| As a kind of emerging pollutants,pharmaceuticals have been frequently reported about their ubiquitous occurrence in the environment.Antibiotics are important pharmaceuticals,which may lead to the occurrence of the antibiotic resistance genes(ARGs)and then cause the antibiotic resistance of bacteria.So the ARGs have gained more attention than ever before.However,the study of ARGs in different environmental medias is still far from enough,the pollution characteristics of pharmaceuticals in typical sources of urban sewage system also needs further investigation.This study provided a theoretical basis for further study of migration and transformation of ARGs and proper usage of pharmaceuticals.In this study,samples from different medias were collected in 5 typical sources of Harbin city during December 2018-January 2020,and the surface water of Songhua River was also obtained in October 2019.13 genes were analyzed in all samples using real time q PCR,18 pharmaceuticals were analyzed in the water samples using UPLC-MS/MS.As for the distribution characteristics of 16 Sr RNA and ARGs in multi-media environment,the quantitative analysis show that: except for the absence of qnr S in the soil samples,there is no significant difference in the types of ARGs detected in dust,water,and soil.Bacterial loading and ARGs have obvious seasonal differences in the three medias,though no significant regular was found,the concentration of pollutants in summer is significantly higher than that of other seasons.According to the sampling sites,the swine farm was the most polluted site.Compared to other studies around the world,the concentration of ARGs in the three media in this study was at a medium or low level.The relative abundance of most ARGs showed the following order: sewage>dust>soil,which is probably because the water environment is more suitable for bacteria to live.The principal component analysis results showed that the pollution characteristics of ARGs in dust and soil have some similarities.The proportion of different ARGs varied among seasons and sampling sites.This study showed the residual characteristics of pharmaceuticals in typical sources of urban sewage,and evaluated the ecological risks of pharmaceuticals in surface water.The results show that: The concentration range of antibiotics is ND-32800ng/L,the concentration range of non-antibiotic pharmaceuticals is ND-23700ng/L.The concentration of pharmaceuticals showed the following order:piggery wastewater>hospital wastewater>domestic sewage>pharmaceutical wastewater.The pharmaceuticals remaining in swine wastewater and pharmaceutical wastewater are mainly antibiotics,while that of domestic sewageand hospital wastewater are mainly non-antibiotic pharmaceuticals.The ecological risk assessment of surface water shows that azithromycin poses a toxic risk to algae and invertebrates.Azithromycin,levofloxacin hydrochloride,ampicillin sodium,and roxithromycin present a risk of selective pressure to the bacteria.This study combined correlation analysis and regression analysis to explore the relationship between antibiotics and ARGs.The results showed that cross-selection and co-selection are widespread in this study.ARGs in dust are less affected by bacterial loading than ARGs in water.Int I1 is significantly correlated with some ARGs in both water and dust,indicating the potential horizontal gene transfer is common in different environmental medias.Some ARGs showed a good linear relationship with 16 Sr RNA or int I1 genes(R2>0.8),which can be used as basic data to further establish mathematical models of antibiotics and ARGs. |
PDF Full Text Request