The Spatial-Temporal Distribution Of Typical Antibiotics In Urban Soil And Their Effects On Microbial Communities

Due to the importance of quinolones（QNs）antibiotics in human medicine,the World Health Organization listed them as the“most important antibacterial drugs”.Moreover,QNs can exist and accumulate in soil for a long time,then lead to the change of the soil ecosystem.As an important component of the soil ecosystem,microbial community plays an important role in the stability of the soil ecosystem.Therefore,in order to describe the spatio-temporal distribution characteristics of QNs and explore the impact on soil microbial communities,Shijiazhuang City was selected as the research area,and surface soil samples were collected in September 2020（autumn）and June 2021（summer）,respectively.Then,the content of QNs,soil physicochemical indicators,and microbial community were analyzed and measured.The research results were listed as follows:1)In terms of spatio-temporal variation,the concentration of QNs in the surface soil showed a decreasing trend from autumn to summer,and the concentration of QNs showed the highest in central region,but lowest in northern region.The average concentration of QNs in autumn and summer soil were 94.88μg·kg^-1and 44.46μg·kg^-1,respectively.Thereinto,the concentration of NOR and CIP were higher than other QNs.2)In terms of risk level,the joint ecological risk and joint resistance risk of QNs in the soil were medium-high risk level(RQ_sum>0.1)and medium risk level(0.1<RQ_sum<1),respectively.The risk level of QNs in the surface soil showed a decreasing trend from autumn to summer.And the concentration of QNs showed the highest in central region.The ecological（RQ>0.1）and resistance risks（RQ<1）of NOR and CIP were the highest.3)In terms of dominant phyla and genera,the relative abundance of Actinobacteria and Proteobacteria showed an increasing trend from summer to autumn,while the relative abundance of Arthrobacter showed a decreasing trend.For composition of microbial communities at genus level,there were significant spatial differences（P<0.05）.In terms of diversity,the Simpson,Ace,and Chao showed a downward trend from autumn to summer,while the OTU showed an upward trend,and there were significant spatial differences in microbial community diversity（P<0.05）.4)For soil physic-chemical factors,the proportion of clay particles in the soil showed an increasing trend,while the sand particles in the soil showed decreasing trend.The content of total phosphorus（TP）,ammonia nitrogen（NH₄⁺-N）,and nitrate nitrogen（NO₃^--N）showed a decreasing trend.For social-economic factors,the central region showed the highest average population and GDP,while the northern and eastern regions showed the highest average agricultural and livestock output values.Through correlation analysis,the concentration of QNs in the soil of Shijiazhuang City was significantly correlated with soil particle size,NO₂^--N,NO₃^--N,and fishery GDP（P<0.05）.5)The correlation analysis results indicated that,in autumn,the main driving factors for microbial community composition,diversity and function were TP,NO₃^--N,NO₂^--N,QNs,and clay particles;In summer,the main driving factors for microbial community composition,diversity and function were TP,NO₂^--N,NO₃^--N,and QNs.