤其是铅已超出管控标准。随着辐射值的增加,土壤中可培养微生物数量显著下降,特别是放线菌和真菌的数量;微生物群落功能多样性指数、物种丰富度指数、优势度、均一性指数显著下降;对碳源利用也逐渐下降,尤其是对酚酸类和胺类碳源,利用率分别下降25.8%、29.7%。RDA分析发现放射性核素是该区域驱动土壤微生物群落代谢发生变化的主要因素。铀矿区放射性污染及伴随的重金属污染明显改变土壤微生物群落结构,抑制了土壤微生物群落的代谢活性,造成土壤微生物群落功能多样性下降。

In order to explore the influence of radioactive and associated pollution on the diversity of soil microbial community near uranium mining area,the soil with different radiation values around the decommissioned uranium mining and metallurgy were collected and taken as research objects.By measuring the physical and chemical properties of the soil,using the plate-counting method and Biolog-ECO microplate culture,the effects of soil radioactive pollution degree and physical and chemical properties on functional diversity of soil microbial community and the number of microbes were analyzed.The results show that the content of heavy metals in radioactive contaminated soil is generally high,especially lead,which exceeds the control standard.With the increase of radiation value,the number of culturable microorganisms in soil decreased significantly,especially the number of actinomycetes and fungi.The functional biodiversity index of microbial community,specific abundance index,dominance,and homogeneousness index decreased significantly;the utilization capacity of carbon sources decreased gradually,especially the utilization rate of phenolic acid and amine decreased 25.8%and 29.7%,respectively.RDA analysis showed that radionuclides were the main factors driving the functional changes of soil microbial community.The radioactive pollution and its associated heavy metal pollution in uranium mining area obviously changed the structure of soil microbial community,inhibited the metabolic activity of soil microbial community,and caused the decrease of functional diversity of soil microbial community.