两种氯化消毒副产物对管网生物膜群落多样性的影响

Effect of two chlorination disinfection by-products on diversity of biofilms in a simulated pipe network reactor

目的探究给水管网中两种主要氯化消毒副产物——卤乙酸和三卤甲烷对给水管网生物膜群落多样性的影响。方法采用平板计数法和流式细胞术结合高通量测序方法,分析管网生物膜内细菌变化以及纲、属水平群落的多样性。结果给水管网中消毒副产物的种类和浓度对生物膜内群落多样性有明显影响,消毒副产物浓度越高,生物膜内细胞总数和异养菌总数越低。未投加消毒副产物的挂片上丰度最高的3类细菌分别为a-变形菌纲(Alphaproteobacteria,55.91%)、β-变形菌纲(Betaproteobacteria,8.99%)和Phycisphaerae纲(5.50%)。两种消毒副产物对细菌群落影响存在明显差异,卤乙酸对β-变形菌纲的抑制作用明显,而三卤甲烷对δ-变形菌纲(Deltaproteobacteria)的抑制作用明显。低浓度消毒副产物使α-变形菌纲的相对丰度升高,而α-变形菌纲包括某些危险的致病菌(如立克次体目)。相关性分析发现,卤乙酸与三卤甲烷分别与β-变形菌纲和δ-变形菌纲具有显著的负相关性(P<0.05)。结论给水管网中消毒副产物对生物膜群落具有明显影响,从管网微生物群落结构的崭新视角来探究管网水消毒副产物的健康危害亦应得到更多关注。

Objective To investigate the effect of two typical chlorination disinfection by-products(DBPs)on the bacterial diversity of biofilms in a simulated pipe network reactor.Methods The flat colony counting method and flow cytometry combined with high-throughput sequencing method were used to analyze the change of bacteria and the bacterial community diversity of the biofilms at the class and genus levels.Results The concentration and the type of the DBPs had a significant effect on the diversity of bacterial community of the biofilms.The total cell number and the total number of heterotrophic bacteria decreased with the concentration of the DBPs.The top three dominant bacteria of the untreated sample were Alphaproteobacteria(55.91%),Betaproteobacteria(8.99%)and Phycisphaerae(5.50%).The effect of two DBPs on the bacterial community was significantly different.Betaproteobacteria were obviously inhibited by haloacetic acid,while Deltapotoeobacteria could be efficiently controlled by trihalomethane.The relative abundance of Alphaproteobacteria which included certain dangerous pathogens such as Rickettsiales was raised at a low concentration of DBPs.Correlation analysis showed that the two DBPs had a significant negative correlation with Betaproteobacteria and Deltapotoeobacteria(P<0.05).Conclusion Since the DBPs have a significant effect on the diversity of the bacterial community of the biofilms,the health risks of DBPs in pipeline water from in terms of bacterial community composition should receive more attention.