Objective To survey the hygienic situation and feature of pollution in outlet water from household water filters in Shanghai.
Methods A total of 320 households were recruited for this study in Jul (summer), Oct (autumn), and Dec (winter). Types of filters and outlet water samples were collected. The monitoring items consisted of iron, manganese, copper, zinc, lead, arsenic, chemical oxygen demand (COD), pH, color, turbidity, total bacterial count, and coliform. Fisher's exact test was used to analyze the rate exceeding national limit.
Results The exceeding rates of heavy metals, turbidity, and pH in the outlet water were lower than 4%. A comparatively higher rate of exceeding in total bacterial count was noticed and the maximum reached 71.0%. Meanwhile, the COD in nearly 40% general water filters with activated carbon did not reach corresponding requirements. For the same season, the exceeding rates of total bacterial count and COD in outlet water from various types of filters were found different significantly in statistics (P<0.05). In summer, significant differences also existed in the exceeding rates of outlet water color among various types of filters (P<0.05). In addition, there were significant differences in the exceeding rates of turbidity and total bacterial count in outlet water from general water filters with activated carbon among different seasons (P<0.05).
Conclusion Hygienic issues are found in the household water filters, and among them microbes and content of organic compounds are the major concerns. The users should strengthen regular maintenance and sanitory management of the filters in using. Additionally special attention to the drinking water sanitation in summer time should be stressed.
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