Objective To understand urban and rural residential drinking water quality in Taizhou city, and provide supports for drinking water safety.
Methods Water samples from all centralized water supply plants at county level and above were monitored in March, May, August, and October 2012, and 30% of the centralized water supply plants at village and town level were randomly selected to be monitored in May and August 2012. The water samples were collected and tested as well as evaluated following the related national standards (GB/T 5750-2006 & GB 5749-2006).
Results A total of 201 centralized water supply plants were enrolled, covering 4 175 887 residents that accounted for 71.2% of the city population. Altogether 1968 water samples were tested, in which 1 256 samples were qualified, and the total qualified rate was 63.8%. The qualified rates of the large and small water supply plants were 89.4% and 43.2% respectively. The qualified rates were 95.9%, 80.8%, and 40.8% for county-level plants, town-level plants, and village-level plants, respectively. The quarterly qualified rate of the county-level plants were 99.1%, 99.2%, 94.5%, and 91.9% for consecutive four quarters in a year respectively. The qualified rates of the village-and town-level centralized water supply units were 61% in the first half of the year and 47.7% in the second half of the year. Regarding the water treatment procedures, the qualified rates were 41.7% for the finished water samples and 75.4% for the tap water samples. The indices with lower qualified rate were microbial and disinfectant. The categories of the water supply plants using complete treatment were 65.2% in large size, 7.7% in small size; 90.0% on county-level, 56.8% on town-level, and only 7.8% on village-level.
Conclusion The representative results show that the qualified rates of drinking water in the selected city are on the low side in general. The treatment techniques applied by the small and village-level water supply plants require to be improved, which is suggested by low qualified rates of various drinking water indices.
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