因其成分复杂，来源多样，活性易变以及容易传播感染，微生物气溶胶给人类健康带来了严重威胁。作为典型污染源之一，污水处理厂的微生物气溶胶污染已逐步引起国内外学者的广泛关注。本文通过大量的文献比较以及咨询美国国家职业安全卫生研究所（NIOSH）的专家后，选择大肠杆菌和沙门氏菌这两种致病性较强的肠道病原微生物作为指示微生物，研究北京市某污水处理厂春季晴朗天气上午时段的微生物气溶胶污染状况，并对其进行定量风险评价。研究应用Anderson六级空气采样器和自然沉降法两种方法采样，参考中国人群暴露参数手册进行暴露评价，类比水中两种病原微生物的剂量-反应关系模型，用微生物定量风险评价（QMRA）的方法对北京市某污水处理厂的格栅间、A/A/O反应池和污泥脱水车间三个主要工艺环节进行人体感染风险评价。结果发现，自然沉降法在测定微生物气溶胶浓度时误差较大，但定性分析结果与Anderson六级空气采样器结果相近；大肠杆菌和沙门氏菌污染在研究中的三个工艺环节呈现相同的空间分布规律，即：浓度大小依次为，A/A/O反应池(2120 0 CFU/m³和1413 0 CFU/m³)>污泥脱水车间（706 0 CFU/m³和1060 499 CFU/m³）>格栅间（0 CFU/m³和353 499 CFU/m³）。从单次感染风险的值来看，沙门氏菌的单次感染风险P_inf是大肠杆菌单次感染风险的60倍至80倍。除了格栅间没有检出沙门氏菌外，A/A/O反应池和污泥脱水车间两个工艺环节沙门氏菌都是主要的风险微生物。其年累积感染风险值在两个环节都接近1，表示有极高的感染风险。

关键词：微生物气溶胶;  健康风险;  定量风险评价

Microbial aerosols are complex, multi-sourced, subjected to change and infectious. Therefore, they posed a threat to human health. Waste water treatment plant (WWTP), being a major source which generates microbial aerosols, has been attracting more and more attention from the academia. This research aims at quantitatively assessing (Quantitative Microbial Risk Assessment) the aerosol risks to human health in major water treatment processes, which are grids, A/A/O tanks and sludge thickening sites, of a Beijing WWTP on a sunny morning in spring. Anderson six-stage bio-samplers and gravitational settling method are employed as contrasts to each other. After a careful literature review and taking into account the expertise from in U.S. National Institute for Occupational Safety and Health, E.coli and salmonella are chosen to be surrogate agents as they are typical markers of fecal contamination and are easily cultured and distinguished. Hereinafter are the findings: for the two sampling methods above, the results are agreed qualitatively but the settling method failed to accurately measure the concentration of ambient microbial aerosols. The concentration of E.coli and salmonella in all three processes are in the same sequence, which is, for salmonella: A/A/O tanks (2120 0 CFU/m³), sludge thickening (706 0 CFU/m³) and grids (0 CFU/m³). For E.coli: A/A/O tanks (1413 0 CFU/m³), sludge thickening (1060 499 CFU/m³) and grids (353 499 CFU/m³). E.coli and salmonella are high in exposure risk, and salmonella is even higher in single exposure risk (P_inf) and annual accumulative exposure risk (P_{a for salm}=1 in both A/A/O tanks and sludge thickening) with exception of that in grid, where salmonella was not detected.

Key Words:  microbial aerosols; health risk; quantitative risk assessment

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