Investigation on Health Safety Status of Secondary Water Supply in Tongzhou District / 环境与健康杂志

ABSTRACT

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.