河南省农村集中式供水微生物污染卫生现状及其影响因素分析

目的：了解河南省农村集中式供水微生物污染卫生现状，分析影响水质微生物的影响因素，为制定农村饮用水安全发展规划提供科学依据。方法：2011-2014年对河南省新乡市8个县（市）农村集中式供水进行采样，并开展卫生学状况调查（水源类型、水期类型、供水规模、季节、地方病和消毒情况等），依据《生活饮用水标准检验方法》（GB/T5750-2006）对出厂水和末梢水进行微生物检测，包括菌落总数、总大肠菌群、耐热大肠菌群和大肠埃希氏菌，并采用Logistic回归分析集中式供水菌落总数超标的影响因素，采用Poisson回归分析集中式供水菌落总数和总大肠菌群数的影响因素。结果：2011-2014年分别采水样824、820、526和636份。供水水源以深井水为主（90.0%），未经任何处理的饮用水水样占70.6%。4年水样的菌落总数合格率分别为76.0%、75.5%、66.5%和72.6%；总大肠菌群合格率依次为97.3%、94.9%、99.6%和94.3%。2011-2014年消毒供水的菌落总数超标率均低于未消毒供水（P<0.05）；2012-2014年末梢水中菌落总数超标率高于出厂水（P<0.05）；2013年和2014年中型供水能力（100~1 000t）工程的供水中菌落总数超标率低于大型供水能力（≥1 000 t）和小型供水能力（<100 t）的供水工程（P<0.05）。Logistic回归分析，丰水期的水样中菌落总数超标率高于枯水期（χ²=12.31，P<0.001）；消毒能够降低菌落总数超标率（χ²=85.32，P<0.001）；以除氟和解决苦咸水为目的的供水工程供水中菌落总数超标率较低（χ²=34.44，P<0.001；χ²=39.44，P<0.001）。Poisson回归分析，丰水期（χ²=6972.75，P<0.001）、未消毒（χ²=5415.46，P<0.001）、末梢水（χ²=97.64，P<0.001）、运营时间长（χ²=26.57，P<0.001）、供水能力小（χ²=4502.57，P<0.001）、以除氟和解决苦咸水为目的的改水工程（χ²=6226.68，P<0.001；χ²=13441.50，P<0.001）的水样中菌落总数较高。而100~1 000t的供水能力工程（χ²=802.18，P<0.001）及以除氟和苦咸水为目的供水工程（χ²=2711.88，P<0.001；χ²=1470.91，P<0.001）水样中的总大肠菌群数较低，丰水期（χ²=16583.10，P<0.001）、未消毒（χ²=276.34，P<0.001）、末梢水（χ²=1205.26，P<0.001）和运营时间长（χ²=3220.58，P<0.001）的水样中总大肠菌群数较高。结论：河南省农村集中式供水消毒比例较低，菌落总数合格率不高，总大肠菌群合格率高。水期类型、是否消毒、水样类型、运行年、供水能力和供水工程目的均不同程度地影响农村集中式供水的水质微生物。

Hygiene condition of microbial contamination of central water supplyin rural areas of Henan province and their influencing factors

Objective:To learn the status of microbial contamination of central water supply in the rural areas of Henan province,and to analysis the influencing factors of water microbial in order to provide basis for making the policy of drinking water safety improvement.Methods:During 2011-2014,the water sampling of central water supply in eight cities (counties)in Xinxiang city of Henan province were selected and the hygiene condition investigation (water source type, water period type, water supply scale, seasonal, local area, and disinfection) was performed.According to the Drinking Water Standard Test Method (GB/T5750-2006),the microorganisms in factory water and tap water were detected, including the total number of colonie, total coliform count, thermotolerant coliform bacteria and Escherichia coli (E.coli).The influencing factors of total number of colonies exceeding the standards were detected by Logistic regression analysis. The influencing factors of total number of colonies and total coliform count were detected by Poisson regression analysis. Results:There were 824, 820, 526,and 636 water samples in each year during 2011-2014.The most source of supply water was deep water (90%).The samples of drinking water without any treatment accounted for 70.6%.The qualified rates of total number of colonies were 76.0%,75.5%,66.5%,and 72.6%,respectively,and the qualified rates of coliform count were 97.3%,94.9%,99.6%,and 94.3%,respectively.The exceeding standard rates of total number of colonies of disinfected central water supply were lower than those of central water supply without disinfection (P<0.05)during 2011-2014.The exceeding standard rates of total number of colonies of tap water were higher than those of produced water during 2012-2014 (P<0.05).The exceeding standard rates of total number of colonies in medium water supply engineering (100-1 000 t)were lower than those in large (≥1 000 t)and small (<100 t) water supply engineerings in 2013 and 2014 (P<0.05).The Logistic regression analysis results showed that the unqualified rate of total number of colonies in wet season was higher than that in dry season (χ2=12.31,P<0.001).The disinfection could reduce the unqualified rate of total number of colonies (χ2=85.32,P<0.001). The unqualified rates of total number of colonies in the engineering for the purpose of removing fluoride and resolving bitter salt water were lower (χ2=34.44,P<0.001;χ2=39.44,P<0.001).The Poisson regression analysis results showed that wet season (χ2=6 972.75,P<0.001),without disinfection (χ2=5 415.46,P<0.001),tap water (χ2=97.64,P<0.001),long operating time (χ2=26.57,P<0.001),low water supply capacity (χ2=4 502.57,P<0.001),the engineering for the purpose of removing fluoride and resolving bitter salt water (χ2=6 226.68,P<0.001;χ2=13 441.50,P<0.001)increased the total number of colonies. The number of E.coli in samples of central water supply was lower in 100-1 000 t of water supply engineerings (χ2=802.18, P<0.001)and the engineering for the purpose of removing fluoride and resolving bitter salt water (χ2=2 711.88, P<0.001;χ2=1 470.91,P<0.001).The number of E.coli in samples of central water supply was higher in the water of wet season (χ2=16 583.10,P<0.001),the water without disinfection (χ2=276.34,P<0.001),tap water (χ2 = 1 205.26,P<0.001)and the water with long operating time (χ2 = 3 220.58,P<0.001). Conclusion:The ratio of disinfection of central water supply in the rural areas of Henan provice is low,the qualified rate of colonies is not high,and the qualified rate of total coliform count was high.The microbial contamination in central supply water in the rural areas is influenced by water period type, disinfection, water sample type, operating time,water supply capacity,and purpose of water supply engineering.