城市尾水排海过程中微生物及主要致病菌扩散规律

城市污水处理厂产生的尾水中含有大量微生物尤其是致病菌,排海后不仅对周围人群产生危害而且对海洋生态安全构成威胁.本研究以青岛市麦岛污水处理厂为研究对象,采用高通量测序技术,研究尾水排海过程中的微生物群落结构,分析尾水中致病菌在排海过程中的动态分布及季节变化规律.结果表明,尾水微生物分布在20~27个菌门,优势菌门为变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes),主要分布在44~65个纲,其中优势菌纲主要分布在变形菌门(Proteobacteria);尾水排海过程中的主要致病菌有55种,致病基因与癌症、心血管、免疫系统、传染性、新陈代谢、神经变性等疾病相关,其中,引起人类和动物腹泻、菌血症相关的弓形杆菌属(Arcobacter spp.)、引发院内感染的条件致病菌不动杆菌属(Acinetobacter spp.)及对海产品养殖和捕捞带来威胁的Shewanella hafniensis等占比例较大.

Diffusion of Microorganism and Main Pathogenic Bacteria During Municipal Treated Wastewater Discharged into Sea

Numerous microorganisms, especially pathogens, exist in treated wastewater, which leads to possible risk to population health and marine ecological security when treated wastewater is discharged into the sea. This study selects Maidao municipal sewage treatment plant as the location. The microbial community and the dynamic distribution and seasonal variation of pathogens are analyzed by high-throughput sequencing technology. The results showed that the microbes in the discharge were distributed into 20 to 27 phyla, and the dominant phyla were Proteobacteria, Firmicutes, and Bacteroidetes, which were mainly distributed in 44 to 65 classes. The predominant pathogens are mainly composed of Gammaproteobacteria, Betaproteobacteria, and Epsilonproteobacteria in the Proteobacteria category. The proportion of most dominant phyla and classes in the sample decreased with an increase in diffusion distance. There were mainly 55 species pathogenic bacteria in the water discharging into the sea. The pathogenic genes in the discharge were mainly related to cancer, cardiovascular disease, immune system diseases, infectious diseases, metabolic diseases, and neurodegenerative diseases. When compared with the blank samples, it was found that the biomass of pathogenic bacteria decreased sharply with the diffusion by the seawater, and most of the pathogens were not detected 1000 m away from the seashore. Arcobacter spp. caused human and animal diarrhea and bacteremia, Acinetobacter spp. caused nosocomial infections, and Shewanella hafniensis posed a threat to seafood farming and fishing. The three species of pathogenic bacteria mentioned above occupied a fairly large proportion of the discharge into the sea.