Objective To test and evaluate various kinds of drinking water sources in Zhoushan Archipelago in 2011 using a surface water assessment model, and to provide evidence for drinking water safety determination.
Methods In 2011, 211 samples from different water sources, areas, waterworks, and quarters were collected for a 28-item water quality test in Zhoushan Archipelago. According to the association with potential adverse health effects, the evaluation indices were classified as toxicological chemicals (I), organic pollutants (II), and general chemicals (III). Index conversion, weighted average, worst factor judgment, Nemerow method, and Delphi consultation were used to weight the 3 classes of indices and to obtain category comprehensive indices. Then weighted average method was adopted to obtain a comprehensive index which was used for general water quality evaluation.
Results Of the water samples detected, the index I was 0.24& #177;0.13, indicating Class I (excellent) of the national surface water standards; the index II was 0.87& #177;0.68, suggesting Class V (heavily polluted) water; the index III was 0.29& #177;0.18, implying Class I (excellent); and the comprehensive index was 0.40& #177;0.19, within the range of Class I (excellent) water. Among the 3 common water sources, the water quality of the reservoir water samples was the best, because its index I and III met Class I (excellent) water standards and its index II were ranked Class III; followed by the mainland water diversion samples, whose index II was Class V (heavily polluted; and the river water samples with the index II graded Class V (seriously polluted) and the category comprehensive index graded Class III (marginal).
Conclusion The quality of surface source water basically meets the requirement of the national Environmental Quality Standards for Surface Water despite the mainland water diversion and river water samples graded heavy organic pollution.
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