Objective To understand microbial contamination of household drinking water and related risk factors in 5 residential groups in Longhua District of Haikou, and to propose suggestions for microbial contamination control.
Methods Households of 5 residential groups in Longhua District were selected by a stratified cluster sampling approach (the A, B, C, D groups were served by central water supply from wells, and the E group by secondary municipal water supply) to conduct a questionnaire survey and drinking water sampling. Bottled water was also included if selected households drank commercial bottled water. Standard plate-count bacteria, total coliforms, and thermotolerant coliform bacteria were detected according to Standard examination methods for drinking water-Microbiological parameters (GB/T 5750.12-2006); secondary municipal water supply and central well water supply were assessed by Standards for drinking water quality (GB 5749-2006), and bottled water by Hygienic standard of bottled purified water for drinking (GB 17324-2003). Statistical analyses were performed.
Results A total of 292 water samples were detected and 194 met the national standard for drinking water quality requirement on standard plate-count bacteria (66.4%):the qualified rates of water samples from secondary municipal water supply, central well water supply and bottled water were 76.9%, 69.7% and 48.4%, respectively (P<0.05); the qualified rates of drinking water samples in five groups were 73.7%, 61.9%, 81.5%, 59.1%, 76.9% respectively (P<0.05). In addition, 90.1% water samples met national requirement on total coliforms and 92.5% on thermotolerant coliform. A non-conditional logistic analysis indicated that the frequency of water container cleansing was a risk factor of microbial contamination in bottled water (OR=23.515, P=0.009).
Conclusion The qualification rates of microbiological indicators in household drinking water are low in the 5 residential groups in Longhua District, but high in bottled water. Sanitary supervision on central water supply and bottled water should be enhanced, and healthy behaviors in drinking water among residents should be widely promoted.
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