Investigation and risk assessment for water quality hygiene in self-supply well water in four northern provinces of China / 中华疾病控制杂志

Objective To understand the water quality of self-supply wells in four provinces of northern China (Heilongjiang, Beijing, Inner Mongolia and Tibet), so as to provide a reference for supervision and management of self-supply wells. Methods Water were sampled from 233 self-supply wells in four northern provinces of China according to standard examination methods for drinking water (GB/T 5750-2006). In total, The samples were tested for 27 kinds of water quality parameters involving sensory properties, chemistry, bacteriology and toxicology, and then evaluated. Results The total unqualified rate of water quality in self-supply well water in four northern provinces of China was 52.36%. The water quality varied greatly among provinces. As for Heilongjiang, the main unqualified indicators of self-supply wells water involved turbidity, visible to the naked eye, manganese, arsenic and nitrate. In relation to Beijing, these referred to the nitrate and microorganism. In case of Inner Mongolia province, these included sulfate and fluoride. With reference to Tibet, these were zinc and chloride. Conclusions To ensure the safety of drinking water for residents, the management, disinfection and purifying measures of self-supply wells should be strengthened basing on their regional differences and water quality characteristics.

Safety evaluation of drinking water along the border of Inner Mongolia / 军事医学

Objective To find out about the sanitary conditions of drinking water along the border line of Inner Mongolia via safety evaluation of drinking water along the border line of Inner Mongolia.Methods 108 samples of drinking water along the border line of Inner Mongolia(70 samples of self-supply source water,21 ones of self-supply tap water and 17 ones of municipal tap water)were collected.Hygienic evaluation of sensory indexes, normal chemical indexes, toxicological indexes and microbiology indexes of water quality was performed according to hygienic standards for drinking water(GB 5749—2006).Results 58 samples were qualified with a total qualified rate of 53.7%.The unqualified rate of the total number of coliforms was the highest(20.4%),followed by fluoride(19.4%).As for deep wells, shallow wells and surface water,there was no statistically significant difference.Compared with municipal tap water,the unqualified rate of self-supply water(28.6%)was higher(17.7%).Conclusion The qualified rate along the border line of Inner Mongolia of drinking water is low.Treatment and disinfection facilities for drinking water,detection devices of water quality are needed.The cleaning and disinfection of storage tanks should be performed periodically in oder to prevent waterborne infectious diseases.

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

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 included:①sensory indicators:standard color,turbidity,smell and taste and visible objects; ②general chemical indicators:pH,iron,manganese,chloride,sulfate,total dissolved solids,total hardness,oxygen consumption and ammonia; ③toxicological indicators:fluoride,arsenic and nitrate; ④microbial indicators:total 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 indicators:in 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 indicators:passing 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.