Response Of Microbial Community To Environment Change In Urban Groundwater Recharge With Reclaimed Water

The problem of over-exploitation of groundwater in northern cities in China is very prominent,and the use of water resources through groundwater recharge,storage and utilization can alleviate this problem to a certain extent.However,due to the ecological risks of reclaimed water and the complexity and fragility of the groundwater environment,accurately judging the impact of reclaimed groundwater and exploring the main sources of risks have become a key issue in ensuring the safety of urban groundwater resources.This study uses high-throughput sequencing methods,combined with on-site investigation,testing and laboratory analysis,to discuss the changes in the microbial community and resistance genes of the groundwater in the drainage and replenishment areas of sewage treatment plants,as well as environmental influence factors,so as to reveal the replenishment of reclaimed water.The main research results obtained in this paper are as follows:(1)The antibiotics contained in the groundwater in the study area are mainly sulfacetamide,sulfapyridine,ofloxacin,norfloxacin,moxifloxacin and ciprofloxacin.There are more than 30 types of antibiotic resistance genes detected,which are distributed in all sampling points.The main types of resistance genes are multidrug resistance genes,fluoroquinolone resistance genes and polymyxin resistance genes,etc.Sulfuritalea hydrogenivorans may carry the most resistance genes in groundwater.(2)The groundwater in the replenishment area and the drainage from the sewage treatment plant contain 2454 common bacterial genus,accounting for 89.1%.There are 458 common resistance genes in groundwater and sewage treatment plant drainage in the replenishment area,accounting for 69.2%,indicating that the groundwater microbial community is significantly affected by the replenishment of sewage treatment plant drainage.The interaction between bacterial species in the microbial community in groundwater is stronger,and there is a higher frequency of horizontal gene transfer between resistance genes.(3)Compared with sewage treatment plant drainage,the overall change in the composition of the groundwater microbial community is less affected by environmental factors,but the input of antibiotics and the increase of inorganic and organic pollutants in the groundwater after replenishment will affect the function and resistance of the groundwater microbial community gene abundance more than wastewater treatment plant drainage.