Study On The Pollution Characteristics And Particle Impact Of Antibiotic Resistance Genes In Urban Rainwater Runoff

As one of the primary sources of urban water pollution,urban stormwater runoff pollution has become one of the current research hotspots.Particularly,as a new environmental pollutant,antibiotic resistance genes(ARGs)has been frequently detected in urban stormwater runoff.However,currently,few studies on the pollution characteristics of ARGs in urban stormwater runoff.Therefore,urban stormwater runoff from Jiangbei New District,Nanjing,was selected as the research object.The research was carried out through field sampling investigation and laboratory test analysis.Through the investigation of ARGs pollution characteristics in urban stormwater runoff,the results show that the numbers of tetracycline,β-lactam and sulfonamide antibiotic resistance bacteria(ARB)in urban stormwater runoff fluctuated within the range of 10~2-10~4CFU/m L;the numbers of all three ARB types were the largest in residential region.The numbers of culturable bacteria and three types of ARB significantly negatively correlated with temperature(P<0.01).The cellular protection ARGs were the dominant species in the detected ARGs from urban stormwater runoff;Sulfonamide resistance genes accounted for the highest proportion of the total ARGs relative abundance in each region,reaching61.7%-82.3%.Total ARGs,tetracycline,sulfonamide and macrolide-lincosamide-streptogramin B(MLSB)resistance genes positively correlated with Mobile genetic elements(MGEs)(P<0.05).The species and relative proportion of ARGs in urban stormwater runoff were similar to those in underlying surface sediments,but were quite different from those in atmospheric aerosols,indicating that underlying surface sediments possibly were the main contributing source of ARGs in urban stormwater runoff.Through the analysis of the attributions of ARGs in urban stormwater runoff,the results show that at the phylum level,Proteobacteria was the dominant microflora with the highest relative abundance,accounting for about 40.80%-83.29%of the total samples.Redundancy analysis showed that the Proteobacteria,Firmicutes and Chloroflexi had significant effects on the distribution pattern of ARGs(P<0.05).At the genus level,there were great differences in the species and abundance of dominant microflora in different regions,Deinococcus,Massilia,Rubellimicrobium and Paracoccus were the common dominant microflora in the three regions.The Enterobacter,Acinetobacter and Deinococcus had great effects on the distribution pattern of ARGs(P<0.05).Through the studies of the effects of particulate matter(PM)on ARGs distribution and propagation,the results show that the relative abundance of ARGs was the highest in PM with size<75μm.Correlation analysis showed that 13 kinds of ARGs were positively correlated with PN/PS and Zeta potentials.The frequency of conjugation transfer and transformation in PM with size<75μm was significantly higher than that in that in other experimental groups and control groups.