2018-2022年三台县农村饮用水微生物指标监测结果分析

Analysis of the monitoring results of microbial indicators in drinking water in rural areas of Santai County from 2018 to 2022

目的 分析三台县2018-2022年农村饮用水微生物指标监测结果,分析处理方式和消毒剂种类对微生物指标的影响,为三台县农村地区饮水安全工作提供参考和建议。方法 根据2018-2022年水质卫生监测方案,在三台县范围内设置农村饮用水监测布点,各年采样量分别为252、248、252、252和404份,合计1 408份。平皿计数法检测菌落总数,酶底物法中的51孔定量盘法检测总大肠菌群和大肠埃希氏菌。参照GB/T 5749-2006进行水质评价,以SPSS 16.0软件进行统计分析,采用Median检验法、Kolmogorov-Smirnov Z检验法及χ^(2)检验法,检验水准为α=0.05。结果 2018-2022年三台县农村饮用水微生物指标合格率为64.7%、63.7%、57.9%、62.7%和87.6%。菌落总数和总大肠菌群中位数总体呈现先升后降、大肠埃希菌中位数也呈下降态势;不同年份菌落总数中位数差异有统计学意义(χ^(2)=11.531,P=0.021),总大肠菌群和大肠埃希菌中位数差异均无统计学意义(χ^(2)=5.932、8.207,P=0.204、0.084)。仅消毒和常规处理水样微生物指标合格率(79.34%、75.97%)高于未处理水样(31.42%),差异有统计学意义(χ^(2)=221.065,P<0.001);仅消毒水样微生物指标合格率高于常规处理水样,但差异无统计学意义(χ^(2)=1.712,P=0.191)。仅消毒和常规处理水样菌落总数、总大肠菌群数、大肠埃希菌数中位数低于未处理水样,其中菌落总数和大肠埃希菌差异有统计学意义(χ^(2)=24.117、6.689;P<0.001,P=0.035)。高纯二氧化氯处理水样微生物指标合格率(76.7%)低于漂白粉处理水样(88.5%),差异有统计学意义(χ^(2)=9.452,P=0.002)。高纯二氧化氯处理水样与漂白粉处理水样比较,菌落总数、总大肠菌群、大肠埃希菌中位数差异无统计学意义(Z=-1.397、-1.086和-0.63,P均>0.05)。结论 三台县农村地区饮用水微生物指标合格率处于较低水平;消毒可以提高农村饮水中微生物指标合格率,降低饮水中微生物指标检出水平,但常规处理消毒措施效果欠佳;高纯二氧化氯消毒效果低于漂白粉。

Objective To analyze the monitoring results of microbial indicators in drinking water in rural areas of Santai County from 2018 to 2022,to analyze the impact of treatment methods and disinfectant types on microbial indicators,and to provide reference and suggestions for drinking water safety in rural areas of the county.Methods In accordance with the Water Quality and Sanitation Monitoring Programme from 2018 to 2022,drinking water monitoring stations in rural areas were established throughout the county.The numbers of samples in each year were 252,248,252,252 and 404,respectively,with a total of 1408 samples.The total colony count was determined by plate counting method,and total coliform and Escherichia coli were quantified by 51-well quantitative plate method based on enzyme substrate technique.Water quality assessment was conducted following GB/T 9-2006 standards.SPSS 16.0 software was employed to conduct statistical analysis.Median test,Kolmogorov-Smirnov Z test and x^(2) test method were used,and the test level wasα=0.05.Results From 2018 to 2022,the qualified rates of microbial indicators of rural drinking water in Santai County were 64.7%,63.7%,57.9%,62.7%and 87.6%,respectively.The medians of the total number of colonies and the total coliform generally increased first and then decreased,and the median of Escherichia coli decreased year by year.There were significant differences in the median of the number of colonies among different years(x^(2)=11.531,P=0.021).There were no significant differences in the medians of the total coliform and the Escherichia coli(x^(2)=5.932 and 8.207,P=0.204 and 0.084).The qualified rates of microbial indicators of only sterilized and conventionally treated water samples(79.34%and 75.97%)were significantly higher than that of untreated water samples(31.42%),and the differences were statistically significant(x^(2)=221.065,P<0.001).The qualified rate of microbial indicators of disinfection water samples was higher than that of conventional water samples,but the difference was not statistically significant(x^(2)=1.712,P=0.191).The total number of bacterial colonies,total coliform bacteria and Escherichia coli in the water samples with disinfection and conventional treatment were lower than those in the untreated water samples,and the differences in the total number of bacterial colonies and the Escherichia coli were statistically significant(x^(2)=24.117 and 6.689;P<0.001 and P=0.035).The qualified rate of microbial indicators of high purity chlorine dioxide treated water samples(76.7%)was significantly lower than that of bleach powder treated water samples(88.5%),and the difference was statistically significant(x^(2)=9.452,P=0.002).There was no significant difference in the medians of the total number of colonies,the total coliform and the Escherichia coli in water samples treated with high purity chlorine dioxide compared with water samples treated with bleach powder(Z=-1.397,-1.086,-0.63,all P>0.05).Conclusions The qualified rate of microbial indicators of drinking water in rural areas of Santai County was at a low level.Disinfection could improve the qualified rate of microbial indicators in rural drinking water and reduce the detection level of microbial indicators in drinking water,but the effect of conventional disinfection was not good.The disinfection effect of high purity chlorine dioxide was lower than that of bleaching powder.