张霞, 陈敏, 侯雪波, 张嘉美, 付晨, 张琳, 高剑晖, 苏瑾. 某市公共交通建筑集中空调冷却水嗜肺军团菌污染现况及影响因素[J]. 环境与职业医学, 2021, 38(4): 402-407. DOI: 10.13213/j.cnki.jeom.2021.20499
引用本文: 张霞, 陈敏, 侯雪波, 张嘉美, 付晨, 张琳, 高剑晖, 苏瑾. 某市公共交通建筑集中空调冷却水嗜肺军团菌污染现况及影响因素[J]. 环境与职业医学, 2021, 38(4): 402-407. DOI: 10.13213/j.cnki.jeom.2021.20499
ZHANG Xia, CHEN Min, HOU Xuebo, ZHANG Jiamei, FU Chen, ZHANG Lin, GAO Jianhui, SU Jin. Legionella pneumophila pollution and influencing factors in cooling water of public transport buildings in a city of China[J]. Journal of Environmental and Occupational Medicine, 2021, 38(4): 402-407. DOI: 10.13213/j.cnki.jeom.2021.20499
Citation: ZHANG Xia, CHEN Min, HOU Xuebo, ZHANG Jiamei, FU Chen, ZHANG Lin, GAO Jianhui, SU Jin. Legionella pneumophila pollution and influencing factors in cooling water of public transport buildings in a city of China[J]. Journal of Environmental and Occupational Medicine, 2021, 38(4): 402-407. DOI: 10.13213/j.cnki.jeom.2021.20499

某市公共交通建筑集中空调冷却水嗜肺军团菌污染现况及影响因素

Legionella pneumophila pollution and influencing factors in cooling water of public transport buildings in a city of China

  • 摘要: 背景

    嗜肺军团菌广泛存在于天然水体及人工水环境中,可引起严重的军团菌病,有关其影响因素及控制策略的研究有限。

    目的

    分析公共交通建筑集中空调冷却水系统嗜肺军团菌污染现况及影响因素,为冷却塔嗜肺军团菌风险管控提供科学依据。

    方法

    于2018年9—10月和2019年8—9月期间,基于方便抽样采集某市公共交通建筑121座集中空调冷却塔水样共174件,对水样进行嗜肺军团菌检测及血清分型,同时检测冷却水的菌落总数、色度、浑浊度、电导率、溶解性总固体、pH、铁、水温、游离性余氯共9项水质指标,同步现场勘查冷却塔周边环境和运行管理状况。采用卡方检验和多因素logistic回归分析水质状况、消毒方式以及管理公司等因素对嗜肺军团菌阳性率的影响。

    结果

    174件冷却水水样中有83件检出嗜肺军团菌,阳性率为47.70%,共检出7种不同血清型的嗜肺军团菌,其中Lp1为优势血清型,占59.04%。卡方检验显示:在不同水温、游离性余氯、溶解性总固体以及铁含量的水质条件下,嗜肺军团菌阳性率差异有统计学意义(P < 0.05);不同运营公司管理下的冷却塔其水系统嗜肺军团菌阳性率间差异有统计学意义(P < 0.05)。进一步多因素logistic回归分析显示:水温是嗜肺军团菌阳性率的主要危险因素(OR=1.250,95% CI:1.111~1.407);与A公司相比,B、C、D公司管理的冷却塔更容易检出嗜肺军团菌(OR=3.704,95% CI:1.264~10.855;OR=3.088,95% CI:1.057~9.019;OR=2.708,95% CI:1.190~6.164)。

    结论

    该市公共交通建筑冷却塔存在嗜肺军团菌污染,水温控制和有效的管理措施是减少嗜肺军团菌生长和传播的关键,从技术和管理层面采取综合措施是公共建筑集中空调冷却水系统军团菌管控的最佳策略。

     

    Abstract: Background

    Legionella pneumophila is found extensively in natural water bodies and artificial water environments, and can cause serious Legionnaires' disease. There are limited studies on the influencing factors and control strategies of Legionella pneumophila.

    Objective

    This study investigates the status of Legionella pneumophila contamination and potential influencing factors in cooling water of central air conditioning system in public transport buildings, aiming to provide scientific evidence for risk control of Legionella pneumophila in cooling towers.

    Methods

    A total of 174 water samples were collected from 121 cooling towers in public transport buildings in the selected city from September to October in 2018 and from August to September in 2019 based on convenient sampling. Legionella pneumophila colony and serotyping were detected in the water samples. Nine water quality indicators were analyzed simultaneously, including the total number of colonies, color, turbidity, conductivity, total dissolved solids, pH, iron, water temperature, and free residual chlorine. The information about cooling tower surrounding environment and operation management was collected by on-site inspection. Chi-square test and multiple logistic regression were used to analyze the influences of water quality, disinfection methods, and management companies on the positive rate of Legionella pneumophila.

    Results

    Of the 174 cooling water samples, 83 samples were Legionella pneumophila positive, with a total positive rate of 47.70%; 7 serotypes were detected, of which the dominant Lp1 accounted for 59.04% of the positive samples. The Chi-square test results showed that under different conditions of water temperature, free residual chlorine, total dissolved solids, and iron, the differences in the positive rate of Legionella pneumophila were statistically significant (P < 0.05); there was also a significant difference in the positive rate of Legionella pneumophila in cooling towers under the management of different operating companies (P < 0.05). Further multiple logistic regression analysis results showed that water temperature (OR=1.250, 95% CI: 1.111-1.407) was the major risk factor for being Legionella pneumophila positive. Compared with company A, cooling towers managed by companies B, C, and D were more likely to be detected Legionella pneumophila positive (OR=3.704, 95%CI: 1.264-10.855; OR=3.088, 95%CI: 1.057-9.019; OR=2.708, 95%CI: 1.190-6.164).

    Conclusion

    Legionella pneumophila contamination exists in the cooling towers of public transport buildings in the selected city. Water temperature control and effective management measures are key to the reduction of the growth and spread of Legionella pneumophila. Taking comprehensive measures at both technical and management levels is the best strategy for the risk control of Legionella pneumophila in central air conditioning cooling water system of public buildings.

     

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