放射性污染对土壤微生物量的影响及尾矿优势菌鉴定

Radionuclide Influences on Soil Microbial Biomass and Identification of Dominant Microorganism of Uranium Tailings

为构建一个灵敏、高效的微生物监测预警体系,作为矿区污染土壤修复指标。本研究采用氯仿熏蒸浸提法测定土壤微生物量碳(Cmic)和微生物量氮(Nmic),并利用16SrDNA系统鉴定培养的优势微生物。结果表明:0~15 cm土壤层的Cmic、Nmic整体上大于15~30 cm土壤层,除8号取样点外,其余各点Cmic、Nmic均低于对照水平。Cmic/Nmic值表明土壤中微生物群落结构变化较大,0~15 cm土壤层中细菌数量明显少于15~30 cm土壤层。对U和226Ra的敏感程度表现为:Nmic>Cmic/Nmic>Cmic;分离所得6株优势菌株,经16SrDNA测序鉴定:B1为蜡样芽孢杆菌(Bacillus cereus);B2为节杆菌(Arthrobacter oryzae);B3为氧化烃微杆菌(Microbacterium hydrocarbonoxydans);B4为粘质沙雷氏菌(Serratia marcescens);B5为氧化微杆菌(Microbacterium oxydans);B6为多粘类芽孢杆菌(Paeribacillus barcinonensis)。结果显示,与对照相比放射性污染土壤中土壤微生物量有不同程度下降,土壤中微生物群落结构变化较大,各点的碳氮比差异也比较明显。

To build a sensitive and efficient forecasting system for contamination soil mediation at mineral area,soil microbial biomass carbon and nitrogen were investigated by chloroform fumigation,and the dominant microorganism was studied by 16 SrDNA.The results showed that Cmic,Nmic at the depth of 0-15 cm soil layer was greater than that in 15-30 cm,in addition to the No.8 sample point,Cmic and Nmic in each point was lower than that of the contrast.Cmic/Nmic showed that considerable changes occurred in microbial community structure,the number of bacteria in 15-30 cm soil layer was higher than that in 0-15 cm soil layer.The sensitive degree of U and226 Ra was Nmic>Cmic/Nmic>Cmic,6 dominant strains were isolated and tested by 16 SrDNA to be B1 Bacillus cereus,B2 Arthrobacter oryzae,B3 Microbacterium hydrocarbonoxydans,B4 Serratia marcescens,B5 Microbacterium oxydans and B6 Paeribacillus barcinonensis.The experiment showed that the radioactive pollution reduced soil microbial quantity compared with the control in different degrees,soil microbial community structure had large change,and the carbon nitrogen ratio of each point had obvious difference.