山东区域大气细颗粒物中微生物群落动态及健康风险研究

Microorganisms are important biological components of inhalable fine particulate matter (PM2.5/PM1.0), which can induce severe respiratory and cardiovascular disease during haze episodes. However, vast majority of studies are focus on the physichemical properties of PM pollutants, less is known about the characterists of inhalable microorganisms and their public health risks. Shandong Province has been suffering from frequent haze events in recent years. This project will investigate the microbial communities, potential pathogens and endotoxin combined with the detection of meteorological factors and physichemical characteristics of fine particulate matter. To clarify the impact of meteorological conditions and physichemical characteristics of fine particles matter on microbial community, the statistical methods include principal component analysis, factor analysis will be performed. To understand the microbial toxicity characteristics (potential pathogens and endoxin), the high-through sequencing (Miseq and metagenomic sequencing) combined with the kinetic chromogenic kits methods will be applied. To analysis the influences of microbial activities on the activation and enhancement of toxicity, the functional gene analysis and metabolic pathways will be used. The work is able to reveal the rule and interaction of regional frequent haze and microbial communities, identify toxicity factors and mechanisms during haze process. And it will provide important scientific basis for the policy development of air pollution control and health hazard prevention.

微生物是大气细颗粒物的重要组成成分，雾霾过程中，附着于可吸入细颗粒物中的微生物进入人体，可引发呼吸系统及心血管疾病。目前对细颗粒物中微生物的群落组成及健康风险因素了解较少。山东省是我国雾霾高发区，本研究从环境生态及健康影响角度出发，采用物理化学分析与分子生物学技术相结合的方法，分析典型雾霾过程中微生物群落组成、病原微生物种类数量、内毒素浓度，同时结合环境因素及细颗粒物物理化特征探讨雾霾高发区微生物群落的特征。明确雾霾发生类型、气象因素、细颗粒物理化特征对微生物群落的影响。了解不同粒径细颗粒物中微生物的健康效应，阐明颗粒物中微生物自身的毒性特征。探讨雾霾环境压力下微生物对颗粒物毒性组分的活化及毒性增强的影响。通过上述研究，可揭示区域性雾霾高发与微生物群落的地域特异性规律，探讨雾霾过程生物毒性因素及其影响机制，为大气污染和健康危害预防措施的制定提供重要的科学依据。

本项目针对山东区域高山、平原、内陆和沿海地区，分析了大气污染过程颗粒物中微生物群落动态，探讨大气污染对微生物群落的影响及健康风险，主要结论如下。（1）针对2015-2016年夏季泰山云雾水中微生物群落的研究发现云雾水中细菌多样性较高，功能预测分析发现参与有机物代谢和疾病感染相关代谢途径，与优势菌Acinetobacter, Stenotrophomonas, Pseudomonas 和Empedobacter相关性较高。LefeSe差异分析表明，污染天云雾水中潜在病原菌种类较多，冗余分析（RDA）显示，云雾水中主要水溶性离子和PM2.5是影响细菌群落的重要因素。内陆气团传输对污染天云水中高浓度的污染物贡献较大。（2）针对华北平原禹城的微生物群落分析表明生物质燃烧期间PM2.5、OC、BC浓度升高，空气污染严重。燃烧导致总细菌和真菌数量升高达105 cells·m-3。革兰氏阴性菌占优势，包括Pseudomonas, Bacillus, Stenotrophomonas, Acidovorax, Staphylococcus。真菌中Cladosporium, Alternaria, Penicillium, Aspergillus和Epicoccum是优势菌。功能分析显示燃烧和非燃烧事件样品中存在差异的代谢途径主要集中于碳水化合物，氨基酸代谢，人类和植物疾病。微生物群落与PM2.5中OC、Mg、K关系密切。燃烧导致微生物群落间联系密切，植物及土壤是微生物主要来源。（3）采集了2017-2018年内陆城市济南和沿海城市威海冬季供暖期样品，与12月和1月相比，3月污染事件受到沙尘的影响，济南样本中鉴定出较高比例的芽孢杆菌。细菌浓度随PM2.5增加呈先增长后降低趋势，在中度污染下浓度最高（106 cells/m3），重度和严重污染下细菌浓度下降（105 cells/m3），可能与高浓度的污染物中毒性作用增强有关。Cyanobacteria属在清洁或轻度污染中占优势，随着PM2.5浓度的升高，机会致病菌Staphylococcus增加，并成为中度污染下丰度最高的细菌（最高达40％）。在重度或严重污染样品中，Deinococcus和Bacillus等对恶劣环境抗性较高的细菌占优势。应采取有效措施控制中度污染下生物气溶胶的健康风险，高浓度生物气溶胶对免疫功能低下人群风险较高。