北京市通州区二次供水卫生现状

目的了解北京市通州区二次供水卫生安全现状,建立健全二次供水卫生管理资料体系。方法以北京市通州区正常供水的二次供水单位为调查对象。于2006年3—6月,采用统一的调查表进行现场调查,依据GB17051—1997《二次供水设施卫生规范》和《北京市生活饮用水设计审查和竣工验收卫生要求》（2003）进行评价;并采集进入二次供水设施前最近点的市政末梢水和经过水箱消毒处理后最近点的二次供水水样,依照《生活饮用水卫生规范》（2001）进行检测,参照《北京市生活饮用水监测管理办法》（1998）和《生活饮用水卫生规范》（2001）进行评价。结果共调查二次供水单位48户,供水人口为147558人。二次供水处理后水样合格率为66.7%（44/66）。不合格项目为氨氮、游离性余氯、细菌总数、浑浊度、肉眼可见物,超标率分别为12.1%（8/66）,9.1%（6/66）,6.1%（4/66）,6.1%（4/66）,4.5%（3/66）。其余项目均合格。以市政供水为水源的二次供水水样合格率[76.4%（42/55）]高于自备水[18.2%（2/11）],差异有统计学意义（P=0.000）。氨氮的合格率[92.7%（51/55）]高于自备水[63.6%（7/11）],差异有统计学意义（P=0.007）。其他指标合格率间,差异均无统计学意义（P〉0.05）。在不考虑游离性余氯的情况下,市政管网末梢水的合格率[100.0%（20/20）]高于以市政供水为水源的二次供水[78.2%（43/55）],差异有统计学意义（P=0.029）;不锈钢、搪瓷钢板、玻璃钢水箱中水样合格率分别为59.3%（16/27）,94.4%（17/18）,77.8%（7/9）,三者间差异有统计学意义（P=0.030）,其中,不锈钢水箱中水样合格率低于搪瓷钢板水箱,差异有统计学意义（P=0.009）。经低位水箱加变频泵处理的二次供水水样合格率[67.3%（37/55）]低于经无负压直供水处理的二次供水水样[70.0%（7/10）],差异无统计学意义（P=0.865）。采用紫外线消毒、氯化消毒、水箱自洁器消毒的二次供水水样细菌总数合格率分别为95.1%（39/41）,100.0%（8/8）,83.3%（5/6）,三者间差异无统计学意义（P=0.377）。结论二次供水水质下降,建议今后加强二次供水的卫生监督工作。

Investigation on Health Safety Status of Secondary Water Supply in Tongzhou District

Objective To investigate the drinking water quality of secondary water supply in Tongzhou District, Beijing in order to establish a data monitoring management system. Methods The uniform questionnaires were used for the on-the-spot investigation at secondary water supply units in the whole district, which included secondary water supply facility situations, environmental sanitary conditions and health management and so on. At the same time, municipal water and secondary supply water were tested. Results 48 units of secondary water supply were investigated. In this investigation, the main systems of secondary water supply were the low water tank added frequency conversion pump(accounts for 77.1%) and the inverter constant pressure water supply system with negative pressure(accounts for 14.3%). According to the hygienic requirements, the unqualified rate of water tank structure, disinfection facility and water tank room were 81.0%, 73.3% and 87.3% respectively; besides, 39.6% of the units used the invalid hygienic licenses, 43.5% of the water managers had no health certificates, and 54.5% of the units had never cleaned their water tanks. The total qualification rate of the secondary water supply was 66.7%. The main items that were not up to the standard were ammonia-nitrogen, free chlorine, recognizable objects with naked eyes, total bacteria count and turbidity. For the different water material, the qualification rate showed a significant difference(P=0.023). Conclusion The drinking water quality of the secondary water supply is lower than before and the preventive hygiene supervision and evaluation is comparatively delayed in the investigated district.