Monitoring results of drinking water quality in Jianhe County of Guizhou Province from 2009 to 2011 / 中国地方病学杂志

ABSTRACT

Objective To find out the hygienic status of rural drinking water in Jianhe County of Guizhou Province.Methods Forty-eight source water and tap water samples from small centralized water supply stations in 12 townships of Jianhe County in dry season and wet period were tested from 2009-2011.The water samples were examined in accordance with the relevant provision of Standard Examination Methods for Drinking Water (B/T5750-2006).The contents included①sensory indicatorsstandard color,turbidity,smell and taste and visible objects; ②general chemical indicatorspH,iron,manganese,chloride,sulfate,total dissolved solids,total hardness,oxygen consumption and ammonia; ③toxicological indicatorsfluoride,arsenic and nitrate; ④microbial indicatorstotal number of colonies,with a total population of Escherichia coli and heat-resistant Escherichia coli Outcome evaluation was carried out in accordance with the Drinking Water Health Standards (B/T 5.749-2006).Results A total of 192 rural water samples were collected in 2009-2011,and 18 samples were qualified,accounting for 9.38％.The differences of water passing rate between groups of years were statistically significant (x2 =14.74,P＜ 0.01).Rural drinking water quality in dry season (18.75％,18/96) was better than that in wet season (0.00％,0/96; x2 =19.76,P ＜ 0.01).Passing rate of source water quality (16.67％,16/96) was higher than that of tap water(2.08％,2/96; x2 =11.95,P ＜ 0.01).Sensory indicators and toxicological indicators of 192 water samples were qualified.General chemical indicatorsin addition to four water samples with pH exceeded the standard(two copies in 2009 and two copies in 2010),other test indicators were qualified.Microbiological indicatorspassing rates of the total number of colonies,Escherichia coli group and heat-resistant Escherichia coli group were 77.08％ (148/192),9.90％ (19/192) and 20.31％ (39/192),respectively.Passing rate of microbes was 18.75％ (18/96) in dry season and 0.00％ (0/96) in wet period,and microbes passing rate was significantly higher in dry season than that of the wet period(x2 =19.76,P ＜ 0.01).Passing rate of microbes was 16.67％(16/96) in source water and 2.08％(2/96) in tap water,and passing rate of the source water was significantly higher than that of the tap water(x2 =11.95,P ＜ 0.01).Conclusions The hygienic status of rural drinking water in rural areas of Jianhe County of Guizhou Province is poor.Microbial pollution is the main reason.