[Monitoring and analysis on variation of quality for floodwater in Wuhan urban areas in 2016]

Objective: To conduct a continuous monitoring of the physical, chemical microbial indicators and overall biological toxicity for water quality in waterlogged urban areas.

Methods: Monitoring sites were chosen in the waterlogging areas in the NanhuYayuan and Banqiao communities of Hongshan District, and the Xinhu village of Xinzhou District, Wuhan City. The South Lake, Yezhi Lake and Shahe River were selected as the corresponding surface water monitoring sites. Samples were collected in an extended period of time for the examination of physical, chemical microbial indicators and the determination of biological toxicity. Statistical analysis was performed using SPSS 11. 0 software package.

Results: The water samples from waterlogged areas generally exhibited poor aesthetic aspects of drinking waters, and these indexes gradually deteriorated with prolonged waterlogging. Among the general chemical indexes, p H value was at an initialhigh level and decreased with time, permanganate index( oxygen consumed) remained at a high level( 3. 83-8. 16 mg/L), nitrite-nitrogen level gradually increased and stabilized for 2-3 days and then gradually decreased, chloride of the waterlogged samples and the corresponding surface water samples were correlated. Toxicological indicators( arsenic, lead, mercury) were not examined. For microbioligical indicators, fecal coliforms was detected at a rate of 47%, and negative result were revealed for pathogenic pathogenic microorganisms( Escherichia coli O157, Vibrio cholerae, Shigella, Salmonella, Staphylococcus aureus) and Rotavirus and Novovirus. The inhibition rate of samples on luminous intensity of Vibrio cholerae was less than 30%.

Conclusion: Although the aesthetic aspects of drinking water were poor and organic and fecal contaminants were present, the risk of health hazards from skin or respiratory exposure was small for residents. After the floodwater subsided, routine preventive disinfection will be sufficient to ensure the safety for waterlogged urban areas. The result of the luminescent bacteria test were in good agreement with the toxicological indicators.